fix: wrap insertEvent with withRetry for concurrent PostToolUse hooks#243
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When many tool calls complete in parallel (e.g., batch Linear get_issue), Claude Code spawns multiple PostToolUse hooks simultaneously. These all open the same per-project SessionDB and compete for the SQLite write lock. While better-sqlite3's busy_timeout (30s) handles most contention, edge cases during transaction lock escalation can still surface SQLITE_BUSY. This causes hooks to fail, and Claude Code reports "hook error" to users. Changes: - Wrap SessionDB.insertEvent() transaction with withRetry() for defense-in-depth against SQLITE_BUSY under concurrent hook access - Set busy_timeout pragma in BunSQLiteAdapter to match better-sqlite3's timeout option (previously ignored, causing immediate SQLITE_BUSY failures under Bun runtime) - Add concurrent insert test verifying multiple DB instances can write to the same file without data loss
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What / Why / How
What: Wrap
SessionDB.insertEvent()withwithRetry()and propagatebusy_timeoutpragma to Bun's SQLite adapter.Why: When many tool calls complete in parallel (e.g., 16 batch
mcp__linear__get_issuecalls during a standup summary), Claude Code spawns multiple PostToolUse hooks simultaneously. These all open the same per-project SessionDB and compete for the SQLite write lock. While better-sqlite3'sbusy_timeout(30s) handles most contention, edge cases during transaction lock escalation can surfaceSQLITE_BUSY, causing Claude Code to reportPostToolUse:mcp__linear__get_issue hook errorto users.Additionally, the
BunSQLiteAdapterfactory was silently dropping thetimeoutoption passed fromSQLiteBase, meaning Bun runtime had nobusy_timeoutat all — concurrent writes would fail immediately withSQLITE_BUSY.How:
src/session/db.ts— Changedtransaction()tothis.withRetry(() => transaction())ininsertEvent, leveraging the existing retry infrastructure inSQLiteBasesrc/db-base.ts— Addedbusy_timeoutpragma inBunDatabaseFactorywhenopts.timeoutis provided, matching better-sqlite3's automatic behaviorAffected platforms
(The Bun
busy_timeoutfix applies to any platform using Bun runtime for the MCP server. ThewithRetryfix applies to all platforms since PostToolUse hooks run with Node.js.)Test plan
Concurrent Insert Resiliencetest intests/session/session-db.test.ts— opens 5SessionDBinstances against the same DB file and inserts events from each, verifying all 5 events are stored without errorsnpm run typecheckpasses cleanChecklist
npm testpasses (6 pre-existing failures unrelated to this change — security, cursor-hooks, vscode-hooks, session-hooks-smoke, hooks/integration)npm run typecheckpassesnextbranch (unless hotfix)