Presubmit script to enforce commit message formatting

1. The first sentence description should be one line <= 64 characters
2. The description body should be wrapped to <= 71 characters
3. Blank lines between the description and the body,
and the body and the meta-tags like Bugs

Bug: angleproject:4662
Change-Id: I966c79d96175da9eee92ef6da20db50d488137b2
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2218696
Reviewed-by: Shahbaz Youssefi <[email protected]>
Reviewed-by: Jamie Madill <[email protected]>
Commit-Queue: Manh Nguyen <[email protected]>

PRESUBMIT.py

@@ -28,6 +28,105 @@
 ]
 
 
+def _CheckCommitMessageFormatting(input_api, output_api):
+
+ def _IsLineBlank(line):
+ return line.isspace() or line == ""
+
+ def _PopBlankLines(lines, reverse=False):
+ if reverse:
+ while len(lines) > 0 and _IsLineBlank(lines[-1]):
+ lines.pop()
+ else:
+ while len(lines) > 0 and _IsLineBlank(lines[0]):
+ lines.pop(0)
+
+ whitelist_strings = ['Revert "', 'Roll ']
+ summary_linelength_warning_lower_limit = 65
+ summary_linelength_warning_upper_limit = 70
+ description_linelength_limit = 71
+
+ if input_api.change.issue:
+ git_output = input_api.gerrit.GetChangeDescription(input_api.change.issue)
+ else:
+ git_output = subprocess.check_output(["git", "log", "-n", "1", "--pretty=format:%B"])
+ commit_msg_lines = git_output.splitlines()
+ _PopBlankLines(commit_msg_lines, True)
+ _PopBlankLines(commit_msg_lines, False)
+ if len(commit_msg_lines) > 0:
+ for whitelist_string in whitelist_strings:
+ if commit_msg_lines[0].startswith(whitelist_string):
+ return []
+ errors = []
+ if git_output.find("\t") != -1:
+ errors.append(output_api.PresubmitError("Tabs are not allowed in commit message."))
+
+ # get rid of the last paragraph, which we assume to always be the tags
+ last_paragraph_line_count = 0
+ while len(commit_msg_lines) > 0 and not _IsLineBlank(commit_msg_lines[-1]):
+ last_paragraph_line_count += 1
+ commit_msg_lines.pop()
+ if last_paragraph_line_count == 0:
+ errors.append(
+ output_api.PresubmitError(
+ "Please ensure that there are tags (e.g., Bug:, Test:) in your description."))
+ if len(commit_msg_lines) > 0:
+ # pop the blank line between tag paragraph and description body
+ commit_msg_lines.pop()
+ if len(commit_msg_lines) > 0 and _IsLineBlank(commit_msg_lines[-1]):
+ errors.append(
+ output_api.PresubmitError('Please ensure that there exists only 1 blank line '
+ 'between tags and description body.'))
+ # pop all the remaining blank lines between tag and description body
+ _PopBlankLines(commit_msg_lines, True)
+ if len(commit_msg_lines) == 0:
+ errors.append(
+ output_api.PresubmitError('Please ensure that your description summary'
+ ' and description body are not blank.'))
+ return errors
+
+ if summary_linelength_warning_lower_limit <= len(commit_msg_lines[0]) \
+ <= summary_linelength_warning_upper_limit:
+ errors.append(
+ output_api.PresubmitPromptWarning(
+ "Your description summary should be on one line of " +
+ str(summary_linelength_warning_lower_limit - 1) + " or less characters."))
+ elif len(commit_msg_lines[0]) > summary_linelength_warning_upper_limit:
+ errors.append(
+ output_api.PresubmitError(
+ "Please ensure that your description summary is on one line of " +
+ str(summary_linelength_warning_lower_limit - 1) + " or less characters."))
+ commit_msg_lines.pop(0) # get rid of description summary
+ if len(commit_msg_lines) == 0:
+ return errors
+ if not _IsLineBlank(commit_msg_lines[0]):
+ errors.append(
+ output_api.PresubmitError('Please ensure the summary is only 1 line and '
+ ' there is 1 blank line between the summary '
+ 'and description body.'))
+ else:
+ commit_msg_lines.pop(0) # pop first blank line
+ if len(commit_msg_lines) == 0:
+ return errors
+ if _IsLineBlank(commit_msg_lines[0]):
+ errors.append(
+ output_api.PresubmitError('Please ensure that there exists only 1 blank line '
+ 'between description summary and description body.'))
+ # pop all the remaining blank lines between description summary and description body
+ _PopBlankLines(commit_msg_lines)
+
+ # loop through description body
+ while len(commit_msg_lines) > 0:
+ if len(commit_msg_lines[0]) > description_linelength_limit:
+ errors.append(
+ output_api.PresubmitError(
+ "Please ensure that your description body is wrapped to " +
+ str(description_linelength_limit) + " characters or less."))
+ return errors
+ commit_msg_lines.pop(0)
+ return errors
+
+
 def _CheckChangeHasBugField(input_api, output_api):
  """Requires that the changelist have a Bug: field from a known project."""
  bugs = input_api.change.BugsFromDescription()
@@ -240,6 +339,7 @@ def CheckChangeOnUpload(input_api, output_api):
  results.extend(
  input_api.canned_checks.CheckPatchFormatted(
  input_api, output_api, result_factory=output_api.PresubmitError))
+ results.extend(_CheckCommitMessageFormatting(input_api, output_api))
  return results