feat(py_wheel): Added requires_file and extra_requires_files attrs (

#1710)

The `compile_pip_requirements` rule promotes having `requirements.in`
files describe python dependencies. This change aims to allow these
files to be the source of truth for constraints by allowing the
`py_wheel` rule to use them for adding requirements to a wheel. This
reduces overhead in needing to maintain two lists of equal information
(one as he `.in` and the other as starlark data).

CHANGELOG.md

@@ -21,6 +21,14 @@ A brief description of the categories of changes:
 
 [0.XX.0]: https://github.com/bazelbuild/rules_python/releases/tag/0.XX.0
 
+### Changed
+
+### Fixed
+
+### Added
+
+* (py_wheel) Added `requires_file` and `extra_requires_files` attributes.
+
 ## 0.29.0 - 2024-01-22
 
 [0.29.0]: https://github.com/bazelbuild/rules_python/releases/tag/0.29.0

examples/wheel/BUILD.bazel

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 load("@bazel_skylib//rules:build_test.bzl", "build_test")
+load("@bazel_skylib//rules:write_file.bzl", "write_file")
 load("//examples/wheel/private:wheel_utils.bzl", "directory_writer", "make_variable_tags")
 load("//python:defs.bzl", "py_library", "py_test")
 load("//python:packaging.bzl", "py_package", "py_wheel")
@@ -269,6 +270,47 @@ py_wheel(
     deps = [":example_pkg"],
 )
 
+write_file(
+    name = "requires_file",
+    out = "requires.txt",
+    content = """\
+# Requirements file
+--index-url https://pypi.com
+
+tomli>=2.0.0
+""".splitlines(),
+)
+
+write_file(
+    name = "extra_requires_file",
+    out = "extra_requires.txt",
+    content = """\
+# Extras Requirements file
+--index-url https://pypi.com
+
+pyyaml>=6.0.0,!=6.0.1
+toml; (python_version == "3.11" or python_version == "3.12") and python_version != "3.8"
+wheel; python_version == "3.11" or python_version == "3.12"
+""".splitlines(),
+)
+
+# py_wheel can use text files to specify their requirements. This
+# can be convenient for users of `compile_pip_requirements` who have
+# granular `requirements.in` files per package. This target shows
+# how to provide this file.
+py_wheel(
+    name = "requires_files",
+    distribution = "requires_files",
+    extra_requires_files = {":extra_requires.txt": "example"},
+    python_tag = "py3",
+    # py_wheel can use text files to specify their requirements. This
+    # can be convenient for users of `compile_pip_requirements` who have
+    # granular `requirements.in` files per package.
+    requires_file = ":requires.txt",
+    version = "0.0.1",
+    deps = [":example_pkg"],
+)
+
 py_test(
     name = "wheel_test",
     srcs = ["wheel_test.py"],
@@ -283,6 +325,7 @@ py_test(
         ":minimal_with_py_package",
         ":python_abi3_binary_wheel",
         ":python_requires_in_a_package",
+        ":requires_files",
         ":use_rule_with_dir_in_outs",
     ],
     deps = [

examples/wheel/wheel_test.py

@@ -438,6 +438,34 @@ def test_rule_expands_workspace_status_keys_in_wheel_metadata(self):
             self.assertNotIn("{BUILD_TIMESTAMP}", version)
             self.assertNotIn("{BUILD_USER}", name)
 
+    def test_requires_file_and_extra_requires_files(self):
+        filename = self._get_path("requires_files-0.0.1-py3-none-any.whl")
+
+        with zipfile.ZipFile(filename) as zf:
+            self.assertAllEntriesHasReproducibleMetadata(zf)
+            metadata_file = None
+            for f in zf.namelist():
+                if os.path.basename(f) == "METADATA":
+                    metadata_file = f
+            self.assertIsNotNone(metadata_file)
+
+            requires = []
+            with zf.open(metadata_file) as fp:
+                for line in fp:
+                    if line.startswith(b"Requires-Dist:"):
+                        requires.append(line.decode("utf-8").strip())
+
+            print(requires)
+            self.assertEqual(
+                [
+                    "Requires-Dist: tomli>=2.0.0;",
+                    "Requires-Dist: pyyaml!=6.0.1,>=6.0.0; extra == 'example'",
+                    'Requires-Dist: toml; ((python_version == "3.11" or python_version == "3.12") and python_version != "3.8") and extra == \'example\'',
+                    'Requires-Dist: wheel; (python_version == "3.11" or python_version == "3.12") and extra == \'example\'',
+                ],
+                requires,
+            )
+
 
 if __name__ == "__main__":
     unittest.main()

python/private/py_wheel.bzl

@@ -122,12 +122,26 @@ _feature_flags = {}
 
 _requirement_attrs = {
     "extra_requires": attr.string_list_dict(
-        doc = "List of optional requirements for this package",
+        doc = ("A mapping of [extras](https://peps.python.org/pep-0508/#extras) options to lists of requirements (similar to `requires`). This attribute " +
+               "is mutually exclusive with `extra_requires_file`."),
+    ),
+    "extra_requires_files": attr.label_keyed_string_dict(
+        doc = ("A mapping of requirements files (similar to `requires_file`) to the name of an [extras](https://peps.python.org/pep-0508/#extras) option " +
+               "This attribute is mutually exclusive with `extra_requires`."),
+        allow_files = True,
     ),
     "requires": attr.string_list(
         doc = ("List of requirements for this package. See the section on " +
                "[Declaring required dependency](https://setuptools.readthedocs.io/en/latest/userguide/dependency_management.html#declaring-dependencies) " +
-               "for details and examples of the format of this argument."),
+               "for details and examples of the format of this argument. This " +
+               "attribute is mutually exclusive with `requires_file`."),
+    ),
+    "requires_file": attr.label(
+        doc = ("A file containing a list of requirements for this package. See the section on " +
+               "[Declaring required dependency](https://setuptools.readthedocs.io/en/latest/userguide/dependency_management.html#declaring-dependencies) " +
+               "for details and examples of the format of this argument. This " +
+               "attribute is mutually exclusive with `requires`."),
+        allow_single_file = True,
     ),
 }
 
@@ -365,15 +379,50 @@ def _py_wheel_impl(ctx):
 
     if ctx.attr.python_requires:
         metadata_contents.append("Requires-Python: %s" % ctx.attr.python_requires)
-    for requirement in ctx.attr.requires:
-        metadata_contents.append("Requires-Dist: %s" % requirement)
 
+    if ctx.attr.requires and ctx.attr.requires_file:
+        fail("`requires` and `requires_file` are mutually exclusive. Please update {}".format(ctx.label))
+
+    for requires in ctx.attr.requires:
+        metadata_contents.append("Requires-Dist: %s" % requires)
+    if ctx.attr.requires_file:
+        # The @ prefixed paths will be resolved by the PyWheel action.
+        # Expanding each line containing a constraint in place of this
+        # directive.
+        metadata_contents.append("Requires-Dist: @%s" % ctx.file.requires_file.path)
+        other_inputs.append(ctx.file.requires_file)
+
+    if ctx.attr.extra_requires and ctx.attr.extra_requires_files:
+        fail("`extra_requires` and `extra_requires_files` are mutually exclusive. Please update {}".format(ctx.label))
     for option, option_requirements in sorted(ctx.attr.extra_requires.items()):
         metadata_contents.append("Provides-Extra: %s" % option)
         for requirement in option_requirements:
             metadata_contents.append(
                 "Requires-Dist: %s; extra == '%s'" % (requirement, option),
             )
+    extra_requires_files = {}
+    for option_requires_target, option in ctx.attr.extra_requires_files.items():
+        if option in extra_requires_files:
+            fail("Duplicate `extra_requires_files` option '{}' found on target {}".format(option, ctx.label))
+        option_requires_files = option_requires_target[DefaultInfo].files.to_list()
+        if len(option_requires_files) != 1:
+            fail("Labels in `extra_requires_files` must result in a single file, but {label} provides {files} from {owner}".format(
+                label = ctx.label,
+                files = option_requires_files,
+                owner = option_requires_target.label,
+            ))
+        extra_requires_files.update({option: option_requires_files[0]})
+
+    for option, option_requires_file in sorted(extra_requires_files.items()):
+        metadata_contents.append("Provides-Extra: %s" % option)
+        metadata_contents.append(
+            # The @ prefixed paths will be resolved by the PyWheel action.
+            # Expanding each line containing a constraint in place of this
+            # directive and appending the extra option.
+            "Requires-Dist: @%s; extra == '%s'" % (option_requires_file.path, option),
+        )
+        other_inputs.append(option_requires_file)
+
     ctx.actions.write(
         output = metadata_file,
         content = "\n".join(metadata_contents) + "\n",
@@ -425,6 +474,7 @@ def _py_wheel_impl(ctx):
         )
 
     ctx.actions.run(
+        mnemonic = "PyWheel",
         inputs = depset(direct = other_inputs, transitive = [inputs_to_package]),
         outputs = [outfile, name_file],
         arguments = [args],

tools/wheelmaker.py

@@ -510,9 +510,36 @@ def main() -> None:
             ) as description_file:
                 description = description_file.read()
 
-        metadata = None
-        with open(arguments.metadata_file, "rt", encoding="utf-8") as metadata_file:
-            metadata = metadata_file.read()
+        metadata = arguments.metadata_file.read_text(encoding="utf-8")
+
+        # This is not imported at the top of the file due to the reliance
+        # on this file in the `whl_library` repository rule which does not
+        # provide `packaging` but does import symbols defined here.
+        from packaging.requirements import Requirement
+
+        # Search for any `Requires-Dist` entries that refer to other files and
+        # expand them.
+        for meta_line in metadata.splitlines():
+            if not meta_line.startswith("Requires-Dist: @"):
+                continue
+            file, _, extra = meta_line[len("Requires-Dist: @") :].partition(";")
+            extra = extra.strip()
+
+            reqs = []
+            for reqs_line in Path(file).read_text(encoding="utf-8").splitlines():
+                reqs_text = reqs_line.strip()
+                if not reqs_text or reqs_text.startswith(("#", "-")):
+                    continue
+
+                req = Requirement(reqs_text)
+                if req.marker:
+                    reqs.append(
+                        f"Requires-Dist: {req.name}{req.specifier}; ({req.marker}) and {extra}"
+                    )
+                else:
+                    reqs.append(f"Requires-Dist: {req.name}{req.specifier}; {extra}")
+
+            metadata = metadata.replace(meta_line, "\n".join(reqs))
 
         maker.add_metadata(
             metadata=metadata,