Propagate google-java-format-diff.py's failures

This adds error handling to expose failures in the script's dependencies. It also adds a `--verbose` flag to aid in debugging.

Repo upload hooks will now properly understand that the fixing script has failed instead of passing silently.

Bug: 254300364
Test: Added invalid flags for google-java-format in google-java-format-diff.py and verified that `repo upload` failed with expected output
Change-Id: I88003dec942b220f112ba80875a6c027e6c2f5c7

1 files changed, 37 insertions, 8 deletions

diff --git a/tools/google-java-format.py b/tools/google-java-format.py
index 8a4f739..e25d781 100755
--- a/tools/google-java-format.py
+++ b/tools/google-java-format.py
@@ -28,8 +28,8 @@ del _path
 # We have to import our local modules after the sys.path tweak.  We can't use
 # relative imports because this is an executable program, not a module.
 # pylint: disable=wrong-import-position
-import rh.shell
-import rh.utils
+import rh.shell # pylint: disable=import-error
+import rh.utils # pylint: disable=import-error
 
 
 def get_parser():
@@ -52,6 +52,8 @@ def get_parser():
     parser.add_argument('files', nargs='*',
                         help='If specified, only consider differences in '
                              'these files.')
+    parser.add_argument('--verbose', action='store_true',
+                        help='Explain what is being done.')
     return parser
 
 
@@ -74,18 +76,45 @@ def main(argv):
     diff_cmd.extend(['--'] + opts.files)
     diff = rh.utils.run(diff_cmd, capture_output=True).stdout
 
-    cmd = [opts.google_java_format_diff, '-p1', '--aosp', '-b', format_path]
+    format_cmd = [
+    	opts.google_java_format_diff,
+    	'-p1',
+    	'--aosp',
+    	'-b',
+    	format_path,
+    ]
     if opts.fix:
-        cmd.extend(['-i'])
+        format_cmd.extend(['-i'])
     if not opts.sort_imports:
-        cmd.extend(['--skip-sorting-imports'])
+        format_cmd.extend(['--skip-sorting-imports'])
 
-    stdout = rh.utils.run(cmd, input=diff, capture_output=True).stdout
-    if stdout:
+    format_cmd_result = rh.utils.run(
+    	format_cmd, input=diff, capture_output=True)
+
+    if format_cmd_result.returncode != 0:
+        print("Failed due to non-zero exit code.")
+        if opts.verbose:
+            # print out the full command that was called, including pipes
+            print("Called:")
+            print(f"    {' '.join(diff_cmd)} |")
+            print(f"    {' '.join(format_cmd)}")
+        for line in format_cmd_result.stdout.splitlines():
+            print(f"[captured stdout]   {line}")
+        for line in format_cmd_result.stderr.splitlines():
+            print(f"[captured stderr]   {line}")
+        return format_cmd_result.returncode
+    if format_cmd_result.stdout:
         print('One or more files in your commit have Java formatting errors.')
         print(f'You can run: {sys.argv[0]} --fix {rh.shell.cmd_to_str(argv)}')
         return 1
-
+    if format_cmd_result.stderr:
+        # We need to use stderr to catch errors in google-java-format since we
+        # cannot listen for a non-zero error code until
+        # https://github.com/google/google-java-format/pull/848 is merged.
+        print("Errors have been captured in stderr.")
+        for line in format_cmd_result.stderr.splitlines():
+            print(f"[captured stderr]   {line}")
+        return 1
     return 0