bot_update: remove cleanup_dir

when git cache is removed, gclient sync fails
and old checkout is moved into cleanup_dir.

It will cause out of disk error during build
because cleanup_dir keeps full old checkout and build artifacts,
which is no longer needed when bot_update
succeeded to checkout.

Remove cleanup_dir after checkout.

Bug: 388307198
Change-Id: I3858e718622a1ef2012fe5b80a5d9b128d96d1d4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/6155955
Commit-Queue: Jie Sheng <jiesheng@google.com>
Reviewed-by: Yiwei Zhang <yiwzhang@google.com>
Auto-Submit: Fumitoshi Ukai <ukai@google.com>
Owners-Override: Jie Sheng <jiesheng@google.com>
Reviewed-by: Junji Watanabe <jwata@google.com>
Reviewed-by: Jie Sheng <jiesheng@google.com>

recipes/recipe_modules/bot_update/resources/bot_update.py

@@ -16,6 +16,7 @@ import optparse
 import os
 import pprint
 import re
+import shutil
 import subprocess
 import sys
 import tempfile
@@ -1142,7 +1143,16 @@ def checkout(options, git_slns, specs, revisions, step_text):
   properties['git_cache_epoch'] = cache_epoch
 
   usage = disk_usage()
-  # TODO(ukai): remove cleanup_dir if available disk space is small?
+  # successfully checked out. remove cleanup_dir to get free disk space.
+  if os.path.exists(cleanup_dir):
+    prev_usage = usage
+    print('Removing cleanup_dir %s' % cleanup_dir)
+    shutil.rmtree(cleanup_dir, ignore_errors=True)
+    usage = disk_usage()
+    print('Release %dGB (%d%%)' %
+          (prev_usage.used_disk_space_gb - usage.used_disk_space_gb,
+           prev_usage.percent_used - usage.percent_used))
+
   step_text = step_text + (' -> [%dGB/%dGB used (%d%%)]' % usage)
 
   # Tell recipes information such as root, got_revision, etc.