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

[Baranov Victor via llvm-commits]

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@@ -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 \
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vbvictor wrote:

Hi, could you please tell my the script works if a person creates a PR with more than 1 commit, e.g:

1) Person creates PR with 3 commits:
`main -> A -> B -> C`

2) CI premerge check starts and makes `git diff C B` and only check formatting between those 2 commits. But what we want is `git diff C main` to properly check formatting.

I'm trying to make a `clang-tidy` CI job similar to this one and this part doesn't work for me.

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