Implement dry-run mode for workflow updates

[Copilot]

Removes TODO at line 90 in update_command.go and implements --dry-run flag for gh aw update command to preview changes without modifying files.

Changes

Core implementation:

• Thread dryRun parameter through update pipeline: UpdateWorkflowsWithExtensionCheck → UpdateActions → UpdateWorkflows → updateWorkflow
• Skip file writes, compilation, fix execution, and PR creation when dryRun=true
• Display "Would update..." instead of "Updated..." in console output

Display changes:

• Show "Running in dry-run mode - no files will be modified" banner at start
• Modified showUpdateSummary() to display planned vs actual changes based on mode

Tests:

• Added update_dry_run_test.go with three test cases verifying no file modifications occur
• Updated existing test signatures to include dryRun parameter

Example Usage

# Preview what would be updated
gh aw update --dry-run

# Output shows:
# ℹ Running in dry-run mode - no files will be modified
# ℹ Would update actions/checkout from v4 to v4.3.1
# ℹ Would update 1 action(s):
#   • actions/checkout
# ℹ Would update and compile 2 workflow(s):
#   • ci-doctor
#   • test-workflow

Pattern follows existing gh aw fix command which defaults to dry-run unless --write is specified.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[Code Quality] Implement dry-run mode for workflow updates</issue_title>
<issue_description>## Description

The pkg/cli/update_command.go file contains a TODO for implementing dry-run mode for workflow updates (line 90). This feature would allow users to preview what changes would be made before actually updating workflows.

Suggested Changes

Implement dry-run functionality in the update command:

1. Add dry-run logic to UpdateWorkflowsWithExtensionCheck() function
2. When --dry-run is specified:
   • Detect which workflows would be updated
   • Show diff of proposed changes
   • Display update summary without making changes
3. Add tests for dry-run behavior

Files Affected

• pkg/cli/update_command.go (line 90 - remove TODO, implement feature)
• pkg/cli/update_workflows.go (add dry-run support)
• pkg/cli/update_command_test.go (add dry-run tests)

Success Criteria

• gh aw update --dry-run shows proposed changes without modifying files
• Output clearly indicates this is a dry-run (no actual changes)
• All existing update tests pass
• New tests verify dry-run behavior
• Update help text documents the --dry-run flag

Source

TODO comment in pkg/cli/update_command.go:90:

// TODO: Implement dry-run mode for workflow updates
return fmt.Errorf("--dry-run mode not yet implemented for workflow updates")

Priority

Low - Nice-to-have feature for safer workflow updates

AI generated by Discussion Task Miner - Code Quality Improvement Agent

Comments on the Issue (you are @copilot in this section)

• Fixes [Code Quality] Implement dry-run mode for workflow updates #9957

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.