Remove own usage of incremental.

setup.cfg

@@ -0,0 +1,2 @@
+[metadata]
+version = attr: towncrier.__version__

setup.py

@@ -1,10 +1,4 @@
 #!/usr/bin/env python
-
-
-# If incremental is not present then setuptools just silently uses v0.0.0 so
-# let's import it and fail instead.
-import incremental  # noqa
-
 from setuptools import find_packages, setup
 
 
@@ -37,17 +31,18 @@
         "Programming Language :: Python :: Implementation :: CPython",
         "Programming Language :: Python :: Implementation :: PyPy",
     ],
-    use_incremental=True,
     python_requires=">=3.7",
     install_requires=[
         "click",
         "click-default-group",
-        "incremental",
         "jinja2",
         "setuptools",
         "tomli",
     ],
-    extras_require={"dev": ["packaging"]},
+    extras_require={
+        "dev": ["packaging"],
+        "incremental": ["incremental"],
+    },
     package_dir={"": "src"},
     packages=find_packages("src"),
     license="MIT",

src/towncrier/__init__.py

@@ -5,7 +5,6 @@
 towncrier, a builder for your news files.
 """
 
-from ._version import __version__
-
+__version__ = "21.9.1.dev0"
 
 __all__ = ["__version__"]

src/towncrier/_project.py

@@ -10,7 +10,12 @@
 
 from importlib import import_module
 
-from incremental import Version
+
+# Incremental is a soft dependency.
+try:
+    from incremental import Version as IncrementalVersion
+except ImportError:
+    IncrementalVersion = None
 
 
 def _get_package(package_dir, package):
@@ -47,7 +52,7 @@ def get_version(package_dir, package):
     if isinstance(version, str):
         return version.strip()
 
-    if isinstance(version, Version):
+    if IncrementalVersion and isinstance(version, IncrementalVersion):
         return version.base().strip()
 
     if isinstance(version, tuple):
@@ -73,6 +78,6 @@ def get_project_name(package_dir, package):
     if isinstance(version, str):
         return package.title()
 
-    if isinstance(version, Version):
+    if IncrementalVersion and isinstance(version, IncrementalVersion):
         # Incremental has support for package names
         return version.package

src/towncrier/_shell.py

@@ -9,18 +9,19 @@
 
 from click_default_group import DefaultGroup
 
-from ._version import __version__
+from towncrier import __version__
+
 from .build import _main as _build_cmd
 from .check import _main as _check_cmd
 from .create import _main as _create_cmd
 
 
 @click.group(cls=DefaultGroup, default="build", default_if_no_args=True)
-@click.version_option(__version__.public())
-def cli():
+@click.version_option(__version__)
+def towncrier():
     pass
 
 
-cli.add_command(_build_cmd)
-cli.add_command(_check_cmd)
-cli.add_command(_create_cmd)
+towncrier.add_command(_build_cmd)
+towncrier.add_command(_check_cmd)
+towncrier.add_command(_create_cmd)

src/towncrier/newsfragments/308.removal

@@ -0,0 +1,4 @@
+Towncrier no longer used `incremental` to manage its version.
+Extracting the target project name and version from an `incremental Version`
+instance is still supported.
+You will need to intall the `incremental` extra dependency.

src/towncrier/test/test_shell.py

@@ -0,0 +1,23 @@
+#
+# Tests for the high-level CLI command.
+# Sub-commands are tested via separate test files.
+#
+from click.testing import CliRunner
+from twisted.trial.unittest import TestCase
+
+from towncrier import __version__
+from towncrier._shell import towncrier
+
+
+class TestCli(TestCase):
+    def test_version(self):
+        """
+        The top level `--version` arguments returns towncrier own version.
+        """
+
+        runner = CliRunner()
+
+        result = runner.invoke(towncrier, ["--version"])
+
+        self.assertEqual(0, result.exit_code)
+        self.assertEqual(result.output.strip(), f"towncrier, version {__version__}")