tools/validate-commit.py: post-commit hook to check for commit issues

During review we might overlook issues with the commit messages. Some
commits somehow ended up IP addresses or local VM hostnames as author
address. Automate detecting such issues as well as other whitespace
issues with the commit message itself (detected by commit-msg).

Note: when installing as post-commit hook, it will also be executed when
doing things like 'git reset --hard'.

Change-Id: Ic638e7f51d89277ac359c04764effb69eb4f2fa1
Reviewed-on: https://code.wireshark.org/review/30225
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>

1 files changed, 183 insertions, 0 deletions

diff --git a/tools/validate-commit.py b/tools/validate-commit.py
new file mode 100755
index 0000000000..1fade51258
--- /dev/null
+++ b/tools/validate-commit.py
@@ -0,0 +1,183 @@
+#!/usr/bin/env python
+# Verifies whether commit messages adhere to the standards.
+# Checks the author name and email and invokes the tools/commit-msg script.
+# Copy this into .git/hooks/post-commit
+#
+# Copyright (c) 2018 Peter Wu <peter@lekensteyn.nl>
+#
+# Wireshark - Network traffic analyzer
+# By Gerald Combs <gerald@wireshark.org>
+# Copyright 1998 Gerald Combs
+#
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+from __future__ import print_function
+
+import argparse
+import difflib
+import os
+import subprocess
+import sys
+import tempfile
+
+
+parser = argparse.ArgumentParser()
+parser.add_argument('commit', nargs='?', default='HEAD',
+                    help='Commit ID to be checked (default %(default)s)')
+
+
+def print_git_user_instructions():
+    print('To configure your name and email for git, run:')
+    print('')
+    print('  git config --global user.name "Your Name"')
+    print('  git config --global user.email "you@example.com"')
+    print('')
+    print('After that update the author of your latest commit with:')
+    print('')
+    print('  git commit --amend --reset-author --no-edit')
+    print('')
+
+
+def verify_name(name):
+    name = name.lower().strip()
+    forbidden_names = ('unknown', 'root', 'user', 'your name')
+    if name in forbidden_names:
+        return False
+    # Warn about names without spaces. Sometimes it is a mistake where the
+    # developer accidentally committed using the system username.
+    if ' ' not in name:
+        print("WARNING: name '%s' does not contain a space." % (name,))
+        print_git_user_instructions()
+    return True
+
+
+def verify_email(email):
+    email = email.lower().strip()
+    try:
+        user, host = email.split('@')
+    except ValueError:
+        # Lacks a '@' (e.g. a plain domain or "foo[AT]example.com")
+        return False
+    tld = host.split('.')[-1]
+
+    # localhost, localhost.localdomain, my.local etc.
+    if 'local' in tld:
+        return False
+
+    # Possibly an IP address
+    if tld.isdigit():
+        return False
+
+    # forbid code.wireshark.org. Submissions could be submitted by other
+    # addresses if one would like to remain anonymous.
+    if host.endswith('.wireshark.org'):
+        return False
+
+    # For documentation purposes only.
+    if host == 'example.com':
+        return False
+
+    # 'peter-ubuntu32.(none)'
+    if '(none)' in host:
+        return False
+
+    return True
+
+
+def tools_dir():
+    if __file__.endswith('.py'):
+        # Assume direct invocation from tools directory
+        return os.path.dirname(__file__)
+    # Otherwise it is a git hook. To support git worktrees, do not manually look
+    # for the .git directory, but query the actual top level instead.
+    cmd = ['git', 'rev-parse', '--show-toplevel']
+    srcdir = subprocess.check_output(cmd, universal_newlines=True).strip()
+    return os.path.join(srcdir, 'tools')
+
+
+def verify_body(body):
+    fd, filename = tempfile.mkstemp()
+    try:
+        os.close(fd)
+        with open(filename, 'w') as f:
+            f.write(body)
+
+        hook_script = os.path.join(tools_dir(), 'commit-msg')
+        cmd = ['sh', hook_script, filename]
+        subprocess.check_output(cmd, universal_newlines=True)
+
+        with open(filename, 'r') as f:
+            newbody = f.read()
+    except OSError as ex:
+        print('Warning: unable to invoke commit-msg hook: %s' % (ex,))
+        return True
+    except subprocess.CalledProcessError as ex:
+        print('Bad commit message (reported by tools/commit-msg):')
+        print(ex.output.strip())
+        return False
+    finally:
+        os.unlink(filename)
+    if newbody != body:
+        old_lines = body.splitlines(True)
+        new_lines = newbody.splitlines(True)
+        diff = difflib.unified_diff(old_lines, new_lines,
+                                    fromfile='OLD/.git/COMMIT_EDITMSG',
+                                    tofile='NEW/.git/COMMIT_EDITMSG')
+        # Clearly mark trailing whitespace (GNU patch supports such comments).
+        diff = [
+            '# NOTE: trailing space on the next line\n%s' % (line,)
+            if len(line) > 2 and line[-2].isspace() else line
+            for line in diff
+        ]
+        print('The commit message does not follow our standards.')
+        print('Please rewrite it (there are likely whitespace issues):')
+        print('')
+        print(''.join(diff))
+        return False
+    return True
+
+
+def main():
+    args = parser.parse_args()
+    commit = args.commit
+    cmd = ['git', 'show', '--no-patch',
+           '--format=%h%n%an%n%ae%n%B', commit, '--']
+    output = subprocess.check_output(cmd, universal_newlines=True)
+    # For some reason there is always an additional LF in the output, drop it.
+    if output.endswith('\n\n'):
+        output = output[:-1]
+    abbrev, author_name, author_email, body = output.split('\n', 3)
+    subject = body.split('\n', 1)[0]
+
+    # If called directly (from the tools directory), print the commit that was
+    # being validated. If called from a git hook (without .py extension), try to
+    # remain silent unless there are issues.
+    if __file__.endswith('.py'):
+        print('Checking commit: %s %s' % (abbrev, subject))
+
+    exit_code = 0
+    if not verify_name(author_name):
+        print('Disallowed author name: {}'.format(author_name))
+        exit_code = 1
+
+    if not verify_email(author_email):
+        print('Disallowed author email address: {}'.format(author_email))
+        exit_code = 1
+
+    if exit_code:
+        print_git_user_instructions()
+
+    if not verify_body(body):
+        exit_code = 1
+
+    return exit_code
+
+
+if __name__ == '__main__':
+    try:
+        sys.exit(main())
+    except subprocess.CalledProcessError as ex:
+        print('\n%s' % ex)
+        sys.exit(ex.returncode)
+    except KeyboardInterrupt:
+        sys.exit(130)