Add Darcs support

CHANGELOG.md

@@ -3,6 +3,7 @@
 
 * Added built-in Semantic Versioning output style in addition to PEP 440.
 * Added style validation for custom output formats.
+* Added Darcs support.
 
 ## v0.4.0 (2019-03-29)
 

README.md

@@ -10,6 +10,7 @@ control system.
 * Version control system support:
   * Git
   * Mercurial
+  * Darcs
 * Version styles:
   * [PEP 440](https://www.python.org/dev/peps/pep-0440)
   * [Semantic Versioning](https://semver.org)

dunamai/__init__.py

@@ -317,6 +317,62 @@ def from_mercurial(cls, pattern: str = _VERSION_PATTERN) -> "Version":
 
         return cls(base, pre=pre, post=post, dev=dev, commit=commit, dirty=dirty)
 
+    @classmethod
+    def from_darcs(cls, pattern: str = _VERSION_PATTERN) -> "Version":
+        r"""
+        Determine a version based on Darcs tags.
+
+        :param pattern: Regular expression matched against the version source.
+            This should contain one capture group named `base` corresponding to
+            the release segment of the source, and optionally another two groups
+            named `pre_type` and `pre_number` corresponding to the type (a, b, rc)
+            and number of prerelease. For example, with a tag like v0.1.0, the
+            pattern would be `v(?P<base>\d+\.\d+\.\d+)`.
+        """
+        code, msg = _run_cmd("darcs status")
+        if code in [0, 1]:
+            dirty = msg != "No changes!"
+        else:
+            raise RuntimeError("Darcs returned code {}".format(code))
+
+        code, description = _run_cmd('darcs log --last 1')
+        if code == 0:
+            if not description:
+                commit = None
+            else:
+                commit = description.split()[1].strip()
+        else:
+            raise RuntimeError("Darcs returned code {}".format(code))
+
+        code, description = _run_cmd('darcs show tags')
+        if code == 0:
+            if not description:
+                return cls("0.0.0", post=0, dev=0, commit=commit, dirty=dirty)
+            tag = description.split()[0]
+        else:
+            raise RuntimeError("Darcs returned code {}".format(code))
+
+        code, description = _run_cmd('darcs log --from-tag {}'.format(tag))
+        if code == 0:
+            # The tag itself is in the list, so offset by 1.
+            distance = -1
+            for line in description.splitlines():
+                if line.startswith("patch "):
+                    distance += 1
+        else:
+            raise RuntimeError("Darcs returned code {}".format(code))
+
+        base, pre = _match_version_pattern(pattern, tag)
+
+        if distance > 0:
+            post = distance
+            dev = 0
+        else:
+            post = None
+            dev = None
+
+        return cls(base, pre=pre, post=post, dev=dev, commit=commit, dirty=dirty)
+
     @classmethod
     def from_any_vcs(cls, pattern: str = None) -> "Version":
         """
@@ -325,13 +381,14 @@ def from_any_vcs(cls, pattern: str = None) -> "Version":
         :param pattern: Regular expression matched against the version source.
             The default value defers to the VCS-specific `from_` functions.
         """
-        vcs = _find_higher_dir(".git", ".hg")
+        vcs = _find_higher_dir(".git", ".hg", "_darcs")
         if not vcs:
             raise RuntimeError("Unable to detect version control system.")
 
         callbacks = {
             ".git": cls.from_git,
             ".hg": cls.from_mercurial,
+            "_darcs": cls.from_darcs,
         }
 
         arguments = []

dunamai/__main__.py

@@ -11,6 +11,7 @@ class Vcs(Enum):
     Any = "any"
     Git = "git"
     Mercurial = "mercurial"
+    Darcs = "darcs"
 
 
 class Style(Enum):
@@ -85,6 +86,7 @@ def from_vcs(
         Vcs.Any: Version.from_any_vcs,
         Vcs.Git: Version.from_git,
         Vcs.Mercurial: Version.from_mercurial,
+        Vcs.Darcs: Version.from_darcs,
     }
 
     arguments = []

tests/test_dunamai.py

@@ -418,6 +418,37 @@ def test__version__from_mercurial(tmp_path):
         assert from_any_vcs() == Version("0.1.0", post=1, dev=0, commit="abc")
 
 
+@pytest.mark.skipif(shutil.which("darcs") is None, reason="Requires Darcs")
+def test__version__from_darcs(tmp_path):
+    vcs = tmp_path / "dunamai-darcs"
+    vcs.mkdir()
+    run = make_run_callback(vcs)
+    from_vcs = make_from_callback(Version.from_darcs)
+
+    with chdir(vcs):
+        run("darcs init")
+        assert from_vcs() == Version("0.0.0", post=0, dev=0, commit=None, dirty=False)
+
+        (vcs / "foo.txt").write_text("hi")
+        assert from_vcs() == Version("0.0.0", post=0, dev=0, commit=None, dirty=True)
+
+        run('darcs add foo.txt')
+        run('darcs record -am "Initial commit"')
+        assert from_vcs() == Version("0.0.0", post=0, dev=0, commit="abc", dirty=False)
+
+        run("darcs tag v0.1.0")
+        assert from_vcs() == Version("0.1.0", commit="abc", dirty=False)
+        assert run("dunamai from darcs") == "0.1.0"
+        assert run("dunamai from any") == "0.1.0"
+
+        (vcs / "foo.txt").write_text("bye")
+        assert from_vcs() == Version("0.1.0", commit="abc", dirty=True)
+
+        run('darcs record -am "Second"')
+        assert from_vcs() == Version("0.1.0", post=1, dev=0, commit="abc")
+        assert from_any_vcs() == Version("0.1.0", post=1, dev=0, commit="abc")
+
+
 def test__version__from_any_vcs(tmp_path):
     with chdir(tmp_path):
         with pytest.raises(RuntimeError):

tests/test_main.py

@@ -10,6 +10,7 @@ def test__parse_args__from():
     )
     assert parse_args(["from", "git"]).vcs == "git"
     assert parse_args(["from", "mercurial"]).vcs == "mercurial"
+    assert parse_args(["from", "darcs"]).vcs == "darcs"
     assert parse_args(["from", "any", "--pattern", r"\d+"]).pattern == r"\d+"
     assert parse_args(["from", "any", "--metadata"]).metadata is True
     assert parse_args(["from", "any", "--no-metadata"]).metadata is False