Use a single checkout for the requested release commit

Checking out the requested SHA once keeps prepare-job checks aligned with the commit being tagged while removing redundant checkout steps.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: cpcloud

.github/workflows/release-cuda-pathfinder.yml

@@ -53,10 +53,6 @@ jobs:
             exit 1
           fi
 
-      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6.0.2
-        with:
-          fetch-depth: 0
-
       - name: Validate version
         id: vars
         env:
@@ -74,24 +70,28 @@ jobs:
             echo "version=${version}"
           } >> "$GITHUB_OUTPUT"
 
-      - name: Validate and resolve commit
-        id: commit
+      - name: Validate commit input format
         env:
           COMMIT_INPUT: ${{ inputs.commit }}
-          DEFAULT_BRANCH: ${{ github.event.repository.default_branch }}
         run: |
           # Require a full SHA to avoid ambiguity and accidental releases.
           if [[ ! "${COMMIT_INPUT}" =~ ^[0-9a-fA-F]{40}$ ]]; then
             echo "::error::Commit must be a full 40-character SHA, got: ${COMMIT_INPUT}"
             exit 1
           fi
 
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6.0.2
+        with:
+          fetch-depth: 0
+          ref: ${{ inputs.commit }}
+
+      - name: Validate and resolve commit
+        id: commit
+        env:
+          DEFAULT_BRANCH: ${{ github.event.repository.default_branch }}
+        run: |
           git fetch --no-tags origin "${DEFAULT_BRANCH}"
-          commit=$(git rev-parse --verify "${COMMIT_INPUT}^{commit}" 2>/dev/null || true)
-          if [[ -z "${commit}" ]]; then
-            echo "::error::Commit not found in repository: ${COMMIT_INPUT}"
-            exit 1
-          fi
+          commit=$(git rev-parse --verify "HEAD^{commit}")
 
           if ! git merge-base --is-ancestor "${commit}" "origin/${DEFAULT_BRANCH}"; then
             echo "::error::Commit ${commit} is not reachable from origin/${DEFAULT_BRANCH}"
@@ -101,12 +101,6 @@ jobs:
           echo "commit=${commit}" >> "$GITHUB_OUTPUT"
           echo "Using release commit: ${commit}"
 
-      - name: Check out release commit
-        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6.0.2
-        with:
-          fetch-depth: 0
-          ref: ${{ steps.commit.outputs.commit }}
-
       - name: Check release notes exist
         env:
           VERSION: ${{ steps.vars.outputs.version }}