docs: validate pinning version, post #2435

.github/workflows/docs-build.yml

@@ -24,6 +24,7 @@ env:
   TOKENIZERS_PARALLELISM: false
   SPHINX_MOCK_REQUIREMENTS: 0
   SPHINX_FETCH_ASSETS: 0
+  SPHINX_PIN_RELEASE_VERSIONS: 1
 
 jobs:
   docs-make:
@@ -69,9 +70,7 @@ jobs:
 
       - name: Full build for deployment
         if: github.event_name != 'pull_request'
-        run: |
-          echo "SPHINX_FETCH_ASSETS=1" >> $GITHUB_ENV
-          echo "SPHINX_PIN_RELEASE_VERSIONS=1" >> $GITHUB_ENV
+        run: echo "SPHINX_FETCH_ASSETS=1" >> $GITHUB_ENV
       - name: make ${{ matrix.target }}
         working-directory: ./docs
         run: make ${{ matrix.target }} --debug --jobs $(nproc) SPHINXOPTS="-W --keep-going"

docs/source/conf.py

@@ -20,7 +20,6 @@
 
 import lai_sphinx_theme
 import torchmetrics
-from lightning_utilities.docs import adjust_linked_external_docs, fetch_external_assets
 from lightning_utilities.docs.formatting import _transform_changelog
 
 _PATH_HERE = os.path.abspath(os.path.dirname(__file__))
@@ -78,6 +77,8 @@ def _set_root_image_path(page_path: str) -> None:
 
 
 if SPHINX_FETCH_ASSETS:
+    from lightning_utilities.docs import fetch_external_assets
+
     fetch_external_assets(
         docs_folder=_PATH_HERE,
         assets_folder="_static/fetched-s3-assets",
@@ -89,6 +90,8 @@ def _set_root_image_path(page_path: str) -> None:
 
 
 if SPHINX_PIN_RELEASE_VERSIONS:
+    from lightning_utilities.docs import adjust_linked_external_docs
+
     adjust_linked_external_docs(
         "https://numpy.org/doc/stable/", "https://numpy.org/doc/{numpy.__version__}/", _PATH_ROOT
     )