enabled fallback of name|package values to project.name

This fallback will only work if the pyproject.toml file
is present.
However, it will work for any combination of pyproject.toml
or towncrier.toml configuration files.

Note, that project.name is a required field in pyproject.toml
files. Hence, the minimal requirement for using towncrier
in python project is a no-op!

Signed-off-by: Nick Papior <nickpapior@gmail.com>

Author: zerothi

docs/configuration.rst

@@ -17,9 +17,8 @@ A minimal configuration for a Python project looks like this:
 .. code-block:: toml
 
    # pyproject.toml
-
-   [tool.towncrier]
-   package = "myproject"
+   [project]
+   name = "myproject"
 
 A minimal configuration for a non-Python project looks like this:
 
@@ -36,9 +35,9 @@ Top level keys
 ``name``
     The name of your project.
 
-    For Python projects that provide a ``package`` key, if left empty then the name will be automatically determined.
+    For Python projects that provide a ``package`` key, if left empty then the name will be automatically determined from the ``package`` key.
 
-    ``""`` by default.
+    Defaults to the key ``[project.name]`` in ``pyproject.toml`` (if present), otherwise defaults to the empty string ``""``.
 
 ``version``
     The version of your project.
@@ -167,6 +166,8 @@ Extra top level keys for Python projects
     Allows ``name`` and ``version`` to be automatically determined from the Python package.
     Changes the default ``directory`` to be a ``newsfragments`` directory within this package.
 
+    Defaults to the key ``[project.name]`` in ``pyproject.toml`` (if present), otherwise defaults to the empty string ``""``.
+
 ``package_dir``
     The folder your package lives.
 

src/towncrier/_settings/load.py

@@ -118,19 +118,44 @@ def load_config(directory: str) -> Config | None:
     towncrier_toml = os.path.join(directory, "towncrier.toml")
     pyproject_toml = os.path.join(directory, "pyproject.toml")
 
+    # In case the [tool.towncrier.name|package] is not specified
+    # we'll read it from [project.name]
+
+    if os.path.exists(pyproject_toml):
+        pyproject_config = load_toml_from_file(pyproject_toml)
+    else:
+        # make it empty so it won't be used as a backup plan
+        pyproject_config = {}
+
     if os.path.exists(towncrier_toml):
-        config_file = towncrier_toml
+        config_toml = towncrier_toml
     elif os.path.exists(pyproject_toml):
-        config_file = pyproject_toml
+        config_toml = pyproject_toml
     else:
         return None
 
-    return load_config_from_file(directory, config_file)
+    # Read the default configuration. Depending on which exists
+    config = load_config_from_file(directory, config_toml)
 
+    # Fallback certain values depending on the [project.name]
+    if project_name := pyproject_config.get("project", {}).get("name", ""):
+        # Fallback to the project name for the configuration name
+        # and the configuration package entries.
+        if not config.name:
+            config.name = project_name
+        if not config.package:
+            config.package = project_name
 
-def load_config_from_file(directory: str, config_file: str) -> Config:
+    return config
+
+
+def load_toml_from_file(config_file: str) -> Mapping[str, Any]:
     with open(config_file, "rb") as conffile:
-        config = tomllib.load(conffile)
+        return tomllib.load(conffile)
+
+
+def load_config_from_file(directory: str, config_file: str) -> Config:
+    config = load_toml_from_file(config_file)
 
     return parse_toml(directory, config)
 

src/towncrier/test/test_settings.py

@@ -194,6 +194,42 @@ def test_towncrier_toml_preferred(self):
         config = load_config(project_dir)
         self.assertEqual(config.package, "a")
 
+    def test_pyproject_name_fallback_both(self):
+        """
+        Towncrier will fallback to the [project.name] value in pyproject.toml.
+        """
+        project_dir = self.mktemp_project(
+            pyproject_toml="""
+                [project]
+                name = "a"
+            """,
+        )
+
+        config = load_config(project_dir)
+        self.assertEqual(config.package, "a")
+        self.assertEqual(config.name, "a")
+
+    def test_pyproject_name_fallback_towncrier(self):
+        """
+        Towncrier will fallback to the [project.name] value in pyproject.toml.
+        """
+        project_dir = self.mktemp_project(
+            towncrier_toml="""
+                [tool.towncrier]
+                package = "a"
+            """,
+            pyproject_toml="""
+                [project]
+                name = "c"
+                [tool.towncrier]
+                name = "b"
+            """,
+        )
+
+        config = load_config(project_dir)
+        self.assertEqual(config.package, "a")
+        self.assertEqual(config.name, "c")
+
     @with_isolated_runner
     def test_load_no_config(self, runner: CliRunner):
         """