feat: Adding variable support for distribution in py_wheel (#1251)

This allows the `distribution` attribute to expand workspace status
keys, just as the
`version` attribute can.

This allows, for example, the VCS's branch name (e.g test, release, etc)
to be part of the
distribution name without having to modify the BUILD file. Having
distinct distribution
names is necessary because tools like pip-compile, which determine
version compatibility
and replacements, and having the same distribution name would mean the
different builds
are seen as equivalent.

Closes #1250

examples/wheel/BUILD.bazel

@@ -94,7 +94,7 @@ build_test(
 py_wheel(
     name = "minimal_with_py_library_with_stamp",
     # Package data. We're building "example_minimal_library-0.0.1-py3-none-any.whl"
-    distribution = "example_minimal_library",
+    distribution = "example_minimal_library{BUILD_USER}",
     python_tag = "py3",
     stamp = 1,
     version = "0.1.{BUILD_TIMESTAMP}",

examples/wheel/wheel_test.py

@@ -374,30 +374,36 @@ def test_rule_creates_directory_and_is_included_in_wheel(self):
                 ],
             )
 
-    def test_rule_sets_stamped_version_in_wheel_metadata(self):
+    def test_rule_expands_workspace_status_keys_in_wheel_metadata(self):
         filename = os.path.join(
             os.environ["TEST_SRCDIR"],
             "rules_python",
             "examples",
             "wheel",
-            "example_minimal_library-0.1._BUILD_TIMESTAMP_-py3-none-any.whl",
+            "example_minimal_library_BUILD_USER_-0.1._BUILD_TIMESTAMP_-py3-none-any.whl",
         )
 
         with zipfile.ZipFile(filename) as zf:
             metadata_file = None
             for f in zf.namelist():
                 self.assertNotIn("_BUILD_TIMESTAMP_", f)
+                self.assertNotIn("_BUILD_USER_", f)
                 if os.path.basename(f) == "METADATA":
                     metadata_file = f
             self.assertIsNotNone(metadata_file)
 
             version = None
+            name = None
             with zf.open(metadata_file) as fp:
                 for line in fp:
-                    if line.startswith(b'Version:'):
+                    if line.startswith(b"Version:"):
                         version = line.decode().split()[-1]
+                    if line.startswith(b"Name:"):
+                        name = line.decode().split()[-1]
             self.assertIsNotNone(version)
+            self.assertIsNotNone(name)
             self.assertNotIn("{BUILD_TIMESTAMP}", version)
+            self.assertNotIn("{BUILD_USER}", name)
 
 
 if __name__ == "__main__":

python/private/py_wheel.bzl

@@ -40,6 +40,12 @@ Name of the distribution.
 
 This should match the project name onm PyPI. It's also the name that is used to
 refer to the package in other packages' dependencies.
+
+Workspace status keys are expanded using `{NAME}` format, for example:
+ - `distribution = "package.{CLASSIFIER}"`
+ - `distribution = "{DISTRIBUTION}"`
+
+For the available keys, see https://bazel.build/docs/user-manual#workspace-status
 """,
     ),
     "platform": attr.string(

tools/wheelmaker.py

@@ -167,12 +167,12 @@ def add_wheelfile(self):
             wheel_contents += "Tag: %s\n" % tag
         self.add_string(self.distinfo_path("WHEEL"), wheel_contents)
 
-    def add_metadata(self, metadata, description, version):
+    def add_metadata(self, metadata, name, description, version):
         """Write METADATA file to the distribution."""
         # https://www.python.org/dev/peps/pep-0566/
         # https://packaging.python.org/specifications/core-metadata/
-        metadata += "Version: " + version
-        metadata += "\n\n"
+        metadata = re.sub("^Name: .*$", "Name: %s" % name, metadata, flags=re.MULTILINE)
+        metadata += "Version: %s\n\n" % version
         # setuptools seems to insert UNKNOWN as description when none is
         # provided.
         metadata += description if description else "UNKNOWN"
@@ -207,18 +207,18 @@ def get_files_to_package(input_files):
     return files
 
 
-def resolve_version_stamp(
-    version: str, volatile_status_stamp: Path, stable_status_stamp: Path
+def resolve_argument_stamp(
+    argument: str, volatile_status_stamp: Path, stable_status_stamp: Path
 ) -> str:
-    """Resolve workspace status stamps format strings found in the version string
+    """Resolve workspace status stamps format strings found in the argument string
 
     Args:
-        version (str): The raw version represenation for the wheel (may include stamp variables)
+        argument (str): The raw argument represenation for the wheel (may include stamp variables)
         volatile_status_stamp (Path): The path to a volatile workspace status file
         stable_status_stamp (Path): The path to a stable workspace status file
 
     Returns:
-        str: A resolved version string
+        str: A resolved argument string
     """
     lines = (
         volatile_status_stamp.read_text().splitlines()
@@ -229,9 +229,9 @@ def resolve_version_stamp(
             continue
         key, value = line.split(" ", maxsplit=1)
         stamp = "{" + key + "}"
-        version = version.replace(stamp, value)
+        argument = argument.replace(stamp, value)
 
-    return version
+    return argument
 
 
 def parse_args() -> argparse.Namespace:
@@ -357,7 +357,16 @@ def main() -> None:
     strip_prefixes = [p for p in arguments.strip_path_prefix]
 
     if arguments.volatile_status_file and arguments.stable_status_file:
-        version = resolve_version_stamp(
+        name = resolve_argument_stamp(
+            arguments.name,
+            arguments.volatile_status_file,
+            arguments.stable_status_file,
+        )
+    else:
+        name = arguments.name
+
+    if arguments.volatile_status_file and arguments.stable_status_file:
+        version = resolve_argument_stamp(
             arguments.version,
             arguments.volatile_status_file,
             arguments.stable_status_file,
@@ -366,7 +375,7 @@ def main() -> None:
         version = arguments.version
 
     with WheelMaker(
-        name=arguments.name,
+        name=name,
         version=version,
         build_tag=arguments.build_tag,
         python_tag=arguments.python_tag,
@@ -398,7 +407,9 @@ def main() -> None:
             with open(arguments.metadata_file, "rt", encoding="utf-8") as metadata_file:
                 metadata = metadata_file.read()
 
-        maker.add_metadata(metadata=metadata, description=description, version=version)
+        maker.add_metadata(
+            metadata=metadata, name=name, description=description, version=version
+        )
 
         if arguments.entry_points_file:
             maker.add_file(