OSV delta generation fix

[ksykulev]

Related issue: Resolves #41571

Changing the way delta artifacts are generated.
changed_files_today.txt and changed_files_yesterday.txt will always look back into git history for any commits added yesterday and today.

• QA'd all new/changed functionality manually

Summary by CodeRabbit

Release Notes

• Bug Fixes
  • Improved repository synchronization to ensure local state accurately reflects the remote main branch.
  • Enhanced file change detection logic for more reliable identification of modified files.
  • Refined output file handling to maintain consistency across synchronization cycles.

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[ksykulev]

@coderabbitai full review

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Full review triggered.

[Copilot]

Pull request overview

Updates the OSV processor sync script to generate “today” and “yesterday” delta artifacts based on commit timestamps (UTC) rather than only comparing the latest fetched SHA, to better support OSV delta generation.

Changes:

• Resets the local ubuntu-security-notices checkout to origin/main during sync.
• Generates changed_files_today.txt and changed_files_yesterday.txt by querying git history for commits within UTC day windows.
• Adds cross-platform handling for “yesterday” date calculation (BSD date -v vs GNU date -d).

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[coderabbitai]

Walkthrough

The script cmd/osv-processor/sync-and-detect-changes.sh was updated to improve repository synchronization and file change detection logic. The changes include adding a hard reset to origin/main after fetching to ensure the local repository matches the remote state, implementing time-based file change detection using git log with --since and --until flags, and ensuring output files for changed files are properly initialized even when no new commits are detected.

Possibly related PRs

• PR #42203: Modifies the same script to handle git reset logic, changed-files generation, and YESTERDAY_UTC computation
• PR #42662: Updates repository sync logic in the same script, including fetch behavior and reset to origin/main

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title 'OSV delta generation fix' directly and clearly summarizes the main change, which involves fixing how delta artifacts are generated for OSV processing.
Description check	✅ Passed	The description adequately explains the change (delta artifact generation method) and includes the related issue number, though it omits most template checklist items appropriate for a script-only change.
Linked Issues check	✅ Passed	The PR changes implement the delta generation mechanism for the OSV cron sync workflow defined in #41571, with the script now properly generating changed_files_today.txt and changed_files_yesterday.txt based on git history.
Out of Scope Changes check	✅ Passed	All changes are confined to cmd/osv-processor/sync-and-detect-changes.sh and directly implement the required delta generation logic; no unrelated modifications are present.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

📝 Generate docstrings

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• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch 41571-osv-cron-fix-2

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@cmd/osv-processor/sync-and-detect-changes.sh`:
- Around line 41-57: The script currently uses bare redirections to create empty
files and then later unconditionally regenerates those same files, causing
redundancy and triggering ShellCheck SC2188; replace the bare redirects with a
POSIX-safe no-op redirect (use ": > \"../changed_files_today.txt\"" and ": >
\"../changed_files_yesterday.txt\"" or equivalent) if you truly need to create
empty placeholders, otherwise remove the entire if/else block that sets/creates
changed_files_today.txt and changed_files_yesterday.txt (and associated
TODAY_UTC/YESTERDAY_UTC logic) so the later unconditional git log generation is
the single source of truth; alternatively, if you want to short-circuit when no
new commits exist, exit the script from the branch before the later
unconditional git log block so the files are not overwritten.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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📥 Commits

Reviewing files that changed from the base of the PR and between e794906 and 9d069e8.

📒 Files selected for processing (1)

• cmd/osv-processor/sync-and-detect-changes.sh

[Copilot]

Pull request overview

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Pull request overview

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Pull request overview

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