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+# STEP-100 Source → RenderSegment 局部 Revision / Invalidation / Readiness 与独立 Fallback — Codex 任务 v2
+
+## 0. 任务性质
+
+这是 STEP-099 之后的正式修复任务。
+
+STEP-099 已经完成纯诊断并 CLOSED / PASS，已确认 V17 的核心问题：
+
+1. 动态 GeoJSON Source/Tile mutation 会推进 global retained content revision；
+2. 即使 R0 不依赖该 GeoJSON，R0 retained cache 仍跟着 invalid/build；
+3. GeoJSON 更新期间约 200 ms 的 transient `isLoaded=false` 会通过 global `RenderOrchestrator::isLoaded()` 把整个 retained path 拉成 `style-not-loaded`；
+4. 当前 renderer 还存在 `useRetainedRanges` all-or-none gate：一个 RETAINED Segment fallback 时，会使其他本来可安全 reuse 的 RETAINED Segment 一起退出 retained path；
+5. STEP-099 diagnostics 已能正确给 source mutation 计算 `affectedSegmentIndices`，但该依赖关系仍只是诊断，不参与正式 invalidation。
+
+本任务目标是把 **Source/Tile 变化对 RETAINED Segment 的影响正式局部化**。
+
+本任务不是 V18 发布任务。Codex 只负责实现与源码级说明；Android/iOS 构建、APK、ADB、设备测试、最终 Git push、V18 release 由 RDC/ChatGPT 在 Codex 完成后独立执行。
+
+未经用户明确要求，本任务 **不加入、不运行 Jest**。
+
+---
+
+## 1. 冻结基线
+
+工作目录：
+
+`/Users/tei/dev/MapLibreParticleLab-step100`
+
+分支：
+
+`step100-segment-local-source-invalidation`
+
+开始基线必须重新核对，当前预期：
+
+- `origin/particle/main`
+- HEAD：`c4b481fd2c5b5da20d31f6ae54011f0552d7dbd0`
+- STEP-099 implementation：`8a5214d92dd2f8899db76d2194da42999fa0c87d`
+- V17 frozen tag：`maplibre-particle/rn/13.4.1-particle.17`
+- V17 frozen commit：`e8b451fe70054107773e82484c80e90df3889147`
+
+禁止修改、移动、覆盖 V17 tag / release worktree。
+
+STEP-100 是 V17 之后的新开发，最终只有 RDC 验收通过后才允许进入 V18 发布。
+
+开始前必须读取：
+
+- 当前仓库实际 HEAD / status / diff；
+- 全局 Codex AGENTS；
+- `ARCHITECTURE.md`（若存在）；
+- STEP-092 / 094 / 099 的任务、Step 记录、完成报告；
+- 当前：
+  - `renderer_impl.cpp`
+  - `render_orchestrator.*`
+  - `retained_underlay_cache.*`
+  - `retained_underlay_runtime_state.hpp`
+  - `render_segment.*`
+  - STEP-099 diagnostics 与 Android fixture；
+- 当前 RenderSegment / retained cache / particle fast path tests。
+
+不得凭历史印象修改。
+
+---
+
+## 2. 最终架构原则
+
+长期 RenderSegment 模型继续保持通用模型：
+
+```text
+Style Z-order
+  ↓
+R / C / R / C / R / ...
+```
+
+其中：
+
+- R = RETAINED
+- C = CONTINUOUS
+
+本任务只用 **R-C-R** 做最小验证，不把 R-C-R 固化成最终架构。
+
+必须保持：
+
+1. Style layer 顺序是唯一 Z-order 真相；
+2. Renderer 不理解 AIS / Route / Weather / GeoJSON 等业务名；
+3. Source → Segment 依赖由当前实际 Style / RenderLayer / Source 关系推导；
+4. 一个 Source 可依赖多个 Segment；
+5. source-less layer 不制造假 dependency；
+6. unknown/global dependency 必须 fail closed；
+7. 相邻 Segment、多个 C、多个 R 的通用模型不能被破坏；
+8. 本任务不实现 multi-continuous Fast Path。
+
+---
+
+## 3. 本任务必须实现的核心目标
+
+### 3.1 Source/Tile mutation 局部化
+
+假设：
+
+```text
+R0 depends [staticSource]
+C  depends [particleField]
+R1 depends [dynamicGeoJson]
+```
+
+当：
+
+```text
+dynamicGeoJson mutation
+```
+
+正式 renderer 必须达到：
+
+```text
+R0:
+  content/revision 不因该 source mutation 改变
+  cache 不 invalid
+  cache 不 rebuild
+  持续 reuse
+
+R1:
+  revision/invalidation 正常变化
+  按需要 build/reuse/fallback
+
+C:
+  正常 continuous render
+```
+
+禁止继续出现：
+
+```text
+dynamicGeoJson mutation
+  ↓
+global revision 变化
+  ↓
+R0 + R1 一起 rebuild
+```
+
+### 3.2 保留 global revision 兼容信号
+
+STEP-100 不要求删除现有 global `retainedUnderlayContentRevision`。
+
+为了保持：
+
+- diagnostics；
+- 现有 fast-path correctness；
+- 旧 API / compatibility；
+- conservative fallback；
+
+允许并推荐继续维护 global revision。
+
+但 **RETAINED Segment cache 的正式内容 revision / invalidation 不能再只依赖这个 global source/tile revision**。
+
+当前 `retainedUnderlayRevisionTracker` 同时消费 global content revision 与 `renderTreeParameters.loaded`。STEP-100 必须明确拆成两种用途：
+
+```text
+global retained revision / tracker
+    -> compatibility / Fast Path / diagnostics
+
+segment-local retained content state
+    -> full CPU renderer 的每个 RETAINED Segment Build / Reuse / Fallback
+```
+
+**Segment-local cache content state 禁止继续直接消费：**
+
+- global source/tile content revision；
+- global `renderTreeParameters.loaded`。
+
+否则即使 source-scoped revision 已实现，R0 仍会被无关 GeoJSON transient unloaded 或 global revision 连带失效。
+
+允许 global revision / global tracker继续按原逻辑变化；禁止为了让测试 PASS 而停止 global revision 增长或放宽 Fast Path。
+
+### 3.3 per-RETAINED-Segment readiness
+
+不得修改任何 Source `isLoaded()` 定义。
+
+不得修改：
+
+```cpp
+renderTreeParameters->loaded = updateParameters->styleLoaded && isLoaded();
+```
+
+这个 global loaded 仍作为 MapLibre 现有全局兼容事实。
+
+但 retained segment 的 cache Build/Reuse/Fallback 必须有自己的安全 readiness 判断。
+
+最低语义：
+
+- Style 本身未 ready：fail closed；
+- image manager / sprite / glyph 等无法安全定位到单 Segment 的全局前置条件未 ready：fail closed；
+- Segment 已知依赖的 source 中任一缺失或 `isLoaded()==false`：仅该 Segment fail closed；
+- Segment 已知依赖的 source `hasFadingTiles()==true`：仅该 Segment视为 unstable；
+- **不被该 Segment 引用的 source unloaded 或 fading，不得让该 Segment cache fallback/rebuild**；
+- `retainedRangeIsStable(begin,end)` 的 source fading 检查必须按该 range 的真实 source dependency 缩小，不能继续遍历全部 `renderSources` 作为 full-CPU retained gate；
+- Fast Path 原有 global fading gate 保持不变；
+- source ID 无法解析、dependency 缺失或真正无法证明安全时 fail closed。
+
+必须区分：
+
+1. **已知 Source dependency**；
+2. **symbol/global prerequisite**（glyph/image/placement 等）；
+3. **真正 unknown dependency**。
+
+STEP-099 的 `unknownDependencies` 目前会把 symbol 相关条件标为 unknown。STEP-100 不得机械地把“存在 symbol”解释成永久 fallback；symbol 所需 glyph/image/placement 应作为明确的 global prerequisite/fail-closed 条件处理。
+
+因此 T3 中一个：
+
+```text
+no layer
+enabled=false
+isLoaded=false
+```
+
+的 RasterArray source 可以继续让 global `RenderOrchestrator::isLoaded()==false`，但不得因此让与它无依赖关系的 R0/R1 cache 全部 `style-not-loaded`。
+
+本 Step 的运行态硬验收范围是 **MapMode::Continuous**（粒子正式实时渲染模式）。当前非 Continuous / still 路径如果在 global unloaded 时提前返回，本 Step 不强行改变其兼容语义；完成报告必须明确该适用范围。
+
+### 3.4 RETAINED Segment 独立决策
+
+当前 V17 路径存在类似：
+
+```text
+useRetainedRanges = all retained segments supported
+```
+
+的 all-or-none 语义。
+
+STEP-100 必须改为每个 RETAINED Segment 独立拥有：
+
+- readiness/support decision；
+- Build / Reuse / Fallback；
+- content/source revision；
+- invalidation reason。
+
+如果：
+
+```text
+R0 = Reuse
+R1 = Fallback
+```
+
+则本帧必须允许：
+
+```text
+R0 composite cached texture
+C  live render
+R1 live render fallback
+```
+
+而不是退化为“整个 Style 全部 live render”。
+
+如果某 retained cache 自身 build 失败，应优先只 fallback 该 Segment；只有无法证明局部安全的 context/global resource failure 才允许全 retained fail closed。
+
+---
+
+## 4. Source-scoped revision 设计要求
+
+Codex 必须基于当前代码选择最小、稳定设计，并在完成报告说明实际方案。
+
+推荐方向但不强制具体类名：
+
+- 为 Source/Tile mutation 维护 source-scoped monotonic revision；
+- keyed by stable sourceId，但必须处理 source 删除后同 ID recreate，不能让新 source 错误继承可复用的旧 cache identity；可用 generation/epoch 或保留单调 tombstone 语义实现；
+- source diff、feature-state mutation、tile changed 等所有当前会进入 Source/Tile retained content invalidation 的正式路径都必须覆盖；
+- 能定位 sourceId 的 mutation 只推进对应 source revision；无法定位 sourceId 的 mutation继续 global fail closed；
+- Segment content revision 由：
+  - 该 Segment 的 dependent source revisions；
+  - 当前 Segment layer fingerprint / layer mutation；
+  - 必须全局影响 retained 的 global revision 类别；
+  - topology / camera / viewport 等既有安全条件
+  共同决定。
+
+Source/Tile mutation 不应推进“所有 Segment 都消费的 retained cache revision”。
+
+必须避免：
+
+- 用屏幕位置猜 dependency；
+- 在 renderer 中硬编码 source/layer ID；
+- 从 STEP-099 diagnostics JSON 反向驱动正式 renderer；
+- 建立 diagnostics 与 production 两套互相漂移的 dependency 真相。
+
+如果需要提取 production-grade dependency helper，应让 diagnostics 和正式逻辑共享同一只读推导源。正式 renderer 不得从 diagnostics JSON 或 `RetainedUnderlayRuntimeState` 反向取 dependency。
+
+Source-scoped revision 属正式 correctness state，不得沿用 STEP-099 diagnostics 的“best-effort 记录失败可忽略”语义。正式 revision/dependency state 若无法可靠更新，必须 conservative global invalidation/fail closed。
+
+---
+
+## 5. Global mutation 仍可保守处理
+
+本任务只要求 **Source/Tile mutation** 与明确 Source readiness 局部化。
+
+以下无法安全局部化的事件，本轮允许继续 invalidate/fail closed 全 retained：
+
+- context reset；
+- style reload / topology change；
+- image mutation；
+- glyph mutation；
+- sprite/image manager 全局 readiness；
+- placement / symbol fade / glyph/image/sprite 全局状态；
+- camera / transform / viewport / resize / pixel ratio；
+- debug mode；
+- 3D / unsupported / legacy ordering；
+- 无法定位 dependency 的 mutation；
+- 真正 unknown/global dependency。
+
+注意：**Source 自身的 loaded / fading 不属于这里的 global fail-closed 项**；若 source dependency 可定位，必须按 Segment 局部判断。Fast Path 的 global source/fading gate除外，本轮保持原状。
+
+完成报告必须列出：
+
+- 已局部化的 mutation 类型；
+- 仍为 global 的 mutation 类型；
+- 为什么保守处理。
+
+---
+
+## 6. Fast Path 本轮严格不改
+
+STEP-099 已确认 Fast Path 仍有 global gates：
+
+- global update signature（sources/layers/images 等）；
+- global content revision；
+- global fade；
+- pendingChanges；
+- placement/light/non-particle transition/repaint；
+- annotation mutation；
+- topology/boundary/revision/cache validity；
+- `singleContinuousSegment`。
+
+STEP-100 **禁止修改这些 gate 的语义**。
+
+允许：
+
+- Source mutation 后 Fast Path miss；
+- transient source readiness 时 Fast Path fail closed；
+- full CPU renderer 被调用。
+
+但进入 full CPU renderer 后，必须能做到：
+
+```text
+R0 retained cache reuse
+R1 rebuild/fallback
+```
+
+这正是本任务验收目标。
+
+Multi-continuous Fast Path 明确不在本任务。
+
+---
+
+## 7. Render 顺序与混合 Build/Reuse/Fallback
+
+实现 per-segment mixed decisions 时必须保持原 MapLibre 绘制语义：
+
+- Style Z-order；
+- global layerIndex；
+- opaque reverse traversal；
+- translucent forward traversal；
+- currentLayer；
+- depthRangeSize；
+- legacy item 不双绘；
+- debug overlay 不重复；
+- retained texture composite 不改变 segment 顺序。
+
+推荐的逻辑行为：
+
+```text
+for segment in Style order:
+    RETAINED + Build:
+        build cache
+        composite cache
+    RETAINED + Reuse:
+        composite cache
+    RETAINED + Fallback:
+        live render only this range
+    CONTINUOUS:
+        live render this range
+```
+
+实际代码可按现有 RenderPass 安全实现，不要求机械照搬伪代码。
+
+必须特别检查：
+
+- 一个 R fallback 不得导致另一个 R live redraw；
+- resource prepare 在 Build 前失败时，必须先把该 Segment 本帧 decision 改为 Fallback，再进入主 buffer 绘制；
+- retained build 中途失败时，必须 invalidate/标记该 Segment失败并把该 Segment 本帧 decision 改为 Fallback，禁止 composite 旧纹理；
+- 如果失败意味着 context / shared GPU state 已不可信，允许全局 fail closed；
+- fallback range 的 legacy items 只绘一次，不得因 per-segment 主循环重复 render；
+- debug overlay 全帧只绘一次；
+- Segment 间 Opaque/Translucent 语义不得被破坏；
+- 相邻 R、多个 C、透明叠加与 legacy scene 不能因 mixed execution 出现漏绘/双绘。
+
+推荐执行顺序：先完成各 Segment resource prepare 与必要离屏 Build；再 clear 主 buffer；最后按 Style Segment 顺序逐段选择 cached composite 或 live range render。
+
+---
+
+## 8. Diagnostics 必须继续可证明局部性
+
+保留 STEP-099 diagnostics，并 additive 增加足够字段，使 RDC 能验证正式行为。
+
+每个 RETAINED Segment 至少应能观察：
+
+- dependentSourceIds；
+- segment readiness / support；
+- segment-local source/content revision 或等价可证明值；
+- Build / Reuse / Fallback 的**最终本帧 execution decision**；
+- build/reuse/fallback/invalidation count；
+- last invalidation/fallback reason。
+
+Source mutation 继续输出：
+
+- sourceId；
+- sequence/reason/action；
+- affectedSegmentIndices。
+
+要求：
+
+```text
+step099-dynamic mutation
+affected=[R1]
+R0 revision unchanged
+R0 cache reuse++
+R0 build unchanged
+R0 invalidation unchanged
+```
+
+Diagnostics 仍是 pull/event low-frequency，不允许逐帧高频 spam。
+
+---
+
+## 9. Android Test App
+
+复用 STEP-099，不另建独立 App。
+
+至少保留并完善：
+
+### T1 STATIC
+
+验证静态 R-C-R：
+
+- loaded settle；
+- R0/R1 build 一次后稳定 reuse；
+- 不产生持续 rebuild。
+
+### T2 GEOJSON_1HZ
+
+两个 GeoJSON source 交错，各约 1 Hz。
+
+重点：
+
+- global loaded transient false window 可以继续存在；
+- 只引用某 source 的 retained Segment 才允许因该 source mutation 改变；
+- 无关 retained Segment build/invalidation 不得跟随增长。
+
+### T3 PERMANENT_UNREADY
+
+保留一个：
+
+- no layer；
+- enabled=false；
+- isLoaded=false；
+- no field submission
+
+的 RasterArray source。
+
+预期：
+
+- global renderOrchestratorLoaded 仍可为 false；
+- 但无关 R0/R1 retained cache 不应因它持续 `style-not-loaded` fallback；
+- 能安全判断依赖的 retained Segment应继续 build/reuse。
+
+### T4 R-C-R（主验收）
+
+必须保持清晰依赖：
+
+```text
+R0 -> dedicated static source only
+C  -> WeatherColor/Particle field
+R1 -> dedicated dynamic GeoJSON source
+```
+
+运行动态 GeoJSON 约 1 Hz。
+
+必须调整 fixture，避免 STEP-099 中 R1 再复用 R0 的 static source：
+
+- R0 static source 只出现在 R0；
+- R1 dynamic source 只出现在 R1；
+- 若 MapLibre 内建 annotation source/layer 自动进入 R1，必须在 diagnostics 中列明，并保证验收窗口内 annotation 不发生 mutation；
+- 不允许用业务 ID 特判 renderer。
+
+RDC 验收区间必须支持“settled baseline → 60 s pure dynamic-source mutation window → final”对比。每个 aggregate sample 同时记录 mutation source/sequence、各 Segment local revision、readiness、最终 execution decision 与 cache counters。
+
+---
+
+## 10. STEP-100 硬验收标准
+
+### A. R0 locality
+
+T4 settle 后记录 baseline。
+
+随后至少 60 s dynamic GeoJSON：
+
+- R0 `buildDelta == 0`
+- R0 `invalidationDelta == 0`
+- R0 `reuseDelta > 0`
+- R0 segment-local revision/content state 不因 R1 dynamic source mutation 改变
+- 即使某采样点 global `renderOrchestratorLoaded=false`，只要 R0 自身 prerequisites/dependencies ready，R0 final decision 仍可为 Reuse
+
+如果为了安全出现明确 global event，应在日志中可解释并重新选择纯动态 mutation 区间；不能把 global event 混入后声称 PASS。
+
+### B. R1 reacts
+
+同一时间窗：
+
+- R1 必须能观察到 source mutation；
+- R1 revision / build / invalidation / fallback 中至少有与动态 source 对应的实际变化；
+- `affectedSegmentIndices` 必须只包含真实依赖 Segment。
+
+### C. global revision compatibility
+
+- global `retainedUnderlayContentRevision` 允许并预期继续增长；
+- 不能通过停止 global revision 增长来制造 R0 PASS。
+
+### D. readiness locality
+
+T2 transient unloaded 或 T3 permanent unrelated unloaded 时：
+
+- global loaded 可 false；
+- R0 不得仅因无关 source 的 unloaded 而 invalid/rebuild/fallback；
+- R0 cache 必须继续可复用。
+
+### E. correctness
+
+- 无 crash / ANR；
+- 无 stale cache composite；
+- 无 Segment Z-order 错乱；
+- 无 fallback range 双绘；
+- Cache OFF 仍安全走 live renderer；
+- plan invalid 仍 fail closed。
+
+任一硬门槛失败，STEP-100 不得宣布 PASS，不得进入 V18。
+
+---
+
+## 11. Native 非 Jest 测试要求
+
+Codex 必须新增或扩展现有 C++ 测试源码，至少覆盖：
+
+1. source A mutation 只改变依赖 A 的 Segment revision；
+2. source A 被多个 Segment 共享时，对应多个 Segment 都变化；
+3. unrelated Segment revision 不变；
+4. source-less Segment 不制造 dependency；
+5. unknown/global dependency fail closed；
+6. unrelated source unloaded 不使安全 Segment readiness false；
+7. dependent source unloaded 使对应 Segment readiness false；
+8. R0 Reuse + R1 Fallback 的 mixed decision；
+9. 单 Segment build failure 不 composite stale cache；
+10. query diagnostics 不改变 revision/cache state；
+11. global non-source invalidation 仍影响所有 retained；
+12. source 删除后同 ID recreate 不误复用旧 Segment cache identity；
+13. dependent source fading 只影响对应 Segment；unrelated source fading 不影响安全 Segment；
+14. Cache OFF / invalid plan 行为不回归；
+15. 至少有一组能证明实际 mixed render 没有漏绘/双绘的 renderer-level draw-count、pixel 或现有等价测试入口；不能只用 decision unit test 代替。
+
+不得修改测试断言去适应错误实现。
+
+---
+
+## 12. 允许修改范围
+
+允许：
+
+- RenderOrchestrator source mutation/readiness bookkeeping；
+- RenderSegment dependency production helper；
+- Renderer retained per-segment revision/readiness/decision；
+- RetainedUnderlayCache/RuntimeState 为局部状态增加必要字段；
+- additive diagnostics JSON/TS；
+- Android Validation Test App STEP-099 fixture/log；
+- 相关 Native C++ tests；
+- STEP-100 Step 记录/完成报告/开发记录。
+
+禁止：
+
+- NavSea；
+- Integration；
+- V17 tag/release worktree；
+- Source `isLoaded()` 定义；
+- Particle field/provider/network；
+- Fast Path gate semantic；
+- `singleContinuousSegment`；
+- multi-continuous Fast Path；
+- 自动改变 Style Z-order；
+- provider/business-specific source/layer ID；
+- unrelated cleanup/refactor；
+- Jest。
+
+---
+
+## 13. Codex 执行边界
+
+Codex 本轮负责：
+
+1. 读取实际源码和任务书；
+2. 实现代码；
+3. 编写 Native 非 Jest 测试源码；
+4. 更新 Android Test App 验证入口；
+5. 执行轻量静态检查，如 `git diff --check`；
+6. 生成中文完成报告。
+
+Codex **不得执行**：
+
+- Android Gradle / APK；
+- ADB / 安装 / 实机；
+- Xcode / iOS device；
+- V18 release；
+- tag；
+- push；
+- Jest。
+
+本轮 Codex 完成报告固定：
+
+`docs/报告/STEP-100_SourceScoped_RenderSegment局部失效_Codex完成报告_v1.md`
+
+Step 记录固定：
+
+`docs/50_Step记录/STEP-100_SourceScoped_RenderSegment局部失效_v1.md`
+
+完成报告必须写清：
+
+- 实际 Codex model / reasoning effort；
+- start HEAD；
+- 修改文件；
+- 生产设计；
+- source revision/readiness 规则；
+- mixed retained decision 规则；
+- Fast Path 明确未改；
+- 测试源码新增情况；
+- 实际执行 / NOT RUN；
+- 风险与 RDC 验收点；
+- 未 commit / 未 push（如果确实如此）。
+
+Codex 不 commit、不 push。由 RDC 验证通过后统一 Git 收尾。
+
+---
+
+## 14. RDC / ChatGPT 后续独立验收
+
+Codex 返回后由 RDC 负责：
+
+1. source/diff 审计；
+2. Native Mac 编译；
+3. Native focused + broad related C++ tests；
+4. Android x86_64 OpenGL validation APK 单次构建；
+5. Mac ADB 直连 FZG1-2；
+6. 自动跑 T1/T2/T3/T4；
+7. 解析 R0/R1 build/reuse/invalidation/revision/readiness；
+8. 确认硬验收标准 A～E；
+9. 若失败，回到 STEP-100 修复，不发布；
+10. 若全部 PASS，完成 STEP-100 Git push；
+11. 再按现有统一发行流程升级到：
+    `maplibre-particle/rn/13.4.1-particle.18`
+12. V18 build/release/public artifact 验证通过后才宣布 V18 发布完成。
+
+---
+
+## 15. 停止条件
+
+Codex 遇到以下任一情况必须停止并报告，不得扩大范围：
+
+- 要修改 Source `isLoaded()` 才能继续；
+- 需要放宽 Fast Path gate；
+- 必须改变 singleContinuous / multi-continuous；
+- production dependency 无法可靠从现有 Style/RenderLayer/Source 推导；
+- per-segment fallback 会破坏 RenderPass/Z-order 且无法在当前范围安全解决；
+- 发现需要 NavSea/Integration 配合；
+- 需要业务 layer/source ID；
+- 需要改变 V17 release。
+
+---
+
+## 16. 本任务最终原则
+
+STEP-100 的目标不是让“全局世界看起来 loaded”。
+
+目标是：
+
+> **即使某个 GeoJSON Source 正在变化或短暂 unready，只要 R0 与它没有依赖关系，R0 retained cache 就必须继续安全 reuse，不能被迫一起刷新。**
+
+Fast Path 是否还能 miss，是后续独立问题。
+
+只有这一点经过 Native + Android R-C-R 实测成立，才允许进入 V18 发布。
diff --git a/docs/50_Step记录/STEP-100_SourceScoped_RenderSegment局部失效_v1.md b/docs/50_Step记录/STEP-100_SourceScoped_RenderSegment局部失效_v1.md
new file mode 100644
index 000000000..8afa14da6
--- /dev/null
+++ b/docs/50_Step记录/STEP-100_SourceScoped_RenderSegment局部失效_v1.md
@@ -0,0 +1,132 @@
+# STEP-100 SourceScoped RenderSegment 局部失效记录 v1
+
+状态：**CLOSED / PASS（Android runtime）**
+日期：2026-10-06
+
+## 基线
+
+- worktree：`/Users/tei/dev/MapLibreParticleLab-step100`
+- branch：`step100-segment-local-source-invalidation`
+- start HEAD：`c4b481fd2c5b5da20d31f6ae54011f0552d7dbd0`
+- V17 tag：`maplibre-particle/rn/13.4.1-particle.17`
+- V17 frozen commit：`e8b451fe70054107773e82484c80e90df3889147`
+
+## 实现
+
+- Source/Tile mutation 增加 source-scoped revision；
+- global retained content revision 继续保留；
+- production renderer 与 diagnostics 共用 source→segment dependency；
+- RETAINED Segment 独立 readiness / stability / Build / Reuse / Fallback；
+- unrelated source unloaded/fading 不再拖垮该 Segment；
+- full CPU mixed execution 支持 R0 Reuse + C Live + R1 Fallback；
+- Fast Path gate、singleContinuous、多 Continuous语义未改；
+- Source::isLoaded 与 global renderTree loaded 语义未改。
+
+## Android Build
+
+标准 validation pipeline 最终：
+
+```text
+RC=0
+BUILD SUCCESS
+variant=OpenglDebug
+abi=x86_64
+apk_bytes=61956640
+libmaplibre_bytes=39636472
+sha256=86e22bf081bf7d3196f0bf0e7c56af51bde01e9f0b01e0bab238cb794273315a
+```
+
+RDC 另修复 validation script 的 pipefail/SIGPIPE 141：
+`awk ... {print $1; exit}` → 完整消费管道。
+
+## FZG1-2
+
+- Android 13
+- API 33
+- x86_64
+- ADB：`192.168.200.139:5555`
+
+### T1 STATIC
+
+- false window：1
+- avg/max：203 ms
+- R0/R1 build=1 后持续 reuse
+
+### T4 R-C-R 主验收
+
+窗口：
+- baseline：tick 8
+- final：tick 130
+- 约 61.6 s
+
+global revision：
+`128 → 973`
+
+R0：
+```text
+build          1 → 1
+invalidation   20 → 20
+reuse          132 → 4042
+sourceRevision unchanged
+```
+
+R1：
+```text
+build          5 → 135
+invalidation   26 → 211
+```
+
+结论：
+- R0 buildDelta=0
+- R0 invalidationDelta=0
+- R0 reuseDelta=+3910
+- global revision 仍增长
+- dynamic source affected=[2]
+
+**主硬门槛 PASS。**
+
+### T2 GEOJSON 1HZ
+
+- 约 35 s
+- falseWindowCount=6
+- avg=203 ms
+- max=205 ms
+- R0 build=1 / invalidation=18 保持稳定，reuse 增长
+
+### T3 PERMANENT UNREADY
+
+global loaded=false 持续约 21.468 s。
+
+unready source：
+- no layer
+- enabled=false
+- isLoaded=false
+
+R0/R1：
+- build=1 不变
+- invalidation=19 不变
+- reuse：11 → 1200
+- decision=reuse
+
+说明 global loaded 兼容事实仍为 false，但无关 retained cache 继续安全复用。
+
+## Native Host Test
+
+Codex 已新增 `RenderSegmentLocality.*` 测试源码。
+
+当前 Intel Mac 缺 `libuv`，Metal host configure 被环境阻塞。RDC 曾尝试 Homebrew 安装，但发现会连带升级 CMake/OpenSSL/Python 且 Intel 无 bottle 支持，已主动停止。
+
+因此：
+- Native host GTest：ENV BLOCKED / NOT RUN
+- Android full native build：PASS
+- Android runtime：PASS
+
+Jest：NOT RUN。
+
+## 结论
+
+STEP-100 功能目标成立：
+
+> GeoJSON Source 更新只刷新依赖它的 retained segment；无关 retained segment 不再一起刷新。
+
+允许进入 V18 unified release。
diff --git a/docs/报告/STEP-100_SourceScoped_RenderSegment局部失效_Codex完成报告_v1.md b/docs/报告/STEP-100_SourceScoped_RenderSegment局部失效_Codex完成报告_v1.md
new file mode 100644
index 000000000..d9b958500
--- /dev/null
+++ b/docs/报告/STEP-100_SourceScoped_RenderSegment局部失效_Codex完成报告_v1.md
@@ -0,0 +1,454 @@
+# STEP-100 SourceScoped RenderSegment 局部失效 — 完成报告 v1
+
+## 1. 最终结论
+
+**CLOSED / PASS（功能与 Android 运行态目标确认）**。
+
+Codex 实现使用：
+- model：`gpt-6-sol`
+- reasoning effort：`high`
+
+RDC 独立完成：
+- 源码 diff 审计；
+- Android x86_64 OpenGL 全量 native build；
+- Validation APK；
+- FZG1-2 自动安装与 T1/T2/T3/T4；
+- STEP-100 60 秒 locality window；
+- validation build script 小型工程修复；
+- Git diff/status 审计。
+
+本 Step 核心目标已确认：
+
+> 动态 GeoJSON Source 更新只影响依赖它的 RETAINED Segment；无关 R0 cache 不再跟着 invalid/rebuild，并且在 global loaded=false 时仍可安全 reuse。
+
+Native host GTest 因当前 Intel Mac 缺 `libuv` 未执行；曾尝试 Homebrew 安装，但 Homebrew 要连带升级 CMake/OpenSSL/Python 且 Intel 已无 bottle 支持，因此 RDC 主动终止，未把环境变化作为任务依赖。Android 最终 C++ native build 与设备运行态用于本轮功能验收。
+
+Jest：**NOT RUN**，用户未要求。
+
+## 2. Git / 基线
+
+- worktree：`/Users/tei/dev/MapLibreParticleLab-step100`
+- branch：`step100-segment-local-source-invalidation`
+- start HEAD：`c4b481fd2c5b5da20d31f6ae54011f0552d7dbd0`
+- start remote：`origin/particle/main = c4b481fd2c5b5da20d31f6ae54011f0552d7dbd0`
+- frozen V17 tag：`maplibre-particle/rn/13.4.1-particle.17`
+- frozen V17 commit：`e8b451fe70054107773e82484c80e90df3889147`
+- V17 tag/release worktree：未修改。
+
+最终 STEP-100 commit / push / remote HEAD 在 Git 收尾后由最终交付回读记录，避免文档自引用。
+
+## 3. 实际修改
+
+生产源码：
+
+- `include/mbgl/renderer/render_segment.hpp`
+- `src/mbgl/renderer/render_orchestrator.hpp`
+- `src/mbgl/renderer/render_orchestrator.cpp`
+- `src/mbgl/renderer/renderer_impl.cpp`
+- `src/mbgl/renderer/retained_underlay_cache.cpp`
+- `src/mbgl/renderer/retained_underlay_runtime_state.hpp`
+- `src/mbgl/renderer/render_segment_json.hpp`
+- `packages/maplibre-particle-rn/src/types.ts`
+
+Test App / tests：
+
+- `platform/android/MapLibreAndroidTestApp/src/main/java/org/maplibre/android/testapp/activity/particle/Step099ReadinessFixture.kt`
+- `platform/android/MapLibreAndroidTestApp/src/main/java/org/maplibre/android/testapp/activity/particle/ParticleCoreLayerValidationActivity.kt`
+- `test/renderer/retained_underlay_cache.test.cpp`
+
+工具：
+
+- `tools/particle_android_validation/build_validation_apk.sh`
+  - RDC 修复 `unzip | awk ... exit` 在 `pipefail` 下偶发 SIGPIPE/141；
+  - 仅移除 awk 的提前 exit，不改变 APK 验证语义。
+
+文档：
+
+- `docs/40_任务/STEP-100_SourceScoped_RenderSegment局部失效_Codex任务_v2.md`
+- `docs/50_Step记录/STEP-100_SourceScoped_RenderSegment局部失效_v1.md`
+- 本报告；
+- `粒子开发记录.md`
+
+## 4. 生产设计
+
+### 4.1 Source-scoped revision
+
+新增正式 source-scoped revision bookkeeping。
+
+明确的 Source/Tile mutation：
+- source diff；
+- feature state；
+- tile changed；
+
+推进对应 sourceId revision。
+
+现有 global `retainedUnderlayContentRevision` 继续增长，供：
+- compatibility；
+- diagnostics；
+- Fast Path fail-closed。
+
+RETAINED Segment cache 不再直接以 global Source/Tile revision 作为内容 revision。
+
+### 4.2 Segment dependency
+
+正式 renderer 与 diagnostics 共用 source→segment 依赖推导。
+
+规则：
+- layer sourceId 决定 source dependency；
+- source-less background 不制造假 dependency；
+- shared source 可影响多个 segment；
+- symbol 的 glyph/image/placement 作为明确 global prerequisite；
+- 真正无法证明的 dependency fail closed。
+
+### 4.3 Per-segment readiness
+
+未修改：
+- `Source::isLoaded()`；
+- `renderTreeParameters->loaded = styleLoaded && isLoaded()`。
+
+full CPU retained path 增加 per-segment source readiness/stability：
+
+- dependent source unloaded → 仅该 Segment fallback；
+- dependent source fading → 仅该 Segment unstable；
+- unrelated source unloaded/fading → 不影响该 Segment；
+- style/image/sprite/glyph/placement/context 等 global prerequisite 仍 fail closed。
+
+### 4.4 Mixed Build / Reuse / Fallback
+
+移除 retained full-CPU path 的 all-or-none `useRetainedRanges` 依赖。
+
+每个 RETAINED Segment独立决定：
+
+- Build
+- Reuse
+- Fallback
+
+主 buffer 按 Style Segment 顺序执行：
+
+- RETAINED Build/Reuse → composite cache
+- RETAINED Fallback → live render only that range
+- CONTINUOUS → live render
+
+因此允许：
+
+```text
+R0 = Reuse
+C  = Live
+R1 = Fallback
+```
+
+不再因为 R1 fallback 把 R0 一起变成 live redraw。
+
+Fast Path gate / `singleContinuousSegment` / multi-continuous Fast Path：**未修改**。
+
+## 5. Android build
+
+首次标准 validation script 的 Gradle 本体实际结果：
+
+```text
+BUILD SUCCESSFUL in 12s
+86 actionable tasks: 6 executed, 80 up-to-date
+```
+
+但脚本在 Gradle 成功后以 141 退出。RDC 用 `bash -x` 精确定位到：
+
+```bash
+LIB_BYTES="$(unzip ... | awk '/.../ {print $1; exit}')"
+```
+
+在 `set -o pipefail` 下触发 SIGPIPE。
+
+RDC 仅去掉 awk 的 `exit`，重跑标准脚本：
+
+```text
+RC=0
+[validation-apk] BUILD SUCCESS
+```
+
+最终 APK：
+
+- variant：OpenglDebug
+- ABI：x86_64
+- apk bytes：61,956,640
+- libmaplibre.so bytes：39,636,472
+- SHA-256：
+  `86e22bf081bf7d3196f0bf0e7c56af51bde01e9f0b01e0bab238cb794273315a`
+
+证据：
+`artifacts/maplibre-particle/android-validation/`
+
+## 6. 设备
+
+- serial：`192.168.200.139:5555`
+- model：FZG1-2
+- Android：13
+- API：33
+- ABI：x86_64
+
+APK 覆盖安装成功，`ParticleCoreLayerValidationActivity` 冷启动成功。
+
+STEP-100 log：
+`artifacts/maplibre-particle/android-validation/step100-logcat.txt`
+
+log SHA-256：
+`e9d18ea987d12cb30e321d0d9c669b2588972aac89e5277920bf1fa9fee8146b`
+
+## 7. T1 STATIC
+
+运行约 20 秒。
+
+aggregate：
+
+```text
+falseWindowCount=1
+falseWindowAvgMs=203
+falseWindowMaxMs=203
+openFalseWindowMs=0
+```
+
+最终：
+
+- R0 build=1
+- R0 reuse=1217
+- R0 decision=reuse
+- R1 build=1
+- R1 reuse=1187
+- R1 decision=reuse
+
+静态 R-C-R 正常。
+
+## 8. T4 R-C-R 主验收
+
+结构：
+
+```text
+R0 -> step099-static
+C  -> particle-fixture
+R1 -> step099-dynamic (+ framework annotation source if present)
+```
+
+window marker：
+
+```text
+baseline tick=8   17:05:21.642
+final    tick=130 17:06:23.240
+```
+
+窗口约 61.6 秒。
+
+dynamic update 总计：68 次。
+
+global revision：
+
+```text
+128 -> 973
+```
+
+说明 global compatibility revision **仍正常增长**，没有通过停掉 global revision“作弊”。
+
+### R0
+
+baseline：
+
+```text
+build=1
+reuse=132
+invalidation=20
+srcRev=5127273714767523329
+decision=reuse
+```
+
+final：
+
+```text
+build=1
+reuse=4042
+invalidation=20
+srcRev=5127273714767523329
+decision=reuse
+```
+
+Delta：
+
+```text
+buildDelta        = 0
+invalidationDelta = 0
+reuseDelta        = +3910
+sourceRevision    = unchanged
+```
+
+**硬门槛 PASS。**
+
+### R1
+
+baseline：
+
+```text
+build=5
+invalidation=26
+```
+
+final：
+
+```text
+build=135
+invalidation=211
+```
+
+动态 Source mutation 正常驱动 R1。
+
+mutation diagnostics 持续：
+
+```text
+sourceId=step099-dynamic
+affected=[2]
+scope=source-local-diagnostic
+```
+
+### loaded false windows
+
+T4：
+
+```text
+falseWindowCount=5
+falseWindowAvgMs=202
+falseWindowMaxMs=203
+openFalseWindowMs=0
+```
+
+即 transient global loaded=false 仍存在，但不再让 R0 build/invalidation 增长。
+
+## 9. T2 双 GeoJSON readiness 回归
+
+约 35 秒。
+
+aggregate：
+
+```text
+falseWindowCount=6
+falseWindowAvgMs=203
+falseWindowMaxMs=205
+openFalseWindowMs=0
+```
+
+R0 在动态窗口保持：
+
+- build=1
+- invalidation=18
+- revision unchanged
+- reuse 持续增长。
+
+R1 随两个动态 GeoJSON 持续 build/invalidate。
+
+结论：
+**DYNAMIC_SOURCE_READINESS_THRASH 仍是 global loaded 事实，但不再误伤无关 retained cache。**
+
+## 10. T3 permanently unready unrelated source
+
+`step099-unready-raster-array`：
+
+- no layer；
+- enabled=false；
+- isLoaded=false。
+
+global：
+
+```text
+renderOrchestratorLoaded=false
+openFalseWindowMs=21468
+```
+
+约 21.468 秒持续 false。
+
+与此同时：
+
+R0：
+- build=1
+- invalidation=19
+- reuse：11 → 1200
+- decision=reuse
+
+R1：
+- build=1
+- invalidation=19
+- reuse：11 → 1200
+- decision=reuse
+
+因此：
+
+> global loaded 仍保持旧兼容语义，但 unrelated permanently-unready source 已不能把无关 RETAINED Segment 拖成 style-not-loaded fallback。
+
+**硬门槛 PASS。**
+
+## 11. Mixed fallback
+
+T4 中 R1 `fallbackCount` 从约 21 增长到 76，而 R0 fallback 计数保持不变，同时 R0 reuse 持续增长。
+
+这证明运行期间真实发生了：
+
+```text
+R0 = Reuse
+R1 = transient Fallback / rebuild
+```
+
+而不是只有“两个段都 ready”的理想场景。
+
+未观察到 crash / ANR。
+
+## 12. Fast Path 边界
+
+RDC diff 审计确认未修改：
+
+- `tryRenderParticleFastFrame`
+- `particleFastPathNonCameraInputsMatch`
+- `singleContinuousSegment`
+- multi-continuous fail-closed
+- global Fast Path signature/fade/contentRevision/pending/placement 等 gate。
+
+STEP-100 只修 full CPU retained locality。
+
+## 13. Native host tests
+
+Codex 已新增 `RenderSegmentLocality.*` C++ 测试源码。
+
+RDC 尝试恢复 `macos-metal` test runner，但 host configure 需要 `libuv`，当前未安装。
+
+尝试 `brew install libuv` 时发现 Intel Homebrew 会连带升级：
+- CMake
+- OpenSSL
+- Python
+- ca-certificates 等
+
+且当前 Intel macOS 已无官方 bottle 支持。为避免污染开发环境，RDC 主动停止。
+
+因此：
+
+- Native host GTest：**ENV BLOCKED / NOT RUN**
+- Android C++ full native build：**PASS**
+- Android device runtime：**PASS**
+
+## 14. Jest / iOS
+
+- Jest：NOT RUN。
+- iOS runtime：本 Step 未运行。
+- V18 unified release：在 STEP-100 Git 收尾后单独执行。
+
+## 15. 最终判定
+
+STEP-100 的核心实现目标全部成立：
+
+1. global revision 继续增长；
+2. R1 GeoJSON mutation 不再 invalid/rebuild R0；
+3. R0 buildDelta=0；
+4. R0 invalidationDelta=0；
+5. R0 reuseDelta>0；
+6. transient unrelated unloaded 不影响 R0 reuse；
+7. permanent unrelated unloaded 不影响 R0 reuse；
+8. mixed Reuse/Fallback 实际发生；
+9. Fast Path 语义未放宽。
+
+因此本 Step 功能与 Android runtime 验收：
+
+**PASS / CLOSED**。
+
+下一步允许进入 V18 unified release。
diff --git a/include/mbgl/renderer/render_segment.hpp b/include/mbgl/renderer/render_segment.hpp
index 8015ccb8b..566f76f68 100644
--- a/include/mbgl/renderer/render_segment.hpp
+++ b/include/mbgl/renderer/render_segment.hpp
@@ -2,7 +2,9 @@
 
 #include <cstdint>
 #include <optional>
+#include <set>
 #include <string>
+#include <unordered_map>
 #include <vector>
 
 namespace mbgl {
@@ -38,6 +40,82 @@ struct StyleLayerDiagnostics {
     bool operator==(const StyleLayerDiagnostics&) const = default;
 };
 
+// The style layer list is the single dependency source for diagnostics and rendering.
+struct RenderSegmentDependencies {
+    std::vector<std::string> sourceIds;
+    std::vector<std::string> globalPrerequisites;
+    bool unknown = false;
+};
+
+inline RenderSegmentDependencies renderSegmentDependencies(const std::vector<StyleLayerDiagnostics>& layers,
+                                                           int32_t begin,
+                                                           int32_t endExclusive) {
+    RenderSegmentDependencies result;
+    if (begin < 0 || endExclusive < begin || endExclusive > static_cast<int32_t>(layers.size())) {
+        result.unknown = true;
+        return result;
+    }
+    std::set<std::string> sources;
+    std::set<std::string> prerequisites;
+    for (int32_t i = begin; i < endExclusive; ++i) {
+        const auto& layer = layers[static_cast<std::size_t>(i)];
+        if (layer.sourceId) sources.insert(*layer.sourceId);
+        if (layer.layerType == "symbol") prerequisites.insert("symbol/glyph/image/placement");
+        if (layer.layerType == "custom" || layer.layerType == "custom-drawable") result.unknown = true;
+        if (layer.layerType != "background" && layer.layerType != "custom" &&
+            layer.layerType != "custom-drawable" && !layer.sourceId) result.unknown = true;
+    }
+    result.sourceIds.assign(sources.begin(), sources.end());
+    result.globalPrerequisites.assign(prerequisites.begin(), prerequisites.end());
+    return result;
+}
+
+class RenderSegmentRevisionBook {
+public:
+    void advanceGlobal() noexcept { ++globalEpoch; }
+    void advanceSource(const std::string& sourceId) { sourceRevisions[sourceId] = ++sequence; }
+    std::optional<uint64_t> revisionFor(const RenderSegmentDependencies& dependencies) const {
+        if (dependencies.unknown) return std::nullopt;
+        uint64_t revision = globalEpoch;
+        for (const auto& id : dependencies.sourceIds) {
+            const auto found = sourceRevisions.find(id);
+            if (found == sourceRevisions.end()) return std::nullopt;
+            for (const unsigned char ch : id) revision = (revision ^ ch) * 1099511628211ULL;
+            revision = (revision ^ found->second) * 1099511628211ULL;
+        }
+        return revision;
+    }
+private:
+    uint64_t globalEpoch = 1;
+    uint64_t sequence = 1;
+    // Retain tombstones: remove + recreate of the same ID always receives a newer identity.
+    std::unordered_map<std::string, uint64_t> sourceRevisions;
+};
+
+struct RenderSegmentSourceStatus { bool loaded = false; bool fading = false; };
+struct RenderSegmentSourceAssessment {
+    bool ready = false;
+    bool stable = false;
+    const char* reason = "unknown-dependency";
+};
+
+template <typename Lookup>
+RenderSegmentSourceAssessment assessRenderSegmentSources(const RenderSegmentDependencies& dependencies,
+                                                        Lookup lookup) {
+    RenderSegmentSourceAssessment result;
+    if (dependencies.unknown) return result;
+    for (const auto& id : dependencies.sourceIds) {
+        const std::optional<RenderSegmentSourceStatus> source = lookup(id);
+        if (!source) { result.reason = "missing-source"; return result; }
+        if (!source->loaded) { result.reason = "source-not-loaded"; return result; }
+        if (source->fading) { result.ready = true; result.reason = "source-fading"; return result; }
+    }
+    result.ready = true;
+    result.stable = true;
+    result.reason = "none";
+    return result;
+}
+
 struct RenderSourceReadinessDiagnostics {
     std::string sourceId;
     std::string sourceType;
@@ -88,6 +166,13 @@ struct RenderSegmentCacheDiagnostics {
     uint64_t build = 0;
     uint64_t reuse = 0;
     uint64_t invalidation = 0;
+    uint64_t fallbackCount = 0;
+    std::string finalDecision{"disabled"};
+    std::string lastFallbackReason{"none"};
+    bool sourceReady = false;
+    bool sourceStable = false;
+    bool supported = false;
+    uint64_t sourceRevision = 0;
     std::string lastInvalidationReason{"none"};
     uint64_t textureCreate = 0;
     uint64_t compositeCreate = 0;
@@ -163,4 +248,24 @@ struct ResolvedRenderSegmentPlan {
     bool operator==(const ResolvedRenderSegmentPlan&) const = default;
 };
 
+// This is the main-buffer traversal used by the renderer. A failed retained range
+// is drawn live exactly once; neighboring cached ranges remain composites.
+template <typename Cached, typename Composite, typename Live>
+void visitRenderSegmentExecution(const ResolvedRenderSegmentPlan& plan,
+                                 Cached cached,
+                                 Composite composite,
+                                 Live live) {
+    if (!plan.valid) {
+        live(0, plan.layerCount);
+        return;
+    }
+    for (const auto& segment : plan.segments) {
+        if (segment.strategy == RenderSegmentStrategy::Retained && cached(segment.segmentIndex)) {
+            composite(segment.segmentIndex);
+        } else {
+            live(segment.beginIndex, segment.endExclusive);
+        }
+    }
+}
+
 } // namespace mbgl
diff --git a/packages/maplibre-particle-rn/src/types.ts b/packages/maplibre-particle-rn/src/types.ts
index d34f3c14d..3adfd26de 100644
--- a/packages/maplibre-particle-rn/src/types.ts
+++ b/packages/maplibre-particle-rn/src/types.ts
@@ -97,6 +97,13 @@ export type RetainedRenderSegmentDiagnostics = Readonly<{
     build: number;
     reuse: number;
     invalidation: number;
+    fallbackCount: number;
+    finalDecision: string;
+    lastFallbackReason: string;
+    sourceReady: boolean;
+    sourceStable: boolean;
+    supported: boolean;
+    sourceRevision: number;
     lastInvalidationReason: string;
     textureCreate: number;
     compositeCreate: number;
diff --git a/platform/android/MapLibreAndroidTestApp/src/main/java/org/maplibre/android/testapp/activity/particle/ParticleCoreLayerValidationActivity.kt b/platform/android/MapLibreAndroidTestApp/src/main/java/org/maplibre/android/testapp/activity/particle/ParticleCoreLayerValidationActivity.kt
index b920af616..6e0c970a5 100644
--- a/platform/android/MapLibreAndroidTestApp/src/main/java/org/maplibre/android/testapp/activity/particle/ParticleCoreLayerValidationActivity.kt
+++ b/platform/android/MapLibreAndroidTestApp/src/main/java/org/maplibre/android/testapp/activity/particle/ParticleCoreLayerValidationActivity.kt
@@ -122,6 +122,10 @@ class ParticleCoreLayerValidationActivity : AppCompatActivity() {
                         if (step099Tick % 2L == 0L) {
                             updateStep099GeoJson(Step099ReadinessFixture.DYNAMIC_SOURCE, step099Tick)
                             refreshStep099Diagnostics(log = true)
+                            if (step099Tick == 8L || step099Tick == 130L) {
+                                Log.i(TAG, "STEP100_WINDOW_MARKER phase=${if (step099Tick == 8L) "baseline" else "final"} " +
+                                    "tick=$step099Tick sourceId=${Step099ReadinessFixture.DYNAMIC_SOURCE}")
+                            }
                         }
                     }
                     else -> if (step099Tick % 2L == 0L) refreshStep099Diagnostics(log = true)
@@ -675,7 +679,12 @@ class ParticleCoreLayerValidationActivity : AppCompatActivity() {
                 } else {
                     "cache=${cache.optString("cacheState")}@${cache.optLong("contentRevision")}" +
                         " b=${cache.optLong("build")} r=${cache.optLong("reuse")}" +
-                        " i=${cache.optLong("invalidation")}/${cache.optString("lastInvalidationReason")}"
+                        " i=${cache.optLong("invalidation")}/${cache.optString("lastInvalidationReason")}" +
+                        " srcRev=${cache.optLong("sourceRevision")}" +
+                        " ready=${cache.optBoolean("sourceReady")}/${cache.optBoolean("sourceStable")}" +
+                        " supported=${cache.optBoolean("supported")}" +
+                        " decision=${cache.optString("finalDecision")}" +
+                        " fallback=${cache.optLong("fallbackCount")}/${cache.optString("lastFallbackReason")}"
                 }
                 add("${segment.optInt("segmentIndex")}:${segment.optString("strategy")}" +
                     "[${segment.optInt("beginIndex")},${segment.optInt("endExclusive")})" +
diff --git a/platform/android/MapLibreAndroidTestApp/src/main/java/org/maplibre/android/testapp/activity/particle/Step099ReadinessFixture.kt b/platform/android/MapLibreAndroidTestApp/src/main/java/org/maplibre/android/testapp/activity/particle/Step099ReadinessFixture.kt
index 52920b889..7405fd537 100644
--- a/platform/android/MapLibreAndroidTestApp/src/main/java/org/maplibre/android/testapp/activity/particle/Step099ReadinessFixture.kt
+++ b/platform/android/MapLibreAndroidTestApp/src/main/java/org/maplibre/android/testapp/activity/particle/Step099ReadinessFixture.kt
@@ -3,7 +3,7 @@ package org.maplibre.android.testapp.activity.particle
 import org.json.JSONArray
 import org.json.JSONObject
 
-/** STEP-099 offline readiness/invalidation fixtures. Diagnostics only; no renderer semantics are changed. */
+/** STEP-099/100 offline source readiness and retained segment fixtures. */
 internal object Step099ReadinessFixture {
     enum class Scenario(val label: String) {
         T1_STATIC("T1 STATIC"),
@@ -14,6 +14,7 @@ internal object Step099ReadinessFixture {
 
     const val PARTICLE_SOURCE = "particle-fixture"
     const val STATIC_SOURCE = "step099-static"
+    const val UPPER_STATIC_SOURCE = "step099-upper-static"
     const val DYNAMIC_SOURCE = "step099-dynamic"
     const val DYNAMIC_SOURCE_B = "step099-dynamic-b"
     const val UNREADY_SOURCE = "step099-unready-raster-array"
@@ -41,6 +42,11 @@ internal object Step099ReadinessFixture {
                 """{"type":"Point","coordinates":[135.0,28.0]}"""
             ))
         }
+        if (scenario == Scenario.T1_STATIC || scenario == Scenario.T3_PERMANENT_UNREADY) {
+            sources.put(UPPER_STATIC_SOURCE, geoJsonSource(
+                """{"type":"Polygon","coordinates":[[[116,4],[154,4],[154,52],[116,52],[116,4]]]}"""
+            ))
+        }
         if (scenario == Scenario.T2_GEOJSON_1HZ) {
             sources.put(DYNAMIC_SOURCE_B, geoJsonSource(
                 """{"type":"Point","coordinates":[136.0,29.0]}"""
@@ -100,11 +106,13 @@ internal object Step099ReadinessFixture {
                     .put("circle-color", "#ff6600")
                     .put("circle-opacity", 0.90)))
         }
-        layers.put(JSONObject()
-            .put("id", UPPER_STATIC_LAYER)
-            .put("type", "fill")
-            .put("source", STATIC_SOURCE)
-            .put("paint", JSONObject().put("fill-color", "#d3a640").put("fill-opacity", 0.38)))
+        if (scenario == Scenario.T1_STATIC || scenario == Scenario.T3_PERMANENT_UNREADY) {
+            layers.put(JSONObject()
+                .put("id", UPPER_STATIC_LAYER)
+                .put("type", "fill")
+                .put("source", UPPER_STATIC_SOURCE)
+                .put("paint", JSONObject().put("fill-color", "#d3a640").put("fill-opacity", 0.38)))
+        }
 
         return JSONObject()
             .put("version", 8)
diff --git a/src/mbgl/renderer/render_orchestrator.cpp b/src/mbgl/renderer/render_orchestrator.cpp
index 716cb4759..f487535c6 100644
--- a/src/mbgl/renderer/render_orchestrator.cpp
+++ b/src/mbgl/renderer/render_orchestrator.cpp
@@ -227,11 +227,38 @@ void RenderOrchestrator::recordReadinessMutation(const char* eventType,
     }
 }
 
+void RenderOrchestrator::advanceRetainedSourceRevision(RetainedUnderlayReason reason,
+                                                       const std::string& sourceId) noexcept {
+    if (sourceId.empty()) {
+        std::lock_guard<std::mutex> lock(readinessDiagnosticsMutex);
+        retainedSegmentRevisions.advanceGlobal();
+        return;
+    }
+    try {
+        std::lock_guard<std::mutex> lock(readinessDiagnosticsMutex);
+        retainedSegmentRevisions.advanceSource(sourceId);
+    } catch (...) {
+        // Correctness state must fail closed if a source revision cannot be recorded.
+        std::lock_guard<std::mutex> lock(readinessDiagnosticsMutex);
+        retainedSegmentRevisions.advanceGlobal();
+    }
+    recordReadinessMutation(readinessEventType(reason), reason, sourceId);
+}
+
 void RenderOrchestrator::advanceRetainedUnderlayContentRevision(
     RetainedUnderlayReason reason,
     const std::optional<std::string>& sourceId) noexcept {
     retainedUnderlayContentReason.store(reason, std::memory_order_release);
     retainedUnderlayContentRevision.fetch_add(1, std::memory_order_acq_rel);
+    if (sourceId && (reason == RetainedUnderlayReason::SourceMutation ||
+                     reason == RetainedUnderlayReason::TileMutation)) {
+        advanceRetainedSourceRevision(reason, *sourceId);
+        return;
+    }
+    {
+        std::lock_guard<std::mutex> lock(readinessDiagnosticsMutex);
+        retainedSegmentRevisions.advanceGlobal();
+    }
     recordReadinessMutation(readinessEventType(reason), reason, sourceId);
 }
 
@@ -484,15 +511,16 @@ std::unique_ptr<RenderTree> RenderOrchestrator::createRenderTree(
 
     const SourceDifference sourceDiff = diffSources(sourceImpls, updateParameters->sources);
     if (!sourceDiff.added.empty() || !sourceDiff.removed.empty() || !sourceDiff.changed.empty()) {
-        advanceRetainedUnderlayContentRevision(RetainedUnderlayReason::SourceMutation);
+        retainedUnderlayContentReason.store(RetainedUnderlayReason::SourceMutation, std::memory_order_release);
+        retainedUnderlayContentRevision.fetch_add(1, std::memory_order_acq_rel);
         for (const auto& entry : sourceDiff.added) {
-            recordReadinessMutation("SourceMutation", RetainedUnderlayReason::SourceMutation, entry.first);
+            advanceRetainedSourceRevision(RetainedUnderlayReason::SourceMutation, entry.first);
         }
         for (const auto& entry : sourceDiff.removed) {
-            recordReadinessMutation("SourceMutation", RetainedUnderlayReason::SourceMutation, entry.first);
+            advanceRetainedSourceRevision(RetainedUnderlayReason::SourceMutation, entry.first);
         }
         for (const auto& entry : sourceDiff.changed) {
-            recordReadinessMutation("SourceMutation", RetainedUnderlayReason::SourceMutation, entry.first);
+            advanceRetainedSourceRevision(RetainedUnderlayReason::SourceMutation, entry.first);
         }
     }
     sourceImpls = updateParameters->sources;
@@ -582,11 +610,13 @@ std::unique_ptr<RenderTree> RenderOrchestrator::createRenderTree(
                 if (!impl.sourceLayer.empty()) value.sourceLayer = impl.sourceLayer;
                 styleLayerDiagnostics.push_back(std::move(value));
             }
+            retainedStyleLayers = styleLayerDiagnostics;
             updateParameters->retainedUnderlayState->recordRenderSegmentResolution(
                 renderSegmentPlan, std::move(styleLayerDiagnostics));
         }
     } else {
         renderSegmentPlan = {};
+        retainedStyleLayers.clear();
     }
 
     // Update all sources and initialize renderItems.
@@ -1119,6 +1149,52 @@ bool RenderOrchestrator::retainedRangeIsStable(TimePoint timePoint, int32_t begi
     return true;
 }
 
+RenderOrchestrator::RetainedSegmentSourceState RenderOrchestrator::retainedSegmentSourceState(
+    int32_t begin, int32_t endExclusive) const {
+    RetainedSegmentSourceState result;
+    const auto dependencies = renderSegmentDependencies(retainedStyleLayers, begin, endExclusive);
+    if (dependencies.unknown) return result;
+    // The global epoch contains only changes whose effect cannot be scoped to one source.
+    {
+        std::lock_guard<std::mutex> lock(readinessDiagnosticsMutex);
+        const auto value = retainedSegmentRevisions.revisionFor(dependencies);
+        if (!value) return result;
+        result.revision = *value;
+    }
+    const auto assessment = assessRenderSegmentSources(dependencies, [&](const std::string& sourceId)
+        -> std::optional<RenderSegmentSourceStatus> {
+        const auto source = renderSources.find(sourceId);
+        if (source == renderSources.end()) return std::nullopt;
+        return RenderSegmentSourceStatus{source->second->isLoaded(), source->second->hasFadingTiles()};
+    });
+    result.ready = assessment.ready;
+    result.stable = assessment.stable;
+    result.reason = assessment.reason;
+    return result;
+}
+
+bool RenderOrchestrator::retainedSegmentIsStable(TimePoint timePoint,
+                                                 int32_t begin,
+                                                 int32_t endExclusive) const {
+    if (renderLight.hasTransition()) return false;
+    if (retainedRangeUsesPlacement(begin, endExclusive) && placementController.hasTransitions(timePoint)) return false;
+    const auto first = std::clamp<int32_t>(begin, 0, static_cast<int32_t>(orderedLayers.size()));
+    const auto last = std::clamp<int32_t>(endExclusive, first, static_cast<int32_t>(orderedLayers.size()));
+    for (int32_t index = first; index < last; ++index) {
+        const auto& layer = orderedLayers[index].get();
+        if (layer.hasTransition() || layer.needsRepaint()) return false;
+    }
+    return true;
+}
+
+bool RenderOrchestrator::retainedGlobalResourcesReady() const {
+    return imageManager->isLoaded();
+}
+
+bool RenderOrchestrator::retainedGlobalLightTransition() const {
+    return renderLight.hasTransition();
+}
+
 bool RenderOrchestrator::retainedUnderlayHasUnsupportedLayer(int32_t boundary) const {
     return retainedRangeHasUnsupportedLayer(0, boundary);
 }
diff --git a/src/mbgl/renderer/render_orchestrator.hpp b/src/mbgl/renderer/render_orchestrator.hpp
index 505eb857a..813c1cf4c 100644
--- a/src/mbgl/renderer/render_orchestrator.hpp
+++ b/src/mbgl/renderer/render_orchestrator.hpp
@@ -128,6 +128,16 @@ public:
     bool retainedUnderlayHasUnsupportedLayer(int32_t boundary) const;
     bool retainedRangeUsesPlacement(int32_t begin, int32_t endExclusive) const;
     bool retainedRangeIsStable(TimePoint, int32_t begin, int32_t endExclusive) const;
+    struct RetainedSegmentSourceState {
+        uint64_t revision = 0;
+        bool ready = false;
+        bool stable = false;
+        const char* reason = "unknown-dependency";
+    };
+    RetainedSegmentSourceState retainedSegmentSourceState(int32_t begin, int32_t endExclusive) const;
+    bool retainedSegmentIsStable(TimePoint, int32_t begin, int32_t endExclusive) const;
+    bool retainedGlobalResourcesReady() const;
+    bool retainedGlobalLightTransition() const;
     bool retainedRangeHasUnsupportedLayer(int32_t begin, int32_t endExclusive) const;
     bool continuousRangeSupportsParticleFastPath(int32_t begin, int32_t endExclusive) const;
     uint64_t retainedRangeContentFingerprint(int32_t begin, int32_t endExclusive) const;
@@ -336,6 +346,7 @@ private:
     void advanceRetainedUnderlayContentRevision(
         RetainedUnderlayReason,
         const std::optional<std::string>& sourceId = std::nullopt) noexcept;
+    void advanceRetainedSourceRevision(RetainedUnderlayReason, const std::string& sourceId) noexcept;
     void recordReadinessMutation(const char* eventType,
                                  RetainedUnderlayReason reason,
                                  const std::optional<std::string>& sourceId = std::nullopt,
@@ -372,6 +383,7 @@ private:
     std::string retainedGlyphURL;
     const void* retainedFontFacesIdentity = nullptr;
     std::atomic<uint64_t> retainedUnderlayContentRevision{1};
+    RenderSegmentRevisionBook retainedSegmentRevisions;
     std::atomic<RetainedUnderlayReason> retainedUnderlayContentReason{RetainedUnderlayReason::None};
 
     struct SourceReadinessEventState {
@@ -394,6 +406,7 @@ private:
     // reallocation on each frame.
     std::vector<Immutable<style::LayerProperties>> filteredLayersForSource;
     RenderLayerReferences orderedLayers;
+    std::vector<StyleLayerDiagnostics> retainedStyleLayers;
     ResolvedRenderSegmentPlan renderSegmentPlan;
     bool renderSegmentStyleReady = false;
     RenderLayerReferences layersNeedPlacement;
diff --git a/src/mbgl/renderer/render_segment_json.hpp b/src/mbgl/renderer/render_segment_json.hpp
index 1e8bffa21..4239e7150 100644
--- a/src/mbgl/renderer/render_segment_json.hpp
+++ b/src/mbgl/renderer/render_segment_json.hpp
@@ -198,6 +198,13 @@ inline std::string renderSegmentDiagnosticsToJSON(const RenderSegmentDiagnostics
             writer.Key("build"); writer.Uint64(cache.build);
             writer.Key("reuse"); writer.Uint64(cache.reuse);
             writer.Key("invalidation"); writer.Uint64(cache.invalidation);
+            writer.Key("fallbackCount"); writer.Uint64(cache.fallbackCount);
+            writer.Key("finalDecision"); writer.String(cache.finalDecision.c_str());
+            writer.Key("lastFallbackReason"); writer.String(cache.lastFallbackReason.c_str());
+            writer.Key("sourceReady"); writer.Bool(cache.sourceReady);
+            writer.Key("sourceStable"); writer.Bool(cache.sourceStable);
+            writer.Key("supported"); writer.Bool(cache.supported);
+            writer.Key("sourceRevision"); writer.Uint64(cache.sourceRevision);
             writer.Key("lastInvalidationReason"); writer.String(cache.lastInvalidationReason.c_str());
             writer.Key("textureCreate"); writer.Uint64(cache.textureCreate);
             writer.Key("compositeCreate"); writer.Uint64(cache.compositeCreate);
diff --git a/src/mbgl/renderer/renderer_impl.cpp b/src/mbgl/renderer/renderer_impl.cpp
index bd81c0659..275e774a2 100644
--- a/src/mbgl/renderer/renderer_impl.cpp
+++ b/src/mbgl/renderer/renderer_impl.cpp
@@ -551,17 +551,17 @@ void Renderer::Impl::render(const RenderTree& renderTree,
     const auto retainedTopologyRevision = particleFastFrame ? retainedUnderlayTopologyTracker.current()
                                                             : retainedUnderlayTopologyTracker.observe(retainedTopology);
     bool legacyInRetainedRange = false;
+    std::vector<bool> legacyInSegment(segmentPlan.segments.size(), false);
     if (retainedMode) {
         for (const auto& item : layerRenderItems) {
             const auto index = static_cast<int32_t>(item.index);
             for (const auto& segment : segmentPlan.segments) {
                 if (segment.strategy == RenderSegmentStrategy::Retained && index >= segment.beginIndex &&
                     index < segment.endExclusive && item.layer.get().usesLegacyRendering()) {
+                    legacyInSegment[segment.segmentIndex] = true;
                     legacyInRetainedRange = true;
-                    break;
                 }
             }
-            if (legacyInRetainedRange) break;
         }
     }
     bool retainedStaticUsesPlacement = false;
@@ -601,7 +601,7 @@ void Renderer::Impl::render(const RenderTree& renderTree,
         .has3D = renderTreeParameters.has3D,
         .unsupportedStaticLayer = retainedUnsupportedStaticLayer,
     };
-    const auto retainedStaticRevision = retainedUnderlayRevisionTracker.observe(
+    retainedUnderlayRevisionTracker.observe(
         retainedRevisionState, retainedUnderlayReasonText(retainedContentReason));
     const bool retainedSupported = retainedMode &&
                                    renderTreeParameters.loaded && !renderTreeParameters.has3D &&
@@ -636,7 +636,8 @@ void Renderer::Impl::render(const RenderTree& renderTree,
     const auto wantsResources = [](RetainedUnderlayDecision decision) {
         return decision == RetainedUnderlayDecision::Build || decision == RetainedUnderlayDecision::Reuse;
     };
-    bool resourcesReady = true;
+    std::vector<RenderOrchestrator::RetainedSegmentSourceState> segmentSourceStates(segmentPlan.segments.size());
+    std::vector<bool> segmentSupportsCache(segmentPlan.segments.size(), false);
     for (const auto& segment : segmentPlan.segments) {
         if (segment.strategy != RenderSegmentStrategy::Retained) continue;
         auto& cache = retainedSegmentCaches[segment.segmentIndex];
@@ -646,34 +647,38 @@ void Renderer::Impl::render(const RenderTree& renderTree,
         const bool layerContentChanged = retainedSegmentFingerprints[segment.segmentIndex] != 0 &&
             retainedSegmentFingerprints[segment.segmentIndex] != fingerprint;
         retainedSegmentFingerprints[segment.segmentIndex] = fingerprint;
-        const auto segmentContentRevision = retainedStaticRevision ^
-            (fingerprint +
-             0x9e3779b97f4a7c15ULL + (retainedStaticRevision << 6U) + (retainedStaticRevision >> 2U));
+        const auto sourceState = orchestrator.retainedSegmentSourceState(
+            segment.beginIndex, segment.endExclusive);
+        segmentSourceStates[segment.segmentIndex] = sourceState;
+        const auto segmentContentRevision = sourceState.revision ^
+            (fingerprint + 0x9e3779b97f4a7c15ULL + (sourceState.revision << 6U) +
+             (sourceState.revision >> 2U)) ^
+            static_cast<uint64_t>(updateParameters->pixelRatio * 1000000.0f);
+        const bool segmentStable = sourceState.stable && orchestrator.retainedSegmentIsStable(
+            renderTreeParameters.timePoint, segment.beginIndex, segment.endExclusive);
+        const bool segmentSupported = retainedMode && updateParameters->styleLoaded &&
+            updateParameters->spriteLoaded && orchestrator.retainedGlobalResourcesReady() &&
+            updateParameters->mode == MapMode::Continuous && !renderTreeParameters.has3D &&
+            renderTreeParameters.debugOptions == MapDebugOptions::NoDebug && segmentStable &&
+            retainedPlacementStable && !legacyInSegment[segment.segmentIndex] &&
+            !orchestrator.retainedRangeHasUnsupportedLayer(segment.beginIndex, segment.endExclusive);
+        segmentSupportsCache[segment.segmentIndex] = segmentSupported;
+        const char* segmentFallbackReason = !sourceState.ready ? sourceState.reason
+            : !sourceState.stable ? sourceState.reason
+            : !updateParameters->styleLoaded || !updateParameters->spriteLoaded ||
+              !orchestrator.retainedGlobalResourcesReady() ? "style-not-loaded"
+            : !segmentStable ? "static-transition" : retainedFallbackReason;
         decision = cache->evaluate(segmentKeys[segment.segmentIndex],
                                    segmentContentRevision,
-                                   retainedSupported,
-                                   retainedFallbackReason,
+                                   segmentSupported,
+                                   segmentFallbackReason,
                                    layerContentChanged ? "layer-mutation"
-                                                       : retainedUnderlayRevisionTracker.reason().c_str());
-        if (resourcesReady && wantsResources(decision)) {
-            resourcesReady = staticData->shaders && cache->prepareResources(
-                context, *staticData->shaders, *segmentKeys[segment.segmentIndex]);
-        }
-    }
-    if (!resourcesReady) {
-        for (const auto& segment : segmentPlan.segments) {
-            if (segment.strategy != RenderSegmentStrategy::Retained) continue;
-            auto& decision = segmentDecisions[segment.segmentIndex];
-            if (wantsResources(decision)) {
-                retainedSegmentCaches[segment.segmentIndex]->markBuildFailed("resource-or-compositor");
-                decision = RetainedUnderlayDecision::Fallback;
-            }
-        }
-    }
-    bool useRetainedRanges = retainedSupported;
-    for (const auto& segment : segmentPlan.segments) {
-        if (segment.strategy == RenderSegmentStrategy::Retained) {
-            useRetainedRanges = useRetainedRanges && wantsResources(segmentDecisions[segment.segmentIndex]);
+                                                       : "source-or-global-mutation");
+        if (wantsResources(decision) &&
+            (!staticData->shaders || !cache->prepareResources(
+                context, *staticData->shaders, *segmentKeys[segment.segmentIndex]))) {
+            cache->markBuildFailed("resource-or-compositor");
+            decision = RetainedUnderlayDecision::Fallback;
         }
     }
 
@@ -726,9 +731,10 @@ void Renderer::Impl::render(const RenderTree& renderTree,
         if (!particleFastFrame) {
             orchestrator.visitDebugLayerGroups([&](LayerGroupBase& layerGroup) { layerGroup.upload(*uploadPass); });
         }
-        if (useRetainedRanges) {
+        if (retainedMode) {
             for (const auto& segment : segmentPlan.segments) {
-                if (segment.strategy == RenderSegmentStrategy::Retained) {
+                if (segment.strategy == RenderSegmentStrategy::Retained &&
+                    wantsResources(segmentDecisions[segment.segmentIndex])) {
                     retainedSegmentCaches[segment.segmentIndex]->upload(*uploadPass);
                 }
             }
@@ -797,10 +803,10 @@ void Renderer::Impl::render(const RenderTree& renderTree,
     };
 
     const auto buildRetainedRange = [&](RetainedUnderlayCache& cache,
-                                        RetainedUnderlayDecision decision,
+                                        RetainedUnderlayDecision& decision,
                                         int32_t begin,
                                         int32_t endExclusive) {
-        if (!useRetainedRanges || decision != RetainedUnderlayDecision::Build || begin >= endExclusive) return;
+        if (decision != RetainedUnderlayDecision::Build || begin >= endExclusive) return;
         bool drawFailed = false;
         bool globalUniformsBound = false;
         try {
@@ -841,7 +847,7 @@ void Renderer::Impl::render(const RenderTree& renderTree,
         }
         if (drawFailed) {
             cache.markBuildFailed("resource-or-compositor");
-            useRetainedRanges = false;
+            decision = RetainedUnderlayDecision::Fallback;
         } else {
             cache.markBuildSucceeded();
         }
@@ -878,7 +884,7 @@ void Renderer::Impl::render(const RenderTree& renderTree,
                                             PaintParameters::depthEpsilon;
 
         // draw layer groups, opaque pass
-        if (useRetainedRanges && retainedMode) {
+        if (retainedMode) {
             orchestrator.visitLayerGroupsInRangeReversed(
                 begin, endExclusive,
                 [&](LayerGroupBase& layerGroup, size_t ordinal) {
@@ -902,7 +908,7 @@ void Renderer::Impl::render(const RenderTree& renderTree,
                                             PaintParameters::depthEpsilon;
 
         // draw layer groups, translucent pass
-        if (useRetainedRanges && retainedMode) {
+        if (retainedMode) {
             orchestrator.visitLayerGroupsInRange(
                 begin, endExclusive,
                 [&](LayerGroupBase& layerGroup, size_t ordinal) {
@@ -929,7 +935,7 @@ void Renderer::Impl::render(const RenderTree& renderTree,
             parameters.currentLayer = i;
             const LayerRenderItem& layerItem = *it;
             const RenderItem& item = layerItem;
-            const bool itemInLiveRange = !useRetainedRanges || !retainedMode ||
+            const bool itemInLiveRange = !retainedMode ||
                 (static_cast<int32_t>(layerItem.index) >= begin &&
                  static_cast<int32_t>(layerItem.index) < endExclusive);
             if (itemInLiveRange && item.hasRenderPass(parameters.pass)) {
@@ -964,20 +970,39 @@ void Renderer::Impl::render(const RenderTree& renderTree,
                                segment.endExclusive);
         }
     }
+    if (retainedRuntimeState) {
+        for (const auto& segment : segmentPlan.segments) {
+            if (segment.strategy != RenderSegmentStrategy::Retained) continue;
+            const auto index = segment.segmentIndex;
+            const auto decision = segmentDecisions[index];
+            const char* decisionText = decision == RetainedUnderlayDecision::Build ? "build" :
+                decision == RetainedUnderlayDecision::Reuse ? "reuse" :
+                decision == RetainedUnderlayDecision::Fallback ? "fallback" : "disabled";
+            const auto& source = segmentSourceStates[index];
+            retainedRuntimeState->recordSegmentExecution(index, source.ready, source.stable,
+                segmentSupportsCache[index], source.revision, decisionText,
+                decision == RetainedUnderlayDecision::Fallback
+                    ? retainedSegmentCaches[index]->getLastInvalidationReason().c_str() : nullptr);
+        }
+    }
     commonClearPass();
     context.bindGlobalUniformBuffers(*parameters.renderPass);
-    if (useRetainedRanges) {
-        for (const auto& segment : segmentPlan.segments) {
-            if (segment.strategy == RenderSegmentStrategy::Retained) {
-                retainedSegmentCaches[segment.segmentIndex]->composite(orchestrator, parameters);
-            } else {
-                drawableOpaquePass(segment.beginIndex, segment.endExclusive);
-                drawableTranslucentPass(segment.beginIndex, segment.endExclusive);
-            }
-        }
-    } else {
+    const bool globalLiveFallback = !retainedMode || renderTreeParameters.has3D ||
+        renderTreeParameters.debugOptions != MapDebugOptions::NoDebug ||
+        updateParameters->mode != MapMode::Continuous || !updateParameters->spriteLoaded ||
+        !orchestrator.retainedGlobalResourcesReady() || !retainedPlacementStable ||
+        orchestrator.retainedGlobalLightTransition();
+    if (globalLiveFallback) {
         drawableOpaquePass(0, segmentPlan.layerCount);
         drawableTranslucentPass(0, segmentPlan.layerCount);
+    } else {
+        visitRenderSegmentExecution(segmentPlan,
+            [&](uint32_t index) { return wantsResources(segmentDecisions[index]); },
+            [&](uint32_t index) { retainedSegmentCaches[index]->composite(orchestrator, parameters); },
+            [&](int32_t begin, int32_t endExclusive) {
+                drawableOpaquePass(begin, endExclusive);
+                drawableTranslucentPass(begin, endExclusive);
+            });
     }
     drawableDebugOverlays();
 
diff --git a/src/mbgl/renderer/retained_underlay_cache.cpp b/src/mbgl/renderer/retained_underlay_cache.cpp
index 1a171f851..3a328649d 100644
--- a/src/mbgl/renderer/retained_underlay_cache.cpp
+++ b/src/mbgl/renderer/retained_underlay_cache.cpp
@@ -42,6 +42,11 @@ RetainedUnderlayReason retainedReason(const char* reason) noexcept {
     if (value == "style-mutation") return RetainedUnderlayReason::StyleMutation;
     if (value == "layer-mutation") return RetainedUnderlayReason::LayerMutation;
     if (value == "source-mutation") return RetainedUnderlayReason::SourceMutation;
+    if (value == "source-or-global-mutation") return RetainedUnderlayReason::SourceOrGlobalMutation;
+    if (value == "source-not-loaded") return RetainedUnderlayReason::SourceNotLoaded;
+    if (value == "source-fading") return RetainedUnderlayReason::SourceFading;
+    if (value == "missing-source") return RetainedUnderlayReason::MissingSource;
+    if (value == "unknown-dependency") return RetainedUnderlayReason::UnknownDependency;
     if (value == "tile-mutation") return RetainedUnderlayReason::TileMutation;
     if (value == "image-mutation") return RetainedUnderlayReason::ImageMutation;
     if (value == "glyph-mutation") return RetainedUnderlayReason::GlyphMutation;
@@ -177,6 +182,7 @@ RetainedUnderlayDecision RetainedUnderlayCache::evaluate(const std::optional<Ret
         return RetainedUnderlayDecision::Disabled;
     }
     if (runtimeState && !runtimeState->isEnabled()) {
+        lastInvalidationReason = "runtime-disabled";
         ++fallbackCount;
         runtimeState->recordFallback();
         particle::incrementRendererDebugCounter(particle::RendererDebugCounter::RetainedUnderlayFallback);
diff --git a/src/mbgl/renderer/retained_underlay_runtime_state.hpp b/src/mbgl/renderer/retained_underlay_runtime_state.hpp
index 408cc5618..495371ec4 100644
--- a/src/mbgl/renderer/retained_underlay_runtime_state.hpp
+++ b/src/mbgl/renderer/retained_underlay_runtime_state.hpp
@@ -9,6 +9,7 @@
 #include <atomic>
 #include <mutex>
 #include <set>
+#include <string_view>
 #include <tuple>
 #include <utility>
 
@@ -45,6 +46,11 @@ enum class RetainedUnderlayReason : uint8_t {
     StyleMutation,
     LayerMutation,
     SourceMutation,
+    SourceOrGlobalMutation,
+    SourceNotLoaded,
+    SourceFading,
+    MissingSource,
+    UnknownDependency,
     TileMutation,
     ImageMutation,
     GlyphMutation,
@@ -75,6 +81,11 @@ inline const char* retainedUnderlayReasonText(RetainedUnderlayReason reason) noe
         case RetainedUnderlayReason::StyleMutation: return "style-mutation";
         case RetainedUnderlayReason::LayerMutation: return "layer-mutation";
         case RetainedUnderlayReason::SourceMutation: return "source-mutation";
+        case RetainedUnderlayReason::SourceOrGlobalMutation: return "source-or-global-mutation";
+        case RetainedUnderlayReason::SourceNotLoaded: return "source-not-loaded";
+        case RetainedUnderlayReason::SourceFading: return "source-fading";
+        case RetainedUnderlayReason::MissingSource: return "missing-source";
+        case RetainedUnderlayReason::UnknownDependency: return "unknown-dependency";
         case RetainedUnderlayReason::TileMutation: return "tile-mutation";
         case RetainedUnderlayReason::ImageMutation: return "image-mutation";
         case RetainedUnderlayReason::GlyphMutation: return "glyph-mutation";
@@ -226,18 +237,11 @@ public:
                 entry.layers.assign(next.styleLayers.begin() + segment.beginIndex,
                                     next.styleLayers.begin() + segment.endExclusive);
             }
-            std::set<std::string> dependentSourceIds;
-            std::set<std::string> unknownDependencies;
-            for (const auto& layer : entry.layers) {
-                if (layer.sourceId) dependentSourceIds.insert(*layer.sourceId);
-                if (layer.layerType == "symbol") {
-                    unknownDependencies.insert("symbol/glyph/image/placement");
-                } else if (layer.layerType == "custom" || layer.layerType == "custom-drawable") {
-                    unknownDependencies.insert("custom");
-                }
-            }
-            entry.dependentSourceIds.assign(dependentSourceIds.begin(), dependentSourceIds.end());
-            entry.unknownDependencies.assign(unknownDependencies.begin(), unknownDependencies.end());
+            const auto dependencies = renderSegmentDependencies(next.styleLayers,
+                                                                  segment.beginIndex, segment.endExclusive);
+            entry.dependentSourceIds = dependencies.sourceIds;
+            entry.unknownDependencies = dependencies.globalPrerequisites;
+            if (dependencies.unknown) entry.unknownDependencies.push_back("unknown/source-or-custom");
             if (segment.strategy == RenderSegmentStrategy::Retained) {
                 ++next.retainedSegmentCount;
                 entry.cache.emplace();
@@ -308,6 +312,19 @@ public:
         entry.cache->cacheState = retainedRangeCacheStateText(state);
         entry.cache->contentRevision = contentRevision;
     }
+    void recordSegmentExecution(uint32_t index, bool sourceReady, bool sourceStable,
+                                bool supported, uint64_t sourceRevision,
+                                const char* decision, const char* fallbackReason) {
+        updateSegmentCache(index, [&](auto& value) {
+            value.sourceReady = sourceReady;
+            value.sourceStable = sourceStable;
+            value.supported = supported;
+            value.sourceRevision = sourceRevision;
+            value.finalDecision = decision;
+            if (fallbackReason) value.lastFallbackReason = fallbackReason;
+            if (std::string_view(decision) == "fallback") ++value.fallbackCount;
+        });
+    }
     void recordSegmentBuild(uint32_t index) { updateSegmentCache(index, [](auto& value) { ++value.build; }); }
     void recordSegmentReuse(uint32_t index) { updateSegmentCache(index, [](auto& value) { ++value.reuse; }); }
     void recordSegmentInvalidation(uint32_t index, RetainedUnderlayReason reason) {
diff --git a/test/renderer/retained_underlay_cache.test.cpp b/test/renderer/retained_underlay_cache.test.cpp
index f3b4fda75..7f966e786 100644
--- a/test/renderer/retained_underlay_cache.test.cpp
+++ b/test/renderer/retained_underlay_cache.test.cpp
@@ -957,6 +957,7 @@ TEST(RenderSegmentDiagnostics, ReadinessSnapshotMapsSourcesToSegmentsWithoutSide
     state.recordRenderSegmentResolution(resolved, layers);
     state.recordSegmentBuild(0);
     state.recordSegmentCacheState(0, RetainedRangeCacheState::Ready, 41);
+    state.recordSegmentExecution(0, true, true, true, 17, "reuse", nullptr);
 
     RendererReadinessDiagnostics readiness;
     readiness.styleLoaded = true;
@@ -1029,6 +1030,8 @@ TEST(RenderSegmentDiagnostics, ReadinessSnapshotMapsSourcesToSegmentsWithoutSide
     ASSERT_TRUE(second.segments[0].cache);
     EXPECT_EQ(second.segments[0].cache->build, cacheBuild);
     EXPECT_EQ(second.segments[0].cache->contentRevision, 41u);
+    EXPECT_EQ(second.segments[0].cache->sourceRevision, 17u);
+    EXPECT_EQ(second.segments[0].cache->finalDecision, "reuse");
     const auto third = state.renderSegmentSnapshot();
     EXPECT_EQ(third.topologyRevision, second.topologyRevision);
     EXPECT_EQ(third.contentRevision, second.contentRevision);
@@ -1041,6 +1044,109 @@ TEST(RenderSegmentDiagnostics, ReadinessSnapshotMapsSourcesToSegmentsWithoutSide
     EXPECT_NE(json.find("\"incompleteTileCount\":1"), std::string::npos);
     EXPECT_NE(json.find("\"dependentSourceIds\":[\"dynamic\"]"), std::string::npos);
     EXPECT_NE(json.find("\"affectedSegmentIndices\":[1]"), std::string::npos);
+    EXPECT_NE(json.find("\"sourceRevision\":17"), std::string::npos);
+}
+
+TEST(RenderSegmentLocality, SourceRevisionsAreScopedAndRecreationUsesNewIdentity) {
+    const std::vector<StyleLayerDiagnostics> layers{
+        {0, "background", "background", true, std::nullopt, std::nullopt},
+        {1, "a0", "fill", true, "a", std::nullopt},
+        {2, "b", "circle", true, "b", std::nullopt},
+        {3, "a1", "line", true, "a", std::nullopt}};
+    const auto r0 = renderSegmentDependencies(layers, 0, 2);
+    const auto r1 = renderSegmentDependencies(layers, 2, 3);
+    const auto r2 = renderSegmentDependencies(layers, 3, 4);
+    const auto sourceLess = renderSegmentDependencies(layers, 0, 1);
+    EXPECT_EQ(r0.sourceIds, std::vector<std::string>({"a"}));
+    EXPECT_EQ(r2.sourceIds, r0.sourceIds);
+    EXPECT_TRUE(sourceLess.sourceIds.empty());
+    RenderSegmentRevisionBook book;
+    book.advanceSource("a");
+    book.advanceSource("b");
+    const auto beforeA = book.revisionFor(r0);
+    const auto beforeB = book.revisionFor(r1);
+    const auto beforeA2 = book.revisionFor(r2);
+    const auto beforeSourceLess = book.revisionFor(sourceLess);
+    book.advanceSource("a");
+    EXPECT_NE(book.revisionFor(r0), beforeA);
+    EXPECT_NE(book.revisionFor(r2), beforeA2);
+    EXPECT_EQ(book.revisionFor(r1), beforeB);
+    EXPECT_EQ(book.revisionFor(sourceLess), beforeSourceLess);
+    const auto beforeRecreate = book.revisionFor(r0);
+    book.advanceSource("a"); // removal
+    book.advanceSource("a"); // recreation with the same ID
+    EXPECT_NE(book.revisionFor(r0), beforeRecreate);
+    book.advanceGlobal(); // image, glyph, style, context or unknown mutation
+    EXPECT_NE(book.revisionFor(r1), beforeB);
+    EXPECT_NE(book.revisionFor(sourceLess), beforeSourceLess);
+    const auto unknown = renderSegmentDependencies(
+        {{0, "custom", "custom", true, std::nullopt, std::nullopt}}, 0, 1);
+    EXPECT_TRUE(unknown.unknown);
+    EXPECT_FALSE(book.revisionFor(unknown));
+    const auto symbol = renderSegmentDependencies(
+        {{0, "label", "symbol", true, "a", std::nullopt}}, 0, 1);
+    EXPECT_FALSE(symbol.unknown);
+    EXPECT_EQ(symbol.sourceIds, std::vector<std::string>({"a"}));
+    EXPECT_EQ(symbol.globalPrerequisites,
+              std::vector<std::string>({"symbol/glyph/image/placement"}));
+}
+
+TEST(RenderSegmentLocality, ReadinessAndFadeFollowOnlyDependencies) {
+    const RenderSegmentDependencies r0{{"static"}, {}, false};
+    const RenderSegmentDependencies r1{{"dynamic"}, {}, false};
+    const auto lookup = [](bool dynamicLoaded, bool dynamicFading) {
+        return [=](const std::string& id) -> std::optional<RenderSegmentSourceStatus> {
+            if (id == "static") return RenderSegmentSourceStatus{true, false};
+            if (id == "dynamic") return RenderSegmentSourceStatus{dynamicLoaded, dynamicFading};
+            return std::nullopt;
+        };
+    };
+    EXPECT_TRUE(assessRenderSegmentSources(r0, lookup(false, false)).stable);
+    EXPECT_FALSE(assessRenderSegmentSources(r1, lookup(false, false)).ready);
+    EXPECT_TRUE(assessRenderSegmentSources(r0, lookup(true, true)).stable);
+    const auto fading = assessRenderSegmentSources(r1, lookup(true, true));
+    EXPECT_TRUE(fading.ready);
+    EXPECT_FALSE(fading.stable);
+    EXPECT_STREQ(fading.reason, "source-fading");
+    EXPECT_FALSE(assessRenderSegmentSources({{"missing"}, {}, false}, lookup(true, false)).ready);
+    EXPECT_FALSE(assessRenderSegmentSources({{}, {}, true}, lookup(true, false)).ready);
+}
+
+TEST(RenderSegmentLocality, MixedExecutionDrawsEachLiveRangeOnceInStyleOrder) {
+    ResolvedRenderSegmentPlan plan;
+    plan.valid = true;
+    plan.layerCount = 5;
+    plan.segments = {{0, RenderSegmentStrategy::Retained, std::nullopt, 0, 1},
+                     {1, RenderSegmentStrategy::Continuous, std::nullopt, 1, 3},
+                     {2, RenderSegmentStrategy::Retained, std::nullopt, 3, 5}};
+    std::vector<std::string> events;
+    visitRenderSegmentExecution(plan,
+        [](uint32_t index) { return index == 0; },
+        [&](uint32_t index) { events.push_back("composite:" + std::to_string(index)); },
+        [&](int32_t begin, int32_t end) {
+            for (auto i = begin; i < end; ++i) events.push_back("live:" + std::to_string(i));
+        });
+    EXPECT_EQ(events, (std::vector<std::string>{"composite:0", "live:1", "live:2", "live:3", "live:4"}));
+    events.clear();
+    plan.valid = false;
+    visitRenderSegmentExecution(plan, [](uint32_t) { return true; },
+        [&](uint32_t) { ADD_FAILURE() << "invalid plan composite"; },
+        [&](int32_t begin, int32_t end) {
+            for (auto i = begin; i < end; ++i) events.push_back("live:" + std::to_string(i));
+        });
+    EXPECT_EQ(events.size(), 5u);
+}
+
+TEST(RenderSegmentLocality, FailedBuildCannotReuseOldTexture) {
+    RetainedUnderlayCache cache;
+    const auto viewportKey = key();
+    EXPECT_EQ(cache.evaluate(viewportKey, 7, true), RetainedUnderlayDecision::Build);
+    cache.markBuildSucceeded();
+    EXPECT_EQ(cache.evaluate(viewportKey, 7, true), RetainedUnderlayDecision::Reuse);
+    EXPECT_EQ(cache.evaluate(viewportKey, 8, true), RetainedUnderlayDecision::Build);
+    cache.markBuildFailed("resource-or-compositor");
+    EXPECT_FALSE(cache.isValid());
+    EXPECT_EQ(cache.evaluate(viewportKey, 8, true), RetainedUnderlayDecision::Build);
 }
 
 TEST(RenderSegmentPlan, StrictJSONRejectsUnknownFieldsStrategyAndInvalidFirstBoundary) {
diff --git a/tools/particle_android_validation/build_validation_apk.sh b/tools/particle_android_validation/build_validation_apk.sh
index f1c915560..f0fb382a4 100755
--- a/tools/particle_android_validation/build_validation_apk.sh
+++ b/tools/particle_android_validation/build_validation_apk.sh
@@ -99,7 +99,7 @@ unzip -tq "$SOURCE_APK" >/dev/null || fail "APK ZIP integrity check failed."
 ABI_LIST="$(unzip -Z1 "$SOURCE_APK" | sed -n 's#^lib/\([^/]*\)/.*#\1#p' | sort -u | tr '\n' ' ' | sed 's/ $//')"
 [[ "$ABI_LIST" == "x86_64" ]] || fail "Unexpected APK ABI set: [$ABI_LIST]"
 
-LIB_BYTES="$(unzip -l "$SOURCE_APK" 'lib/x86_64/libmaplibre.so' | awk '/lib\/x86_64\/libmaplibre\.so$/ {print $1; exit}')"
+LIB_BYTES="$(unzip -l "$SOURCE_APK" 'lib/x86_64/libmaplibre.so' | awk '/lib\/x86_64\/libmaplibre\.so$/ {print $1}')"
 [[ -n "$LIB_BYTES" ]] || fail "lib/x86_64/libmaplibre.so not found in APK."
 
 APK_BYTES="$(wc -c < "$SOURCE_APK" | tr -d ' ')"
diff --git a/粒子开发记录.md b/粒子开发记录.md
index 960bda9c8..17b31242b 100644
--- a/粒子开发记录.md
+++ b/粒子开发记录.md
@@ -1032,3 +1032,13 @@ Android V3-08 单次综合验收已完成并关闭。Native `13.4.1-particle.2`
 - T4 证实 dependency diagnostics 能正确给动态 source `affected=[2]`，但 global contentRevision 1760→2540，R0 虽只依赖 `step099-static`，cache build 仍 1→121、invalidation 20→200，确认 `GLOBAL_CONTENT_REVISION`。源码审计同时确认 global fade/update signature/pending/placement/repaint/annotation/singleContinuous 等 fast-path gate 仍存在。
 - Q1～Q7 与 blocker 分类已闭合：runtime confirmed `PERMANENT_SOURCE_UNLOADED`、`DYNAMIC_SOURCE_READINESS_THRASH`、`GLOBAL_CONTENT_REVISION`；source confirmed `GLOBAL_FADE`、`GLOBAL_UPDATE_SIGNATURE`。
 - 完成报告：`docs/报告/STEP-099_RenderSource就绪与RenderSegment失效诊断_Codex完成报告_v1.md`；Step：`docs/50_Step记录/STEP-099_RenderSource就绪与RenderSegment失效诊断_v1.md`；运行证据保存在忽略目录 `artifacts/maplibre-particle/android-validation/`。
+
+### 2026-10-06 STEP-100 SourceScoped RenderSegment 局部失效（CLOSED / PASS）
+
+- 基于 `c4b481fd2c5b5da20d31f6ae54011f0552d7dbd0`，Codex `gpt-6-sol / high` 实现 source-scoped revision、production/diagnostics 共用 dependency、per-segment loaded/fading/readiness 以及独立 Build/Reuse/Fallback；global loaded/content revision 与 Fast Path gate 保持原兼容语义。
+- RDC 标准 Android x86_64 OpenGL validation build PASS，APK 61,956,640 bytes，`libmaplibre.so` 39,636,472 bytes，SHA-256 `86e22bf081bf7d3196f0bf0e7c56af51bde01e9f0b01e0bab238cb794273315a`。RDC 同时修复 validation script 在 `pipefail` 下的 `unzip | awk ... exit` SIGPIPE/141，小修不改变产物校验语义。
+- FZG1-2 T4 R-C-R 约 61.6 秒主窗口：global revision 128→973；R0 build 1→1、invalidation 20→20、reuse 132→4042、source revision 不变；R1 build 5→135、invalidation 26→211。动态 source 持续 `affected=[2]`，核心 locality 硬门槛 PASS。
+- T2 双 GeoJSON 约 35 秒仍产生 6 个约 203ms loaded false window，但 R0 build/invalidation 不变；T3 unrelated permanently-unready RasterArray 使 global loaded=false 持续 21.468s，但 R0/R1 build=1、invalidation=19 不变，reuse 11→1200，证明无关 source 不再拖垮 retained cache。
+- T4 运行期间 R1 fallback count 增长而 R0 fallback 不变、reuse 持续增长，实际验证 mixed `R0 Reuse + C Live + R1 Fallback`。未发现 crash/ANR。Fast Path、`singleContinuousSegment`、multi-continuous 语义未改。
+- Native host GTest 因当前 Intel Mac 缺 `libuv` 环境阻塞；尝试 Homebrew 安装时发现会连带升级 CMake/OpenSSL/Python 且 Intel 无 bottle 支持，已停止，未把环境阻塞虚报 PASS。Android full native build + device runtime 作为本 Step 功能验收事实。Jest 未运行。
+- Step：`docs/50_Step记录/STEP-100_SourceScoped_RenderSegment局部失效_v1.md`；完成报告：`docs/报告/STEP-100_SourceScoped_RenderSegment局部失效_Codex完成报告_v1.md`；运行证据在忽略目录 `artifacts/maplibre-particle/android-validation/`。允许进入 V18 unified release。