fix: raise errors when unable to locate the previous commit in local history

.github/workflows/test.yml

@@ -37,7 +37,7 @@ jobs:
 
     steps:
       - name: Checkout branch
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+        uses: actions/checkout@v4
       - name: shellcheck
         uses: reviewdog/action-shellcheck@v1.19
 
@@ -46,7 +46,7 @@ jobs:
     outputs:
       files_changed: ${{ steps.changed_files.outputs.files_changed }}
     steps:
-      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+      - uses: actions/checkout@v4
         with:
           persist-credentials: false
           fetch-depth: 0
@@ -123,7 +123,7 @@ jobs:
     if: needs.build.outputs.files_changed != 'true'
     steps:
       - name: Checkout into dir1
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+        uses: actions/checkout@v4
         with:
           repository: ${{ github.event.pull_request.head.repo.full_name }}
           submodules: true
@@ -163,7 +163,7 @@ jobs:
           path: dir2/dist
 
       - name: Checkout into dir2
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+        uses: actions/checkout@v4
         with:
           repository: ${{ github.event.pull_request.head.repo.full_name }}
           submodules: true
@@ -198,7 +198,7 @@ jobs:
 
     steps:
       - name: Checkout branch
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+        uses: actions/checkout@v4
         with:
           repository: ${{ github.event.pull_request.head.repo.full_name }}
           fetch-depth: 0
@@ -256,7 +256,7 @@ jobs:
 
     steps:
       - name: Checkout branch
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+        uses: actions/checkout@v4
         with:
           repository: ${{ github.event.pull_request.head.repo.full_name }}
           fetch-depth: 0
@@ -294,7 +294,7 @@ jobs:
 
     steps:
       - name: Checkout branch
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+        uses: actions/checkout@v4
         with:
           repository: ${{ github.event.pull_request.head.repo.full_name }}
           fetch-depth: 0
@@ -332,7 +332,7 @@ jobs:
 
     steps:
       - name: Checkout branch
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+        uses: actions/checkout@v4
         with:
           repository: ${{ github.event.pull_request.head.repo.full_name }}
           fetch-depth: ${{ matrix.fetch-depth }}
@@ -364,7 +364,7 @@ jobs:
 
     steps:
       - name: Checkout branch
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+        uses: actions/checkout@v4
         with:
           ref: ${{ github.event.pull_request.head.sha }}
 
@@ -396,7 +396,7 @@ jobs:
 
     steps:
       - name: Checkout branch
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+        uses: actions/checkout@v4
         with:
           fetch-depth: ${{ matrix.fetch-depth }}
           persist-credentials: false
@@ -425,7 +425,7 @@ jobs:
 
     steps:
       - name: Checkout branch
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+        uses: actions/checkout@v4
 
       - name: Download build assets
         uses: actions/download-artifact@v3
@@ -479,7 +479,7 @@ jobs:
 
     steps:
       - name: Checkout branch
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+        uses: actions/checkout@v4
 
       - name: Download build assets
         uses: actions/download-artifact@v3
@@ -534,7 +534,7 @@ jobs:
       pull-requests: read
     steps:
       - name: Checkout into dir1
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+        uses: actions/checkout@v4
         with:
           repository: ${{ github.event.pull_request.head.repo.full_name }}
           submodules: true
@@ -570,7 +570,7 @@ jobs:
 
     steps:
       - name: Checkout branch
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+        uses: actions/checkout@v4
         with:
           ref: ${{ github.event.pull_request.head.sha || github.sha }}
           submodules: recursive
@@ -613,7 +613,7 @@ jobs:
 
     steps:
       - name: Checkout branch
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+        uses: actions/checkout@v4
         with:
           ref: ${{ github.event.pull_request.head.sha || github.sha }}
           submodules: recursive
@@ -665,7 +665,7 @@ jobs:
 
     steps:
       - name: Checkout branch
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+        uses: actions/checkout@v4
         with:
           ref: ${{ github.event.pull_request.head.sha || github.sha }}
           submodules: recursive
@@ -805,6 +805,56 @@ jobs:
           else
             cat "deleted_files/test/test deleted.txt"
           fi
+
+  test-since-last-remote-commit:
+    name: Test changed-files since last remote commit
+    runs-on: ubuntu-latest
+    needs: build
+    if: needs.build.outputs.files_changed != 'true'
+    strategy:
+      fail-fast: false
+      max-parallel: 4
+      matrix:
+        fetch-depth: [0, 1, 2]
+
+    steps:
+      - name: Checkout branch
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event.pull_request.head.sha }}
+          repository: ${{ github.event.pull_request.head.repo.full_name }}
+          submodules: true
+          fetch-depth: ${{ matrix.fetch-depth }}
+
+      - name: Download build assets
+        uses: actions/download-artifact@v3
+        with:
+          name: build-assets
+
+      - name: Run changed-files with since_last_remote_commit
+        id: changed-files-since-last-remote-commit
+        continue-on-error: true
+        uses: ./
+        with:
+          since_last_remote_commit: true
+
+      - name: Verify failed
+        if: steps.changed-files-since-last-remote-commit.outcome != 'failure' && matrix.fetch-depth == 1 && github.event_name != 'push'
+        run: |
+          echo "Expected: (failure) got ${{ steps.changed-files-since-last-remote-commit.outcome }}"
+          exit 1
+
+      - name: Verify succeeded
+        if: steps.changed-files-since-last-remote-commit.outcome != 'success' && matrix.fetch-depth != 1
+        run: |
+          echo "Expected: (success) got ${{ steps.changed-files-since-last-remote-commit.outcome }}"
+          exit 1
+
+      - name: Show output
+        run: |
+          echo '${{ toJSON(steps.changed-files-since-last-remote-commit.outputs) }}'
+        shell:
+          bash
 
   test:
     name: Test changed-files
@@ -820,7 +870,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+        uses: actions/checkout@v4
         with:
           submodules: true
           repository: ${{ github.event.pull_request.head.repo.full_name }}
@@ -841,16 +891,6 @@ jobs:
           echo '${{ toJSON(steps.changed-files.outputs) }}'
         shell:
           bash
-      - name: Run changed-files with since_last_remote_commit
-        id: changed-files-since-last-remote-commit
-        uses: ./
-        with:
-          since_last_remote_commit: true
-      - name: Show output
-        run: |
-          echo '${{ toJSON(steps.changed-files-since-last-remote-commit.outputs) }}'
-        shell:
-          bash
       - name: Run changed-files with dir name
         id: changed-files-dir-name
         uses: ./

src/commitSha.ts

@@ -426,8 +426,8 @@ export const getSHAForPullRequestEvent = async (
           github.context.payload.action &&
           github.context.payload.action === 'synchronize'
         ) {
-          core.warning(
-            'Unable to locate the remote branch head sha. Falling back to the previous commit in the local history.'
+          throw Error(
+            'Unable to locate the previous commit in the local history. Please ensure to checkout pull request HEAD commit instead of the merge commit. See: https://github.com/actions/checkout/blob/main/README.md#checkout-pull-request-head-commit-instead-of-merge-commit)'
           )
         } else {
           core.info(