Detect the build tool and thus the version

README.md

@@ -29,29 +29,22 @@ release:
   - uses: actions/checkout@v2
   - uses: brettcannon/release-often@v1
     with:
-      build-tool: flit
       changelog-path: doc/CHANGELOG.rst
       github-token: ${{ secret.GITHUB_TOKEN }}
       pypi-token: ${{ secrets.PYPI_TOKEN }}
 ```
 
 ### Inputs
-#### `build-tool`
-The build tool used for the project. Acceptable values are:
-- flit
-- poetry
-
-Leaving this input out will disable automatic version bumping.
 
 #### `changelog-path`
-The path to the changelog file. Paths must end in one of the following extensions to denote the file format:
+**Required**: The path to the changelog file. Paths must end in one of the following extensions to denote the file format:
 - `.md`
 - `.rst`
 
 Leaving this input out will disable automatic changelog updating.
 
 #### `github-token`
-The GitHub access token (i.e. `${{ secrets.GITHUB_TOKEN }}`). This allows for committing changes back to the repository.
+**Required**: The GitHub access token (i.e. `${{ secrets.GITHUB_TOKEN }}`). This allows for committing changes back to the repository.
 
 Leaving this input out will disable committing any changes made and creating a release.
 
@@ -60,13 +53,6 @@ The [PyPI API token](https://pypi.org/help/#apitoken) for this project. It is **
 
 Leaving this input out will disable uploading to PyPI.
 
-### Outputs
-#### `version`
-The new version of the project. Set to the empty string if a version change did not occur.
-
-#### `artifacts`
-Directory containing the built artifacts (traditionally `dist/`).
-
 
 ## Details
 ### Update version

release_often/__main__.py

@@ -1,6 +1,27 @@
+from gidgethub import actions
+
+from . import version
+
+
+def update_version():
+    build_tool, version_file = version.find_details(actions.workspace())
+    if build_tool is None:
+        # XXX
+        pass
+    file_contents = version_file.read_text(encoding="utf-8")
+    current_version = build_tool.read_version(file_contents)
+    new_version = version.bump_by_label(actions.event(), current_version)
+    new_contents = build_tool.change_version(
+        file_contents, current_version, new_version
+    )
+    version_file.write_text(new_contents, encoding="utf-8")
+
+
 if __name__ == "__main__":
-    # Update the version number.
-    # XXX get current version
-    # XXX map label to enum (probably need gidgethub.actions.webhook_event())
-    # XXX update version
+    update_version()
+    # XXX update changelog
+    # XXX build the project
+    # XXX Commit the changes
+    # XXX Upload to PyPI
+    # XXX Create a release on GitHub
     pass

release_often/version.py

@@ -2,6 +2,8 @@
 
 import packaging
 
+from . import flit, poetry
+
 
 @enum.unique
 class BumpLevel(enum.Enum):
@@ -31,3 +33,18 @@ def bump(version, bump_by):
         return f"{major}.{minor}.{micro}.post{post}"
     else:
         return None
+
+
+def find_details(directory):
+    """Find the build tool and the file containing the current version."""
+    for build_tool in (flit, poetry):
+        try:
+            return build_tool, build_tool.version_file_path(directory)
+        except (ValueError, TypeError):
+            pass
+    else:
+        return None, None
+
+
+def bump_by_label(event, old_version):
+    """Calculate the new version based on the pull request event."""

tests/test_version.py

@@ -1,6 +1,7 @@
 import pytest
 
 from release_often import version
+from release_often import flit, poetry
 
 
 @pytest.mark.parametrize(
@@ -16,3 +17,14 @@
 )
 def test_bump(given, level, expect):
     assert version.bump(given, level) == expect
+
+
+@pytest.mark.parametrize(
+    "test_path,build_tool,file_path",
+    [("poetry", poetry, "pyproject.toml"), ("flit/top_module", flit, "pkg.py")],
+)
+def test_version_file_path(data_path, test_path, build_tool, file_path):
+    directory = data_path / test_path
+    result = version.find_details(directory)
+    assert result[0] == build_tool
+    assert result[1] == directory / file_path