[rocm7.1_internal_testing] Add workflow to create IFU tags

.github/workflows/create_ifu_tag.yml

@@ -0,0 +1,116 @@
+name: Create git tags for IFU PRs
+
+on:
+  pull_request:
+    types: [closed]
+
+permissions:
+  contents: write        # create/push tags
+  pull-requests: write   # edit PR body
+
+jobs:
+  tag-ifu:
+    # Only proceed if: merged AND title has both markers
+    if: >
+      github.event.pull_request.merged == true &&
+      contains(github.event.pull_request.title, '[AUTOGENERATED]') &&
+      contains(github.event.pull_request.title, 'IFU')
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout base repo (full history)
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event.pull_request.base.ref }}
+          fetch-depth: 0
+
+      - name: Configure Git user
+        run: |
+          git config user.name  "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+
+      - name: Derive key SHAs (rocm base, upstream main, merge)
+        id: shas
+        shell: bash
+        run: |
+          set -euo pipefail
+
+          PR_NUM="${{ github.event.pull_request.number }}"
+          UPSTREAM_BASE_REF="${{ github.event.pull_request.base.ref }}" #Refers to upstream branch
+          HEAD_SHA="${{ github.event.pull_request.head.sha }}" #Refers to HEAD commit in PR branch 
+          MERGE_SHA="${{ github.event.pull_request.merge_commit_sha }}" #Refers to merge commit that landed the PR
+
+          # The ROCm base commit is the first parent of the merge commit that landed the PR
+          # (i.e., the base branch tip BEFORE this PR merged).
+          ROCM_BASE_SHA=$(git rev-parse "${MERGE_SHA}^1")  #Tip Of Tree of rocm branch pre-IFU merge
+
+          # Add and fetch upstream to identify the upstream/main commit that HEAD integrated.
+          git remote add upstream "https://github.com/pytorch/pytorch.git"
+          git fetch upstream "$UPSTREAM_BASE_REF"
+
+          # Heuristic: the upstream commit integrated by the PR's head is the merge-base
+          # between the PR head commit and upstream/main as fetched now.
+          # This gives you the exact upstream commit (or the best common ancestor) that HEAD included.
+          UPSTREAM_MAIN_SHA=$(git merge-base "${HEAD_SHA}" "upstream/$UPSTREAM_BASE_REF") #Tip of Tree of upstream branch that we pulled locally
+          echo "PR_NUM=$PR_NUM"                           
+          echo "UPSTREAM_BASE_REF=$UPSTREAM_BASE_REF"                       
+          echo "HEAD_SHA=$HEAD_SHA"                       
+          echo "MERGE_SHA=$MERGE_SHA"                     
+          echo "ROCM_BASE_SHA=$ROCM_BASE_SHA"            
+          echo "UPSTREAM_MAIN_SHA=$UPSTREAM_MAIN_SHA"     
+
+
+          echo "PR_NUM=$PR_NUM"                           >> "$GITHUB_OUTPUT"
+          echo "UPSTREAM_BASE_REF=$UPSTREAM_BASE_REF"     >> "$GITHUB_OUTPUT"
+          echo "HEAD_SHA=$HEAD_SHA"                       >> "$GITHUB_OUTPUT"
+          echo "MERGE_SHA=$MERGE_SHA"                     >> "$GITHUB_OUTPUT"
+          echo "ROCM_BASE_SHA=$ROCM_BASE_SHA"             >> "$GITHUB_OUTPUT"
+          echo "UPSTREAM_MAIN_SHA=$UPSTREAM_MAIN_SHA"     >> "$GITHUB_OUTPUT"
+
+      - name: Extract tag base from PR title
+        id: tagname
+        run: |
+          TITLE="${{ github.event.pull_request.title }}"
+          # Remove everything up to and including "[AUTOGENERATED]"
+          BASE_TAG=$(echo "$TITLE" | sed -E 's/^\[AUTOGENERATED\][[:space:]]*//')
+
+          echo "BASE_TAG=$BASE_TAG" 
+          echo "PRE_TAG=${BASE_TAG}_pre" 
+          echo "POST_TAG=${BASE_TAG}_post" 
+
+          echo "BASE_TAG=$BASE_TAG" >> $GITHUB_OUTPUT
+          echo "PRE_TAG=${BASE_TAG}_pre" >> $GITHUB_OUTPUT
+          echo "POST_TAG=${BASE_TAG}_post" >> $GITHUB_OUTPUT
+
+      - name: Create pre/post tags 
+        shell: bash
+        run: |
+          set -euo pipefail
+          echo "Tagging:"
+          echo "  ${{ steps.tagname.outputs.PRE_TAG }}  @ ${{ steps.shas.outputs.ROCM_BASE_SHA }}"
+          echo "  ${{ steps.tagname.outputs.POST_TAG }} @ ${{ steps.shas.outputs.MERGE_SHA }}"
+
+          git tag -a "${{ steps.tagname.outputs.PRE_TAG }}"  -m "IFU pre (PR #${{ steps.shas.outputs.PR_NUM }})"  "${{ steps.shas.outputs.ROCM_BASE_SHA }}" 
+          git tag -a "${{ steps.tagname.outputs.POST_TAG }}" -m "IFU post (PR #${{ steps.shas.outputs.PR_NUM }})" "${{ steps.shas.outputs.MERGE_SHA }}"
+
+          #Force pushing is safe. If we land a new PR, we'd wanna retag a commit if we have to.
+          git push origin "refs/tags/${{ steps.tagname.outputs.PRE_TAG }}" -f
+          git push origin "refs/tags/${{ steps.tagname.outputs.POST_TAG  }}" -f
+
+      - name: Append rocm_base & upstream_main to PR body
+        env:
+          GH_TOKEN: ${{ secrets.IFU_GITHUB_TOKEN }}
+        shell: bash
+        run: |
+          set -euo pipefail
+          # Read current body
+          PR="${{ steps.shas.outputs.PR_NUM }}"
+          CURR=$(gh api repos/${{ github.repository }}/pulls/$PR --jq .body)
+          APPEND=$'\n'"rocm_base: ${{ steps.shas.outputs.ROCM_BASE_SHA }}"$'\n'"upstream_main: ${{ steps.shas.outputs.UPSTREAM_MAIN_SHA }}"$'\n'
+          NEW_BODY="${CURR}${APPEND}"
+
+          # Write to a temp file and update PR body
+          printf '%s' "$NEW_BODY" > body.txt
+          gh api --method PATCH -H  "Accept: application/vnd.github+json" \
+            repos/${{ github.repository }}/pulls/$PR -F body=@body.txt
+