[CI] Change cached_checkout's bool merge param to merge_ref (inte…

…l#10333)

I plan to use the extra level of explicit control to lock in build and
e2e-tests steps in pre-commit in the next PR.

.github/workflows/linux_matrix_e2e_on_nightly.yml

@@ -53,7 +53,7 @@ jobs:
       ref: ${{ inputs.ref }}
       reset_gpu: ${{ matrix.reset_gpu }}
       # TODO: should we do the merge?
-      merge: false
+      merge_ref: ''
 
   aws_start:
     name: AWS Start
@@ -77,7 +77,7 @@ jobs:
       ref: ${{ inputs.ref }}
       reset_gpu: false
       # TODO: should we do the merge?
-      merge: false
+      merge_ref: ''
 
   aws_stop:
     name: AWS Stop

.github/workflows/linux_single_e2e.yml

@@ -19,8 +19,12 @@ on:
         type: string
       reset_gpu:
         type: string
-      merge:
+      merge_ref:
+        description: |
+          Commit-ish to merge post-checkout if non-empty. Must be reachable from
+          the default_branch input paramter.
         type: string
+        default: 'FETCH_HEAD'
 
       sycl_toolchain_artifact:
         type: string
@@ -61,10 +65,10 @@ jobs:
       with:
         path: llvm
         ref: ${{ inputs.ref }}
+        merge_ref: ${{ inputs.merge_ref }}
         # We run build and HIP E2E tests under different users on the same
         # runners, so need to use distinct cache paths.
         cache_path: "/__w/repo_cache_e2e/"
-        merge: ${{ inputs.merge }}
     - name: Install drivers
       if: env.compute_runtime_tag != ''
       run: |

.github/workflows/sycl_linux_build_and_test.yml

@@ -78,10 +78,12 @@ on:
         description: 'Filter matches for the changed files in the PR'
         default: '[llvm, clang, sycl, llvm_spirv, xptifw, libclc, libdevice]'
         required: false
-      merge:
-        description: 'Merge default branch after the checkout'
-        type: boolean
-        default: true
+      merge_ref:
+        description: |
+          Commit-ish to merge post-checkout if non-empty. Must be reachable from
+          the default_branch input paramter.
+        type: string
+        default: 'FETCH_HEAD'
       retention-days:
         description: 'Artifacts retention period'
         type: string
@@ -111,8 +113,8 @@ jobs:
       with:
         path: src
         ref: ${{ inputs.build_ref || github.sha }}
+        merge_ref: ${{ inputs.merge_ref }}
         cache_path: "/__w/repo_cache/"
-        merge: ${{ inputs.merge }}
     - name: Configure
       env:
         CC: ${{ inputs.cc }}
@@ -231,8 +233,8 @@ jobs:
       extra_cmake_args: '${{ matrix.cmake_args }} ${{ inputs.lts_cmake_extra_args }}'
       target_devices: ${{ matrix.targets }}
       ref: ${{ inputs.build_ref || github.sha }}
+      merge_ref: ${{ inputs.merge_ref }}
       reset_gpu: ${{ contains(matrix.runs-on, 'gen9') && contains(matrix.runs-on, 'Linux') }}
-      merge: ${{ inputs.merge }}
 
       sycl_toolchain_artifact: sycl_linux_${{ inputs.build_artifact_suffix }}
       sycl_toolchain_archive: ${{ inputs.artifact_archive_name }}

.github/workflows/sycl_nightly.yml

@@ -23,7 +23,7 @@ jobs:
     with:
       build_cache_root: "/__w/"
       build_artifact_suffix: default-2204
-      merge: false
+      merge_ref: ''
       retention-days: 90
       lts_matrix: ${{ needs.test_matrix.outputs.lts_lx_matrix }}
       lts_aws_matrix: ${{ needs.test_matrix.outputs.lts_aws_matrix }}
@@ -39,7 +39,7 @@ jobs:
       build_cache_suffix: opaque_pointers
       build_artifact_suffix: opaque_pointers-2204
       build_configure_extra_args: "--hip --cuda --enable-esimd-emulator --cmake-opt=-DSPIRV_ENABLE_OPAQUE_POINTERS=TRUE"
-      merge: false
+      merge_ref: ''
 
   windows_default:
     name: Windows

.github/workflows/sycl_post_commit.yml

@@ -31,7 +31,7 @@ jobs:
       lts_matrix: ${{ needs.test_matrix.outputs.lts_lx_matrix }}
       cts_matrix: ${{ needs.test_matrix.outputs.cts_matrix }}
       lts_aws_matrix: ${{ needs.test_matrix.outputs.lts_aws_matrix }}
-      merge: false
+      merge_ref: ''
 
   windows_default:
     name: Windows

.github/workflows/sycl_precommit.yml

@@ -50,8 +50,8 @@ jobs:
         path: src
         fetch-depth: ${{ env.PR_FETCH_DEPTH }}
         ref: ${{ github.event.pull_request.head.sha }}
+        merge_ref: ''
         cache_path: "/__w/repo_cache/"
-        merge: false
     - name: Run clang-format
       uses: ./devops/actions/clang-format
       with:

devops/actions/cached_checkout/action.yml

@@ -6,6 +6,11 @@ inputs:
     default: ${{ github.repository }}
   ref:
     description: 'Commit-ish to checkout'
+  merge_ref:
+    description: |
+      Commit-ish to merge post-checkout if non-empty. Must be reachable from the
+      default_branch input paramter.
+    default: 'FETCH_HEAD'
   path:
     description: 'Path to checkout repo to'
   fetch-depth:
@@ -16,9 +21,6 @@ inputs:
   default_branch:
     description: 'Name of the default branch'
     default: 'sycl'
-  merge:
-    description: 'Merge default branch after the checkout'
-    default: true
 
 runs:
   using: 'composite'
@@ -51,7 +53,7 @@ runs:
       echo $GIT_ALTERNATE_OBJECT_DIRECTORIES > ${{ inputs.path }}/.git/objects/info/alternates
   - name: Merge sycl HEAD into current branch
     shell: bash
-    if: ${{ inputs.merge == 'true' }}
+    if: ${{ inputs.merge_ref != '' }}
     env:
       DEFAULT_BRANCH: ${{ inputs.default_branch }}
     run: |
@@ -63,4 +65,4 @@ runs:
       # Set fake identity to fulfil git requirements
       git config --local user.email "actions@github.com"
       git config --local user.name "GitHub Actions"
-      git merge --no-ff --no-commit origin/$DEFAULT_BRANCH
+      git merge --no-ff --no-commit ${{ inputs.merge_ref }}