From 4e92a46fb71cab92a23b0189dde4b9499fba071a Mon Sep 17 00:00:00 2001
From: Pavel Raiskup <praiskup@redhat.com>
Date: Fri, 6 Sep 2024 11:05:42 +0200
Subject: [PATCH] Rebase the checkout on top of target branch

This change will fail the action in case of rebase conflicts, but it
seems acceptable (the PR can not be merged anyway).  If needed, we may
end-up some implementing some fallback in the future.
---
 action.yml    |  3 +++
 container/cmd | 11 +++++++++--
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/action.yml b/action.yml
index 4f383e2..8fe7442 100644
--- a/action.yml
+++ b/action.yml
@@ -47,3 +47,6 @@ outputs:
 runs:
   using: docker
   image: docker://quay.io/copr/vcs-diff-lint:latest
+  env:
+    INPUT_PULL_REQUEST_ID: ${{ github.event.pull_request.number }}
+    INPUT_PULL_REQUEST_HEAD: ${{ github.event.pull_request.head.sha }}
diff --git a/container/cmd b/container/cmd
index 7173ad7..936d717 100755
--- a/container/cmd
+++ b/container/cmd
@@ -24,7 +24,7 @@ is_true() {
 }
 
 if is_true "$INPUT_DEBUG" || is_true "$RUNNER_DEBUG"; then
-    ( echo "== GitHub ENV VARS ==" ; env | grep ^GITHUB ) >&2
+    ( echo "== GitHub ENV VARS ==" ; env | grep -e ^GITHUB -e ^INPUT_ ) >&2
     set -x
 fi
 
@@ -76,7 +76,14 @@ if test "$GITHUB_EVENT_NAME" = 'pull_request'; then
     git config --global advice.detachedHead false
     git config --global init.defaultBranch main
 
-    git fetch origin "$target_branch:$target_branch" &>/dev/null
+    (
+        echo "## Rebasing $INPUT_PULL_REQUEST_HEAD onto $target_branch ##"
+        is_true "$INPUT_DEBUG" || exec &>/dev/null
+        git fetch origin "$target_branch:$target_branch"
+        git fetch origin "+$INPUT_PULL_REQUEST_HEAD:refs/remotes/pull-requests/pr-detached-$INPUT_PULL_REQUEST_ID"
+        git checkout "$INPUT_PULL_REQUEST_HEAD"
+        git rebase "origin/$target_branch"
+    )
 
     test -z "$INPUT_SUBDIRECTORY" || INPUT_SUBDIRECTORIES=$INPUT_SUBDIRECTORY
     test -z "$INPUT_SUBDIRECTORIES" && INPUT_SUBDIRECTORIES=.