fix(sqlite-native): restore kv error hook

[NathanFlurry]

Description

Please include a summary of the changes and the related issue. Please also include relevant motivation and context.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[NathanFlurry]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• chore(engine): publish engine bases in ci #4649 : 3 dependent PRs (#4650 , #4652 , #4666 )
• chore: lockfile lefthook #4647
• fix(rivetkit): surface native sqlite kv errors to callers #4645
• fix(rivetkit): prevent sleep races during disconnect and db work #4644
• fix(rivetkit): isolate engine envoys and propagate startup failures #4643
• test(rivetkit): remove wasm sqlite-only fixtures and coverage #4642
• chore(sqlite-vfs): remove wasm sqlite packages and workspace wiring #4641
• chore(rivetkit): remove wasm sqlite runtime #4614
• fix(sqlite-native): restore native startup kv preload #4639
• fix(sqlite-native): delete metadata before chunk range #4638
• fix(sqlite-native): keep truncate cache coherent #4637
• fix(sqlite-vfs): use delete range for truncate cleanup #4636
• fix(sqlite-native): restore kv error hook #4635 👈 (View in Graphite)
• perf(sqlite-native): avoid cloning cached read chunks #4634
• perf(sqlite-native): gate kv operation labels #4633
• perf(sqlite-native): reuse read cache for partial writes #4632
• perf(sqlite-native): remove delete file existence probe #4631
• fix(sqlite-native): gate native read cache behind env var #4630
• fix(pegboard): isolate runner config dc lookup failures #4625 : 1 other dependent PR (#4626 )
• docs(pegboard): note runner config upsert split write risk #4624
• fix(pegboard): unpack global runner config keys correctly #4623
• fix(pegboard-gateway): enforce tunnel message state #4622
• fix(pegboard-runner): clear terminal tunnel routes #4621
• fix(pegboard): skip protocol version keys in runner pool backfill #4620
• fix(pegboard): create missing normal runner configs #4619
• fix(epoxy): reuse cached optimistic value #4618
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[claude]

PR Review: fix(sqlite-native): restore kv error hook

Overview

This PR restores the KV error hook in the native SQLite VFS layer and improves error propagation from native Rust storage failures to the JavaScript layer. The changes enable richer error messages when an actor's KV store becomes unavailable (e.g., during actor shutdown).

---

Positive Changes

• Error propagation chain is well-designed: Rust VFS captures KV error, stores it in VfsContext::last_error, kv_vfs_get_last_error exposes it to SQLite, NativeDatabase::take_last_kv_error exposes it to the NAPI layer, and JS wrapNativeStorageError wraps it with a user-friendly message. Clean layered design.
• notGlobal: config.notGlobal ?? false: Good defensive fix preventing undefined from leaking in place of false.
• read_cache.as_ref().and_then(...) and value.as_deref(): Correctness fixes, presumably needed after read_cache became Option<...>.
• sqlite_error_message helper: Improves open/pragma error messages with the actual SQLite error string instead of just the error code.
• Tracing in on_error: Correctly uses structured tracing::error! per project conventions.

---

Issues and Suggestions

kv_vfs_get_last_error truncation not signalled (vfs.rs)

Per the SQLite VFS spec, xGetLastError should return non-zero when the message is truncated (bytes.len() > max_len). The current implementation always returns 0 even when truncated. Low severity since SQLite treats this as a hint, but worth fixing for spec compliance.

---

Implicit fall-through after wrapNativeStorageError (wrapper.js)

In all three try-catch blocks, wrapNativeStorageError always throws so runtime behavior is correct. However, static analysers see an implicit undefined return after the call. Consider making the never-returning intent explicit by having wrapNativeStorageError return the Error instead of throwing it internally, and using throw wrapNativeStorageError(nativeDb, error) at the call sites.

---

KvVfs::take_last_kv_error missing safety comment (vfs.rs ~line 1270)

The unsafe block dereferences ctx_ptr with no safety comment. A brief comment (e.g. // Safety: ctx_ptr is valid for the lifetime of KvVfs) would follow standard practice for unsafe blocks in this codebase.

---

Clear-on-success could race with JS error handling (vfs.rs)

clear_last_error is called after every successful KV operation. SQLite can internally make cleanup calls after an I/O error, so a KV failure followed by a successful cleanup call erases the error before the JS catch block calls takeLastKvError. The window is small in practice, but it is a real race. Consider only consuming the error at JS exception-catch time rather than clearing it on every success.

---

No tests

The PR checklist leaves the test box unchecked. Given this is a non-trivial error-path change across the Rust/NAPI/JS boundary, a test that triggers a KV failure and asserts the resulting JS error message contains the expected text would be valuable.