fix issue #128: return None from missmatched parse calls

CHANGELOG.rst

@@ -1,3 +1,9 @@
+v1.15.2
+=======
+
+* fix issue #128: return None when a scm specific parse fails in a worktree to ease parse reuse
+
+
 v1.15.1
 =======
 

setup.py

@@ -34,6 +34,7 @@ def scm_config():
         local_scheme=get_local_node_and_date,
     )
 
+
 with open('README.rst') as fp:
     long_description = fp.read()
 

setuptools_scm/git.py

@@ -77,7 +77,10 @@ def parse(root, describe_command=DEFAULT_DESCRIBE, pre_parse=warn_on_shallow):
     """
     if not has_command('git'):
         return
-    wd = GitWorkdir(root)
+
+    wd = GitWorkdir.from_potential_worktree(root)
+    if wd is None:
+        return
     if pre_parse:
         pre_parse(wd)
     rev_node = wd.node()

setuptools_scm/hg.py

@@ -26,6 +26,8 @@ def parse(root):
     if not has_command('hg'):
         return
     l = do('hg id -i -t', root).split()
+    if not l:
+        return
     node = l.pop(0)
     tags = tags_to_versions(l)
     # filter tip in degraded mode on old setuptools

testing/test_git.py

@@ -92,6 +92,12 @@ def test_find_files_stop_at_root_git(wd):
     assert integration.find_files(str(wd.cwd/'project')) == []
 
 
+@pytest.mark.issue(128)
+def test_parse_no_worktree(tmpdir):
+    ret = git.parse(str(tmpdir))
+    assert ret is None
+
+
 def test_alphanumeric_tags_match(wd):
     wd.commit_testfile()
     wd('git tag newstyle-development-started')

testing/test_mercurial.py

@@ -1,5 +1,5 @@
 from setuptools_scm import format_version
-from setuptools_scm.hg import archival_to_version
+from setuptools_scm.hg import archival_to_version, parse
 from setuptools_scm import integration
 
 import pytest
@@ -12,6 +12,7 @@ def wd(wd):
     wd.commit_command = 'hg commit -m test-{reason} -u test -d "0 0"'
     return wd
 
+
 archival_mapping = {
     '1.0': {'tag': '1.0'},
     '1.1.dev3+n000000000000': {
@@ -101,3 +102,9 @@ def test_version_in_merge(wd):
     wd.commit_testfile()
     wd('hg merge --tool :merge')
     assert wd.version is not None
+
+
+@pytest.mark.issue(128)
+def test_parse_no_worktree(tmpdir):
+    ret = parse(str(tmpdir))
+    assert ret is None