Set ignoreSubmodule=all for all repos.

Bug: 1415507

Change-Id: I840508c6972e4640793a12aba287ed8dedfe64c5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/4641611
Reviewed-by: Josip Sokcevic <sokcevic@chromium.org>
Commit-Queue: Joanna Wang <jojwang@chromium.org>

gclient_scm.py

@@ -559,6 +559,22 @@ class GitWrapper(SCMWrapper):
                    (e.returncode, e.stderr.decode('utf-8')))
       return True
 
+  def set_config(f):
+    def wrapper(*args):
+      return_val = f(*args)
+      if os.path.exists(os.path.join(args[0].checkout_path, '.git')):
+        # If diff.ignoreSubmodules is not already set, set it to `all`.
+        currentIgnore = subprocess2.capture(
+            ['git', 'config', '--get', 'diff.ignoreSubmodules'],
+            cwd=args[0].checkout_path).strip()
+        if not currentIgnore:
+          subprocess2.capture(['git', 'config', 'diff.ignoreSubmodules', 'all'],
+                              cwd=args[0].checkout_path).strip()
+      return return_val
+
+    return wrapper
+
+  @set_config
   def update(self, options, args, file_list):
     """Runs git to update or transparently checkout the working copy.
 

tests/gclient_scm_test.py

@@ -393,6 +393,8 @@ class ManagedGitWrapperTestCase(BaseGitWrapperTestCase):
     self.assertEqual(file_list, expected_file_list)
     self.assertEqual(scm.revinfo(options, (), None),
                       'a7142dc9f0009350b96a11f372b6ea658592aa95')
+    self.assertEqual(scm._Capture(['config', '--get', 'diff.ignoreSubmodules']),
+                     'all')
     sys.stdout.close()
 
   def testUpdateMerge(self):