contrib/devtools/github-merge.py

   1 #!/usr/bin/env python3
   2 # Copyright (c) 2016 The Bitcoin Core developers
   3 # Distributed under the MIT software license, see the accompanying
   4 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
   5
   6 # This script will locally construct a merge commit for a pull request on a
   7 # github repository, inspect it, sign it and optionally push it.
   8
   9 # The following temporary branches are created/overwritten and deleted:
  10 # * pull/$PULL/base (the current master we're merging onto)
  11 # * pull/$PULL/head (the current state of the remote pull request)
  12 # * pull/$PULL/merge (github's merge)
  13 # * pull/$PULL/local-merge (our merge)
  14
  15 # In case of a clean merge that is accepted by the user, the local branch with
  16 # name $BRANCH is overwritten with the merged result, and optionally pushed.
  17 from __future__ import division,print_function,unicode_literals
  18 import os
  19 from sys import stdin,stdout,stderr
  20 import argparse
  21 import hashlib
  22 import subprocess
  23 import json,codecs
  24 try:
  25     from urllib.request import Request,urlopen
  26 except:
  27     from urllib2 import Request,urlopen
  28
  29 # External tools (can be overridden using environment)
  30 GIT = os.getenv('GIT','git')
  31 BASH = os.getenv('BASH','bash')
  32
  33 # OS specific configuration for terminal attributes
  34 ATTR_RESET = ''
  35 ATTR_PR = ''
  36 COMMIT_FORMAT = '%h %s (%an)%d'
  37 if os.name == 'posix': # if posix, assume we can use basic terminal escapes
  38     ATTR_RESET = '\033[0m'
  39     ATTR_PR = '\033[1;36m'
  40     COMMIT_FORMAT = '%C(bold blue)%h%Creset %s %C(cyan)(%an)%Creset%C(green)%d%Creset'
  41
  42 def git_config_get(option, default=None):
  43     '''
  44     Get named configuration option from git repository.
  45     '''
  46     try:
  47         return subprocess.check_output([GIT,'config','--get',option]).rstrip().decode('utf-8')
  48     except subprocess.CalledProcessError as e:
  49         return default
  50
  51 def retrieve_pr_info(repo,pull):
  52     '''
  53     Retrieve pull request information from github.
  54     Return None if no title can be found, or an error happens.
  55     '''
  56     try:
  57         req = Request("https://api.github.com/repos/"+repo+"/pulls/"+pull)
  58         result = urlopen(req)
  59         reader = codecs.getreader('utf-8')
  60         obj = json.load(reader(result))
  61         return obj
  62     except Exception as e:
  63         print('Warning: unable to retrieve pull information from github: %s' % e)
  64         return None
  65
  66 def ask_prompt(text):
  67     print(text,end=" ",file=stderr)
  68     stderr.flush()
  69     reply = stdin.readline().rstrip()
  70     print("",file=stderr)
  71     return reply
  72
  73 def get_symlink_files():
  74     files = sorted(subprocess.check_output([GIT, 'ls-tree', '--full-tree', '-r', 'HEAD']).splitlines())
  75     ret = []
  76     for f in files:
  77         if (int(f.decode('utf-8').split(" ")[0], 8) & 0o170000) == 0o120000:
  78             ret.append(f.decode('utf-8').split("\t")[1])
  79     return ret
  80
  81 def tree_sha512sum(commit='HEAD'):
  82     # request metadata for entire tree, recursively
  83     files = []
  84     blob_by_name = {}
  85     for line in subprocess.check_output([GIT, 'ls-tree', '--full-tree', '-r', commit]).splitlines():
  86         name_sep = line.index(b'\t')
  87         metadata = line[:name_sep].split() # perms, 'blob', blobid
  88         assert(metadata[1] == b'blob')
  89         name = line[name_sep+1:]
  90         files.append(name)
  91         blob_by_name[name] = metadata[2]
  92
  93     files.sort()
  94     # open connection to git-cat-file in batch mode to request data for all blobs
  95     # this is much faster than launching it per file
  96     p = subprocess.Popen([GIT, 'cat-file', '--batch'], stdout=subprocess.PIPE, stdin=subprocess.PIPE)
  97     overall = hashlib.sha512()
  98     for f in files:
  99         blob = blob_by_name[f]
 100         # request blob
 101         p.stdin.write(blob + b'\n')
 102         p.stdin.flush()
 103         # read header: blob, "blob", size
 104         reply = p.stdout.readline().split()
 105         assert(reply[0] == blob and reply[1] == b'blob')
 106         size = int(reply[2])
 107         # hash the blob data
 108         intern = hashlib.sha512()
 109         ptr = 0
 110         while ptr < size:
 111             bs = min(65536, size - ptr)
 112             piece = p.stdout.read(bs)
 113             if len(piece) == bs:
 114                 intern.update(piece)
 115             else:
 116                 raise IOError('Premature EOF reading git cat-file output')
 117             ptr += bs
 118         dig = intern.hexdigest()
 119         assert(p.stdout.read(1) == b'\n') # ignore LF that follows blob data
 120         # update overall hash with file hash
 121         overall.update(dig.encode("utf-8"))
 122         overall.update("  ".encode("utf-8"))
 123         overall.update(f)
 124         overall.update("\n".encode("utf-8"))
 125     p.stdin.close()
 126     if p.wait():
 127         raise IOError('Non-zero return value executing git cat-file')
 128     return overall.hexdigest()
 129
 130
 131 def parse_arguments():
 132     epilog = '''
 133         In addition, you can set the following git configuration variables:
 134         githubmerge.repository (mandatory),
 135         user.signingkey (mandatory),
 136         githubmerge.host (default: git@github.com),
 137         githubmerge.branch (no default),
 138         githubmerge.testcmd (default: none).
 139     '''
 140     parser = argparse.ArgumentParser(description='Utility to merge, sign and push github pull requests',
 141             epilog=epilog)
 142     parser.add_argument('pull', metavar='PULL', type=int, nargs=1,
 143         help='Pull request ID to merge')
 144     parser.add_argument('branch', metavar='BRANCH', type=str, nargs='?',
 145         default=None, help='Branch to merge against (default: githubmerge.branch setting, or base branch for pull, or \'master\')')
 146     return parser.parse_args()
 147
 148 def main():
 149     # Extract settings from git repo
 150     repo = git_config_get('githubmerge.repository')
 151     host = git_config_get('githubmerge.host','git@github.com')
 152     opt_branch = git_config_get('githubmerge.branch',None)
 153     testcmd = git_config_get('githubmerge.testcmd')
 154     signingkey = git_config_get('user.signingkey')
 155     if repo is None:
 156         print("ERROR: No repository configured. Use this command to set:", file=stderr)
 157         print("git config githubmerge.repository <owner>/<repo>", file=stderr)
 158         exit(1)
 159     if signingkey is None:
 160         print("ERROR: No GPG signing key set. Set one using:",file=stderr)
 161         print("git config --global user.signingkey <key>",file=stderr)
 162         exit(1)
 163
 164     host_repo = host+":"+repo # shortcut for push/pull target
 165
 166     # Extract settings from command line
 167     args = parse_arguments()
 168     pull = str(args.pull[0])
 169
 170     # Receive pull information from github
 171     info = retrieve_pr_info(repo,pull)
 172     if info is None:
 173         exit(1)
 174     title = info['title']
 175     # precedence order for destination branch argument:
 176     #   - command line argument
 177     #   - githubmerge.branch setting
 178     #   - base branch for pull (as retrieved from github)
 179     #   - 'master'
 180     branch = args.branch or opt_branch or info['base']['ref'] or 'master'
 181
 182     # Initialize source branches
 183     head_branch = 'pull/'+pull+'/head'
 184     base_branch = 'pull/'+pull+'/base'
 185     merge_branch = 'pull/'+pull+'/merge'
 186     local_merge_branch = 'pull/'+pull+'/local-merge'
 187
 188     devnull = open(os.devnull,'w')
 189     try:
 190         subprocess.check_call([GIT,'checkout','-q',branch])
 191     except subprocess.CalledProcessError as e:
 192         print("ERROR: Cannot check out branch %s." % (branch), file=stderr)
 193         exit(3)
 194     try:
 195         subprocess.check_call([GIT,'fetch','-q',host_repo,'+refs/pull/'+pull+'/*:refs/heads/pull/'+pull+'/*'])
 196     except subprocess.CalledProcessError as e:
 197         print("ERROR: Cannot find pull request #%s on %s." % (pull,host_repo), file=stderr)
 198         exit(3)
 199     try:
 200         subprocess.check_call([GIT,'log','-q','-1','refs/heads/'+head_branch], stdout=devnull, stderr=stdout)
 201     except subprocess.CalledProcessError as e:
 202         print("ERROR: Cannot find head of pull request #%s on %s." % (pull,host_repo), file=stderr)
 203         exit(3)
 204     try:
 205         subprocess.check_call([GIT,'log','-q','-1','refs/heads/'+merge_branch], stdout=devnull, stderr=stdout)
 206     except subprocess.CalledProcessError as e:
 207         print("ERROR: Cannot find merge of pull request #%s on %s." % (pull,host_repo), file=stderr)
 208         exit(3)
 209     try:
 210         subprocess.check_call([GIT,'fetch','-q',host_repo,'+refs/heads/'+branch+':refs/heads/'+base_branch])
 211     except subprocess.CalledProcessError as e:
 212         print("ERROR: Cannot find branch %s on %s." % (branch,host_repo), file=stderr)
 213         exit(3)
 214     subprocess.check_call([GIT,'checkout','-q',base_branch])
 215     subprocess.call([GIT,'branch','-q','-D',local_merge_branch], stderr=devnull)
 216     subprocess.check_call([GIT,'checkout','-q','-b',local_merge_branch])
 217
 218     try:
 219         # Go up to the repository's root.
 220         toplevel = subprocess.check_output([GIT,'rev-parse','--show-toplevel']).strip()
 221         os.chdir(toplevel)
 222         # Create unsigned merge commit.
 223         if title:
 224             firstline = 'Merge #%s: %s' % (pull,title)
 225         else:
 226             firstline = 'Merge #%s' % (pull,)
 227         message = firstline + '\n\n'
 228         message += subprocess.check_output([GIT,'log','--no-merges','--topo-order','--pretty=format:%h %s (%an)',base_branch+'..'+head_branch]).decode('utf-8')
 229         try:
 230             subprocess.check_call([GIT,'merge','-q','--commit','--no-edit','--no-ff','-m',message.encode('utf-8'),head_branch])
 231         except subprocess.CalledProcessError as e:
 232             print("ERROR: Cannot be merged cleanly.",file=stderr)
 233             subprocess.check_call([GIT,'merge','--abort'])
 234             exit(4)
 235         logmsg = subprocess.check_output([GIT,'log','--pretty=format:%s','-n','1']).decode('utf-8')
 236         if logmsg.rstrip() != firstline.rstrip():
 237             print("ERROR: Creating merge failed (already merged?).",file=stderr)
 238             exit(4)
 239
 240         symlink_files = get_symlink_files()
 241         for f in symlink_files:
 242             print("ERROR: File %s was a symlink" % f)
 243         if len(symlink_files) > 0:
 244             exit(4)
 245
 246         # Put tree SHA512 into the message
 247         try:
 248             first_sha512 = tree_sha512sum()
 249             message += '\n\nTree-SHA512: ' + first_sha512
 250         except subprocess.CalledProcessError as e:
 251             printf("ERROR: Unable to compute tree hash")
 252             exit(4)
 253         try:
 254             subprocess.check_call([GIT,'commit','--amend','-m',message.encode('utf-8')])
 255         except subprocess.CalledProcessError as e:
 256             printf("ERROR: Cannot update message.",file=stderr)
 257             exit(4)
 258
 259         print('%s#%s%s %s %sinto %s%s' % (ATTR_RESET+ATTR_PR,pull,ATTR_RESET,title,ATTR_RESET+ATTR_PR,branch,ATTR_RESET))
 260         subprocess.check_call([GIT,'log','--graph','--topo-order','--pretty=format:'+COMMIT_FORMAT,base_branch+'..'+head_branch])
 261         print()
 262
 263         # Run test command if configured.
 264         if testcmd:
 265             if subprocess.call(testcmd,shell=True):
 266                 print("ERROR: Running %s failed." % testcmd,file=stderr)
 267                 exit(5)
 268
 269             # Show the created merge.
 270             diff = subprocess.check_output([GIT,'diff',merge_branch+'..'+local_merge_branch])
 271             subprocess.check_call([GIT,'diff',base_branch+'..'+local_merge_branch])
 272             if diff:
 273                 print("WARNING: merge differs from github!",file=stderr)
 274                 reply = ask_prompt("Type 'ignore' to continue.")
 275                 if reply.lower() == 'ignore':
 276                     print("Difference with github ignored.",file=stderr)
 277                 else:
 278                     exit(6)
 279             reply = ask_prompt("Press 'd' to accept the diff.")
 280             if reply.lower() == 'd':
 281                 print("Diff accepted.",file=stderr)
 282             else:
 283                 print("ERROR: Diff rejected.",file=stderr)
 284                 exit(6)
 285         else:
 286             # Verify the result manually.
 287             print("Dropping you on a shell so you can try building/testing the merged source.",file=stderr)
 288             print("Run 'git diff HEAD~' to show the changes being merged.",file=stderr)
 289             print("Type 'exit' when done.",file=stderr)
 290             if os.path.isfile('/etc/debian_version'): # Show pull number on Debian default prompt
 291                 os.putenv('debian_chroot',pull)
 292             subprocess.call([BASH,'-i'])
 293             reply = ask_prompt("Type 'm' to accept the merge.")
 294             if reply.lower() == 'm':
 295                 print("Merge accepted.",file=stderr)
 296             else:
 297                 print("ERROR: Merge rejected.",file=stderr)
 298                 exit(7)
 299
 300         second_sha512 = tree_sha512sum()
 301         if first_sha512 != second_sha512:
 302             print("ERROR: Tree hash changed unexpectedly",file=stderr)
 303             exit(8)
 304
 305         # Sign the merge commit.
 306         reply = ask_prompt("Type 's' to sign off on the merge.")
 307         if reply == 's':
 308             try:
 309                 subprocess.check_call([GIT,'commit','-q','--gpg-sign','--amend','--no-edit'])
 310             except subprocess.CalledProcessError as e:
 311                 print("Error signing, exiting.",file=stderr)
 312                 exit(1)
 313         else:
 314             print("Not signing off on merge, exiting.",file=stderr)
 315             exit(1)
 316
 317         # Put the result in branch.
 318         subprocess.check_call([GIT,'checkout','-q',branch])
 319         subprocess.check_call([GIT,'reset','-q','--hard',local_merge_branch])
 320     finally:
 321         # Clean up temporary branches.
 322         subprocess.call([GIT,'checkout','-q',branch])
 323         subprocess.call([GIT,'branch','-q','-D',head_branch],stderr=devnull)
 324         subprocess.call([GIT,'branch','-q','-D',base_branch],stderr=devnull)
 325         subprocess.call([GIT,'branch','-q','-D',merge_branch],stderr=devnull)
 326         subprocess.call([GIT,'branch','-q','-D',local_merge_branch],stderr=devnull)
 327
 328     # Push the result.
 329     reply = ask_prompt("Type 'push' to push the result to %s, branch %s." % (host_repo,branch))
 330     if reply.lower() == 'push':
 331         subprocess.check_call([GIT,'push',host_repo,'refs/heads/'+branch])
 332
 333 if __name__ == '__main__':
 334     main()
 335