Allow users to mute stacked changes dogfood message.

Bug: 1443304
Change-Id: Idecda2ca5e059c069f38cf099e83e7e0ae932ce2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/4537944
Reviewed-by: Gavin Mak <gavinmak@google.com>
Auto-Submit: Joanna Wang <jojwang@chromium.org>
Commit-Queue: Joanna Wang <jojwang@chromium.org>
diff --git a/git_cl.py b/git_cl.py
index b97ed25..ab6ad73 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -4762,9 +4762,15 @@
     print('No previous patchsets, so --retry-failed has no effect.')
     options.retry_failed = False
 
-  dogfood_stacked_changes = os.environ.get(DOGFOOD_STACKED_CHANGES_VAR) != '0'
 
-  if dogfood_stacked_changes:
+  disable_dogfood_stacked_changes = os.environ.get(
+      DOGFOOD_STACKED_CHANGES_VAR) == '0'
+  dogfood_stacked_changes = os.environ.get(DOGFOOD_STACKED_CHANGES_VAR) == '1'
+
+  # Only print message for folks who don't have DOGFOOD_STACKED_CHANGES set
+  # to an expected value.
+  if (options.squash and not dogfood_stacked_changes
+      and not disable_dogfood_stacked_changes):
     print(
         'This repo has been enrolled in the stacked changes dogfood.\n'
         '`git cl upload` now uploads the current branch and all upstream '
@@ -4772,13 +4778,16 @@
         'Patches can now be reapplied with --force:\n'
         '`git cl patch --reapply --force`.\n'
         'Googlers may visit go/stacked-changes-dogfood for more information.\n'
-        'To opt-out use `export DOGFOOD_STACKED_CHANGES=0`. '
+        '\n'
+        'Depot Tools no longer sets new uploads to "WIP". Please update the\n'
+        '"Set new changes to "work in progress" by default" checkbox at\n'
+        'https://<host>-review.googlesource.com/settings/\n'
+        '\n'
+        'To opt-out use `export DOGFOOD_STACKED_CHANGES=0`.\n'
+        'To hide this message use `export DOGFOOD_STACKED_CHANGES=1`.\n'
         'File bugs at https://bit.ly/3Y6opoI\n')
 
-  if options.squash and dogfood_stacked_changes:
-    print('Depot Tools no longer sets new uploads to "WIP". Please update the\n'
-          '"Set new changes to "work in progress" by default" checkbox at\n'
-          'https://<host>-review.googlesource.com/settings/\n')
+  if options.squash and not disable_dogfood_stacked_changes:
     if options.dependencies:
       parser.error('--dependencies is not available for this dogfood workflow.')