feat: Adding Artifact reuse and stage skip functionality to multi-arch CI

.github/workflows/multi_arch_ci.yml

@@ -42,6 +42,25 @@ on:
         type: string
         default: ""
         description: "Workflow run ID to copy prebuilt stage artifacts from; required when prebuilt_stages is set"
+      stage_reuse_mode:
+        type: choice
+        default: "dry-run"
+        options:
+          - "dry-run"
+          - "reuse-stage"
+        # This drives the AUTOMATIC stage-reuse detection layer, which is
+        # separate from the manual `prebuilt_stages` input above. dry-run only
+        # reports which unaffected stages could be reused; reuse-stage actually
+        # reuses them (skips the build and copies artifacts from a baseline run).
+        description: "dry-run (report only) | reuse-stage (auto-reuse unaffected stages)"
+      stage_reuse_max_age_hours:
+        type: string
+        default: "72"
+        description: "Automatic stage reuse: reject baseline runs older than this many hours"
+      stage_reuse_commit_history:
+        type: string
+        default: "50"
+        description: "Automatic stage reuse: number of recent branch commits to fetch for ancestry"
       changed_projects:
         type: string
         default: ""
@@ -86,6 +105,9 @@ jobs:
       windows_test_labels: ${{ inputs.windows_test_labels || '' }}
       prebuilt_stages: ${{ inputs.prebuilt_stages || '' }}
       baseline_run_id: ${{ inputs.baseline_run_id || '' }}
+      stage_reuse_mode: ${{ inputs.stage_reuse_mode || 'dry-run' }}
+      stage_reuse_max_age_hours: ${{ inputs.stage_reuse_max_age_hours || '72' }}
+      stage_reuse_commit_history: ${{ inputs.stage_reuse_commit_history || '50' }}
       build_pytorch: ${{ github.event_name != 'workflow_dispatch' || inputs.build_pytorch }}
       build_jax: ${{ github.event_name != 'workflow_dispatch' || inputs.build_jax }}
 

.github/workflows/setup_multi_arch.yml

@@ -43,6 +43,23 @@ on:
         description: "Workflow run ID to copy prebuilt stage artifacts from."
         type: string
         default: ""
+      stage_reuse_mode:
+        description: >-
+          Automatic stage-reuse mode (separate from the manual prebuilt_stages
+          input): "dry-run" (default) only reports which unaffected stages could
+          be reused; "reuse-stage" actually reuses them.
+        type: string
+        default: "dry-run"
+      stage_reuse_max_age_hours:
+        description: >-
+         Automatic stage reuse: reject baseline runs older than this many hours. default: "72"
+        type: string
+        default: "72"
+      stage_reuse_commit_history:
+        description: >-
+          Automatic stage reuse: number of recent branch commits to fetch for ancestry. default: "50"
+        type: string
+        default: "50"
       build_pytorch:
         description: "Build PyTorch wheels."
         type: boolean
@@ -159,6 +176,10 @@ jobs:
           WINDOWS_TEST_LABELS: ${{ inputs.windows_test_labels }}
           PREBUILT_STAGES: ${{ inputs.prebuilt_stages }}
           BASELINE_RUN_ID: ${{ inputs.baseline_run_id }}
+          STAGE_REUSE_MODE: ${{ inputs.stage_reuse_mode }}
+          STAGE_REUSE_CURRENT_SHA: ${{ steps.checkout.outputs.commit }}
+          STAGE_REUSE_MAX_AGE_HOURS: ${{ inputs.stage_reuse_max_age_hours }}
+          STAGE_REUSE_COMMIT_HISTORY: ${{ inputs.stage_reuse_commit_history }}
           # Skip path filtering for external repos (git sha won't exist in TheRock)
           SKIP_PATH_FILTERS: ${{ inputs.external_repo != '' && 'true' || '' }}
           CI_CONFIG_PATH: ci-config