Make CR and trailing whitespace errors.

The canned CR and trailing whitespace presubmit checks only emit
warnings, so no one pays any attention to them and they don't fail the
build. All trailing whitespace was removed recently, and it has already
returned. This makes these checks actual errors so they will fail the
presubmit check on the bots, so that they will actually be seen.

Change-Id: I5d774ae45a68b8eb881548d0158c37a8f5fe052e
Reviewed-on: https://skia-review.googlesource.com/59164
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>

1 files changed, 19 insertions, 9 deletions

diff --git a/PRESUBMIT.py b/PRESUBMIT.py
index 271cd13ada..dec667d988 100644
--- a/PRESUBMIT.py
+++ b/PRESUBMIT.py
@@ -234,6 +234,18 @@ def _CheckGNFormatted(input_api, output_api):
   return results
 
 
+class _WarningsAsErrors():
+  def __init__(self, output_api):
+    self.output_api = output_api
+    self.old_warning = None
+  def __enter__(self):
+    self.old_warning = self.output_api.PresubmitPromptWarning
+    self.output_api.PresubmitPromptWarning = self.output_api.PresubmitError
+    return self.output_api
+  def __exit__(self, ex_type, ex_value, ex_traceback):
+    self.output_api.PresubmitPromptWarning = self.old_warning
+
+
 def _CommonChecks(input_api, output_api):
   """Presubmit checks common to upload and commit."""
   results = []
@@ -246,15 +258,13 @@ def _CommonChecks(input_api, output_api):
                        x.LocalPath().endswith('.c') or
                        x.LocalPath().endswith('.cc') or
                        x.LocalPath().endswith('.cpp'))
-  results.extend(
-      _CheckChangeHasEol(
-          input_api, output_api, source_file_filter=sources))
-  results.extend(
-      input_api.canned_checks.CheckChangeHasNoCR(
-          input_api, output_api, source_file_filter=sources))
-  results.extend(
-      input_api.canned_checks.CheckChangeHasNoStrayWhitespace(
-          input_api, output_api, source_file_filter=sources))
+  results.extend(_CheckChangeHasEol(
+      input_api, output_api, source_file_filter=sources))
+  with _WarningsAsErrors(output_api):
+    results.extend(input_api.canned_checks.CheckChangeHasNoCR(
+        input_api, output_api, source_file_filter=sources))
+    results.extend(input_api.canned_checks.CheckChangeHasNoStrayWhitespace(
+        input_api, output_api, source_file_filter=sources))
   results.extend(_PythonChecks(input_api, output_api))
   results.extend(_JsonChecks(input_api, output_api))
   results.extend(_IfDefChecks(input_api, output_api))