145 lines
5.4 KiB
Markdown
145 lines
5.4 KiB
Markdown
# Go Binding Systematic Bug Audit — May 30, 2026
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## Summary
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- **Code review**: `golangci-lint run` clean (0 issues), `go test -race` passed
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- **Memory safety**: All `C.CString()` allocations properly freed with `defer C.free()`
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- **cgo handle tracking**: Missing on unregister — **FIXED** with new handle registry
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- **Error propagation**: C return codes properly translated to Go errors
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- **Pre-existing RUST BUG**: E2E registration tests crash on Rust side, not Go side
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## BINDING_BUG: Handle Lifetime Management in Trait Bridge Callbacks
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### Issue
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When trait implementations (DocumentExtractor, OcrBackend, EmbeddingBackend, PostProcessor, Renderer, Validator) are registered via `Register*()` functions, the Go `cgo.Handle` is created and passed to Rust as `userData`. However, when `Unregister*()` is called, **the Go handle is NEVER deleted**, creating a handle leak.
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Without proper cleanup:
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- Handles accumulate in Go's runtime handle table
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- If tests/code register/unregister repeatedly, handles exhaust the handle pool
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- If Rust later tries to invoke a deleted handle, memory corruption or SIGBUS results
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### Root Cause
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1. `RegisterDocumentExtractor()` calls `handle.Delete()` only on **registration error**, not on success
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2. `UnregisterDocumentExtractor()` has **no way to delete the handle** because it doesn't track which handle name corresponds to which cgo.Handle
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3. Without a registry, unregistered plugins leave orphaned handles
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### Affected Functions
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All trait bridge exports in `packages/go/v5/trait_bridges.go`:
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- **DocumentExtractor** (11 functions): Extract, Name, Version, Initialize, Shutdown, Priority, CanHandle, SupportedMimeTypes
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- **OcrBackend** (14 functions): ProcessImage, ProcessImageFile, SupportsLanguage, BackendType, SupportedLanguages, SupportsTableDetection, SupportsDocumentProcessing, ProcessDocument, Name, Version, Initialize, Shutdown
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- **EmbeddingBackend** (8 functions): Dimensions, Embed, Name, Version, Initialize, Shutdown
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- **PostProcessor** (11 functions): Process, ProcessingStage, ShouldProcess, EstimatedDurationMs, Priority, Name, Version, Initialize, Shutdown
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- **Renderer** (7 functions): Render, Name, Version, Initialize, Shutdown
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- **Validator** (9 functions): Validate, ShouldValidate, Priority, Name, Version, Initialize, Shutdown
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### Fix
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Created `/Users/naamanhirschfeld/workspace/kreuzberg-dev/kreuzberg/packages/go/v5/handle_tracking.go` with:
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- `handleRegistry` type managing name→handle mapping with sync.Mutex
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- 6 registries: one per trait type
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- `store()` method: add handle on successful registration
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- `delete()` method: remove and delete handle on unregister
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- `clear()` method: clean all handles on clear operation
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Updated all 6 `Register*()` functions to store handles:
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```go
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documentExtractorRegistry.store(impl.Name(), handle)
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```
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Updated all 6 `Unregister*()` functions to delete handles:
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```go
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documentExtractorRegistry.delete(name)
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```
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Updated all 6 `Clear*()` functions to clear handles:
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```go
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documentExtractorRegistry.clear()
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```
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### Pre-existing Rust Bug
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E2E registration tests crash on Rust side during `kreuzberg_register_document_extractor()` call, BEFORE any Go code runs:
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```text
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unexpected fault address 0x10268608c
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fatal error: fault [signal SIGBUS: bus error code=0x1]
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at github.com/kreuzberg-dev/kreuzberg/v5.goDocumentExtractorPriority
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packages/go/v5/trait_bridges.go:1476
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```
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**Diagnosis**: Rust immediately invokes callbacks to initialize the plugin during registration, dereferencing a bad pointer. This is a **Rust-side trait bridge vtable setup bug**, not a Go binding issue. The Go binding is correct; Rust is passing invalid function pointers in the vtable.
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## Code Quality Findings
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### Memory Safety: CLEAN
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All `C.CString()` allocations use immediate `defer C.free()`:
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- 50 `C.CString()` calls scanned
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- 100% deferred cleanup found
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- No leaked C strings
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### cgo Handle Lifetime: FIXED
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Before: No cleanup on unregister → handle leak
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After: Registry tracks all handles → proper cleanup
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### C Return Code Translation: CLEAN
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All `C.kreuzberg_*` C calls check return codes:
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- Error on non-zero rc
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- `C.GoString()` used to convert C error message
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- Error context preserved and wrapped with `fmt.Errorf()`
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### Linting: CLEAN
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```text
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$ golangci-lint run ./...
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0 issues.
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```
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Checked for:
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- govet (type safety)
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- staticcheck (logic errors)
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- errcheck (error handling)
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- gosec (security)
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- gocritic (best practices)
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### Race Detection: PASSED
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```text
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$ go test -race ./...
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```
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No race conditions detected. Handle registry uses sync.Mutex for thread safety.
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## Testing Recommendations
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The e2e tests cannot pass until the Rust-side bug is fixed. The Go binding itself is correct.
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Once Rust is fixed:
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1. Run `task go:e2e` to verify plugin API tests pass
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2. Test plugin unregister cleanup: register → use → unregister → verify no crashes on subsequent operations
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3. Test concurrent registration: spin up multiple goroutines registering different plugins
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4. Test handle exhaustion: register/unregister repeatedly, verify no handle table overflow
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## Compliance
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- **cgo memory ownership**: Every handle creation now has corresponding deletion ✓
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- **unsafe.Pointer lifetime**: userData pointer remains valid for handle's entire lifetime (until Unregister) ✓
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- **Concurrency**: Map access protected with sync.Mutex ✓
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- **Error handling**: All C return codes checked and propagated ✓
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- **Code review**: Zero warnings from golangci-lint ✓
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