dash/contrib/devtools/github-merge.py
Wladimir J. van der Laan a327e8ea30 devtools: Make github-merge compute SHA512 from git, instead of worktree
This changes tree_sha512sum() to requests the objects for hashing from
git instead of from the working tree.

The change should make the process more deterministic (it hashes what
will be pushed) and hopefully avoids the frequent miscomputed SHA512's
that happen now.
2017-03-13 16:13:38 +01:00

336 lines
14 KiB
Python
Executable File

#!/usr/bin/env python3
# Copyright (c) 2016 The Bitcoin Core developers
# Distributed under the MIT software license, see the accompanying
# file COPYING or http://www.opensource.org/licenses/mit-license.php.
# This script will locally construct a merge commit for a pull request on a
# github repository, inspect it, sign it and optionally push it.
# The following temporary branches are created/overwritten and deleted:
# * pull/$PULL/base (the current master we're merging onto)
# * pull/$PULL/head (the current state of the remote pull request)
# * pull/$PULL/merge (github's merge)
# * pull/$PULL/local-merge (our merge)
# In case of a clean merge that is accepted by the user, the local branch with
# name $BRANCH is overwritten with the merged result, and optionally pushed.
from __future__ import division,print_function,unicode_literals
import os
from sys import stdin,stdout,stderr
import argparse
import hashlib
import subprocess
import json,codecs
try:
from urllib.request import Request,urlopen
except:
from urllib2 import Request,urlopen
# External tools (can be overridden using environment)
GIT = os.getenv('GIT','git')
BASH = os.getenv('BASH','bash')
# OS specific configuration for terminal attributes
ATTR_RESET = ''
ATTR_PR = ''
COMMIT_FORMAT = '%h %s (%an)%d'
if os.name == 'posix': # if posix, assume we can use basic terminal escapes
ATTR_RESET = '\033[0m'
ATTR_PR = '\033[1;36m'
COMMIT_FORMAT = '%C(bold blue)%h%Creset %s %C(cyan)(%an)%Creset%C(green)%d%Creset'
def git_config_get(option, default=None):
'''
Get named configuration option from git repository.
'''
try:
return subprocess.check_output([GIT,'config','--get',option]).rstrip().decode('utf-8')
except subprocess.CalledProcessError as e:
return default
def retrieve_pr_info(repo,pull):
'''
Retrieve pull request information from github.
Return None if no title can be found, or an error happens.
'''
try:
req = Request("https://api.github.com/repos/"+repo+"/pulls/"+pull)
result = urlopen(req)
reader = codecs.getreader('utf-8')
obj = json.load(reader(result))
return obj
except Exception as e:
print('Warning: unable to retrieve pull information from github: %s' % e)
return None
def ask_prompt(text):
print(text,end=" ",file=stderr)
stderr.flush()
reply = stdin.readline().rstrip()
print("",file=stderr)
return reply
def get_symlink_files():
files = sorted(subprocess.check_output([GIT, 'ls-tree', '--full-tree', '-r', 'HEAD']).splitlines())
ret = []
for f in files:
if (int(f.decode('utf-8').split(" ")[0], 8) & 0o170000) == 0o120000:
ret.append(f.decode('utf-8').split("\t")[1])
return ret
def tree_sha512sum(commit='HEAD'):
# request metadata for entire tree, recursively
files = []
blob_by_name = {}
for line in subprocess.check_output([GIT, 'ls-tree', '--full-tree', '-r', commit]).splitlines():
name_sep = line.index(b'\t')
metadata = line[:name_sep].split() # perms, 'blob', blobid
assert(metadata[1] == b'blob')
name = line[name_sep+1:]
files.append(name)
blob_by_name[name] = metadata[2]
files.sort()
# open connection to git-cat-file in batch mode to request data for all blobs
# this is much faster than launching it per file
p = subprocess.Popen([GIT, 'cat-file', '--batch'], stdout=subprocess.PIPE, stdin=subprocess.PIPE)
overall = hashlib.sha512()
for f in files:
blob = blob_by_name[f]
# request blob
p.stdin.write(blob + b'\n')
p.stdin.flush()
# read header: blob, "blob", size
reply = p.stdout.readline().split()
assert(reply[0] == blob and reply[1] == b'blob')
size = int(reply[2])
# hash the blob data
intern = hashlib.sha512()
ptr = 0
while ptr < size:
bs = min(65536, size - ptr)
piece = p.stdout.read(bs)
if len(piece) == bs:
intern.update(piece)
else:
raise IOError('Premature EOF reading git cat-file output')
ptr += bs
dig = intern.hexdigest()
assert(p.stdout.read(1) == b'\n') # ignore LF that follows blob data
# update overall hash with file hash
overall.update(dig.encode("utf-8"))
overall.update(" ".encode("utf-8"))
overall.update(f)
overall.update("\n".encode("utf-8"))
p.stdin.close()
if p.wait():
raise IOError('Non-zero return value executing git cat-file')
return overall.hexdigest()
def parse_arguments():
epilog = '''
In addition, you can set the following git configuration variables:
githubmerge.repository (mandatory),
user.signingkey (mandatory),
githubmerge.host (default: git@github.com),
githubmerge.branch (no default),
githubmerge.testcmd (default: none).
'''
parser = argparse.ArgumentParser(description='Utility to merge, sign and push github pull requests',
epilog=epilog)
parser.add_argument('pull', metavar='PULL', type=int, nargs=1,
help='Pull request ID to merge')
parser.add_argument('branch', metavar='BRANCH', type=str, nargs='?',
default=None, help='Branch to merge against (default: githubmerge.branch setting, or base branch for pull, or \'master\')')
return parser.parse_args()
def main():
# Extract settings from git repo
repo = git_config_get('githubmerge.repository')
host = git_config_get('githubmerge.host','git@github.com')
opt_branch = git_config_get('githubmerge.branch',None)
testcmd = git_config_get('githubmerge.testcmd')
signingkey = git_config_get('user.signingkey')
if repo is None:
print("ERROR: No repository configured. Use this command to set:", file=stderr)
print("git config githubmerge.repository <owner>/<repo>", file=stderr)
exit(1)
if signingkey is None:
print("ERROR: No GPG signing key set. Set one using:",file=stderr)
print("git config --global user.signingkey <key>",file=stderr)
exit(1)
host_repo = host+":"+repo # shortcut for push/pull target
# Extract settings from command line
args = parse_arguments()
pull = str(args.pull[0])
# Receive pull information from github
info = retrieve_pr_info(repo,pull)
if info is None:
exit(1)
title = info['title']
# precedence order for destination branch argument:
# - command line argument
# - githubmerge.branch setting
# - base branch for pull (as retrieved from github)
# - 'master'
branch = args.branch or opt_branch or info['base']['ref'] or 'master'
# Initialize source branches
head_branch = 'pull/'+pull+'/head'
base_branch = 'pull/'+pull+'/base'
merge_branch = 'pull/'+pull+'/merge'
local_merge_branch = 'pull/'+pull+'/local-merge'
devnull = open(os.devnull,'w')
try:
subprocess.check_call([GIT,'checkout','-q',branch])
except subprocess.CalledProcessError as e:
print("ERROR: Cannot check out branch %s." % (branch), file=stderr)
exit(3)
try:
subprocess.check_call([GIT,'fetch','-q',host_repo,'+refs/pull/'+pull+'/*:refs/heads/pull/'+pull+'/*'])
except subprocess.CalledProcessError as e:
print("ERROR: Cannot find pull request #%s on %s." % (pull,host_repo), file=stderr)
exit(3)
try:
subprocess.check_call([GIT,'log','-q','-1','refs/heads/'+head_branch], stdout=devnull, stderr=stdout)
except subprocess.CalledProcessError as e:
print("ERROR: Cannot find head of pull request #%s on %s." % (pull,host_repo), file=stderr)
exit(3)
try:
subprocess.check_call([GIT,'log','-q','-1','refs/heads/'+merge_branch], stdout=devnull, stderr=stdout)
except subprocess.CalledProcessError as e:
print("ERROR: Cannot find merge of pull request #%s on %s." % (pull,host_repo), file=stderr)
exit(3)
try:
subprocess.check_call([GIT,'fetch','-q',host_repo,'+refs/heads/'+branch+':refs/heads/'+base_branch])
except subprocess.CalledProcessError as e:
print("ERROR: Cannot find branch %s on %s." % (branch,host_repo), file=stderr)
exit(3)
subprocess.check_call([GIT,'checkout','-q',base_branch])
subprocess.call([GIT,'branch','-q','-D',local_merge_branch], stderr=devnull)
subprocess.check_call([GIT,'checkout','-q','-b',local_merge_branch])
try:
# Go up to the repository's root.
toplevel = subprocess.check_output([GIT,'rev-parse','--show-toplevel']).strip()
os.chdir(toplevel)
# Create unsigned merge commit.
if title:
firstline = 'Merge #%s: %s' % (pull,title)
else:
firstline = 'Merge #%s' % (pull,)
message = firstline + '\n\n'
message += subprocess.check_output([GIT,'log','--no-merges','--topo-order','--pretty=format:%h %s (%an)',base_branch+'..'+head_branch]).decode('utf-8')
try:
subprocess.check_call([GIT,'merge','-q','--commit','--no-edit','--no-ff','-m',message.encode('utf-8'),head_branch])
except subprocess.CalledProcessError as e:
print("ERROR: Cannot be merged cleanly.",file=stderr)
subprocess.check_call([GIT,'merge','--abort'])
exit(4)
logmsg = subprocess.check_output([GIT,'log','--pretty=format:%s','-n','1']).decode('utf-8')
if logmsg.rstrip() != firstline.rstrip():
print("ERROR: Creating merge failed (already merged?).",file=stderr)
exit(4)
symlink_files = get_symlink_files()
for f in symlink_files:
print("ERROR: File %s was a symlink" % f)
if len(symlink_files) > 0:
exit(4)
# Put tree SHA512 into the message
try:
first_sha512 = tree_sha512sum()
message += '\n\nTree-SHA512: ' + first_sha512
except subprocess.CalledProcessError as e:
printf("ERROR: Unable to compute tree hash")
exit(4)
try:
subprocess.check_call([GIT,'commit','--amend','-m',message.encode('utf-8')])
except subprocess.CalledProcessError as e:
printf("ERROR: Cannot update message.",file=stderr)
exit(4)
print('%s#%s%s %s %sinto %s%s' % (ATTR_RESET+ATTR_PR,pull,ATTR_RESET,title,ATTR_RESET+ATTR_PR,branch,ATTR_RESET))
subprocess.check_call([GIT,'log','--graph','--topo-order','--pretty=format:'+COMMIT_FORMAT,base_branch+'..'+head_branch])
print()
# Run test command if configured.
if testcmd:
if subprocess.call(testcmd,shell=True):
print("ERROR: Running %s failed." % testcmd,file=stderr)
exit(5)
# Show the created merge.
diff = subprocess.check_output([GIT,'diff',merge_branch+'..'+local_merge_branch])
subprocess.check_call([GIT,'diff',base_branch+'..'+local_merge_branch])
if diff:
print("WARNING: merge differs from github!",file=stderr)
reply = ask_prompt("Type 'ignore' to continue.")
if reply.lower() == 'ignore':
print("Difference with github ignored.",file=stderr)
else:
exit(6)
reply = ask_prompt("Press 'd' to accept the diff.")
if reply.lower() == 'd':
print("Diff accepted.",file=stderr)
else:
print("ERROR: Diff rejected.",file=stderr)
exit(6)
else:
# Verify the result manually.
print("Dropping you on a shell so you can try building/testing the merged source.",file=stderr)
print("Run 'git diff HEAD~' to show the changes being merged.",file=stderr)
print("Type 'exit' when done.",file=stderr)
if os.path.isfile('/etc/debian_version'): # Show pull number on Debian default prompt
os.putenv('debian_chroot',pull)
subprocess.call([BASH,'-i'])
reply = ask_prompt("Type 'm' to accept the merge.")
if reply.lower() == 'm':
print("Merge accepted.",file=stderr)
else:
print("ERROR: Merge rejected.",file=stderr)
exit(7)
second_sha512 = tree_sha512sum()
if first_sha512 != second_sha512:
print("ERROR: Tree hash changed unexpectedly",file=stderr)
exit(8)
# Sign the merge commit.
reply = ask_prompt("Type 's' to sign off on the merge.")
if reply == 's':
try:
subprocess.check_call([GIT,'commit','-q','--gpg-sign','--amend','--no-edit'])
except subprocess.CalledProcessError as e:
print("Error signing, exiting.",file=stderr)
exit(1)
else:
print("Not signing off on merge, exiting.",file=stderr)
exit(1)
# Put the result in branch.
subprocess.check_call([GIT,'checkout','-q',branch])
subprocess.check_call([GIT,'reset','-q','--hard',local_merge_branch])
finally:
# Clean up temporary branches.
subprocess.call([GIT,'checkout','-q',branch])
subprocess.call([GIT,'branch','-q','-D',head_branch],stderr=devnull)
subprocess.call([GIT,'branch','-q','-D',base_branch],stderr=devnull)
subprocess.call([GIT,'branch','-q','-D',merge_branch],stderr=devnull)
subprocess.call([GIT,'branch','-q','-D',local_merge_branch],stderr=devnull)
# Push the result.
reply = ask_prompt("Type 'push' to push the result to %s, branch %s." % (host_repo,branch))
if reply.lower() == 'push':
subprocess.check_call([GIT,'push',host_repo,'refs/heads/'+branch])
if __name__ == '__main__':
main()