Fix fork PR docs workflow

.github/workflows/build-sphinx.yml

@@ -11,10 +11,9 @@ permissions: read-all
 env:
   GH_BOT_NAME: 'github-actions[bot]'
   GH_BOT_EMAIL: 'github-actions[bot]@users.noreply.github.com'
-  GH_EVENT_OPEN_PR_UPSTREAM: ${{ github.event_name == 'pull_request' && github.event.action != 'closed' &&
-                                 github.event.pull_request && !github.event.pull_request.base.repo.fork }}
   GH_EVENT_PUSH_UPSTREAM: ${{ github.ref == 'refs/heads/master' && github.event_name == 'push' &&
                               github.event.ref == 'refs/heads/master' && github.event.repository && !github.event.repository.fork }}
+  GH_EVENT_PR_OPEN: ${{ github.event_name == 'pull_request' && github.event.action != 'closed' }}
   PUBLISH_DIR: doc/_build/html/
 
 defaults:
@@ -191,6 +190,26 @@ jobs:
       - name: Copy backend docs
         run: cp -r dpnp/backend/doc/html ${{ env.PUBLISH_DIR }}/backend_doc
 
+      # Detect if this is a fork PR
+      - name: Check if fork PR
+        id: check_fork
+        run: |
+          IS_FORK="false"
+          if [ "${{ github.event_name }}" == "pull_request" ] && [ "${{ github.event.pull_request.head.repo.fork }}" == "true" ]; then
+            IS_FORK="true"
+          fi
+          echo "is_fork=$IS_FORK" >> "$GITHUB_OUTPUT"
+          echo "Is fork PR: $IS_FORK"
+
+      # Upload artifact for fork PRs
+      - name: Upload docs artifact (Fork PRs)
+        if: env.GH_EVENT_PR_OPEN == 'true' && steps.check_fork.outputs.is_fork == 'true'
+        uses: actions/upload-artifact@65462800fd760344b1a7b4382951275a0abb4808 # v4.3.3
+        with:
+          name: pr-${{ github.event.number }}-docs
+          path: ${{ env.PUBLISH_DIR }}
+          retention-days: 30
+
       # The step is only used to build docs while pushing a PR to "master"
       - name: Deploy docs
         if: env.GH_EVENT_PUSH_UPSTREAM == 'true'
@@ -206,7 +225,7 @@ jobs:
 
       # The step is only used to build docs while pushing to PR branch
       - name: Publish pull-request docs
-        if: env.GH_EVENT_OPEN_PR_UPSTREAM == 'true'
+        if: env.GH_EVENT_PR_OPEN == 'true' && steps.check_fork.outputs.is_fork == 'false'
         uses: peaceiris/actions-gh-pages@4f9cc6602d3f66b9c108549d475ec49e8ef4d45e # v4.0.0
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
@@ -220,8 +239,10 @@ jobs:
           user_email: ${{ env.GH_BOT_EMAIL }}
 
       # The step is only used to build docs while pushing to PR branch
+      # Note: Fork PRs have read-only GITHUB_TOKEN and cannot post comments
+      # See: https://docs.github.com/en/actions/writing-workflows/choosing-when-your-workflow-runs/events-that-trigger-workflows#workflows-in-forked-repositories
       - name: Comment with URL to published pull-request docs
-        if: env.GH_EVENT_OPEN_PR_UPSTREAM == 'true'
+        if: env.GH_EVENT_PR_OPEN == 'true' && steps.check_fork.outputs.is_fork == 'false'
         env:
           PR_NUM: ${{ github.event.number }}
         uses: mshick/add-pr-comment@8e4927817251f1ff60c001f04568532b38e0b4a0 # v3.11.0.8.3.11.0
@@ -235,7 +256,7 @@ jobs:
   clean:
     if: |
       github.event_name == 'pull_request' && github.event.action == 'closed' &&
-      github.event.pull_request && !github.event.pull_request.base.repo.fork
+      github.event.pull_request.head.repo && !github.event.pull_request.head.repo.fork
 
     needs: build-and-deploy
 

CHANGELOG.md

@@ -27,6 +27,7 @@ This release is compatible with NumPy 2.4.5.
 * Fixed incorrect in-place advanced indexing for 4D arrays when using `range` or `list` as index keys [#2872](https://github.com/IntelPython/dpnp/pull/2872)
 * Fixed `conda build` command syntax in GitHub workflows and documentation to use `conda-build` [#2888](https://github.com/IntelPython/dpnp/pull/2888)
 * Fixed incorrect `dpnp.tensor.acosh` result for `complex(±0, NaN)` special case to match the Python Array API specification [#2914](https://github.com/IntelPython/dpnp/pull/2914)
+* Fixed fork PR documentation workflow failures by implementing conditional publishing strategy: upstream PRs publish to GitHub Pages with comment, fork PRs upload artifacts [#2910](https://github.com/IntelPython/dpnp/pull/2910)
 
 ### Security