[bug 1108755] Add a git commit message linter

bin/hooks/lint.commit-msg

@@ -0,0 +1,47 @@
+#!/bin/bash
+#
+# Run the commit message linters
+#
+# If this file is not in the `.git/hooks` directory, executing it will
+# prompt to install it.
+
+DIR=$(dirname $0)
+COMMIT_MSG_FILE=$1
+
+function lint() {
+    echo 'Linting the commit message...'
+    ./bin/lint_commit_msg.py $COMMIT_MSG_FILE
+    LINT_STATUS=$?
+    if [[ $LINT_STATUS -ne 0 ]]; then
+        echo
+        echo "Lint errors found. Please fix the above and retry."
+        echo "Alternatively, run 'git commit --no-verify' to ignore lint errors."
+        exit 1
+    fi
+}
+
+function install() {
+    echo -ne "Would you like to install the commit message linter? "
+    while true; do
+        read yn
+        case $yn in
+            [Yy]* ) break;;
+            [Nn]* ) exit 1;;
+            * ) echo "Please enter 'y' or 'n'."
+        esac
+    done
+
+    GITDIR=$(git rev-parse --git-dir)
+    if [[ -e $GITDIR/hooks/commit-msg ]]; then
+        echo "You already have a git commit message hook. Bailing."
+        exit 1
+    fi
+
+    ln -s ../../bin/hooks/lint.commit-msg $GITDIR/hooks/commit-msg
+}
+
+if echo $DIR | grep -E ".git/hooks$" > /dev/null; then
+    lint
+else
+    install
+fi

bin/lint_commit_msg.py

@@ -0,0 +1,79 @@
+#!/usr/bin/env python
+
+import sys
+import re
+
+import requests
+from requests.exceptions import (
+    ConnectionError,
+    Timeout
+    )
+
+BUG_PREFIX_REGEX = r'\[bug (\d+)\]'
+
+
+def are_lines_not_more_than_79_chars(contents):
+    if filter(lambda x: len(x) > 79, contents):
+        print('Error:')
+        print('The commit message should not have more than '
+              '79 characters per line')
+        return False
+    return True
+
+
+def is_bug_number_in_right_format(contents):
+    summary = contents[0]
+    if (re.compile(r'\bbug\b', flags=re.IGNORECASE).search(summary) and
+            re.search(r'\b#{0,1}\d+\b', summary)):
+        bug_format_regex = re.compile(BUG_PREFIX_REGEX,
+                                      flags=re.IGNORECASE)
+        valid_bug_format = bug_format_regex.match(summary)
+        if not valid_bug_format:
+            print('Specify the bug number in the format '
+                  '[bug xxxxxxx] at the beginning of the commit summary')
+            return False
+    return True
+
+
+def print_bug_info(contents):
+    summary = contents[0]
+    bug_id_regex = re.compile(BUG_PREFIX_REGEX,
+                              flags=re.IGNORECASE)
+    is_a_bug = bug_id_regex.match(summary)
+    if is_a_bug:
+        bug_id = is_a_bug.group(1)
+        url = 'https://bugzilla.mozilla.org/rest/bug/{}'.format(bug_id)
+        try:
+            response = requests.get(url, timeout=60.0)
+            response_dict = response.json()
+            if ('error' in response_dict and response_dict['error']):
+                print('Bug with id {} not found.'.format(bug_id))
+                return False
+            bug_info = response_dict['bugs'][0]
+            print('{} - {}'.format(bug_id,
+                                   bug_info['summary']))
+            print('Assigned to: {}'.format(bug_info['assigned_to']))
+        except ValueError:
+            print('Error parsing response from Bugzilla REST API')
+        except (ConnectionError, Timeout):
+            print('Unable to contact Mozilla Bugzilla')
+    return True
+
+LINT_FUNCTIONS = [is_bug_number_in_right_format,
+                  are_lines_not_more_than_79_chars,
+                  print_bug_info]
+
+
+def lint_commit_msg(commit_msg_file):
+    with open(commit_msg_file) as commit_contents:
+        commit_msg = commit_contents.readlines()
+        return_values = map(lambda x: x(commit_msg), LINT_FUNCTIONS)
+        if not all(return_values):
+            return 1
+    return 0
+
+if __name__ == '__main__':
+    commit_msg_file = sys.argv[1]
+    errors_found = lint_commit_msg(commit_msg_file)
+    if errors_found:
+        sys.exit(1)