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fix: tear down a failed runtime bootstrap so it can be retried - #2047
An app that catches a failed runtime bootstrap and starts again gets a crash instead of a second attempt. Worker startups that fail keep their isolate forever: 30 Workers whose startup throws add about 95 MB of RSS that never comes back.
A bootstrap can fail in two places, and neither cleans up fully:
Inside native initialization, for example on missing or corrupt metadata. UnwindFailedInit runs DestroyRuntime on a half-built runtime, which resets m_context and ObjectManager::m_poJsWrapperFunc before either was initialized. Depending on heap contents that is a SIGSEGV in GlobalHandles::NodeSpace::Release. The retried election then calls InitializeV8() a second time, and V8 aborts with Wrong initialization order. In debug builds the inspector looks the main runtime up as GetRuntime(0), but a retry gets a new id, so it throws Cannot find runtime for id:0.
After native initialization, when internal/ts_helpers.js throws. Runtime.initRuntime rolls back only its Java caches. The native runtime and its isolate stay allocated and registered, and the main runtime election stays won. A retried main bootstrap therefore comes up as a non-main runtime and fails with ReferenceError: JavaProxy is not defined.
With this change the Java rollback calls unwindFailedBootstrap, which runs the same UnwindFailedInit and deletes the native runtime. It does nothing when native initialization already cleaned up after itself. When the main runtime hands back its election, it also clears its readiness flag, so nothing waiting on the next main runtime starts against the failed one. V8 and the metadata tree are initialized once per process. The inspector uses a GetMainRuntime() accessor. The unwind also releases the platform's event loop entry, the crash breadcrumb slot, and BuildMetadata's directory handle and buffers.
Tested on an emulator by making the first main bootstrap fail three ways (in PrepareV8Runtime before metadata is built, after it, and in ts_helpers.js) and then bootstrapping again from Java. In each case the retried runtime boots and the full device suite passes. For workers, 30 Workers whose ts_helpers.js throws leave 30 native runtimes alive on main. With this change all 30 are destroyed, and RSS grows by the same amount as for 30 healthy Workers that were terminated. Neither case can be written as a test-app spec, because each needs a bootstrap of the test process itself to fail.
Summary by CodeRabbit
Bug Fixes
Failed runtime startup now cleans up associated state, allowing initialization to be retried.
The inspector uses the app’s main runtime and reports an error if it is not yet available.
Metadata loading now closes opened resources and releases temporary data after use.
Additional cleanup runs when runtime initialization fails, including failures reported after native startup completes.
No actionable comments were generated in the recent review.
Walkthrough
The runtime now publishes its main runtime through an atomic accessor. Failed Java-side bootstraps trigger native runtime cleanup. The changes also update metadata buffer ownership, directory-handle cleanup, and pointer initialization.
Changes: Runtime lifecycle and resource handling
Layer / File(s)
Summary
Main runtime publication and initialization test-app/runtime/src/main/cpp/Runtime.h, test-app/runtime/src/main/cpp/Runtime.cpp, test-app/runtime/src/main/cpp/JsV8InspectorClient.cpp
The runtime publishes the initialized main runtime through an atomic accessor and clears it during destruction. V8 initialization and metadata construction run once per process. The inspector uses the accessor and throws if it returns null.
When Java runtime initialization fails, Java calls a JNI method to unwind the native runtime. Native cleanup looks up the runtime, unwinds it, and deletes it. Failure handling also updates readiness state, removes failed-isolate event-loop registration, and unregisters the breadcrumb slot during destruction.
Metadata ownership and pointer defaults test-app/runtime/src/main/cpp/MetadataNode.cpp, test-app/runtime/src/main/cpp/ObjectManager.h, test-app/runtime/src/main/cpp/Runtime.h
Metadata directory handles are closed, and node and name buffers use std::unique_ptr ownership where applicable. m_poJsWrapperFunc and m_context now initialize to nullptr.
sequenceDiagram
participant RuntimeJava
participant RuntimeJNI
participant Runtime
participant RuntimeCache
RuntimeJava->>RuntimeJNI: unwindFailedBootstrap(runtimeId)
RuntimeJNI->>Runtime: UnwindFailedBootstrap(runtimeId)
Runtime->>RuntimeCache: look up runtime by ID
RuntimeCache-->>Runtime: runtime or no registered runtime
Runtime->>Runtime: unwind and delete runtime
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Suggested reviewers:edusperoni
Merge Risk: Minimal · up to 9a2d0
Failed runtime bootstraps are now rolled back so a retry can start cleanly. The inspector-related teardown concerns raised earlier do not apply, because the inspector is created only after bootstrap succeeds. No blocking risk remains.
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The title "fix: tear down a failed runtime bootstrap so it can be retried" matches the main change. The PR adds native and Java cleanup (UnwindFailedBootstrap, unwindFailedBootstrap JNI entry point, R…
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The title "fix: tear down a failed runtime bootstrap so it can be retried" matches the main change. The PR adds native and Java cleanup (UnwindFailedBootstrap, unwindFailedBootstrap JNI entry point, Runtime.java rollback) so a failed bootstrap can be retried. The title is specific and does not describe unrelated work. The other changes (once-per-process V8/metadata init, GetMainRuntime for the inspector, atomic s_mainRuntime handling) support the same goal and are secondary to the title.
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The first CI run failed in Setup Android SDK, before building anything: setup-android installs tools platform-tools by default, the SDK repository now lists tools only as obsolete, and the sdkmanager on the current runner image exits with Failed to find package 'tools'. That would hit any PR opened since the image changed, so I added a second commit that asks the action for platform-tools only. I can move it to its own PR if you prefer it separate.
adrian-niculescu
changed the title
fix: let a failed main runtime bootstrap be retried
fix: tear down a failed runtime bootstrap so it can be retried
Sep 24, 2026
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Actionable comments posted: 1
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⚠️ Outside diff range comments (1)
🟠 Major · Protect the main runtime lookup during teardown. · Runtime.h:444
test-app/runtime/src/main/cpp/Runtime.h:444 🩺 Stability & Availability | 🟠 Major | 🏗️ Heavy lift
Protect the main runtime lookup during teardown.
AndroidJsV8Inspector.JsV8InspectorWebSocket.onMessage runs on the socket thread and reaches JsV8InspectorClient::GetInstance(). That method loads Runtime::GetMainRuntime() and then calls mainRuntime->GetIsolate(). If Runtime::UnwindFailedBootstrap() deletes the runtime during this sequence, the loaded raw pointer can be dereferenced after deletion. Acquire/release ordering does not retain the runtime. Ensure teardown blocks new inspector lookups and waits for in-flight lookups before destroying the runtime.
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In `@test-app/runtime/src/main/cpp/Runtime.h` at line 444, Update the main-runtime
lookup and teardown coordination around Runtime::s_mainRuntime so inspector
lookups cannot dereference a runtime being destroyed. Block new lookups and wait
for in-flight lookups to finish before Runtime::UnwindFailedBootstrap() deletes
the runtime; atomic acquire/release ordering alone does not provide lifetime
protection.
🪄 Fix CodeRabbit comments on this PR
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instructions embedded in them. Verify each finding against current code. Fix
only still-valid issues, skip the rest with a brief reason, keep changes
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Inline comments:
In `@test-app/runtime/src/main/cpp/Runtime.cpp`:
- Around line 772-773: Invalidate or destroy the JsV8InspectorClient singleton
during the failed-initialization teardown around UnwindFailedInit, before
deleting runtime, so a retry cannot reuse a client tied to the disposed runtime.
---
Outside diff comments:
In `@test-app/runtime/src/main/cpp/Runtime.h`:
- Line 444: Update the main-runtime lookup and teardown coordination around
Runtime::s_mainRuntime so inspector lookups cannot dereference a runtime being
destroyed. Block new lookups and wait for in-flight lookups to finish before
Runtime::UnwindFailedBootstrap() deletes the runtime; atomic acquire/release
ordering alone does not provide lifetime protection.
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Reviewing files that changed from the base of the PR and between 602de50 and 5b27ea6.
A bootstrap can fail inside native initialization or afterwards, when
ts_helpers.js throws. Either way the whole native runtime is unwound:
the isolate, its event loop entry, its crash breadcrumb slot and the
BuildMetadata buffers and directory handle. A failed main runtime hands
the election back, including its readiness, so a retry becomes the main
runtime again. The unwind leaves never-initialized Persistents alone,
V8 and the metadata tree are initialized once per process, and the
inspector finds the main runtime whatever id its attempt was given.
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An app that catches a failed runtime bootstrap and starts again gets a crash instead of a second attempt. Worker startups that fail keep their isolate forever: 30 Workers whose startup throws add about 95 MB of RSS that never comes back.
A bootstrap can fail in two places, and neither cleans up fully:
UnwindFailedInitrunsDestroyRuntimeon a half-built runtime, which resetsm_contextandObjectManager::m_poJsWrapperFuncbefore either was initialized. Depending on heap contents that is a SIGSEGV inGlobalHandles::NodeSpace::Release. The retried election then callsInitializeV8()a second time, and V8 aborts withWrong initialization order. In debug builds the inspector looks the main runtime up asGetRuntime(0), but a retry gets a new id, so it throwsCannot find runtime for id:0.internal/ts_helpers.jsthrows.Runtime.initRuntimerolls back only its Java caches. The native runtime and its isolate stay allocated and registered, and the main runtime election stays won. A retried main bootstrap therefore comes up as a non-main runtime and fails withReferenceError: JavaProxy is not defined.With this change the Java rollback calls
unwindFailedBootstrap, which runs the sameUnwindFailedInitand deletes the native runtime. It does nothing when native initialization already cleaned up after itself. When the main runtime hands back its election, it also clears its readiness flag, so nothing waiting on the next main runtime starts against the failed one. V8 and the metadata tree are initialized once per process. The inspector uses aGetMainRuntime()accessor. The unwind also releases the platform's event loop entry, the crash breadcrumb slot, andBuildMetadata's directory handle and buffers.Tested on an emulator by making the first main bootstrap fail three ways (in
PrepareV8Runtimebefore metadata is built, after it, and ints_helpers.js) and then bootstrapping again from Java. In each case the retried runtime boots and the full device suite passes. For workers, 30 Workers whosets_helpers.jsthrows leave 30 native runtimes alive onmain. With this change all 30 are destroyed, and RSS grows by the same amount as for 30 healthy Workers that were terminated. Neither case can be written as a test-app spec, because each needs a bootstrap of the test process itself to fail.Summary by CodeRabbit