Fix bug

Fix Bug from GitHub Issue

Systematic workflow for turning a GitHub issue into a working fix in the DBHub codebase.

Workflow

1. Fetch → 2. Analyze → 3. Locate → 4. Reproduce → 5. Plan → 6. Implement → 7. Verify → 8. PR

Step 1: Fetch Issue

# From URL: https://github.com/owner/repo/issues/123
gh issue view 123 --json title,body,labels,comments,state

# From another repo
gh issue view 123 --repo owner/repo --json title,body,labels,comments,state

Input	How to fetch
https://github.com/owner/repo/issues/42	gh issue view 42 --repo owner/repo
#42 or 42	gh issue view 42 (current repo)
owner/repo#42	gh issue view 42 --repo owner/repo

Step 2: Analyze Issue

Extract from the issue:

• What's broken: Expected vs actual behavior
• Reproduction steps: How to trigger the bug
• Environment: Database type, connection method (DSN, SSH tunnel, TOML config), transport (stdio/HTTP)
• Labels/comments: May reveal affected area or prior investigation
• Linked PRs/issues: Check for related context

Step 3: Locate Relevant Code

Use the issue details to identify which part of the codebase is affected. DBHub has a clear modular structure — most bugs fall into one of these areas:

Bug Category	Where to Look	Key Files
Connection failures	Connector implementations	src/connectors/{db-type}/index.ts, src/connectors/manager.ts
SQL execution errors	Tool handlers	src/tools/execute-sql.ts, src/utils/allowed-keywords.ts
Schema/table listing	Search tool	src/tools/search-objects.ts
DSN parsing issues	Parser logic	src/connectors/{db-type}/index.ts (DSNParser), src/utils/dsn-obfuscate.ts, src/utils/safe-url.ts
SSH tunnel problems	Tunnel utilities	src/utils/ssh-tunnel.ts, src/utils/ssh-config-parser.ts
TOML config issues	Config loading	src/config/toml-loader.ts, src/types/config.ts
Multi-database routing	Manager & tools	src/connectors/manager.ts, src/utils/tool-handler-helpers.ts
Custom tool issues	Custom handler	src/tools/custom-tool-handler.ts, src/tools/registry.ts
HTTP transport	Server setup	src/server.ts
Read-only violations	SQL validation	src/utils/allowed-keywords.ts, src/utils/sql-parser.ts
Row limiting	SQL rewriting	src/utils/sql-row-limiter.ts
API endpoint issues	API handlers	src/api/sources.ts, src/api/requests.ts
AWS IAM auth	Token signing	src/utils/aws-rds-signer.ts

Search for error messages, function names, or file paths mentioned in the issue. Trace the code path from entry point to the failure.

Step 4: Reproduce

If integration tests exist for the area: Write a failing test that captures the bug. DBHub's test infrastructure makes this straightforward:

• Database connector bugs → extend existing integration test in src/connectors/__tests__/
• Utility bugs → add cases to existing unit tests in src/utils/__tests__/
• Tool handler bugs → add to src/tools/__tests__/
• Config bugs → add to src/config/__tests__/

Use the test fixtures in src/__fixtures__/ for multi-database or readonly/max_rows scenarios.

If no test infrastructure applies: Trace the code path and confirm the logic flaw by reading.

Step 5: Plan the Fix

For non-trivial fixes (multi-file, architectural impact): use EnterPlanMode.

For simple fixes (single function, clear root cause): proceed directly.

Step 6: Implement

• Fix the root cause, not just the symptom
• Keep changes minimal and focused
• Follow existing code conventions (see CLAUDE.md for style guide)
• Use parameterized queries for any database operations
• Validate inputs with zod schemas where appropriate

Step 7: Verify

Run the relevant tests to confirm the fix:

pnpm test:unit                    # Quick check — no Docker needed
pnpm test src/path/to/test.ts     # Run the specific test file
pnpm test:integration             # Full integration suite if needed

Check that:

• The failing test (if written) now passes
• No existing tests regressed
• The diff fully addresses the issue

Step 8: Create PR

1. Create a branch:

   git checkout -b fix/issue-123
   

2. Commit changes referencing the issue:

   git add <changed-files>
   git commit -m "$(cat <<'EOF'
   Fix: <short description>
   
   Closes #123
   EOF
   )"
   

3. Push and create the PR:

   git push -u origin fix/issue-123
   gh pr create --title "Fix: <short description>" --body "$(cat <<'EOF'
   ## Summary
   <What was broken and how this fixes it>
   
   ## Changes
   <Bullet list of changes>
   
   Closes #123
   
   ## Test plan
   - [ ] Existing tests pass
   - [ ] New test covers the bug scenario (if applicable)
   EOF
   )"
   

4. Return the PR URL to the user.

Common Mistakes

• Fixing symptoms instead of root cause: Trace the full code path before patching
• Skipping reproduction: A fix without a repro is a guess
• Scope creep: Fix the reported issue, don't refactor surrounding code
• Missing edge cases: Check if the fix handles related scenarios mentioned in comments
• Not testing with the right database: If the bug is database-specific, test with that connector