Reland "git-cl: Remove unused and duplicate functions."

This is a reland of e3a49aa4

GetRelativeRoot was fixed to use '.' instead of None

Original change's description:
> git-cl: Remove unused and duplicate functions.
>
> Remove unused functions, and use scm.GIT where possible to reduce
> duplication.
>
> Change-Id: I24f05e7b3ae04743e97b6665ee668f44d6acc294
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2116938
> Reviewed-by: Anthony Polito <apolito@google.com>
> Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>

Change-Id: I54bd1d34d3501a38bf8af2f9e70059d58fa538a5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2125293Reviewed-by: Anthony Polito <apolito@google.com>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>

gclient_scm.py

@@ -230,18 +230,6 @@ class GitWrapper(SCMWrapper):
       filter_kwargs['predicate'] = self.out_cb
     self.filter = gclient_utils.GitFilter(**filter_kwargs)
 
-  @staticmethod
-  def BinaryExists():
-    """Returns true if the command exists."""
-    try:
-      # We assume git is newer than 1.7.  See: crbug.com/114483
-      result, version = scm.GIT.AssertVersion('1.7')
-      if not result:
-        raise gclient_utils.Error('Git version is older than 1.7: %s' % version)
-      return result
-    except OSError:
-      return False
-
   def GetCheckoutRoot(self):
     return scm.GIT.GetCheckoutRoot(self.checkout_path)
 

scm.py

@@ -4,6 +4,7 @@
 
 """SCM-specific utility classes."""
 
+import distutils.version
 import glob
 import io
 import os
@@ -113,8 +114,8 @@ class GIT(object):
   def Capture(args, cwd, strip_out=True, **kwargs):
     env = GIT.ApplyEnvVars(kwargs)
     output = subprocess2.check_output(
-        ['git'] + args, cwd=cwd, stderr=subprocess2.PIPE, env=env,
-        **kwargs).decode('utf-8', 'replace')
+        ['git'] + args, cwd=cwd, stderr=subprocess2.PIPE, env=env, **kwargs)
+    output = output.decode('utf-8', 'replace')
     return output.strip() if strip_out else output
 
   @staticmethod
@@ -406,13 +407,7 @@ class GIT(object):
     """Asserts git's version is at least min_version."""
     if cls.current_version is None:
       current_version = cls.Capture(['--version'], '.')
-      matched = re.search(r'version ([0-9\.]+)', current_version)
-      cls.current_version = matched.group(1)
-    current_version_list = list(map(only_int, cls.current_version.split('.')))
-    for min_ver in map(int, min_version.split('.')):
-      ver = current_version_list.pop(0)
-      if ver < min_ver:
-        return (False, cls.current_version)
-      elif ver > min_ver:
-        return (True, cls.current_version)
-    return (True, cls.current_version)
+      matched = re.search(r'git version (.+)', current_version)
+      cls.current_version = distutils.version.LooseVersion(matched.group(1))
+    min_version = distutils.version.LooseVersion(min_version)
+    return (min_version <= cls.current_version, cls.current_version)

tests/gclient_scm_test.py

@@ -214,9 +214,6 @@ from :3
     self.relpath = '.'
     self.base_path = join(self.root_dir, self.relpath)
     self.enabled = self.CreateGitRepo(self.sample_git_import, self.base_path)
-    self._original_GitBinaryExists = gclient_scm.GitWrapper.BinaryExists
-    mock.patch('gclient_scm.GitWrapper.BinaryExists',
-               staticmethod(lambda : True)).start()
     mock.patch('sys.stdout', StringIO()).start()
     self.addCleanup(mock.patch.stopall)
     self.addCleanup(gclient_utils.rmtree, self.root_dir)

tests/scm_unittest.py

@@ -38,6 +38,23 @@ class GitWrapperTestCase(unittest.TestCase):
     self.assertEqual(scm.GIT.GetEmail(self.root_dir), 'mini@me.com')
     mockCapture.assert_called_with(['config', 'user.email'], cwd=self.root_dir)
 
+  @mock.patch('scm.GIT.Capture')
+  def testAssertVersion(self, mockCapture):
+    cases = [
+        ('1.7', True),
+        ('1.7.9', True),
+        ('1.7.9.foo-bar-baz', True),
+        ('1.8', True),
+        ('1.6.9', False),
+    ]
+    for expected_version, expected_ok in cases:
+      class GIT(scm.GIT):
+        pass
+      mockCapture.return_value = 'git version ' + expected_version
+      ok, version = GIT.AssertVersion('1.7')
+      self.assertEqual(expected_ok, ok)
+      self.assertEqual(expected_version, version)
+
   def testRefToRemoteRef(self):
     remote = 'origin'
     refs = {