feat(providers): add scm provider reading version from the last tag matching tag_format

Author: noirbizarre

Diff for: commitizen/providers.py

@@ -1,15 +1,18 @@
 from __future__ import annotations
 
 import json
+import re
 from abc import ABC, abstractmethod
 from pathlib import Path
-from typing import Any, ClassVar, cast
+from typing import Any, ClassVar, Pattern, cast
 
 import importlib_metadata as metadata
 import tomlkit
+from packaging.version import VERSION_PATTERN, Version
 
 from commitizen.config.base_config import BaseConfig
 from commitizen.exceptions import VersionProviderUnknown
+from commitizen.git import get_tags
 
 ENTRYPOINT = "commitizen.provider"
 DEFAULT = "commitizen"
@@ -157,6 +160,41 @@ class ComposerProvider(JsonProvider):
     indent = 4
 
 
+class ScmProvider(VersionProvider):
+    """
+    A provider dedicated to be coupled with `setuptools-scm`
+    or any package manager `-scm` provider.
+
+    Version is fetched from git history (using `git describe`)
+    and does not need to be set back.
+    """
+
+    TAG_FORMAT_REGEXS = {
+        "$version": r".+",
+        "$major": r"\d+",
+        "$minor": r"\d+",
+        "$patch": r"\d+",
+        "$prerelease": r"\w+",
+        "$devrelease": r"(\.?dev\d+)?",
+    }
+
+    def _tag_format_matcher(self) -> Pattern[str]:
+        tag_format = self.config.settings.get("tag_format") or VERSION_PATTERN
+        for var, pattern in self.TAG_FORMAT_REGEXS.items():
+            tag_format = tag_format.replace(var, pattern)
+        return re.compile(f"^{tag_format}$", re.VERBOSE | re.IGNORECASE)
+
+    def get_version(self) -> str:
+        matcher = self._tag_format_matcher()
+        return next(
+            (str(Version(t.name)) for t in get_tags() if matcher.match(t.name)), "0.0.0"
+        )
+
+    def set_version(self, version: str):
+        # Not necessary
+        pass
+
+
 def get_provider(config: BaseConfig) -> VersionProvider:
     """
     Get the version provider as defined in the configuration

Diff for: docs/config.md

@@ -123,12 +123,16 @@ Commitizen provides some version providers for some well known formats:
 | name | description |
 | ---- | ----------- |
 | `commitizen` | Default version provider: Fetch and set version in commitizen config. |
+| `scm` | Fetch the version from git and does not need to set it back |
 | `pep621` | Get and set version from `pyproject.toml` `project.version` field |
 | `poetry` | Get and set version from `pyproject.toml` `tool.poetry.version` field |
 | `cargo` | Get and set version from `Cargo.toml` `project.version` field |
 | `npm` | Get and set version from `package.json` `project.version` field |
 | `composer` | Get and set version from `composer.json` `project.version` field |
 
+!!! note
+    The `scm` provider is meant to be used with `setuptools-scm` or any packager `*-scm` plugin.
+
 ### Custom version provider
 
 You can add you own version provider by extending `VersionProvider` and exposing it on the `commitizen.provider` entrypoint.

Diff for: pyproject.toml

@@ -111,6 +111,7 @@ composer = "commitizen.providers:ComposerProvider"
 npm = "commitizen.providers:NpmProvider"
 pep621 = "commitizen.providers:Pep621Provider"
 poetry = "commitizen.providers:PoetryProvider"
+scm = "commitizen.providers:ScmProvider"
 
 [tool.isort]
 profile = "black"

Diff for: tests/test_version_providers.py

@@ -3,7 +3,7 @@
 import os
 from pathlib import Path
 from textwrap import dedent
-from typing import TYPE_CHECKING, Iterator
+from typing import TYPE_CHECKING, Iterator, Optional
 
 import pytest
 
@@ -16,8 +16,10 @@
     NpmProvider,
     Pep621Provider,
     PoetryProvider,
+    ScmProvider,
     get_provider,
 )
+from tests.utils import create_file_and_commit, create_tag
 
 if TYPE_CHECKING:
     from pytest_mock import MockerFixture
@@ -185,3 +187,45 @@ def test_composer_provider(config: BaseConfig, chdir: Path):
         }
         """
     )
+
+
+TEST_VERSION = "0.1.0"
+
+
+@pytest.mark.parametrize(
+    "tag_format,tag",
+    (
+        ("v$version", f"v{TEST_VERSION}"),
+        ("v$minor.$major.$patch", f"v{TEST_VERSION}"),
+        (None, TEST_VERSION),
+    ),
+)
+@pytest.mark.usefixtures("tmp_git_project")
+def test_scm_provider(config: BaseConfig, tag_format: Optional[str], tag: str):
+    create_file_and_commit("test: fake commit")
+    create_tag(tag)
+    create_file_and_commit("test: fake commit")
+    create_tag("should-not-match")
+
+    config.settings["version_provider"] = "scm"
+    config.settings["tag_format"] = tag_format
+
+    provider = get_provider(config)
+    assert isinstance(provider, ScmProvider)
+    assert provider.get_version() == TEST_VERSION
+
+    # SHould not fail on set_version()
+    provider.set_version("43.1")
+
+
+@pytest.mark.usefixtures("tmp_git_project")
+def test_scm_provider_default_triple_zero_without_matching_tag(config: BaseConfig):
+    create_file_and_commit("test: fake commit")
+    create_tag("should-not-match")
+    create_file_and_commit("test: fake commit")
+
+    config.settings["version_provider"] = "scm"
+
+    provider = get_provider(config)
+    assert isinstance(provider, ScmProvider)
+    assert provider.get_version() == "0.0.0"