[scm] Fix _load_config to support multi-line

Bug: 1501984, 324449654
Change-Id: Ibe64317e92731735f4ab23c8491eb42e960f9432
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/5279207
Auto-Submit: Aravind Vasudevan <aravindvasudev@google.com>
Reviewed-by: Josip Sokcevic <sokcevic@chromium.org>
Commit-Queue: Aravind Vasudevan <aravindvasudev@google.com>

scm.py

@@ -121,15 +121,17 @@ class GIT(object):
         """
         if cwd not in GIT._CONFIG_CACHE:
             try:
-                rawConfig = GIT.Capture(['config', '--list'],
+                rawConfig = GIT.Capture(['config', '--list', '-z'],
                                         cwd=cwd,
                                         strip_out=False)
             except subprocess2.CalledProcessError:
                 return {}
 
             cfg = defaultdict(list)
-            for line in rawConfig.splitlines():
-                key, value = map(str.strip, line.split('=', 1))
+
+            # Splitting by '\x00' gets an additional empty string at the end.
+            for line in rawConfig.split('\x00')[:-1]:
+                key, value = map(str.strip, line.split('\n', 1))
                 cfg[key].append(value)
 
             GIT._CONFIG_CACHE[cwd] = cfg

tests/scm_unittest.py

@@ -15,6 +15,7 @@ sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 from testing_support import fake_repos
 
 import scm
+import subprocess
 import subprocess2
 
 
@@ -29,9 +30,9 @@ class GitWrapperTestCase(unittest.TestCase):
 
     @mock.patch('scm.GIT.Capture')
     def testGetEmail(self, mockCapture):
-        mockCapture.return_value = 'user.email = mini@me.com'
+        mockCapture.return_value = 'user.email\nmini@me.com\x00'
         self.assertEqual(scm.GIT.GetEmail(self.root_dir), 'mini@me.com')
-        mockCapture.assert_called_with(['config', '--list'],
+        mockCapture.assert_called_with(['config', '--list', '-z'],
                                        cwd=self.root_dir,
                                        strip_out=False)
 
@@ -207,6 +208,14 @@ class RealGitTest(fake_repos.FakeReposTestBase):
         self.assertEqual('set-value',
                          scm.GIT.GetConfig(self.cwd, key, 'default-value'))
 
+        scm.GIT._clear_config(self.cwd)
+        subprocess.run(['git', 'config', key, 'line 1\nline 2\nline 3'],
+                       cwd=self.cwd)
+        self.assertEqual('line 1\nline 2\nline 3',
+                         scm.GIT.GetConfig(self.cwd, key))
+        self.assertEqual('line 1\nline 2\nline 3',
+                         scm.GIT.GetConfig(self.cwd, key, 'default-value'))
+
         scm.GIT.SetConfig(self.cwd, key)
         self.assertIsNone(scm.GIT.GetConfig(self.cwd, key))
         self.assertEqual('default-value',