[llvm] [Github] Simplify Getting Changed Files in Code Formatting Workflow (PR #133023)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-github-workflow

Author: Aiden Grossman (boomanaiden154)

<details>
<summary>Changes</summary>

This patch changes getting changed files in the pr code format job to just checking out the previous two commits (the merge commit and its porent, the current commit latest in main), which allows us to just diff the merge commit. This means we do not have to checkout the ref through the merge base, which should save approximately a minute per job (or much more in some cases where the PR is particularly out of date).

---
Full diff: https://github.com/llvm/llvm-project/pull/133023.diff


1 Files Affected:

- (modified) .github/workflows/pr-code-format.yml (+5-10) 


``````````diff
diff --git a/.github/workflows/pr-code-format.yml b/.github/workflows/pr-code-format.yml
index b08e5c21ca62e..2c06c8bdddea6 100644
--- a/.github/workflows/pr-code-format.yml
+++ b/.github/workflows/pr-code-format.yml
@@ -21,14 +21,7 @@ jobs:
       - name: Fetch LLVM sources
         uses: actions/checkout at 11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
-          ref: ${{ github.event.pull_request.head.sha }}
-
-      - name: Checkout through merge base
-        uses: rmacklin/fetch-through-merge-base at bfe4d03a86f9afa52bc1a70e9814fc92a07f7b75 # v0.3.0
-        with:
-          base_ref: ${{ github.event.pull_request.base.ref }}
-          head_ref: ${{ github.event.pull_request.head.sha }}
-          deepen_length: 500
+          fetch-depth: 2
 
       - name: Get changed files
         id: changed-files
@@ -36,6 +29,8 @@ jobs:
         with:
           separator: ","
           skip_initial_fetch: true
+          base_sha: 'HEAD~1'
+          sha: 'HEAD'
 
       # We need to pull the script from the main branch, so that we ensure
       # we get the latest version of this script.
@@ -89,8 +84,8 @@ jobs:
             --write-comment-to-file \
             --token ${{ secrets.GITHUB_TOKEN }} \
             --issue-number $GITHUB_PR_NUMBER \
-            --start-rev $(git merge-base $START_REV $END_REV) \
-            --end-rev $END_REV \
+            --start-rev HEAD~1 \
+            --end-rev HEAD \
             --changed-files "$CHANGED_FILES"
 
       - uses: actions/upload-artifact at 26f96dfa697d77e81fd5907df203aa23a56210a8 #v4.3.0

``````````

</details>


https://github.com/llvm/llvm-project/pull/133023