script for backporting patches from cpython.
diff --git a/backport.py b/backport.py
new file mode 100644
index 0000000..147e3e6
--- /dev/null
+++ b/backport.py
@@ -0,0 +1,107 @@
+import re
+from argparse import ArgumentParser
+from os.path import dirname, abspath
+from subprocess import check_output, call
+
+
+def git(command, repo):
+ return check_output('git '+command, cwd=repo, shell=True).decode()
+
+
+def repo_state_bad(mock_repo):
+ status = git('status', mock_repo)
+ if 'You are in the middle of an am session' in status:
+ print(f'Mock repo at {mock_repo} needs cleanup:\n')
+ call('git status', shell=True)
+ return True
+
+
+def cleanup_old_patches(mock_repo):
+ print('cleaning up old patches:')
+ call('rm -vf /tmp/*.mock.patch', shell=True)
+ call('find . -name "*.rej" -print -delete', shell=True, cwd=mock_repo)
+
+
+def find_initial_cpython_rev():
+ with open('lastsync.txt') as source:
+ return source.read().strip()
+
+
+def cpython_revs_affecting_mock(cpython_repo, start):
+ revs = git(f'log --no-merges --format=%H {start}.. '
+ f'-- Lib/unittest/mock.py Lib/unittest/test/testmock/',
+ repo=cpython_repo).split()
+ revs.reverse()
+ print(f'{len(revs)} patches to backport')
+ return revs
+
+
+def has_been_backported(mock_repo, cpython_rev):
+ backport_rev = git(f'log --format=%H --grep "Backports: {cpython_rev}"',
+ repo=mock_repo).strip()
+ if backport_rev:
+ print(f'{cpython_rev} backported in {backport_rev}')
+ return True
+ print(f'{cpython_rev} has not been backported')
+
+
+def extract_patch_for(cpython_repo, rev):
+ return git(f'format-patch -1 --no-stat --keep-subject --signoff --stdout {rev}',
+ repo=cpython_repo)
+
+
+def munge(rev, patch):
+
+ sign_off = 'Signed-off-by:'
+ patch = patch.replace(sign_off, f'Backports: {rev}\n{sign_off}', 1)
+
+ for pattern, sub in (
+ ('(a|b)/Lib/unittest/mock.py', r'\1/mock/mock.py'),
+ ('(a|b)/Lib/unittest/test/testmock/(.+)', r'\1/mock/tests/\2'),
+ ('(a|b)/Misc/NEWS', r'\1/NEWS'),
+ ):
+ patch = re.sub(pattern, sub, patch)
+ return patch
+
+
+def apply_patch(mock_repo, rev, patch):
+ patch_path = f'/tmp/{rev}.mock.patch'
+
+ with open(patch_path, 'w') as target:
+ target.write(patch)
+ print(f'wrote {patch_path}')
+
+ call(f'git am -k --reject {patch_path}', cwd=mock_repo, shell=True)
+
+
+def main():
+ args = parse_args()
+
+ if repo_state_bad(args.mock):
+ return
+
+ cleanup_old_patches(args.mock)
+
+ initial_cpython_rev = find_initial_cpython_rev()
+
+ revs = cpython_revs_affecting_mock(args.cpython, initial_cpython_rev)
+ for rev in revs:
+
+ if has_been_backported(args.mock, rev):
+ continue
+
+ patch = extract_patch_for(args.cpython, rev)
+ patch = munge(rev, patch)
+ apply_patch(args.mock, rev, patch)
+ break
+
+
+def parse_args():
+ parser = ArgumentParser()
+ parser.add_argument('--cpython', default='../cpython')
+ parser.add_argument('--mock', default=abspath(dirname(__file__)))
+ return parser.parse_args()
+
+
+if __name__ == '__main__':
+ main()