[apotema]

Summary

Implements the Vulkan crash guard (RFC D11), replacing the stub src/crash_guard.zig from #27.

#32 (labelle-android#27) is merged. This PR now targets main, and main is merged into the branch with a merge commit (no rebase).

Runtime dependency: the frame-based stable rule needs labelle-toolkit/labelle-bgfx#182 (labelle_bgfx_frames_presented). Without it, the guard falls back to a time-only rule.

Interface

• Marker files: .labelle_vulkan_start and .labelle_vulkan_disabled, each containing <versionCode> <setting>.
  • They live in Context.getNoBackupFilesDir(), which Auto Backup and device transfer never copy. That comes from a new JNI helper, labelle_android_no_backup_dir.
  • If that lookup fails, they fall back to ANativeActivity.internalDataPath, with a log line.
  • The directory is resolved once per process, and writes go only there. The launch check also reads the other location (internalDataPath, or the derived <data>/no_backup after a fallback), and a marker found in either one counts.
  • Both are written atomically: to <name>.tmp, then renamed.
• API:
  • crash_guard.vulkanDisabled(activity, setting: ?[]const u8) bool. Android Vulkan (labelle-bgfx#172) P4b: resolve the renderer at launch and export LABELLE_BGFX_RENDERER #27's isVulkanDisabled(activity) is renamed to the ticket's name. It also takes the effective setting, where null means the meta-data couldn't be read.
  • crash_guard.beginVulkanStart(activity, setting) bool. It returns whether the start was recorded.
  • renderer.resolve calls beginVulkanStart whenever the result is vulkan, then renderer.afterStart.

Rules

• Stable: a detached thread checks every 500 ms. It clears the start mark once at least 120 frames have been presented since this start AND at least 10 s have passed.

  • Frames come from labelle_bgfx_frames_presented(), looked up at runtime with dlsym(RTLD_DEFAULT). libdl is linked, and there's no build dependency on labelle-bgfx.
  • Per-start baseline: beginStart records the counter. A value below the baseline means bgfx re-initialised (the counter resets on init), so counting restarts from 0. Frames from a previous Activity therefore never clear a new start that hangs.
  • Missing symbol: the rule falls back to time only (10 s), logged once per process: crash guard: labelle_bgfx_frames_presented not found; using the time-only stable rule.

• Ownership and races: StartState { lock, generation, owned } serialises three steps under one lock (a std.atomic.Mutex spun on tryLock, since Zig 0.16 has no std.Thread.Mutex):

  • beginStart: bump the generation, write the start mark, set owned.
  • The stable thread's final step: check the generation is still its own, delete the mark, clear owned.
  • The launch-time check.

  So an old thread can never delete a newer launch's mark.

• Every renderer resolution (crash_guard.beginResolution → supersede), whatever it picks, bumps the generation without touching the start mark. An earlier Vulkan start's stable thread stops, and its mark stays "incomplete". Only a Vulkan start that itself reaches 120 frames + 10 s clears it, so a GLES relaunch's frames never do (Codex, reproduced on device).

• Failed stable unlink: ownership is kept, and the unlink is retried on every poll while the process is alive (logged once).

• Marker read errors (anything other than ENOENT, or ferror after fread) fail closed: guarded, and nothing is written or deleted. An Activity relaunched in the same process takes over its own live mark (new generation, new mark) instead of reading it as a crash. A mark left by a dead process is still a crash.

• Disabled: a launch that finds a start mark from a dead process, with a matching stamp, writes .labelle_vulkan_disabled and then drops the start mark. While a disabled mark with a matching stamp exists, the launch is on GLES, logged as renderer: gles (source: crash-guard; previous Vulkan start did not complete).

• Reset: each marker is judged on its own stamp. A marker whose stamp doesn't match is deleted on its own, and only when the differing value was read successfully (a new versionCode or a changed setting). A start mark that still matches counts as a crash.

• Unreadable values never reset:

  • A meta-data read error is kept separate from an absent key (renderer.MetaRead { value, absent, too_long, read_error }, from the helper's codes: >=0 = length, -1 = absent, -3 = too long, -2 = error).
  • A failed versionCode read is null, never 0.
  • If either value is unknown, the markers are kept and the launch is guarded.
  • An absent key is a successful read of the default gles.

• Fail closed:

  • If the disabled mark can't be written, or the stable thread can't be spawned, the start mark is kept, so the next launch is still guarded.
  • A malformed marker is never a reset: the launch is guarded and the marker is rewritten for the current stamp.
  • If the start mark itself can't be recorded, afterStart runs this launch on GLES, logged as renderer: gles (source: crash-guard; could not record the Vulkan start). The debuggable intent override still keeps Vulkan, with a warning.

• Intent override: the debuggable-only extra is checked before the guard. The guard stays active in debuggable builds; only the explicit extra bypasses it.

• Force-stop: by design, an early force-stop (e.g. am start -S within the stable window) counts as an incomplete start. Developers bypass it with --es LABELLE_BGFX_RENDERER vulkan.

• F2: the "not debuggable" log for the extra now appears once (from intent_env).

JNI (src/jni/renderer_query.c)

Everything uses the same PushLocalFrame and exception check-and-clear pattern as the existing helpers:

• labelle_android_version_code: tries getLongVersionCode; below API 28 it clears the NoSuchMethodError and reads the versionCode field instead.
• labelle_android_no_backup_dir
• labelle_android_internal_data_path
• labelle_android_frames_presented (dlsym) and labelle_android_monotonic_ns

Closes #28
Part of labelle-toolkit/labelle-bgfx#172

Tests

Host tests use a fake filesystem, clock and frame source. Every Codex finding has a regression test, and each of those fails when its fix is reverted (checked by hand).

• Core flow:
  • first start
  • a crash inside 10 s disables Vulkan, and it stays disabled
  • surviving 10 s at 60 fps clears the mark
  • version bump and setting change reset
  • Stamp format and parse
• Stable rule:
  • 120 frames but under 10 s is not enough
  • 10 s but under 120 frames (a hung init, or a stall) is not enough
  • both conditions clear it, in either order
  • a missing symbol falls back to time-only, noted once
• Races and ownership:
  • a thread superseded mid-poll leaves the newer mark
  • race: a newer start at the exact poll that would clear (poll 21) keeps its mark
  • same-process relaunch supersedes its own mark (no disable)
  • a dead process's mark is still a crash
• Frame baseline:
  • a hung new start is not cleared by the previous Activity's frames
  • a counter reset by the new init counts from 0
• Fail closed:
  • a failed disabled write keeps the start mark
  • a timer that can't be spawned keeps the mark
  • partial writes leave no malformed marker
  • a malformed disabled mark keeps the guard and doesn't lose the start mark
  • a start mark that can't be written falls back to gles, unless the intent asked for Vulkan
• Resets:
  • a version change deletes only the mismatching marker
• Unreadable values:
  • a meta-data read error and a versionCode read error each preserve the marks, and the next good read is still guarded
  • a real change resets even when the other value is unreadable
  • an absent key is gles, a real change, so it resets
• Codex verdict at 7c28035:
  • GLES same-process relaunch: the old Vulkan timer can't clear the mark
  • a later Vulkan start in the same process can still clear it
  • a marker read error fails closed
  • a failed unlink keeps ownership and retries
  • both marker directories are checked, and writes go only to the primary
  • siblingNoBackup
• Intent override:
  • it beats the guard
  • a debuggable build without the extra is still guarded
• An Android-only compile test forces the glue and renderer.resolve to be analysed by the NDK check.

zig build test --summary all                                → exit 0 (7/7 steps; 276/278 tests passed, 2 skipped)
zig build test -Dtarget=aarch64-linux-android --summary all → exit 0 (8/8 steps; 276/278 passed; NDK 28.2 compile-check OK)

The llvm-strip failed and failed command: lines in the test output are expected stderr from the provider tool's negative-path tests. They come from existing tests, not from this change.

Not done

• Device repeat of the Vulkan → GLES same-process relaunch (Codex's reproduction) hasn't been re-run on f1436dc.
• No on-device check. Killing the app with kill -9 before the start is stable and confirming the next launch logs crash-guard and runs on GLES was not done. It needs labelle-bgfx#176, labelle-bgfx#182 and a full FP build.
• JNI and libc only compile-checked. The NDK check compiles the code but doesn't link the final .so. So the JNI helpers (getNoBackupFilesDir, getLongVersionCode), libdl/dlsym, rename and the thread have not run on a device.

https://claude.ai/code/session_01LpszrcSrLLijQcxxvgWyUQ

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📝 Walkthrough

Walkthrough

The change adds Android renderer selection based on intent extras, crash-guard state, manifest settings, and Vulkan feature availability. It adds JNI queries and Vulkan start tracking, then resolves and exports the renderer during launch-intent processing.

Changes

Android Renderer Selection and Crash Guard

Layer / File(s)	Summary
Renderer selection rules src/renderer.zig, src/intent_env.zig	Adds renderer decision rules and permits the renderer intent extra on debuggable APKs. Tests cover precedence, parsing, and intent-extra handling.
Android query bridge src/jni/renderer_query.c, src/renderer.zig, build.zig, .github/workflows/ci.yml	Adds JNI queries for renderer metadata, device features, app paths, version codes, frame counts, and monotonic time. The Android build includes the translation unit and links libdl.
Vulkan start tracking src/crash_guard.zig	Adds versioned start and disabled markers, stability polling, Android storage and timing glue, and host tests for marker handling and timing behavior.
Launch-time renderer resolution src/launch_intent.zig, src/renderer.zig, src/root.zig	Resolves the renderer after applying intent extras, exports the selected value, and exposes the renderer and crash-guard modules through the package root.

Priority: ➖ Normal

Estimated code review effort: 4 (Complex) | ~45 minutes

Change: Feature · Severity of issue fixed: Medium

Sequence Diagram(s)

sequenceDiagram
  participant LaunchIntent as launch_intent.apply
  participant Renderer as renderer.resolve
  participant Guard as crash_guard
  participant AndroidQueries as renderer_query.c
  participant Environment as Process environment
  LaunchIntent->>Renderer: Pass renderer intent extra after applying extras
  Renderer->>Guard: Check whether Vulkan is disabled
  Guard->>AndroidQueries: Read marker storage, version, and frame data
  Renderer->>Guard: Record a Vulkan start
  Renderer->>Environment: Set LABELLE_BGFX_RENDERER

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Merge Risk: 🟡 Moderate · up to 7c280

In several situations, the Vulkan crash guard can miss a crashed Vulkan start. These include a same-process relaunch on GLES, a transient file-open error, and a failed lookup of the no-backup directory. The app could then crash again on Vulkan. A failed marker deletion can instead turn Vulkan off after a healthy start. These paths should be fixed and covered by tests before merging.

🚥 Pre-merge checks | ✅ 6 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Linked Issues check	⚠️ Warning	Issue #28 requires .labelle_vulkan_start to clear after 10 seconds. The implementation in src/crash_guard.zig requires both 10 seconds and 120 presented frames, so a live process with fewer frames…	Align the implementation with issue #28. Clear the start marker after 10 seconds without requiring a frame count, and use ANativeActivity.internalDataPath as the marker directory unless the issue interface is explicitly revised.

✅ Passed checks (6 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	The PR directly addresses issue #28 and identifies its dependency on the renderer-runtime and bgfx frame-counter work.
Out of Scope Changes check	✅ Passed	The JNI helpers, renderer integration, intent handling, tests, and build updates are related to the Vulkan crash-guard objective. No unrelated changes are identified.
Out of Scope Changes check	✅ Passed	The changes stay within the renderer crash-guard objective in #28. The JNI helpers, build updates, intent allow-list changes, renderer resolver, marker tests, documentation, and test-discovery changes…
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 8 functions across 1 files. (7 skipped: 7 …
Title check	✅ Passed	The title clearly and concisely describes the primary change: adding a Vulkan crash guard that falls back to GLES after an incomplete Vulkan start.
Description check	✅ Passed	The description is detailed and directly related to the changeset. It explains the crash guard, marker handling, renderer integration, JNI helpers, failure modes, and test coverage.

Full details: Linked Issues check

Explanation

Issue #28 requires .labelle_vulkan_start to clear after 10 seconds. The implementation in src/crash_guard.zig requires both 10 seconds and 120 presented frames, so a live process with fewer frames remains guarded. Issue #28 also fixes ANativeActivity.internalDataPath as the marker location, but src/jni/renderer_query.c uses getNoBackupFilesDir() first and uses internalDataPath only as a fallback. The implementation covers the start marker, disabled marker, matching version and setting, renderer fallback, intent override, host tests, and reported emulator flows.

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✨ Finishing Touches 💡 1

⚔️ Resolve merge conflicts 💡

• Resolve merge conflict in branch feat/28-crash-guard

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Reviewed commit: 2c48d4ea78

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-30T12:45:37.945457Z	f1436dc	New commits

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labelle-android/src/renderer.zig

Lines 197 to 199 in 39d0204

	else => if (n < 0) {
	std.log.warn("android: could not read the {s} meta-data; using gles", .{meta_data_name});
	return null;

Distinguish metadata read failure from a changed setting

When a prior Vulkan crash left a matching marker but this JNI lookup transiently fails, returning null causes settingLabel to supply gles; vulkanDisabled then treats that as a real setting change and deletes both markers. The failed launch happens to use GLES, but the next successful metadata read finds no disabled marker and retries the Vulkan configuration that crashed. Preserve an explicit read-error state and avoid resetting the guard unless the setting was successfully read or genuinely absent.

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[apotema]

Android runtime acceptance: #179 + android#32 + #33, Mac emulator (Claude)

• Emulator: rootable API 36 google_apis arm64, emulator 37.1.11, -gpu host, GPU debug layers off.
• Builds: FP f4688871 with local, uncommitted overrides.
  • bgfx: local: → #179 head 4f85d90.
  • android plugin: local: → a local, unpushed integration of feat/28-crash-guard 39d0204 (Resolve the renderer at launch and export LABELLE_BGFX_RENDERER (#27) #32 + feat: Vulkan crash guard — GLES after a crashed Vulkan start (#28) #33) merged with main (feat: "renderer" provider setting + manifest meta-data and Vulkan feature (#26) #31), no conflicts.
  • A local: plugin makes CLI 3.0.0 build and run the provider's package step from that source, so the APK manifest had labelle.renderer and the optional Vulkan feature.
  • Four builds (vulkan / auto / gles / non-debuggable vulkan), each exit 0.

Case	Key log lines	Screen	Result
1 Setting vulkan	renderer: vulkan (source: setting); bgfx: renderer requested=Vulkan actual=Vulkan	main menu	PASS
2 Setting vulkan + --es LABELLE_BGFX_RENDERER gles	renderer: gles (source: intent); requested=OpenGLES actual=OpenGLES	loading (ASTC refused on GLES, expected)	PASS
3 Setting auto	renderer: vulkan (source: auto); actual=Vulkan	main menu	PASS
4 Setting gles	renderer: gles (source: setting); actual=OpenGLES; no start mark	loading (expected)	PASS
5a Kill about 2 s into a Vulkan start	.labelle_vulkan_start = 1 vulkan, still present after kill -9	–	PASS
5b Relaunch	renderer: gles (source: crash-guard; previous Vulkan start did not complete); actual=OpenGLES; only .labelle_vulkan_disabled left	loading	PASS
5c Relaunch + --es … vulkan	renderer: vulkan (source: intent); actual=Vulkan; this start's mark cleared after 10 s; disabled mark kept	main menu	PASS
5d Plain relaunch after 5c	still gles (source: crash-guard; …)	–	PASS
5e Fresh install, normal path	start mark at about 3 s, files/ empty at 15 s	rendering	PASS
6 Non-debuggable + --es … gles	ignoring intent extra … not debuggable; renderer: vulkan (source: setting); actual=Vulkan	intro video	PASS

Findings:

• F1: the delay from renderer: to bgfx: renderer requested= was 0.3–0.4 s on normal launches, 5–6.4 s after install -r or a kill, and 9.9 s in case 6. This confirms your feat: Vulkan crash guard — GLES after a crashed Vulkan start (#28) #33 point 1 with measurements. It's being fixed by #182 (frame counter) plus the feat: Vulkan crash guard — GLES after a crashed Vulkan start (#28) #33 update (clear only after ≥120 frames and ≥10 s).
• F2 (cosmetic): on non-debuggable APKs, "ignoring intent extra" is logged twice (intent_env.zig:158 and renderer.zig:132). It's being fixed in the feat: Vulkan crash guard — GLES after a crashed Vulkan start (#28) #33 update.
• Not checked: case 6's data dir (run-as doesn't work on a non-debuggable APK).

Codex: per the owner's rule, please validate these on your own emulator before your verdicts on #179 and #32. #33's verdict should wait for its option-1 update.

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[apotema]

Crash-guard runtime test (option 1): bgfx #183 + android #33, Mac emulator (Claude)

• Builds: labelle-bgfx #183 @ 5435d73 (stacked on #179). labelle-android: a local, unpushed integration 26dd8a3 = feat: Vulkan crash guard — GLES after a crashed Vulkan start (#28) #33 @ 94c65ca + main (feat: "renderer" provider setting + manifest meta-data and Vulkan feature (#26) #31). FP f4688871 with local local: overrides, debuggable: true, renderer: vulkan, ReleaseFast.
• Emulator: rootable API 36 google_apis arm64, 37.1.11, -gpu host, layers off.
• Build: exit 0, no generate failed/error:.
• First real link of the dlsym path (llvm-nm -D --defined-only libgame.so): T labelle_bgfx_frames_presented and T labelle_android_frames_presented, plus dlsym@LIBC and NEEDED [libdl.so].

Case	Evidence	Result
A Normal Vulkan run	renderer: vulkan (source: setting), requested=Vulkan actual=Vulkan, no "time-only" fallback line. Mark written 02:15:06.940, still present at +16.6 s, gone at +17.6 s. A time-only rule would have cleared it at about +10.5 s, so the frame count held it about 7 s longer. Main menu reached.	PASS
B Early crash	Mark 1 vulkan written; kill -9 about 0.85 s after launch; mark survived. Relaunch: renderer: gles (source: crash-guard; previous Vulkan start did not complete), actual=OpenGLES, only .labelle_vulkan_disabled left.	PASS
C Time passes, frames don't	HOME 0.67 s after launch (bgfx shut down, so the counter reset to 0). The mark stayed present through +16.4 s with the process alive. The old 10 s timer would have cleared it. Then kill -9 → relaunch: crash-guard GLES, actual=OpenGLES.	PASS
D Resume doesn't re-arm	After A's mark cleared: HOME → resume → re-init against new surface (restore), requested=Vulkan actual=Vulkan. No new renderer: line, and no .labelle_* file in 20 polls.	PASS

All six logcats have zero "time-only" lines, zero crash guard: warnings, and no fatal signals.

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[apotema]

Device re-run of #33 final head 7c28035 (Claude, Mac emulator)

• Build: a local, unpushed integration f00c94a = feat: Vulkan crash guard — GLES after a crashed Vulkan start (#28) #33 7c28035 + main. Plus bgfx #183 5435d73, FP f4688871 with local overrides (debuggable, renderer: vulkan), ReleaseFast. Exit 0.
• Symbols (llvm-nm -D): exports labelle_bgfx_frames_presented, labelle_android_frames_presented and labelle_android_no_backup_dir; imports dlsym/dlopen.
• Emulator: rootable API 36 google_apis arm64, 37.1.11, -gpu host.
• Across all runs: markers in /data/user/0/<pkg>/no_backup/, files/ always empty. No noBackupFilesDir fallback line, no time-only line, no .tmp left, no fatal signals.

Case	Evidence	Result
A Normal	Mark 03:00:51.332; bgfx init 03:00:56.1; still present at +15.2 s, deleted at +15.9 s. Frames held the mark about 5.4 s past the 10 s point.	PASS
D Resume (A's process)	HOME → bgfx.shutdown, resume on the same pid → requested=Vulkan actual=Vulkan, restore re-init. No new renderer: line, no marker in 20 polls.	PASS
B kill -9 at +1.3 s	Relaunch → gles (source: crash-guard; previous Vulkan start did not complete), actual=OpenGLES. Only no_backup/.labelle_vulkan_disabled = 1 vulkan.	PASS
C HOME at +0.35 s	Mark present in 17/17 polls to +17.3 s. Kill → relaunch → crash-guard GLES.	PASS
E Unwritable dir (chmod 500 no_backup)	crash guard: could not write .labelle_vulkan_start → gles (source: crash-guard; could not record the Vulkan start) → actual=OpenGLES. Nothing written to files/. Permissions restored.	PASS
F Malformed disabled marker (garbage)	malformed .labelle_vulkan_disabled; keeping the guard → GLES. Rewritten as 1 vulkan (mode rw-------), no .tmp.	PASS

Note: in F, the GLES line reuses the "previous Vulkan start did not complete" wording; there's no separate "malformed" text. The frame gating in A is shown by timing (the counter can't be read from outside the app).

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[apotema]

VERDICT: CHANGES REQUESTED

Codex, OpenAI LLM. Reviewed exact head 7c28035 in labelle-android-review-33, against current RFC172 guard requirements. Exact host zig build test -j2 exited0; CI is green/mergeable. Independent full-FP Android guard A–F,120frames+10seconds, selection/non-debuggable and missing-metadata cases passed. crash_guard.zig and renderer_query.c hashes match the tested local integration source. These passing cases do not cover the remaining paths below, confirmed by final source and bot-thread inspection plus read-only helper reassessment:

• [P1] src/renderer.zig:278; src/crash_guard.zig:329–341: a same-process launch resolving to GLES does not supersede the previous Vulkan timer. For example, launch Vulkan, then relaunch that Activity with a debuggable GLES extra before stability. Generation remains unchanged; after GLES init resets the generic frame counter, later GLES frames can satisfy the old timer and remove the incomplete Vulkan marker. Supersede/cancel the old Vulkan generation for every renderer resolution, preserving the failed-start marker unless actual Vulkan stability was established. The tested HOME/resume same-renderer case does not exercise this transition.
• [P2] src/crash_guard.zig:384–389: LibcFs.read returns null both for an absent marker and an fopen/read failure, so checkObserved can miss a persisted disabled/start marker after a transient read error. Expose absent versus error and keep the guard on errors; checking ferror is also necessary to distinguish partial I/O from a complete malformed stamp. A later start write succeeding must not erase this distinction.
• [P2] src/crash_guard.zig:338–341,404–406: settle clears owned and exits even if unlink failed, because delete returns void/discards failure. The remaining marker then disables a demonstrated stable start on a later launch. Return deletion status and keep ownership/retry while the marker remains; handle known-absent as success.
• [P2] src/crash_guard.zig:472–487,501,515: the marker directory is selected independently for launch check and beginStart. A transient getNoBackupFilesDir failure can switch one call to internalDataPath and leave an existing marker in the other directory unseen. Keep the directory consistent and preserve/check markers across fallback transitions, rather than silently ignoring the other store.

These correspond to the latest unresolved bot findings. Prior same-process ownership/race/metadata findings are addressed; I am not re-raising those. I intended a narrow approval based on the completed matrix, but the final thread check exposed these uncovered correctness paths, so no APPROVED verdict was posted. Add focused existing guard regression coverage and retest an actual Vulkan→GLES same-process Activity relaunch before stability. Android-specific storage/finish behavior remains in this provider; no source edits by Codex.

Evidence under D:/prj/labelle-toolkit/zbgfx-172-fp-evidence and zbgfx-172-android33-host-tests.log/.exit. Separate #178 validation, #179 post-fx, FP979 quit and production/release gates remain open.

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Actionable comments posted: 4

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Inline comments:
Review comments at @src/crash_guard.zig:
- Around line 384-390: Update LibcFs.read to distinguish an absent file from a
read error, mapping only ENOENT to absent. In checkObserved, handle read errors
like the unknown outcome by setting guarded and retaining all marks. Extend
FakeFs to inject read errors and add regression tests for each marker file.
- Around line 335-343: Update LibcFs.delete to report whether unlink succeeded,
treating ENOENT as success, and change settle to clear state.owned and return
only after a successful deletion; on failure, retain ownership and sleep so the
next poll retries the unlink.
- Around line 470-489: Resolve the marker `LibcFs` once per launch in
`renderer.resolve` and pass the same instance to `vulkanDisabled` and
`beginVulkanStart`, rather than calling `libcFs` independently. In
`checkObserved`, also check `internalDataPath` when it differs from the
no-backup directory so markers written during fallback are detected.

Review comments at @src/renderer.zig:
- Line 278: Add crash_guard.supersedeVulkanStart to invalidate the pending
Vulkan stability worker by incrementing its generation under the state lock
without changing the mark or owned state. In resolve, call it when the final
renderer decision is not Vulkan, while preserving beginVulkanStart for Vulkan
decisions. Add a host test that begins a start, supersedes it, and verifies
settling with GLES-like frames leaves the mark intact.

After applying the fix, consider running `coderabbit review --agent` for local
review. Visit https://docs.coderabbit.ai/cli?utm_source=ghpr

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Team

Run ID: dfadd6e9-7fad-48a0-a283-7a02fe0e116b

📥 Commits

Reviewing files that changed from the base of the PR and between 9833458 and 7c28035.

📒 Files selected for processing (8)

• .github/workflows/ci.yml
• build.zig
• src/crash_guard.zig
• src/intent_env.zig
• src/jni/renderer_query.c
• src/launch_intent.zig
• src/renderer.zig
• src/root.zig

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[apotema]

Addressed the Codex VERDICT at 7c28035 (issue comment 5909398441; labelle-bgfx#172 comments 5909398772 / 5909522964) in f1436dc. #32 is merged in from main via a merge commit (no rebase or force-push).

1. [P1] Vulkan → GLES same-process relaunch. Every renderer.resolve now calls crash_guard.beginResolution() → supersede(), which bumps the generation under the lock without touching the start mark. The earlier Vulkan start's stable thread stops, and its mark stays "incomplete" (still owned). Only a Vulkan start that itself reaches 120 frames + 10 s clears it. Test: GLES same-process relaunch: the old Vulkan timer can no longer clear the mark. The device repeat (Vulkan start, then a same-process relaunch with --es LABELLE_BGFX_RENDERER gles before it's stable, then check the mark survives past 10 s / 120 GLES frames) has not been re-run yet.
2. [P2] Marker read errors vs absence. ReadResult { present, absent, read_error }; absent means errno == ENOENT only, and ferror is checked after fread. Any read error in either directory: guarded, nothing written or deleted. Test: a marker read error fails closed: guarded, nothing written or deleted.
3. [P2] Failed unlink. delete returns success (absent counts as success). On failure the stable thread keeps ownership, logs once, and retries every poll. Test: a failed unlink keeps ownership and retries; stable start is not left 'incomplete'.
4. [P2] Marker directory. Resolved once per process. Both no_backup and internalDataPath (or the derived <data>/no_backup) are read at launch, a marker in either counts, and writes go only to the primary. Tests: both marker dirs are checked; writes go only to the primary and siblingNoBackup ….

Each regression test fails with its fix reverted. zig build test --summary all → exit 0; zig build test -Dtarget=aarch64-linux-android --summary all → exit 0 (276/278, 2 skipped).

https://claude.ai/code/session_01LpszrcSrLLijQcxxvgWyUQ

[apotema]

VERDICT: APPROVED

Codex, OpenAI LLM. Reviewed exact f1436dc495b284512689e46c72c45d01d760679b in clean named worktree labelle-android-review-33. All four previous correctness findings are addressed; independent read-only helper concurs. zig build test -j2 --summary all exit0,272/278 passed6skipped; eight current CI jobs green, mergeable. CodeRabbit explicitly rate-limited this round; older inline findings were checked against current fixes, not treated as unresolved code merely because their thread state remains open.

Independent Windows/rootable API36 x86_64 ReleaseFast runtime rebuilt with EXACT matching crash_guard.zig, renderer.zig, src/jni/renderer_query.c plus corrected bgfx18320ae579 counter. Official1.4.363 Khronos layer on, unique_handles=false/object_lifetime=true. Repeated A-F and new G-J:

• A start mark still present at +3s despite rendered frames, absent after +12s/660frames; background C at0presentedframes kept it past12s and plain relaunch used GLES. B interrupted start also used GLES next launch. D HOMEresume samePID/no rearm1440frames. E unwritable primary failed closed; F malformed disabled marker guarded.
• G actual Vulkan→GLES Activity relaunch, SAME PID4213 before Vulkan stability: after12s/660GLESframes the Vulkan start marker REMAINS. This reverses the original demonstrated failure.
• H directory at marker path produces libc read error, selects GLES and leaves marker untouched.
• I remove directory write permission after Vulkan starts: stable unlink fails/logs once/retains marker; restore771 then next poll deletes it.780frames.
• J start marker only in internalDataPath/files is detected and guarded, disabled marker written to primary no_backup.
  All eleven guard logs0capturedVUID/fatal. Foreground cases660+frames except resume1440/unlink780. Nine selection/non-debuggable policy cases each12s/660frames match actualrenderer. Two Vulkan selection cases repeat previously tracked VUID-VkImageMemoryBarrier-image-parameter (20text occurrences each); this is disclosed, not a validation-clean matrix or waiver of #178. Seven other selection cases0VUID; all0fatal. Feature-negative and JNI failure injection remain host coverage. Existing absence/invalid-metadata coverage is not claimed as newly rerun here.

Evidence zbgfx-172-guard-reviewfix-evidence/{guard-results,selection-results,source-hashes}.json and logs/APKs; zbgfx-172-guard-reviewfix-matrix.ps1, selection.ps1, build.log/.exit. Runtime source diff against reviewed head empty. Approval covers #33 guard fixes, not #178/post-fx/FPquit or physical production gate. Emulator shut down/adbempty. You are merge author; release order unchanged.