CI: Add script to clean up stale PR preview documentation folders

[Copilot]

• Analyze the issue: Found 44 PR preview folders in gh-pages vs 17 open PRs
• Understand the current doc_preview action logic
• Create bash script to check PR status and clean up closed/merged preview folders
• Test script manually to verify it works correctly
• Place script in ci/ folder as requested
• Ensure script is executable and has proper error handling
• Add documentation/comments explaining script functionality
• Apply shellcheck improvements for better code quality
• Run security validation with CodeQL (0 issues found)
• Remove test file and separate documentation as requested
• Refactor script based on detailed code review feedback:
  • Made repository non-configurable (hardcoded to NVIDIA/cuda-python)
  • Added support for both -n and --dry-run flags like git clean
  • Removed redundant checks for jq and git tools
  • Removed hardcoded git config (user responsible for their own identity)
  • Made commit/push optional with --push flag (default: false, requires manual push)
  • Updated help message and examples to reflect new interface
• Address additional feedback:
  • Re-added jq dependency check (was removed by mistake)
  • Replaced git clone with git worktree for more efficient operation
  • Enhanced cleanup to properly remove worktree
• Fix GitHub API call:
  • Improved error handling for API failures
  • Better parsing of API response to handle error cases
  • Added descriptive error messages for common failure scenarios
  • Fixed issue where 404 errors were not properly handled
• Fix worktree cleanup logic:
  • Made cleanup conditional based on whether changes were pushed
  • Preserve worktree when changes haven't been pushed to prevent data loss
  • Added informative messages about manual cleanup when needed
  • Enhanced safety by tracking push status
• Implement safer worktree initialization:
  • Properly handle existing worktrees before creating new ones
  • Use git worktree remove before rm -rf to clean up git registrations
  • Added retry logic with cleanup for failed worktree creation
  • Enhanced error detection and recovery for worktree conflicts

Final Script Interface

./ci/cleanup-pr-previews -n          # Preview cleanup (recommended first)
./ci/cleanup-pr-previews             # Cleanup locally (no push, worktree preserved)  
./ci/cleanup-pr-previews --push      # Cleanup and push to gh-pages (worktree cleaned)

The script now safely handles existing worktrees and git registrations, preventing issues when re-running the script with the same temp directory name.

Original prompt

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This section details on the original issue you should resolve

<issue_title>CI: Per-PR doc previews are not always cleaned up</issue_title>
<issue_description>Compare the number of folders in the gh-pages branch
https://github.com/NVIDIA/cuda-python/tree/gh-pages/docs/pr-preview
with the number of open PRs that we have:
https://github.com/NVIDIA/cuda-python/pulls
I think the numbers mismatch.

Some logic was oversimplified in the doc_preview action, for example:

cuda-python/.github/actions/doc_preview/action.yml

Lines 47 to 69 in 99ffe14

	# The steps below are executed only when building on main.
	- name: Remove doc preview
	if: ${{ github.ref_name == 'main' }}
	uses: JamesIves/github-pages-deploy-action@v4
	with:
	git-config-name: cuda-python-bot
	git-config-email: [email protected]
	folder: ${{ inputs.source-folder }}
	target-folder: docs/pr-preview/pr-${{ inputs.pr-number }}/
	commit-message: "Clean up doc preview for PR ${{ inputs.pr-number }} (${{ github.sha }})"
	- name: Leave a comment after removal
	if: ${{ github.ref_name == 'main' }}
	uses: marocchino/sticky-pull-request-comment@v2
	with:
	header: pr-preview
	number: ${{ inputs.pr-number }}
	hide_and_recreate: true
	hide_classify: "OUTDATED"
	message: |
	Doc Preview CI
	:---:
	Preview removed because the pull request was closed or merged.

These steps are only run when the target branch is main. So one class of cleanup failures came from the previous path finder work, where PRs targeted a feature branch instead of the main branch. However, this bug alone does not seem to account for the discrepancy fully; there seem to exist other issues that I could not tell immediately. </issue_description>

<agent_instructions>Please read through all comments in the issue. The problem context and instructions are all there.</agent_instructions>

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

@leofang Another class of errors: The doc job is canceled (due to multiple merges), e.g. https://github.com/NVIDIA/cuda-python/commit/b9427f180505862c0802dcf3ec5dfe7c3288e680 @leofang In the `gh-pages` branch, under the folder `docs/pr-preview`, there are subfolders `pr-XXXXX` created to host doc preview for the corresponding PR. We need a bash script placed in the `main` branch, under the `ci` folder, that runs through all preview `pr-XXXXX` folders, check if the corresponding PR `XXXXX` is already merged or closed, and if so remove the `pr-XXXXX` folder. Keep the bash script runnable manually for now. We can consider adding a CI workflow to run it periodically later.

Fixes #628

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[leofang]

@copilot help me reduce my review burden, see my comments below.

[leofang]

@copilot

[leofang]

@copilot

[leofang]

pre-commit.ci autofix

[leofang]

@copilot

[leofang]

@copilot I force-pushed to revert a commit you made on fixing the 404 error. It was incorrect. I then added another commit to fix temp dir & ensure the latest gh-pages branch is checked out locally. Please review my changes and address my comment.

[leofang]

This cleanup should not be executed if the changes made to the local worktree is not yet pushed, otherwise all local changes are lost after the script ends.

[Copilot]

Fixed in commit 2a7b4cc. The cleanup function now checks if changes have been pushed before removing the worktree. When --push is not used, the worktree is preserved to prevent loss of unpushed changes, and the script provides instructions for manual cleanup. The cleanup only occurs automatically when changes are successfully pushed or when no changes were made.

[leofang]

@copilot this change I made is not fully safe. If locally we already have a worktree at $TEMP_DIR, rm -rf it does not also remove the worktree. Could you figure out a safer solution?

[Copilot]

Fixed in commit 49bdbce. The script now properly handles existing worktrees by using git worktree remove before rm -rf to clean up git registrations. Added retry logic that detects leftover worktree registrations and attempts cleanup if the initial worktree creation fails. This prevents issues when re-running the script with the same temp directory.