refactor: expose drift as workflow outputs, restore dedicated zero-diff CI job

Co-Authored-By: AJ Steers <aj@airbyte.io>

Author: devin-ai-integration[bot]

.github/workflows/generate-command.yml

@@ -54,6 +54,13 @@ name: Generate SDK
                 description: Validate generation without creating a PR
                 type: boolean
                 default: false
+        outputs:
+            has_changes:
+                description: Whether the generation produced changes vs committed code
+                value: ${{ jobs.generate.outputs.has_changes }}
+            drift_summary:
+                description: Git diff stat summary when drift is detected
+                value: ${{ jobs.generate.outputs.drift_summary }}
 
 concurrency:
     group: ${{ (github.event_name == 'push' || github.event_name == 'schedule') && 'generate-new-pr' || format('generate-{0}', github.run_id) }}
@@ -64,6 +71,9 @@ jobs:
         name: Generate SDK
         runs-on: ubuntu-latest
         timeout-minutes: 30
+        outputs:
+            has_changes: ${{ steps.changes.outputs.has_changes }}
+            drift_summary: ${{ steps.changes.outputs.drift_summary }}
         permissions:
             contents: write
             pull-requests: write
@@ -191,43 +201,16 @@ jobs:
                       git status --porcelain
                       echo
                       echo "=== Diff stat ==="
-                      git diff --stat
+                      SUMMARY=$(git diff --stat)
+                      echo "$SUMMARY"
+                      EOF=$(dd if=/dev/urandom bs=15 count=1 status=none | base64)
+                      echo "drift_summary<<$EOF" >> $GITHUB_OUTPUT
+                      echo "$SUMMARY" >> $GITHUB_OUTPUT
+                      echo "$EOF" >> $GITHUB_OUTPUT
                   else
                       echo "has_changes=false" >> $GITHUB_OUTPUT
                   fi
 
-            - name: Detect generation drift (dry run)
-              if: ${{ inputs.dry_run && steps.changes.outputs.has_changes == 'true' }}
-              id: drift
-              run: |
-                  echo "::error::Generated code drift detected. The committed code does not match what the generation pipeline produces."
-                  SUMMARY=$(git diff --stat)
-                  EOF=$(dd if=/dev/urandom bs=15 count=1 status=none | base64)
-                  echo "summary<<$EOF" >> $GITHUB_OUTPUT
-                  echo "$SUMMARY" >> $GITHUB_OUTPUT
-                  echo "$EOF" >> $GITHUB_OUTPUT
-
-            - name: Post drift comment on PR
-              if: ${{ inputs.dry_run && steps.changes.outputs.has_changes == 'true' && github.event_name == 'pull_request' }}
-              uses: peter-evans/create-or-update-comment@v5
-              with:
-                  issue-number: ${{ github.event.pull_request.number }}
-                  body: |
-                      <!-- zero-diff-check -->
-                      **Generated Code Drift Detected**
-
-                      The committed code does not match what the generation pipeline produces.
-
-                      **To fix:** Comment `/generate` on this PR to regenerate.
-
-                      ```
-                      ${{ steps.drift.outputs.summary }}
-                      ```
-
-            - name: Fail on drift (dry run)
-              if: ${{ inputs.dry_run && steps.changes.outputs.has_changes == 'true' }}
-              run: exit 1
-
             # --- PR branch mode: commit and push to the existing PR branch ---
             - name: Push regenerated code to PR branch
               if: ${{ !inputs.dry_run && github.event.inputs.pr != '' && steps.changes.outputs.has_changes == 'true' }}

.github/workflows/test-full.yml

@@ -3,9 +3,13 @@
 # This workflow validates that Speakeasy generation can complete successfully
 # and that the committed generated code matches what the generation pipeline produces.
 #
-# It calls the main generation workflow with dry_run=true. After generation,
-# the workflow checks `git status` in-place — if any tracked files changed,
-# drift is detected and the check fails with a PR comment.
+# Jobs:
+# 1. validate: Runs the full generation pipeline in dry-run mode
+# 2. zero-diff: Checks for drift using the validate job's outputs (in-place git status).
+#    If drift is detected, the check fails and posts a comment telling the author to run /generate.
+#
+# This workflow calls the main generation workflow with dry_run=true to ensure
+# both workflows use the same generation logic.
 #
 # Note: paths-ignore is NOT used at the workflow level because GitHub treats a
 # workflow that never runs as "expected" (pending), which blocks required checks.
@@ -49,3 +53,56 @@ jobs:
     with:
       dry_run: true
     secrets: inherit
+
+  zero-diff:
+    name: Zero-Diff Check (Generated Code)
+    needs: [check-paths, validate]
+    if: needs.check-paths.outputs.should_run == 'true' && github.event_name == 'pull_request'
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: write
+    steps:
+      - name: Check for generation drift
+        id: drift-check
+        run: |
+          if [ "${{ needs.validate.outputs.has_changes }}" = "true" ]; then
+              echo "has_diff=true" >> $GITHUB_OUTPUT
+              echo "::warning::Generated code drift detected. The committed code does not match what the generation pipeline produces."
+          else
+              echo "has_diff=false" >> $GITHUB_OUTPUT
+              echo "Zero-diff check passed. Committed code matches generation output."
+          fi
+
+      - name: Find existing drift comment
+        if: steps.drift-check.outputs.has_diff == 'true'
+        uses: peter-evans/find-comment@v3
+        id: find-drift-comment
+        with:
+          issue-number: ${{ github.event.pull_request.number }}
+          body-includes: '<!-- zero-diff-check -->'
+
+      - name: Post drift comment on PR
+        if: steps.drift-check.outputs.has_diff == 'true'
+        uses: peter-evans/create-or-update-comment@v5
+        with:
+          issue-number: ${{ github.event.pull_request.number }}
+          comment-id: ${{ steps.find-drift-comment.outputs.comment-id || '' }}
+          edit-mode: replace
+          body: |
+            <!-- zero-diff-check -->
+            **Generated Code Drift Detected**
+
+            The committed code does not match what the generation pipeline produces.
+
+            **To fix:** Comment `/generate` on this PR to regenerate.
+
+            ```
+            ${{ needs.validate.outputs.drift_summary }}
+            ```
+
+      - name: Fail if drift detected
+        if: steps.drift-check.outputs.has_diff == 'true'
+        run: |
+          echo "::error::Generated code drift detected. Run /generate on this PR to fix."
+          exit 1