1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
#!/usr/bin/env python
#
#
#                             Ravenbrook
#                    <https://www.ravenbrook.com/>
#
#           P4-BISECT -- FIND CHANGE THAT INTRODUCED A BUG
#
#            Gareth Rees, Ravenbrook Limited, 2014-04-14
#
#
# 1. INTRODUCTION
#
# This script automates (or partly automates) the process of finding,
# by binary search, the change that introduced a bug.
#
# The interface is modelled closely on git-bisect(1).

import argparse
from functools import partial
import json
from os import unlink
import p4
import subprocess
import sys

BISECT_FILE = '.p4-bisect'

def error(msg):
    sys.stderr.write(msg)
    sys.stderr.write('\n')
    exit(1)

def sync(*filespecs):
    try:
        p4.do('sync', *filespecs)
    except p4.Error as e:
        if 'file(s) up-to-date' not in e.args[0]:
            raise

class State(object):
    def __init__(self, **d):
        self.filespec = d['filespec']
        self.changes = d['changes']
        if 'current' in d:
            self.current = d['current']

    @classmethod
    def load(cls):
        try:
            with open(BISECT_FILE, 'r') as f:
                return cls(**json.load(f))
        except FileNotFoundError:
            error("p4-bisect not in progress here.")

    def save(self):
        with open(BISECT_FILE, 'w') as f:
            json.dump(vars(self), f)

    def update(self):
        n = len(self.changes)
        if n == 0:
            print("no changes remaining.".format(**vars(self)))
        elif n == 1:
            print("{} change remaining: {}.".format(n, self.changes[0]))
        elif n == 2:
            print("{} changes remaining: [{}, {}]."
                  .format(n, self.changes[0], self.changes[-1]))
        else:
            print("{} changes remaining: [{}, ..., {}]."
                  .format(n, self.changes[0], self.changes[-1]))
        if n > 0:
            self.current = self.changes[n // 2]
            print("Syncing to changelevel {current}.".format(**vars(self)))
            sync(*['{}@{}'.format(f, self.current) for f in self.filespec])
        self.save()

def help(parser, args):
    parser.print_help()

def start(args):
    args.filespec = args.filespec or ['...']
    changes = sorted(int(c['change']) for c in p4.run('changes', *args.filespec))
    if not changes:
        error("No changes for {}".format(' '.join(args.filespec)))
    if args.good is None:
        args.good = changes[0]
    if args.bad is None:
        args.bad = changes[-1]
    state = State(filespec=args.filespec,
                  changes=[c for c in changes if args.good <= c <= args.bad])
    state.update()

def good(args):
    state = State.load()
    print("Change {current} good.".format(**vars(state)))
    state.changes = [c for c in state.changes if c > state.current]
    state.update()

def bad(args):
    state = State.load()
    print("Change {current} bad.".format(**vars(state)))
    state.changes = [c for c in state.changes if c < state.current]
    state.update()

def skip(args):
    state = State.load()
    print("Skipping change {current}.".format(**vars(state)))
    state.changes.remove(state.current)
    state.update()

def reset(args):
    state = State.load()
    sync(*state.filespec)
    unlink(BISECT_FILE)

def run(args):
    while True:
        state = State.load()
        if not state.changes:
            break
        result = subprocess.call([args.cmd] + args.args)
        if result == 0:
            good(None)
        elif result == 125:
            skip(None)
        elif 0 < result < 128:
            bad(None)
        else:
            exit(result)

def main(argv):
    parser = argparse.ArgumentParser(
        prog='p4-bisect', epilog='For help on CMD, use p4-bisect CMD -h')
    subparsers = parser.add_subparsers()
    a = subparsers.add_parser

    help_parser = a('help', help='show this help message')
    help_parser.set_defaults(func=partial(help, parser))

    start_parser = a('start', help='start a p4-bisect session')
    aa = start_parser.add_argument
    start_parser.add_argument('-f', '--filespec', action='append',
                              help='filespec(s) to search')
    start_parser.add_argument('good', nargs='?', type=int,
                              help='known good changelevel')
    start_parser.add_argument('bad', nargs='?', type=int,
                              help='known bad changelevel')
    start_parser.set_defaults(func=start)

    good_parser = a('good', help='declare current revision good')
    good_parser.set_defaults(func=good)

    bad_parser = a('bad', help='declare current revision bad')
    bad_parser.set_defaults(func=bad)

    skip_parser = a('skip', help='skip current revision')
    skip_parser.set_defaults(func=skip)

    reset_parser = a('reset', help='finish p4-bisect session')
    reset_parser.set_defaults(func=reset)

    run_parser = a('run', help='run p4-bisect session automatically')
    run_parser.add_argument('cmd',
                            help='command that determines if current '
                            'changelevel is good or bad')
    run_parser.add_argument('args', nargs=argparse.REMAINDER,
                            help='arguments to pass to cmd')
    run_parser.set_defaults(func=run)

    args = parser.parse_args(argv[1:])
    args.func(args)

if __name__ == '__main__':
    main(sys.argv)