Add mechanism to write version information to a file

Author: virtuald

README.md

@@ -6,6 +6,8 @@ the following functionality:
 
 * Download a zip file from a specified URL
 * Download a zip file from a maven repository using maven coordinates
+* Write project version information to a file (primarily useful when not
+  already using a dynamic version source that provides this)
 
 See [config](src/hatch_robotpy/config.py) for `pyproject.toml` configuration.
 

src/hatch_robotpy/config.py

@@ -156,6 +156,17 @@ def _update_with_platform(self, platform):
 
 @dataclasses.dataclass
 class HookConfig:
+    """
+    .. code-block:: toml
+
+        [tool.hatch.build.hooks.robotpy]
+
+    """
+
+    #: When set, writes a simple python file with the project version to the
+    #: specified file (relative to the root of the project).
+    version_file: T.Optional[str] = None
+
     maven_lib_download: T.List[MavenLibDownload] = dataclasses.field(
         default_factory=list
     )

src/hatch_robotpy/plugin.py

@@ -23,6 +23,29 @@ class DownloadHook(BuildHookInterface):
     PLUGIN_NAME = "robotpy"
 
     def initialize(self, version: str, build_data: T.Dict[str, T.Any]) -> None:
+        self.process_version(version, build_data)
+        self.process_downloads(version, build_data)
+
+    def process_version(self, version: str, build_data: T.Dict[str, T.Any]) -> None:
+        version_file = self.parsed_cfg.version_file
+        if version_file is None:
+            return
+
+        version = self.metadata.version
+        version_path = pathlib.PurePosixPath(version_file)
+
+        with open(version_path, "w") as fp:
+            fp.writelines(
+                [
+                    "# This file is automatically generated, DO NOT EDIT\n",
+                    "\n",
+                    f'version = __version__ = "{version}"\n',
+                ]
+            )
+
+        build_data["artifacts"].append(f"/{version_path}")
+
+    def process_downloads(self, version: str, build_data: T.Dict[str, T.Any]) -> None:
         # Don't need to generate files when creating an sdist
         # - this violates the idea that an sdist should be able to be used
         #   offline, but because we're downloading the external artifacts