refactor(provider): split provider code and related tests into individual files for maintainability (#830)

Author: davidlday

commitizen/providers.py

@@ -0,0 +1,46 @@
+from __future__ import annotations
+
+from typing import cast
+
+import importlib_metadata as metadata
+
+from commitizen.config.base_config import BaseConfig
+from commitizen.exceptions import VersionProviderUnknown
+
+from commitizen.providers.base_provider import VersionProvider
+from commitizen.providers.cargo_provider import CargoProvider
+from commitizen.providers.commitizen_provider import CommitizenProvider
+from commitizen.providers.composer_provider import ComposerProvider
+from commitizen.providers.npm_provider import NpmProvider
+from commitizen.providers.pep621_provider import Pep621Provider
+from commitizen.providers.poetry_provider import PoetryProvider
+from commitizen.providers.scm_provider import ScmProvider
+
+__all__ = [
+    "get_provider",
+    "CargoProvider",
+    "CommitizenProvider",
+    "ComposerProvider",
+    "NpmProvider",
+    "Pep621Provider",
+    "PoetryProvider",
+    "ScmProvider",
+]
+
+PROVIDER_ENTRYPOINT = "commitizen.provider"
+DEFAULT_PROVIDER = "commitizen"
+
+
+def get_provider(config: BaseConfig) -> VersionProvider:
+    """
+    Get the version provider as defined in the configuration
+
+    :raises VersionProviderUnknown: if the provider named by `version_provider` is not found.
+    """
+    provider_name = config.settings["version_provider"] or DEFAULT_PROVIDER
+    try:
+        (ep,) = metadata.entry_points(name=provider_name, group=PROVIDER_ENTRYPOINT)
+    except ValueError:
+        raise VersionProviderUnknown(f'Version Provider "{provider_name}" unknown.')
+    provider_cls = ep.load()
+    return cast(VersionProvider, provider_cls(config))