[CI Failure Doctor] TypeScript Type Error in close_older_issues.cjs - Accessing .stack on unknown type

[github-actions]

Summary

The CI workflow (run #21219744664) failed due to a TypeScript type safety error in close_older_issues.cjs. The code attempts to access the .stack property directly on a catch clause error variable without a type guard, which TypeScript correctly flags as unsafe.

Failure Details

• Run: #21219744664
• Commit: ff3cdd2
• PR: Clean up smoke trigger label after successful test run #10997 - Clean up smoke trigger label after successful test run
• Trigger: push (main branch)
• Failed Job: js (step: Run tests - typecheck phase)

Root Cause Analysis

TypeScript Error TS18046

close_older_issues.cjs:315:36 - error TS18046: 'error' is of type 'unknown'.

315       core.error(`  Stack trace: ${error.stack || "(not available)"}`);
                                       ~~~~~

Why This Fails

As of TypeScript 4.4+, catch clause variables default to unknown instead of any for better type safety. The code at line 315 attempts to access error.stack without first checking that error is actually an Error object.

Current Code (Line 311-317)

} catch (error) {
  core.info("");
  core.error(`✗ Failed to close issue #${issue.number}`);
  core.error(`  Error: ${getErrorMessage(error)}`);  // ✅ Correct - uses helper
  core.error(`  Stack trace: ${error.stack || "(not available)"}`);  // ❌ Error - direct access
  // Continue with other issues even if one fails
}

Correct Pattern Used in Other Files

All other files in the codebase correctly use type guards:

// create_issue.cjs:537 - instanceof check
core.info(`Error details: ${error instanceof Error ? error.stack : String(error)}`);

// mcp_logger.cjs:44-45 - instanceof check
if (error instanceof Error && error.stack) {
  logger.debug(`${prefix}Stack trace: ${error.stack}`);
}

// safe_inputs_mcp_server_http.cjs:299-300 - 'in' operator check
if ("stack" in error && error.stack) {
  errorLogger.debug(`Stack trace:\n${error.stack}`);
}

Recommended Fix

Option 1: Use instanceof check (recommended)

} catch (error) {
  core.info("");
  core.error(`✗ Failed to close issue #${issue.number}`);
  core.error(`  Error: ${getErrorMessage(error)}`);
  if (error instanceof Error && error.stack) {
    core.error(`  Stack trace: ${error.stack}`);
  }
  // Continue with other issues even if one fails
}

Option 2: Use 'in' operator check

core.error(`  Stack trace: ${"stack" in error && error.stack ? error.stack : "(not available)"}`);

Option 3: Remove stack trace logging (simplest)

// Just remove line 315 - the error message from getErrorMessage() is usually sufficient

Impact

• Severity: Medium (blocks CI, but easy fix)
• Time to Fix: ~5 minutes
• Affected Area: JavaScript test job in CI pipeline

Prevention Strategy

For AI Coding Agents

Add to developer instructions:

## TypeScript Catch Clause Error Handling

**ALWAYS use type guards when accessing error properties in catch clauses:**

```javascript
// ❌ WRONG - TypeScript error TS18046
} catch (error) {
  console.log(error.stack);  // Error: 'error' is of type 'unknown'
}

// ✅ CORRECT - Use instanceof type guard
} catch (error) {
  if (error instanceof Error) {
    console.log(error.stack);
  }
}

// ✅ CORRECT - Use 'in' operator
} catch (error) {
  if ("stack" in error && error.stack) {
    console.log(error.stack);
  }
}

// ✅ CORRECT - Use helper function (preferred in this codebase)
} catch (error) {
  const errorMessage = getErrorMessage(error);  // Handles unknown type safely
  console.log(errorMessage);
}

Pattern used in this codebase:

• Use getErrorMessage(error) helper from error_helpers.cjs for error messages
• Use error instanceof Error check before accessing .stack, .message, or other Error properties
• Always run npm run typecheck before committing JavaScript changes

### Pre-Commit Checklist

```bash
cd actions/setup/js
npm ci
npm run typecheck  # MUST pass
npm test          # MUST pass

Historical Context

This is the first occurrence of this specific error pattern in the repository. The error was introduced as part of PR #10997, which was a large commit (2570 files changed) that appears to include a bulk repository update or merge.

Investigation Metadata

• Pattern: TYPESCRIPT_ERROR_UNKNOWN_TYPE (1st occurrence)
• Investigation Record: /tmp/gh-aw/cache-memory/investigations/2026-01-21-21219744664.json
• Created: 2026-01-21T17:51:25Z

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[github-actions]

🍪 Issue Monster has assigned this to Copilot!

I've identified this issue as a high-priority candidate for automated resolution (priority score: 50.0) and assigned it to the Copilot agent.

Issue: TypeScript Type Error in close_older_issues.cjs
Priority: Bug + CI Failure
Fix Area: JavaScript error handling with type guards

The Copilot agent will analyze the issue and create a pull request with the fix.

Om nom nom! 🍪

AI generated by Issue Monster

[github-actions]

🔄 Duplicate CI Failure Detected

Run: #21221935467
Commit: ff4f141
Trigger: push (main branch)
Failed Job: js (step: Run tests - typecheck phase)

Same Error Pattern

close_older_issues.cjs(315,36): error TS18046: 'error' is of type 'unknown'.

Context

This is the same TypeScript type error reported in the original issue. The problem persists from commit ff3cdd2 to ff4f141, indicating that the fix from issue #11063 has not yet been applied.

Status

• ✅ Root cause already identified in issue description above
• ✅ Fix options already documented (use instanceof Error type guard)
• ⏳ Awaiting fix implementation

Commit Context

The failing commit is from PR #11070 - "chore: campaign discovery via label-based approach", which appears to be a large merge/update (similar to the original failing commit). The TypeScript error in close_older_issues.cjs:315 is the same line identified in the original investigation.

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🤖 Duplicate failure detected by CI Failure Doctor

AI generated by CI Failure Doctor