Never lock a dirty version

Fixes #104

gitman/models/source.py

@@ -131,6 +131,6 @@ def identify(self, allow_dirty=True, allow_missing=True):
 
     def lock(self):
         """Return a locked version of the current source."""
-        _, _, revision = self.identify(allow_missing=False)
+        _, _, revision = self.identify(allow_dirty=False, allow_missing=False)
         source = self.__class__(self.repo, self.name, revision, self.link)
         return source

setup.py

@@ -79,6 +79,6 @@ def read_descriptions():
     ],
 
     install_requires=[
-        'YORM==1.2b4',
+        'YORM==1.2b5',
     ],
 )

tests/test_api.py

@@ -11,7 +11,7 @@
 
 import gitman
 from gitman.models import Config
-from gitman.exceptions import InvalidRepository
+from gitman.exceptions import UncommittedChanges, InvalidRepository
 
 from .utilities import strip
 
@@ -329,6 +329,13 @@ def it_records_specified_dependencies(config):
           rev: 9bf18e16b956041f0267c21baad555a23237b52e
         """) == config.__mapper__.text
 
+    def it_should_fail_on_dirty_repositories(config):
+        expect(gitman.update(depth=1, lock=False)) == True
+        os.remove("deps/gitman_1/.project")
+
+        with pytest.raises(UncommittedChanges):
+            gitman.lock()
+
     def it_should_fail_on_invalid_repositories(config):
         os.system("mkdir deps && touch deps/gitman_1")