fix: building from sdist fails

setup.py

@@ -1,11 +1,17 @@
 #!/usr/bin/env python
 
+import os
 import sys
-import versioneer
 
 from distutils.text_file import TextFile
 from skbuild import setup
 
+# Add current folder to path
+# This is required to import versioneer in an isolated pip build
+sys.path.append(os.path.dirname(os.path.abspath(__file__)))
+
+import versioneer  # noqa: E402
+
 
 with open('README.rst', 'r') as fp:
     readme = fp.read()

tests/test_distribution.py

@@ -3,7 +3,7 @@
 import pytest
 import textwrap
 
-from path import Path
+from path import Path, matchers
 
 DIST_DIR = os.path.abspath(os.path.join(os.path.dirname(__file__), '../dist'))
 
@@ -26,6 +26,21 @@ def _check_cmake_install(virtualenv, tmpdir):
     assert output[:len(expected)].lower() == expected.lower()
 
 
+@pytest.mark.skipif(not Path(DIST_DIR).exists(), reason="dist directory does not exist")
+def test_source_distribution(virtualenv, tmpdir):
+    sdists = Path(DIST_DIR).files(match=matchers.CaseInsensitive("*.tar.gz"))
+    if not sdists:
+        pytest.skip("no source distribution available")
+    assert len(sdists) == 1
+
+    if "SETUP_CMAKE_ARGS" in os.environ:
+        virtualenv.env["SKBUILD_CONFIGURE_OPTIONS"] = os.environ["SETUP_CMAKE_ARGS"]
+    virtualenv.run("pip install %s" % sdists[0])
+    assert "cmake" in virtualenv.installed_packages()
+
+    _check_cmake_install(virtualenv, tmpdir)
+
+
 @pytest.mark.skipif(not Path(DIST_DIR).exists(), reason="dist directory does not exist")
 def test_wheel(virtualenv, tmpdir):
     wheels = Path(DIST_DIR).files(match="*.whl")

versioneer.py

@@ -1283,7 +1283,22 @@ def render_pep440_post(pieces):
     if pieces["closest-tag"]:
         rendered = pieces["closest-tag"]
         if pieces["distance"] or pieces["dirty"]:
-            rendered += ".post%d" % pieces["distance"]
+            if ".post" in rendered:
+                # update the existing post tag
+                start = rendered.index(".post") + 5
+                if len(rendered) == start:
+                    rendered += "%d" % pieces["distance"]
+                else:
+                    end = start + 1
+                    while end <= len(rendered) and rendered[start:end].isdigit():
+                        end += 1
+                    end -= 1
+                    distance = pieces["distance"]
+                    if start != end:
+                        distance += int(rendered[start:end])
+                    rendered = rendered[:start] + "%d" % distance + rendered[end:]
+            else:
+                rendered += ".post%d" % pieces["distance"]
             if pieces["dirty"]:
                 rendered += ".dev0"
             rendered += plus_or_dot(pieces)