Fix

Author: tautschnig

.github/workflows/update-subtree.yml

@@ -132,15 +132,35 @@ jobs:
           echo "MERGE_CONFLICTS=maybe" >> $GITHUB_ENV
         fi
 
+    - name: Create Pull Request to update subtree/library
+      if: ${{ env.MERGE_CONFLICTS != 'noop' && env.SUBTREE_PR_EXISTS == 'no' }}
+      uses: peter-evans/create-pull-request@v7
+      with:
+        title: 'Update subtree/library to ${{ env.NEXT_TOOLCHAIN_DATE }}'
+        body: >
+          This is an automated PR to update the subtree/library branch to the changes
+          from ${{ env.CURRENT_TOOLCHAIN_DATE }} (rust-lang/rust@${{ env.CURRENT_COMMIT_HASH }})
+          to ${{ env.NEXT_TOOLCHAIN_DATE }} (rust-lang/rust@${{ env.NEXT_COMMIT_HASH }}), inclusive.
+
+          **Review this PR as usual, but do not merge this PR using the GitHub web interface.
+          Instead, once it is approved, use `git push` to literally push the changes to `subtree/library`
+          without any rebase or merge.**
+        branch: update-subtree/library
+        delete-branch: true
+        base: subtree/library
+        path: verify-rust-std
+
     - name: Merge subtree/library changes
       if: ${{ env.MERGE_CONFLICTS != 'noop' && env.MERGE_PR_EXISTS == 'no' }}
       run: |
-        # The below must be done before any call to the create-pull-request
-        # action as said action resets branches locally, implying that
-        # `subtree/library` no longer is what the above instructions created.
         cd verify-rust-std
-        if ! git rev-parse --verify subtree/library; then
+        # create-pull-request resets branches locally, implying that
+        # `subtree/library` no longer is what the above instructions created.
+        if [ "${SUBTREE_PR_EXISTS}" = "yes" ]; then
           git checkout -t -b subtree/library origin/update-subtree/library
+        else
+          git checkout subtree/library
+          git reset --hard origin/update-subtree/library
         fi
         git checkout main
 
@@ -173,24 +193,6 @@ jobs:
         git -c user.name=gitbot -c user.email=git@bot \
           commit -m "Update Kani version to ${KANI_COMMIT_HASH}" tool_config/kani-version.toml
 
-    - name: Create Pull Request to update subtree/library
-      if: ${{ env.MERGE_CONFLICTS != 'noop' && env.SUBTREE_PR_EXISTS == 'no' }}
-      uses: peter-evans/create-pull-request@v7
-      with:
-        title: 'Update subtree/library to ${{ env.NEXT_TOOLCHAIN_DATE }}'
-        body: >
-          This is an automated PR to update the subtree/library branch to the changes
-          from ${{ env.CURRENT_TOOLCHAIN_DATE }} (rust-lang/rust@${{ env.CURRENT_COMMIT_HASH }})
-          to ${{ env.NEXT_TOOLCHAIN_DATE }} (rust-lang/rust@${{ env.NEXT_COMMIT_HASH }}), inclusive.
-
-          **Review this PR as usual, but do not merge this PR using the GitHub web interface.
-          Instead, once it is approved, use `git push` to literally push the changes to `subtree/library`
-          without any rebase or merge.**
-        branch: update-subtree/library
-        delete-branch: true
-        base: subtree/library
-        path: verify-rust-std
-
     - name: Create Pull Request without conflicts
       if: ${{ env.MERGE_CONFLICTS == 'no' && env.MERGE_PR_EXISTS == 'no' }}
       uses: peter-evans/create-pull-request@v7