fix bug #1183 prompt validation

[k-bieniek]

Summary

Fixes prompt validation workflow failures when triggered outside of a pull request context (e.g., workflow_dispatch or push events).

Problem

The validate-prompts workflow assumed github.event.pull_request.base.ref was always set, causing failures when:

• The workflow runs via workflow_dispatch (manual trigger) where base.ref is empty
• git diff exits non-zero when no matching instruction files are found, breaking subsequent steps
• Generate PR comment and Post PR comment steps attempted to post to a PR that does not exist in non-PR runs

Changes

• Fallback base ref: When base.ref is not available (non-PR context), falls back to HEAD^ instead of crashing on an empty BASE_BRANCH
• Error-safe diff: git diff now uses 2>/dev/null || true to prevent step failure when no .md files match
• PR-only comment steps: Generate PR comment and Post PR comment are now gated with github.event_name == 'pull_request' so they are skipped gracefully on non-PR triggers
• Consistent ref variable: BASE_BRANCH env var renamed to BASE_REF; the resolved ref is propagated via step output (base_ref) so later steps handle both branch-name refs (origin/<branch>) and the HEAD^ fallback correctly

Testing

• PR trigger: existing behavior preserved — git fetch + diff against origin/<base> as before
• Manual dispatch / push: workflow now completes without error; comment steps are skipped

Fixes #1183

[isolomatov-gd]

/rosetta review this PR please

[github-actions]

Rosetta Triage Review

Summary: This PR fixes a bug in the validate-prompts.yml workflow where github.event.pull_request.base.ref was used unconditionally, causing failures when the workflow runs outside a pull_request event context (e.g., push or manual dispatch). It also adds a guard on the PR comment steps so they only run during pull_request events.

Findings:

• Fix is correct: The conditional check for github.event.pull_request.base.ref with a HEAD^ fallback properly handles non-PR triggers. The || true on the git diff command prevents pipeline failures when no matching files are found.
• Output wiring: The new base_ref output is correctly threaded from changed-files step to the validation and comment steps — replaces the previously unused BASE_BRANCH env variable.
• PR comment guard: Adding github.event_name == 'pull_request' to the Generate PR comment and Post PR comment conditions is the right fix — these steps require a PR context to post comments.
• Empty PR body: The PR description is blank. For traceability, it should reference what bug #1183 is and briefly describe the root cause and fix.

Suggestions:

• Add a one-paragraph PR description explaining the root cause (workflow triggered outside PR context), the symptom (job failure), and the fix (conditional base ref + event guard).
• Consider whether HEAD^ is the right fallback for all non-PR triggers — on a fresh branch with a single commit or a squash-merge scenario it may produce unexpected diffs. origin/main or origin/${{ github.event.repository.default_branch }} could be a safer fallback if the workflow is triggered by push to non-main branches.
• The 2>/dev/null suppresses errors on the git show call; this is fine since the outer if block already handles the missing-base-version case gracefully.

Automated triage by Rosetta agent

[isolomatov-gd]

/rosetta please update PR description

[github-actions]

Rosetta — PR Description Updated

I've updated the PR description based on the diff analysis. Here's what was added:

Summary: Fixes prompt validation failures when triggered outside a PR context (manual dispatch, push events).

Problem documented:

• github.event.pull_request.base.ref is empty on non-PR triggers, causing git fetch to fail
• git diff could exit non-zero with no matching files, breaking the step
• Comment-posting steps attempted to post to a non-existent PR on non-PR runs

Changes documented:

• Fallback to HEAD^ when base.ref is not set
• git diff with 2>/dev/null || true for graceful no-match handling
• Generate PR comment and Post PR comment gated on github.event_name == 'pull_request'
• BASE_BRANCH → BASE_REF with step-output propagation for consistent ref handling

Automated triage by Rosetta agent

[github-actions]

Rosetta Triage Review

Summary: This PR fixes the validate-prompts GitHub Actions workflow to handle non-PR trigger contexts (e.g., workflow_dispatch, push events) by adding a fallback base ref, suppressing non-zero git diff exit codes, and gating PR comment steps behind an event_name == 'pull_request' condition.

Findings:

• Fix is well-scoped and addresses the root causes clearly: missing base ref, unsafe git diff exit, and unconditional PR comment steps
• Renaming BASE_BRANCH to BASE_REF is semantically accurate since it can now hold either a branch name or HEAD^
• Step output propagation (echo "base_ref=$BASE_REF" >> $GITHUB_OUTPUT) is correct and consistent
• 2>/dev/null || true is the appropriate pattern for suppressing git diff failures when no matching files are found
• PR description clearly explains the problem, changes, and manual test scenarios

Suggestions (optional):

• Minor edge case: the HEAD^ fallback will fail on a repository with only a single commit (no parent). Consider using git rev-parse --verify HEAD^ 2>/dev/null && echo HEAD^ || echo 4b825dc642cb6eb9a060e54bf8d69288fbee4904 or git diff --name-only $BASE_REF 2>/dev/null || true (single-dot) as a further safeguard, though this is unlikely to affect this repo in practice

Automated triage by Rosetta agent