[git_auth] Move auto configure logic

Bug: b/351071334
Change-Id: Ic6574f86208b22e406e36f8cd45a564ea74ec7f9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/5742793
Reviewed-by: Yiwei Zhang <yiwzhang@google.com>
Commit-Queue: Allen Li <ayatane@chromium.org>

git_auth.py

@@ -223,6 +223,31 @@ class ConfigChanger(object):
         self._set_config_func(*args, **kwargs)
 
 
+def AutoConfigure(cwd: str, cl: git_cl.Changelist) -> None:
+    """Configure Git authentication automatically.
+
+    This tracks when the config that has already been applied and skips
+    doing anything if so.
+
+    This may modify the global Git config and the local repo config as
+    needed.
+    """
+    latestVer: int = ConfigChanger.VERSION
+    v: int = 0
+    try:
+        v = int(
+            scm.GIT.GetConfig(cwd, 'depot-tools.gitauthautoconfigured') or '0')
+    except ValueError:
+        v = 0
+    if v < latestVer:
+        logging.debug(
+            'Automatically configuring Git repo authentication'
+            ' (current version: %r, latest: %r)', v, latestVer)
+        ConfigureRepo(cwd, cl)
+        scm.GIT.SetConfig(cwd, 'depot-tools.gitAuthAutoConfigured',
+                          str(latestVer))
+
+
 def Configure(cwd: str, cl: git_cl.Changelist) -> None:
     """Configure Git authentication.
 

git_cl.py

@@ -2347,23 +2347,7 @@ class Changelist(object):
             return
 
         if newauth.Enabled():
-            latestVer: int = git_auth.ConfigChanger.VERSION
-            v: int = 0
-            try:
-                v = int(
-                    scm.GIT.GetConfig(settings.GetRoot(),
-                                      'depot-tools.gitauthautoconfigured',
-                                      default='0'))
-            except ValueError:
-                v = 0
-            if v < latestVer:
-                logging.debug(
-                    'Automatically configuring Git repo authentication (current version: %r, latest: %r)',
-                    v, latestVer)
-                git_auth.ConfigureRepo(os.getcwd(), Changelist())
-                scm.GIT.SetConfig(settings.GetRoot(),
-                                  'depot-tools.gitAuthAutoConfigured',
-                                  str(latestVer))
+            git_auth.AutoConfigure(os.getcwd(), Changelist())
             return
 
         # Lazy-loader to identify Gerrit and Git hosts.