Restack skill

.github/skills/restack/SKILL.md

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+---
+name: restack
+description: Only invoke when explicitly instructed to
+---
+
+You need to "re-stack" your commits to match the following format:
+ * A failing test case
+ * A commit, or series of commits, that fixes the failing test case
+ * (Optional) a follow-up commit that checks in any modified baselines
+
+Since you can't force-push, start with a commit that undoes all your prior changes and gets you back to `main`.
+
+Then add your test case(s) in a single commit.
+A test case isn't necessarily a new file; it could be a modification to an existing test or a change in the test configuration.
+Ensure that at least one test in the full run fails - you might be operating on a bad PR that didn't actually introduce a failing scenario!
+If zero tests failed, abort and post a message explaining what you observed.
+Remember that baseline tests do not "fail" in the traditional sense; they are used to verify that the output matches the expected baseline.
+You should examine the PR description to determine what the desired passing baseline should look like.
+
+Then, add your fix.
+You can break this apart into multiple commits if it's more logical to review that way; use your judgment.
+Ensure that this makes the test pass.
+Again, be mindful of how baselines work - a failed baseline test just means a diff; review that diff for correctness vis a vis the goal of the PR.
+Do not accept baseline diffs yet!
+
+Finally, if there are baseline diffs, commit those in a separate commit.
+
+Ensure that the final diff you have matches the original diff you started with; this process should not introduce any unintended changes.