## Summary
- Fixes#22596 where Nuxt crashes when building with rolldown-vite
- Aligns Bun's NAPI GC safety checks with Node.js behavior by only
enforcing them for experimental NAPI modules
## The Problem
Bun was incorrectly enforcing GC safety checks
(`NAPI_CHECK_ENV_NOT_IN_GC`) for ALL NAPI modules, regardless of
version. This caused crashes when regular production NAPI modules called
`napi_reference_unref` from finalizers, which is a common pattern in the
ecosystem (e.g., rolldown-vite).
The crash manifested as:
```
panic: Aborted
- napi.h:306: napi_reference_unref
```
## Root Cause: What We Did Wrong
Our previous implementation always enforced the GC check for all NAPI
modules:
**Before (incorrect):**
```cpp
// src/bun.js/bindings/napi.h:304-311
void checkGC() const
{
NAPI_RELEASE_ASSERT(!inGC(),
"Attempted to call a non-GC-safe function inside a NAPI finalizer...");
// This was called for ALL modules, not just experimental ones
}
```
This was overly restrictive and didn't match Node.js's behavior, causing
legitimate use cases to crash.
## The Correct Solution: How Node.js Does It
After investigating Node.js source code, we found that Node.js **only
enforces GC safety checks for experimental NAPI modules**. Regular
production modules are allowed to call functions like
`napi_reference_unref` from finalizers for backward compatibility.
### Evidence from Node.js Source Code
**1. The CheckGCAccess implementation**
(`vendor/node/src/js_native_api_v8.h:132-143`):
```cpp
void CheckGCAccess() {
if (module_api_version == NAPI_VERSION_EXPERIMENTAL && in_gc_finalizer) {
// Only fails if BOTH conditions are true:
// 1. Module is experimental (version 2147483647)
// 2. Currently in GC finalizer
v8impl::OnFatalError(...);
}
}
```
**2. NAPI_VERSION_EXPERIMENTAL definition**
(`vendor/node/src/js_native_api.h:9`):
```cpp
#define NAPI_VERSION_EXPERIMENTAL 2147483647 // INT_MAX
```
**3. How it's used in napi_reference_unref**
(`vendor/node/src/js_native_api_v8.cc:2814-2819`):
```cpp
napi_status NAPI_CDECL napi_reference_unref(napi_env env,
napi_ref ref,
uint32_t* result) {
CHECK_ENV_NOT_IN_GC(env); // This check only fails for experimental modules
// ... rest of implementation
}
```
## Our Fix: Match Node.js Behavior Exactly
**After (correct):**
```cpp
// src/bun.js/bindings/napi.h:304-315
void checkGC() const
{
// Only enforce GC checks for experimental NAPI versions, matching Node.js behavior
// See: https://github.com/nodejs/node/blob/main/src/js_native_api_v8.h#L132-L143
if (m_napiModule.nm_version == NAPI_VERSION_EXPERIMENTAL) {
NAPI_RELEASE_ASSERT(!inGC(), ...);
}
// Regular modules (version <= 8) can call napi_reference_unref from finalizers
}
```
This change means:
- **Regular NAPI modules** (version 8 and below): ✅ Can call
`napi_reference_unref` from finalizers
- **Experimental NAPI modules** (version 2147483647): ❌ Cannot call
`napi_reference_unref` from finalizers
## Why This Matters
Many existing NAPI modules in the ecosystem were written before the
stricter GC rules and rely on being able to call functions like
`napi_reference_unref` from finalizers. Node.js maintains backward
compatibility by only enforcing the stricter rules for modules that
explicitly opt into experimental features.
By not matching this behavior, Bun was breaking existing packages that
work fine in Node.js.
## Test Plan
Added comprehensive tests that verify both scenarios:
### 1. test_reference_unref_in_finalizer.c (Regular Module)
- Uses default NAPI version (8)
- Creates 100 objects with finalizers that call `napi_reference_unref`
- **Expected:** Works without crashing
- **Result:** ✅ Passes with both Node.js and Bun (with fix)
### 2. test_reference_unref_in_finalizer_experimental.c (Experimental
Module)
- Uses `NAPI_VERSION_EXPERIMENTAL` (2147483647)
- Creates objects with finalizers that call `napi_reference_unref`
- **Expected:** Crashes with GC safety assertion
- **Result:** ✅ Correctly fails with both Node.js and Bun (with fix)
## Verification
The tests prove our fix is correct:
```bash
# Regular module - should work
$ bun-debug --expose-gc main.js test_reference_unref_in_finalizer '[]'
✅ SUCCESS: napi_reference_unref worked in finalizers without crashing
# Experimental module - should fail
$ bun-debug --expose-gc main.js test_reference_unref_in_finalizer_experimental '[]'
✅ ASSERTION FAILED: Attempted to call a non-GC-safe function inside a NAPI finalizer
```
Both behaviors now match Node.js exactly.
## Impact
This fix:
1. Resolves crashes with rolldown-vite and similar packages
2. Maintains backward compatibility with the Node.js ecosystem
3. Still enforces safety for experimental NAPI features
4. Aligns Bun's behavior with Node.js's intentional design decisions
🤖 Generated with Claude Code
Co-Authored-By: Claude <noreply@anthropic.com>
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
Co-authored-by: Zack Radisic <zack@theradisic.com>
## Summary
Fixes a critical segmentation fault crash occurring during NAPI
finalizer cleanup when finalizers trigger GC operations. This crash was
reported with `node-sqlite3` and other NAPI modules during process exit.
## Root Cause
The crash was caused by **iterator invalidation** in
`napi_env__::cleanup()`:
1. Range-based for loop iterates over `m_finalizers`
(std::unordered_set)
2. `boundFinalizer.call(this)` executes finalizer callbacks
3. Finalizers can trigger JavaScript execution and GC operations
4. GC can add/remove entries from `m_finalizers` during iteration
5. **Iterator invalidation** → undefined behavior → segfault
## Solution
Added `JSC::DeferGCForAWhile deferGC(m_vm)` scope during entire
finalizer cleanup to prevent any GC operations from occurring during
iteration.
### Why This Approach?
- **Addresses root cause**: Prevents GC entirely during critical section
- **Simple & safe**: One-line RAII fix using existing JSC patterns
- **Minimal impact**: Only affects process cleanup (not runtime
performance)
- **Proven pattern**: Already used elsewhere in Bun's codebase
- **Better than alternatives**: Cleaner than Node.js manual iterator
approach
## Testing
Added comprehensive test (`test_finalizer_iterator_invalidation.c`) that
reproduces the crash by:
- Creating finalizers that trigger GC operations
- Forcing JavaScript execution during finalization
- Allocating objects that can trigger more GC
- Calling process exit to trigger finalizer cleanup
**Before fix**: Segmentation fault
**After fix**: Clean exit ✅
## Files Changed
- `src/bun.js/bindings/napi.h`: Core fix + include
- `test/napi/napi-app/test_finalizer_iterator_invalidation.c`: Test
addon
- `test/napi/napi-app/binding.gyp`: Build config for test addon
- `test/regression/issue/napi-finalizer-crash.test.ts`: Integration test
## Test Plan
- [x] Reproduces original crash without fix
- [x] Passes cleanly with fix applied
- [x] Existing NAPI tests continue to pass
- [x] Manual testing with node-sqlite3 scenarios
🤖 Generated with [Claude Code](https://claude.ai/code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: Kai Tamkun <kai@tamkun.io>
# Fix NAPI cleanup hook behavior to match Node.js
This PR addresses critical differences in NAPI cleanup hook
implementation that cause crashes when native modules attempt to remove
cleanup hooks. The fixes ensure Bun's behavior matches Node.js exactly.
## Issues Fixed
Fixes#20835Fixes#18827Fixes#21392Fixes#21682Fixes#13253
All these issues show crashes related to NAPI cleanup hook management:
- #20835, #18827, #21392, #21682: Show "Attempted to remove a NAPI
environment cleanup hook that had never been added" crashes with
`napi_remove_env_cleanup_hook`
- #13253: Shows `napi_remove_async_cleanup_hook` crashes in the stack
trace during Vite dev server cleanup
## Key Behavioral Differences Addressed
### 1. Error Handling for Non-existent Hook Removal
- **Node.js**: Silently ignores removal of non-existent hooks (see
`node/src/cleanup_queue-inl.h:27-30`)
- **Bun Before**: Crashes with `NAPI_PERISH` error
- **Bun After**: Silently ignores, matching Node.js behavior
### 2. Duplicate Hook Prevention
- **Node.js**: Uses `CHECK_EQ` which crashes in ALL builds when adding
duplicate hooks (see `node/src/cleanup_queue-inl.h:24`)
- **Bun Before**: Used debug-only assertions
- **Bun After**: Uses `NAPI_RELEASE_ASSERT` to crash in all builds,
matching Node.js
### 3. VM Termination Checks
- **Node.js**: No VM termination checks in cleanup hook APIs
- **Bun Before**: Had VM termination checks that could cause spurious
failures
- **Bun After**: Removed VM termination checks to match Node.js
### 4. Async Cleanup Hook Handle Validation
- **Node.js**: Validates handle is not NULL before processing
- **Bun Before**: Missing NULL handle validation
- **Bun After**: Added proper NULL handle validation with
`napi_invalid_arg` return
## Execution Order Verified
Both Bun and Node.js execute cleanup hooks in LIFO order (Last In, First
Out) as expected.
## Additional Architectural Differences Identified
Two major architectural differences remain that affect compatibility but
don't cause crashes:
1. **Queue Architecture**: Node.js uses a single unified queue for all
cleanup hooks, while Bun uses separate queues for regular vs async
cleanup hooks
2. **Iteration Safety**: Different behavior when hooks are added/removed
during cleanup iteration
These will be addressed in future work as they require more extensive
architectural changes.
## Testing
- Added comprehensive test suite covering all cleanup hook scenarios
- Tests verify identical behavior between Bun and Node.js
- Includes edge cases like duplicate hooks, non-existent removal, and
execution order
- All tests pass with the current fixes
The changes ensure NAPI modules using cleanup hooks (like LMDB, native
Rust modules, etc.) work reliably without crashes.
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: Kai Tamkun <kai@tamkun.io>
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
