Add metadata.load for loading metadata from a source dir with sup…

…port for a BUILD_ENVIRONMENT setting. Set BUILD_ENVIRONMENT=current to bypass isolation when loading metadata. Ref pypa/build#556.

jaraco/packaging/metadata.py

@@ -0,0 +1,14 @@
+import os
+
+from build import util
+
+
+def load(
+    source_dir: util.StrPath,
+    isolated: bool = os.environ.get('BUILD_ENVIRONMENT', 'isolated') == 'isolated',
+    **kwargs,
+):
+    """
+    Allow overriding the isolation behavior at the enviroment level.
+    """
+    return util.project_wheel_metadata(source_dir, isolated, **kwargs)

jaraco/packaging/sphinx.py

@@ -16,9 +16,10 @@
 import sphinx.util.docutils
 from docutils.parsers.rst import directives
 
-from build.util import project_wheel_metadata as load_metadata
 from jaraco.context import suppress
 
+from .metadata import load
+
 
 def setup(app):
     app.add_config_value('package_url', '', '')
@@ -97,7 +98,8 @@ def _load_metadata_from_wheel():
     """
     wheel = os.environ['JARACO_PACKAGING_SPHINX_WHEEL']
     warnings.warn(
-        "JARACO_PACKAGING_SPHINX_WHEEL is deprecated; fix pypa/build#556 instead",
+        "JARACO_PACKAGING_SPHINX_WHEEL is deprecated; "
+        "use BUILD_ENVIRONMENT=current instead",
         DeprecationWarning,
     )
     (dist,) = metadata.distributions(path=[wheel])
@@ -110,7 +112,7 @@ def load_config_from_setup(app):
     """
     # for now, assume project root is one level up
     root = os.path.join(app.confdir, '..')
-    meta = _load_metadata_from_wheel() or load_metadata(root)
+    meta = _load_metadata_from_wheel() or load(root)
     app.config.project = meta['Name']
     app.config.version = app.config.release = meta['Version']
     app.config.package_url = meta['Home-page']

newsfragments/556.feature.rst

@@ -0,0 +1 @@
+Add ``metadata.load`` for loading metadata from a source dir with support for a BUILD_ENVIRONMENT setting. Set BUILD_ENVIRONMENT=current to bypass isolation when loading metadata. Ref pypa/build#556.