This file is indexed.

/usr/lib/python2.7/dist-packages/mercurial/scmutil.py is in mercurial-common 4.5.3-1ubuntu2.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

   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
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
# scmutil.py - Mercurial core utility functions
#
#  Copyright Matt Mackall <mpm@selenic.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import errno
import glob
import hashlib
import os
import re
import socket
import subprocess
import weakref

from .i18n import _
from .node import (
    hex,
    nullid,
    short,
    wdirid,
    wdirrev,
)

from . import (
    encoding,
    error,
    match as matchmod,
    obsolete,
    obsutil,
    pathutil,
    phases,
    pycompat,
    revsetlang,
    similar,
    url,
    util,
    vfs,
)

if pycompat.iswindows:
    from . import scmwindows as scmplatform
else:
    from . import scmposix as scmplatform

termsize = scmplatform.termsize

class status(tuple):
    '''Named tuple with a list of files per status. The 'deleted', 'unknown'
       and 'ignored' properties are only relevant to the working copy.
    '''

    __slots__ = ()

    def __new__(cls, modified, added, removed, deleted, unknown, ignored,
                clean):
        return tuple.__new__(cls, (modified, added, removed, deleted, unknown,
                                   ignored, clean))

    @property
    def modified(self):
        '''files that have been modified'''
        return self[0]

    @property
    def added(self):
        '''files that have been added'''
        return self[1]

    @property
    def removed(self):
        '''files that have been removed'''
        return self[2]

    @property
    def deleted(self):
        '''files that are in the dirstate, but have been deleted from the
           working copy (aka "missing")
        '''
        return self[3]

    @property
    def unknown(self):
        '''files not in the dirstate that are not ignored'''
        return self[4]

    @property
    def ignored(self):
        '''files not in the dirstate that are ignored (by _dirignore())'''
        return self[5]

    @property
    def clean(self):
        '''files that have not been modified'''
        return self[6]

    def __repr__(self, *args, **kwargs):
        return (('<status modified=%r, added=%r, removed=%r, deleted=%r, '
                 'unknown=%r, ignored=%r, clean=%r>') % self)

def itersubrepos(ctx1, ctx2):
    """find subrepos in ctx1 or ctx2"""
    # Create a (subpath, ctx) mapping where we prefer subpaths from
    # ctx1. The subpaths from ctx2 are important when the .hgsub file
    # has been modified (in ctx2) but not yet committed (in ctx1).
    subpaths = dict.fromkeys(ctx2.substate, ctx2)
    subpaths.update(dict.fromkeys(ctx1.substate, ctx1))

    missing = set()

    for subpath in ctx2.substate:
        if subpath not in ctx1.substate:
            del subpaths[subpath]
            missing.add(subpath)

    for subpath, ctx in sorted(subpaths.iteritems()):
        yield subpath, ctx.sub(subpath)

    # Yield an empty subrepo based on ctx1 for anything only in ctx2.  That way,
    # status and diff will have an accurate result when it does
    # 'sub.{status|diff}(rev2)'.  Otherwise, the ctx2 subrepo is compared
    # against itself.
    for subpath in missing:
        yield subpath, ctx2.nullsub(subpath, ctx1)

def nochangesfound(ui, repo, excluded=None):
    '''Report no changes for push/pull, excluded is None or a list of
    nodes excluded from the push/pull.
    '''
    secretlist = []
    if excluded:
        for n in excluded:
            ctx = repo[n]
            if ctx.phase() >= phases.secret and not ctx.extinct():
                secretlist.append(n)

    if secretlist:
        ui.status(_("no changes found (ignored %d secret changesets)\n")
                  % len(secretlist))
    else:
        ui.status(_("no changes found\n"))

def callcatch(ui, func):
    """call func() with global exception handling

    return func() if no exception happens. otherwise do some error handling
    and return an exit code accordingly. does not handle all exceptions.
    """
    try:
        try:
            return func()
        except: # re-raises
            ui.traceback()
            raise
    # Global exception handling, alphabetically
    # Mercurial-specific first, followed by built-in and library exceptions
    except error.LockHeld as inst:
        if inst.errno == errno.ETIMEDOUT:
            reason = _('timed out waiting for lock held by %r') % inst.locker
        else:
            reason = _('lock held by %r') % inst.locker
        ui.warn(_("abort: %s: %s\n") % (inst.desc or inst.filename, reason))
        if not inst.locker:
            ui.warn(_("(lock might be very busy)\n"))
    except error.LockUnavailable as inst:
        ui.warn(_("abort: could not lock %s: %s\n") %
               (inst.desc or inst.filename,
                encoding.strtolocal(inst.strerror)))
    except error.OutOfBandError as inst:
        if inst.args:
            msg = _("abort: remote error:\n")
        else:
            msg = _("abort: remote error\n")
        ui.warn(msg)
        if inst.args:
            ui.warn(''.join(inst.args))
        if inst.hint:
            ui.warn('(%s)\n' % inst.hint)
    except error.RepoError as inst:
        ui.warn(_("abort: %s!\n") % inst)
        if inst.hint:
            ui.warn(_("(%s)\n") % inst.hint)
    except error.ResponseError as inst:
        ui.warn(_("abort: %s") % inst.args[0])
        if not isinstance(inst.args[1], basestring):
            ui.warn(" %r\n" % (inst.args[1],))
        elif not inst.args[1]:
            ui.warn(_(" empty string\n"))
        else:
            ui.warn("\n%r\n" % util.ellipsis(inst.args[1]))
    except error.CensoredNodeError as inst:
        ui.warn(_("abort: file censored %s!\n") % inst)
    except error.RevlogError as inst:
        ui.warn(_("abort: %s!\n") % inst)
    except error.InterventionRequired as inst:
        ui.warn("%s\n" % inst)
        if inst.hint:
            ui.warn(_("(%s)\n") % inst.hint)
        return 1
    except error.WdirUnsupported:
        ui.warn(_("abort: working directory revision cannot be specified\n"))
    except error.Abort as inst:
        ui.warn(_("abort: %s\n") % inst)
        if inst.hint:
            ui.warn(_("(%s)\n") % inst.hint)
    except ImportError as inst:
        ui.warn(_("abort: %s!\n") % inst)
        m = str(inst).split()[-1]
        if m in "mpatch bdiff".split():
            ui.warn(_("(did you forget to compile extensions?)\n"))
        elif m in "zlib".split():
            ui.warn(_("(is your Python install correct?)\n"))
    except IOError as inst:
        if util.safehasattr(inst, "code"):
            ui.warn(_("abort: %s\n") % inst)
        elif util.safehasattr(inst, "reason"):
            try: # usually it is in the form (errno, strerror)
                reason = inst.reason.args[1]
            except (AttributeError, IndexError):
                # it might be anything, for example a string
                reason = inst.reason
            if isinstance(reason, unicode):
                # SSLError of Python 2.7.9 contains a unicode
                reason = encoding.unitolocal(reason)
            ui.warn(_("abort: error: %s\n") % reason)
        elif (util.safehasattr(inst, "args")
              and inst.args and inst.args[0] == errno.EPIPE):
            pass
        elif getattr(inst, "strerror", None):
            if getattr(inst, "filename", None):
                ui.warn(_("abort: %s: %s\n") % (
                    encoding.strtolocal(inst.strerror), inst.filename))
            else:
                ui.warn(_("abort: %s\n") % encoding.strtolocal(inst.strerror))
        else:
            raise
    except OSError as inst:
        if getattr(inst, "filename", None) is not None:
            ui.warn(_("abort: %s: '%s'\n") % (
                encoding.strtolocal(inst.strerror), inst.filename))
        else:
            ui.warn(_("abort: %s\n") % encoding.strtolocal(inst.strerror))
    except MemoryError:
        ui.warn(_("abort: out of memory\n"))
    except SystemExit as inst:
        # Commands shouldn't sys.exit directly, but give a return code.
        # Just in case catch this and and pass exit code to caller.
        return inst.code
    except socket.error as inst:
        ui.warn(_("abort: %s\n") % inst.args[-1])

    return -1

def checknewlabel(repo, lbl, kind):
    # Do not use the "kind" parameter in ui output.
    # It makes strings difficult to translate.
    if lbl in ['tip', '.', 'null']:
        raise error.Abort(_("the name '%s' is reserved") % lbl)
    for c in (':', '\0', '\n', '\r'):
        if c in lbl:
            raise error.Abort(_("%r cannot be used in a name") % c)
    try:
        int(lbl)
        raise error.Abort(_("cannot use an integer as a name"))
    except ValueError:
        pass

def checkfilename(f):
    '''Check that the filename f is an acceptable filename for a tracked file'''
    if '\r' in f or '\n' in f:
        raise error.Abort(_("'\\n' and '\\r' disallowed in filenames: %r") % f)

def checkportable(ui, f):
    '''Check if filename f is portable and warn or abort depending on config'''
    checkfilename(f)
    abort, warn = checkportabilityalert(ui)
    if abort or warn:
        msg = util.checkwinfilename(f)
        if msg:
            msg = "%s: %s" % (msg, util.shellquote(f))
            if abort:
                raise error.Abort(msg)
            ui.warn(_("warning: %s\n") % msg)

def checkportabilityalert(ui):
    '''check if the user's config requests nothing, a warning, or abort for
    non-portable filenames'''
    val = ui.config('ui', 'portablefilenames')
    lval = val.lower()
    bval = util.parsebool(val)
    abort = pycompat.iswindows or lval == 'abort'
    warn = bval or lval == 'warn'
    if bval is None and not (warn or abort or lval == 'ignore'):
        raise error.ConfigError(
            _("ui.portablefilenames value is invalid ('%s')") % val)
    return abort, warn

class casecollisionauditor(object):
    def __init__(self, ui, abort, dirstate):
        self._ui = ui
        self._abort = abort
        allfiles = '\0'.join(dirstate._map)
        self._loweredfiles = set(encoding.lower(allfiles).split('\0'))
        self._dirstate = dirstate
        # The purpose of _newfiles is so that we don't complain about
        # case collisions if someone were to call this object with the
        # same filename twice.
        self._newfiles = set()

    def __call__(self, f):
        if f in self._newfiles:
            return
        fl = encoding.lower(f)
        if fl in self._loweredfiles and f not in self._dirstate:
            msg = _('possible case-folding collision for %s') % f
            if self._abort:
                raise error.Abort(msg)
            self._ui.warn(_("warning: %s\n") % msg)
        self._loweredfiles.add(fl)
        self._newfiles.add(f)

def filteredhash(repo, maxrev):
    """build hash of filtered revisions in the current repoview.

    Multiple caches perform up-to-date validation by checking that the
    tiprev and tipnode stored in the cache file match the current repository.
    However, this is not sufficient for validating repoviews because the set
    of revisions in the view may change without the repository tiprev and
    tipnode changing.

    This function hashes all the revs filtered from the view and returns
    that SHA-1 digest.
    """
    cl = repo.changelog
    if not cl.filteredrevs:
        return None
    key = None
    revs = sorted(r for r in cl.filteredrevs if r <= maxrev)
    if revs:
        s = hashlib.sha1()
        for rev in revs:
            s.update('%d;' % rev)
        key = s.digest()
    return key

def walkrepos(path, followsym=False, seen_dirs=None, recurse=False):
    '''yield every hg repository under path, always recursively.
    The recurse flag will only control recursion into repo working dirs'''
    def errhandler(err):
        if err.filename == path:
            raise err
    samestat = getattr(os.path, 'samestat', None)
    if followsym and samestat is not None:
        def adddir(dirlst, dirname):
            match = False
            dirstat = os.stat(dirname)
            for lstdirstat in dirlst:
                if samestat(dirstat, lstdirstat):
                    match = True
                    break
            if not match:
                dirlst.append(dirstat)
            return not match
    else:
        followsym = False

    if (seen_dirs is None) and followsym:
        seen_dirs = []
        adddir(seen_dirs, path)
    for root, dirs, files in os.walk(path, topdown=True, onerror=errhandler):
        dirs.sort()
        if '.hg' in dirs:
            yield root # found a repository
            qroot = os.path.join(root, '.hg', 'patches')
            if os.path.isdir(os.path.join(qroot, '.hg')):
                yield qroot # we have a patch queue repo here
            if recurse:
                # avoid recursing inside the .hg directory
                dirs.remove('.hg')
            else:
                dirs[:] = [] # don't descend further
        elif followsym:
            newdirs = []
            for d in dirs:
                fname = os.path.join(root, d)
                if adddir(seen_dirs, fname):
                    if os.path.islink(fname):
                        for hgname in walkrepos(fname, True, seen_dirs):
                            yield hgname
                    else:
                        newdirs.append(d)
            dirs[:] = newdirs

def binnode(ctx):
    """Return binary node id for a given basectx"""
    node = ctx.node()
    if node is None:
        return wdirid
    return node

def intrev(ctx):
    """Return integer for a given basectx that can be used in comparison or
    arithmetic operation"""
    rev = ctx.rev()
    if rev is None:
        return wdirrev
    return rev

def formatchangeid(ctx):
    """Format changectx as '{rev}:{node|formatnode}', which is the default
    template provided by cmdutil.changeset_templater"""
    repo = ctx.repo()
    return formatrevnode(repo.ui, intrev(ctx), binnode(ctx))

def formatrevnode(ui, rev, node):
    """Format given revision and node depending on the current verbosity"""
    if ui.debugflag:
        hexfunc = hex
    else:
        hexfunc = short
    return '%d:%s' % (rev, hexfunc(node))

def revsingle(repo, revspec, default='.', localalias=None):
    if not revspec and revspec != 0:
        return repo[default]

    l = revrange(repo, [revspec], localalias=localalias)
    if not l:
        raise error.Abort(_('empty revision set'))
    return repo[l.last()]

def _pairspec(revspec):
    tree = revsetlang.parse(revspec)
    return tree and tree[0] in ('range', 'rangepre', 'rangepost', 'rangeall')

def revpair(repo, revs):
    if not revs:
        return repo.dirstate.p1(), None

    l = revrange(repo, revs)

    if not l:
        first = second = None
    elif l.isascending():
        first = l.min()
        second = l.max()
    elif l.isdescending():
        first = l.max()
        second = l.min()
    else:
        first = l.first()
        second = l.last()

    if first is None:
        raise error.Abort(_('empty revision range'))
    if (first == second and len(revs) >= 2
        and not all(revrange(repo, [r]) for r in revs)):
        raise error.Abort(_('empty revision on one side of range'))

    # if top-level is range expression, the result must always be a pair
    if first == second and len(revs) == 1 and not _pairspec(revs[0]):
        return repo.lookup(first), None

    return repo.lookup(first), repo.lookup(second)

def revrange(repo, specs, localalias=None):
    """Execute 1 to many revsets and return the union.

    This is the preferred mechanism for executing revsets using user-specified
    config options, such as revset aliases.

    The revsets specified by ``specs`` will be executed via a chained ``OR``
    expression. If ``specs`` is empty, an empty result is returned.

    ``specs`` can contain integers, in which case they are assumed to be
    revision numbers.

    It is assumed the revsets are already formatted. If you have arguments
    that need to be expanded in the revset, call ``revsetlang.formatspec()``
    and pass the result as an element of ``specs``.

    Specifying a single revset is allowed.

    Returns a ``revset.abstractsmartset`` which is a list-like interface over
    integer revisions.
    """
    allspecs = []
    for spec in specs:
        if isinstance(spec, int):
            spec = revsetlang.formatspec('rev(%d)', spec)
        allspecs.append(spec)
    return repo.anyrevs(allspecs, user=True, localalias=localalias)

def meaningfulparents(repo, ctx):
    """Return list of meaningful (or all if debug) parentrevs for rev.

    For merges (two non-nullrev revisions) both parents are meaningful.
    Otherwise the first parent revision is considered meaningful if it
    is not the preceding revision.
    """
    parents = ctx.parents()
    if len(parents) > 1:
        return parents
    if repo.ui.debugflag:
        return [parents[0], repo['null']]
    if parents[0].rev() >= intrev(ctx) - 1:
        return []
    return parents

def expandpats(pats):
    '''Expand bare globs when running on windows.
    On posix we assume it already has already been done by sh.'''
    if not util.expandglobs:
        return list(pats)
    ret = []
    for kindpat in pats:
        kind, pat = matchmod._patsplit(kindpat, None)
        if kind is None:
            try:
                globbed = glob.glob(pat)
            except re.error:
                globbed = [pat]
            if globbed:
                ret.extend(globbed)
                continue
        ret.append(kindpat)
    return ret

def matchandpats(ctx, pats=(), opts=None, globbed=False, default='relpath',
                 badfn=None):
    '''Return a matcher and the patterns that were used.
    The matcher will warn about bad matches, unless an alternate badfn callback
    is provided.'''
    if pats == ("",):
        pats = []
    if opts is None:
        opts = {}
    if not globbed and default == 'relpath':
        pats = expandpats(pats or [])

    def bad(f, msg):
        ctx.repo().ui.warn("%s: %s\n" % (m.rel(f), msg))

    if badfn is None:
        badfn = bad

    m = ctx.match(pats, opts.get('include'), opts.get('exclude'),
                  default, listsubrepos=opts.get('subrepos'), badfn=badfn)

    if m.always():
        pats = []
    return m, pats

def match(ctx, pats=(), opts=None, globbed=False, default='relpath',
          badfn=None):
    '''Return a matcher that will warn about bad matches.'''
    return matchandpats(ctx, pats, opts, globbed, default, badfn=badfn)[0]

def matchall(repo):
    '''Return a matcher that will efficiently match everything.'''
    return matchmod.always(repo.root, repo.getcwd())

def matchfiles(repo, files, badfn=None):
    '''Return a matcher that will efficiently match exactly these files.'''
    return matchmod.exact(repo.root, repo.getcwd(), files, badfn=badfn)

def parsefollowlinespattern(repo, rev, pat, msg):
    """Return a file name from `pat` pattern suitable for usage in followlines
    logic.
    """
    if not matchmod.patkind(pat):
        return pathutil.canonpath(repo.root, repo.getcwd(), pat)
    else:
        ctx = repo[rev]
        m = matchmod.match(repo.root, repo.getcwd(), [pat], ctx=ctx)
        files = [f for f in ctx if m(f)]
        if len(files) != 1:
            raise error.ParseError(msg)
        return files[0]

def origpath(ui, repo, filepath):
    '''customize where .orig files are created

    Fetch user defined path from config file: [ui] origbackuppath = <path>
    Fall back to default (filepath with .orig suffix) if not specified
    '''
    origbackuppath = ui.config('ui', 'origbackuppath')
    if not origbackuppath:
        return filepath + ".orig"

    # Convert filepath from an absolute path into a path inside the repo.
    filepathfromroot = util.normpath(os.path.relpath(filepath,
                                                     start=repo.root))

    origvfs = vfs.vfs(repo.wjoin(origbackuppath))
    origbackupdir = origvfs.dirname(filepathfromroot)
    if not origvfs.isdir(origbackupdir) or origvfs.islink(origbackupdir):
        ui.note(_('creating directory: %s\n') % origvfs.join(origbackupdir))

        # Remove any files that conflict with the backup file's path
        for f in reversed(list(util.finddirs(filepathfromroot))):
            if origvfs.isfileorlink(f):
                ui.note(_('removing conflicting file: %s\n')
                        % origvfs.join(f))
                origvfs.unlink(f)
                break

        origvfs.makedirs(origbackupdir)

    if origvfs.isdir(filepathfromroot) and not origvfs.islink(filepathfromroot):
        ui.note(_('removing conflicting directory: %s\n')
                % origvfs.join(filepathfromroot))
        origvfs.rmtree(filepathfromroot, forcibly=True)

    return origvfs.join(filepathfromroot)

class _containsnode(object):
    """proxy __contains__(node) to container.__contains__ which accepts revs"""

    def __init__(self, repo, revcontainer):
        self._torev = repo.changelog.rev
        self._revcontains = revcontainer.__contains__

    def __contains__(self, node):
        return self._revcontains(self._torev(node))

def cleanupnodes(repo, replacements, operation, moves=None, metadata=None):
    """do common cleanups when old nodes are replaced by new nodes

    That includes writing obsmarkers or stripping nodes, and moving bookmarks.
    (we might also want to move working directory parent in the future)

    By default, bookmark moves are calculated automatically from 'replacements',
    but 'moves' can be used to override that. Also, 'moves' may include
    additional bookmark moves that should not have associated obsmarkers.

    replacements is {oldnode: [newnode]} or a iterable of nodes if they do not
    have replacements. operation is a string, like "rebase".

    metadata is dictionary containing metadata to be stored in obsmarker if
    obsolescence is enabled.
    """
    if not replacements and not moves:
        return

    # translate mapping's other forms
    if not util.safehasattr(replacements, 'items'):
        replacements = {n: () for n in replacements}

    # Calculate bookmark movements
    if moves is None:
        moves = {}
    # Unfiltered repo is needed since nodes in replacements might be hidden.
    unfi = repo.unfiltered()
    for oldnode, newnodes in replacements.items():
        if oldnode in moves:
            continue
        if len(newnodes) > 1:
            # usually a split, take the one with biggest rev number
            newnode = next(unfi.set('max(%ln)', newnodes)).node()
        elif len(newnodes) == 0:
            # move bookmark backwards
            roots = list(unfi.set('max((::%n) - %ln)', oldnode,
                                  list(replacements)))
            if roots:
                newnode = roots[0].node()
            else:
                newnode = nullid
        else:
            newnode = newnodes[0]
        moves[oldnode] = newnode

    with repo.transaction('cleanup') as tr:
        # Move bookmarks
        bmarks = repo._bookmarks
        bmarkchanges = []
        allnewnodes = [n for ns in replacements.values() for n in ns]
        for oldnode, newnode in moves.items():
            oldbmarks = repo.nodebookmarks(oldnode)
            if not oldbmarks:
                continue
            from . import bookmarks # avoid import cycle
            repo.ui.debug('moving bookmarks %r from %s to %s\n' %
                          (oldbmarks, hex(oldnode), hex(newnode)))
            # Delete divergent bookmarks being parents of related newnodes
            deleterevs = repo.revs('parents(roots(%ln & (::%n))) - parents(%n)',
                                   allnewnodes, newnode, oldnode)
            deletenodes = _containsnode(repo, deleterevs)
            for name in oldbmarks:
                bmarkchanges.append((name, newnode))
                for b in bookmarks.divergent2delete(repo, deletenodes, name):
                    bmarkchanges.append((b, None))

        if bmarkchanges:
            bmarks.applychanges(repo, tr, bmarkchanges)

        # Obsolete or strip nodes
        if obsolete.isenabled(repo, obsolete.createmarkersopt):
            # If a node is already obsoleted, and we want to obsolete it
            # without a successor, skip that obssolete request since it's
            # unnecessary. That's the "if s or not isobs(n)" check below.
            # Also sort the node in topology order, that might be useful for
            # some obsstore logic.
            # NOTE: the filtering and sorting might belong to createmarkers.
            isobs = unfi.obsstore.successors.__contains__
            torev = unfi.changelog.rev
            sortfunc = lambda ns: torev(ns[0])
            rels = [(unfi[n], tuple(unfi[m] for m in s))
                    for n, s in sorted(replacements.items(), key=sortfunc)
                    if s or not isobs(n)]
            if rels:
                obsolete.createmarkers(repo, rels, operation=operation,
                                       metadata=metadata)
        else:
            from . import repair # avoid import cycle
            tostrip = list(replacements)
            if tostrip:
                repair.delayedstrip(repo.ui, repo, tostrip, operation)

def addremove(repo, matcher, prefix, opts=None, dry_run=None, similarity=None):
    if opts is None:
        opts = {}
    m = matcher
    if dry_run is None:
        dry_run = opts.get('dry_run')
    if similarity is None:
        similarity = float(opts.get('similarity') or 0)

    ret = 0
    join = lambda f: os.path.join(prefix, f)

    wctx = repo[None]
    for subpath in sorted(wctx.substate):
        submatch = matchmod.subdirmatcher(subpath, m)
        if opts.get('subrepos') or m.exact(subpath) or any(submatch.files()):
            sub = wctx.sub(subpath)
            try:
                if sub.addremove(submatch, prefix, opts, dry_run, similarity):
                    ret = 1
            except error.LookupError:
                repo.ui.status(_("skipping missing subrepository: %s\n")
                                 % join(subpath))

    rejected = []
    def badfn(f, msg):
        if f in m.files():
            m.bad(f, msg)
        rejected.append(f)

    badmatch = matchmod.badmatch(m, badfn)
    added, unknown, deleted, removed, forgotten = _interestingfiles(repo,
                                                                    badmatch)

    unknownset = set(unknown + forgotten)
    toprint = unknownset.copy()
    toprint.update(deleted)
    for abs in sorted(toprint):
        if repo.ui.verbose or not m.exact(abs):
            if abs in unknownset:
                status = _('adding %s\n') % m.uipath(abs)
            else:
                status = _('removing %s\n') % m.uipath(abs)
            repo.ui.status(status)

    renames = _findrenames(repo, m, added + unknown, removed + deleted,
                           similarity)

    if not dry_run:
        _markchanges(repo, unknown + forgotten, deleted, renames)

    for f in rejected:
        if f in m.files():
            return 1
    return ret

def marktouched(repo, files, similarity=0.0):
    '''Assert that files have somehow been operated upon. files are relative to
    the repo root.'''
    m = matchfiles(repo, files, badfn=lambda x, y: rejected.append(x))
    rejected = []

    added, unknown, deleted, removed, forgotten = _interestingfiles(repo, m)

    if repo.ui.verbose:
        unknownset = set(unknown + forgotten)
        toprint = unknownset.copy()
        toprint.update(deleted)
        for abs in sorted(toprint):
            if abs in unknownset:
                status = _('adding %s\n') % abs
            else:
                status = _('removing %s\n') % abs
            repo.ui.status(status)

    renames = _findrenames(repo, m, added + unknown, removed + deleted,
                           similarity)

    _markchanges(repo, unknown + forgotten, deleted, renames)

    for f in rejected:
        if f in m.files():
            return 1
    return 0

def _interestingfiles(repo, matcher):
    '''Walk dirstate with matcher, looking for files that addremove would care
    about.

    This is different from dirstate.status because it doesn't care about
    whether files are modified or clean.'''
    added, unknown, deleted, removed, forgotten = [], [], [], [], []
    audit_path = pathutil.pathauditor(repo.root, cached=True)

    ctx = repo[None]
    dirstate = repo.dirstate
    walkresults = dirstate.walk(matcher, subrepos=sorted(ctx.substate),
                                unknown=True, ignored=False, full=False)
    for abs, st in walkresults.iteritems():
        dstate = dirstate[abs]
        if dstate == '?' and audit_path.check(abs):
            unknown.append(abs)
        elif dstate != 'r' and not st:
            deleted.append(abs)
        elif dstate == 'r' and st:
            forgotten.append(abs)
        # for finding renames
        elif dstate == 'r' and not st:
            removed.append(abs)
        elif dstate == 'a':
            added.append(abs)

    return added, unknown, deleted, removed, forgotten

def _findrenames(repo, matcher, added, removed, similarity):
    '''Find renames from removed files to added ones.'''
    renames = {}
    if similarity > 0:
        for old, new, score in similar.findrenames(repo, added, removed,
                                                   similarity):
            if (repo.ui.verbose or not matcher.exact(old)
                or not matcher.exact(new)):
                repo.ui.status(_('recording removal of %s as rename to %s '
                                 '(%d%% similar)\n') %
                               (matcher.rel(old), matcher.rel(new),
                                score * 100))
            renames[new] = old
    return renames

def _markchanges(repo, unknown, deleted, renames):
    '''Marks the files in unknown as added, the files in deleted as removed,
    and the files in renames as copied.'''
    wctx = repo[None]
    with repo.wlock():
        wctx.forget(deleted)
        wctx.add(unknown)
        for new, old in renames.iteritems():
            wctx.copy(old, new)

def dirstatecopy(ui, repo, wctx, src, dst, dryrun=False, cwd=None):
    """Update the dirstate to reflect the intent of copying src to dst. For
    different reasons it might not end with dst being marked as copied from src.
    """
    origsrc = repo.dirstate.copied(src) or src
    if dst == origsrc: # copying back a copy?
        if repo.dirstate[dst] not in 'mn' and not dryrun:
            repo.dirstate.normallookup(dst)
    else:
        if repo.dirstate[origsrc] == 'a' and origsrc == src:
            if not ui.quiet:
                ui.warn(_("%s has not been committed yet, so no copy "
                          "data will be stored for %s.\n")
                        % (repo.pathto(origsrc, cwd), repo.pathto(dst, cwd)))
            if repo.dirstate[dst] in '?r' and not dryrun:
                wctx.add([dst])
        elif not dryrun:
            wctx.copy(origsrc, dst)

def readrequires(opener, supported):
    '''Reads and parses .hg/requires and checks if all entries found
    are in the list of supported features.'''
    requirements = set(opener.read("requires").splitlines())
    missings = []
    for r in requirements:
        if r not in supported:
            if not r or not r[0].isalnum():
                raise error.RequirementError(_(".hg/requires file is corrupt"))
            missings.append(r)
    missings.sort()
    if missings:
        raise error.RequirementError(
            _("repository requires features unknown to this Mercurial: %s")
            % " ".join(missings),
            hint=_("see https://mercurial-scm.org/wiki/MissingRequirement"
                   " for more information"))
    return requirements

def writerequires(opener, requirements):
    with opener('requires', 'w') as fp:
        for r in sorted(requirements):
            fp.write("%s\n" % r)

class filecachesubentry(object):
    def __init__(self, path, stat):
        self.path = path
        self.cachestat = None
        self._cacheable = None

        if stat:
            self.cachestat = filecachesubentry.stat(self.path)

            if self.cachestat:
                self._cacheable = self.cachestat.cacheable()
            else:
                # None means we don't know yet
                self._cacheable = None

    def refresh(self):
        if self.cacheable():
            self.cachestat = filecachesubentry.stat(self.path)

    def cacheable(self):
        if self._cacheable is not None:
            return self._cacheable

        # we don't know yet, assume it is for now
        return True

    def changed(self):
        # no point in going further if we can't cache it
        if not self.cacheable():
            return True

        newstat = filecachesubentry.stat(self.path)

        # we may not know if it's cacheable yet, check again now
        if newstat and self._cacheable is None:
            self._cacheable = newstat.cacheable()

            # check again
            if not self._cacheable:
                return True

        if self.cachestat != newstat:
            self.cachestat = newstat
            return True
        else:
            return False

    @staticmethod
    def stat(path):
        try:
            return util.cachestat(path)
        except OSError as e:
            if e.errno != errno.ENOENT:
                raise

class filecacheentry(object):
    def __init__(self, paths, stat=True):
        self._entries = []
        for path in paths:
            self._entries.append(filecachesubentry(path, stat))

    def changed(self):
        '''true if any entry has changed'''
        for entry in self._entries:
            if entry.changed():
                return True
        return False

    def refresh(self):
        for entry in self._entries:
            entry.refresh()

class filecache(object):
    '''A property like decorator that tracks files under .hg/ for updates.

    Records stat info when called in _filecache.

    On subsequent calls, compares old stat info with new info, and recreates the
    object when any of the files changes, updating the new stat info in
    _filecache.

    Mercurial either atomic renames or appends for files under .hg,
    so to ensure the cache is reliable we need the filesystem to be able
    to tell us if a file has been replaced. If it can't, we fallback to
    recreating the object on every call (essentially the same behavior as
    propertycache).

    '''
    def __init__(self, *paths):
        self.paths = paths

    def join(self, obj, fname):
        """Used to compute the runtime path of a cached file.

        Users should subclass filecache and provide their own version of this
        function to call the appropriate join function on 'obj' (an instance
        of the class that its member function was decorated).
        """
        raise NotImplementedError

    def __call__(self, func):
        self.func = func
        self.name = func.__name__.encode('ascii')
        return self

    def __get__(self, obj, type=None):
        # if accessed on the class, return the descriptor itself.
        if obj is None:
            return self
        # do we need to check if the file changed?
        if self.name in obj.__dict__:
            assert self.name in obj._filecache, self.name
            return obj.__dict__[self.name]

        entry = obj._filecache.get(self.name)

        if entry:
            if entry.changed():
                entry.obj = self.func(obj)
        else:
            paths = [self.join(obj, path) for path in self.paths]

            # We stat -before- creating the object so our cache doesn't lie if
            # a writer modified between the time we read and stat
            entry = filecacheentry(paths, True)
            entry.obj = self.func(obj)

            obj._filecache[self.name] = entry

        obj.__dict__[self.name] = entry.obj
        return entry.obj

    def __set__(self, obj, value):
        if self.name not in obj._filecache:
            # we add an entry for the missing value because X in __dict__
            # implies X in _filecache
            paths = [self.join(obj, path) for path in self.paths]
            ce = filecacheentry(paths, False)
            obj._filecache[self.name] = ce
        else:
            ce = obj._filecache[self.name]

        ce.obj = value # update cached copy
        obj.__dict__[self.name] = value # update copy returned by obj.x

    def __delete__(self, obj):
        try:
            del obj.__dict__[self.name]
        except KeyError:
            raise AttributeError(self.name)

def extdatasource(repo, source):
    """Gather a map of rev -> value dict from the specified source

    A source spec is treated as a URL, with a special case shell: type
    for parsing the output from a shell command.

    The data is parsed as a series of newline-separated records where
    each record is a revision specifier optionally followed by a space
    and a freeform string value. If the revision is known locally, it
    is converted to a rev, otherwise the record is skipped.

    Note that both key and value are treated as UTF-8 and converted to
    the local encoding. This allows uniformity between local and
    remote data sources.
    """

    spec = repo.ui.config("extdata", source)
    if not spec:
        raise error.Abort(_("unknown extdata source '%s'") % source)

    data = {}
    src = proc = None
    try:
        if spec.startswith("shell:"):
            # external commands should be run relative to the repo root
            cmd = spec[6:]
            proc = subprocess.Popen(cmd, shell=True, bufsize=-1,
                                    close_fds=util.closefds,
                                    stdout=subprocess.PIPE, cwd=repo.root)
            src = proc.stdout
        else:
            # treat as a URL or file
            src = url.open(repo.ui, spec)
        for l in src:
            if " " in l:
                k, v = l.strip().split(" ", 1)
            else:
                k, v = l.strip(), ""

            k = encoding.tolocal(k)
            try:
                data[repo[k].rev()] = encoding.tolocal(v)
            except (error.LookupError, error.RepoLookupError):
                pass # we ignore data for nodes that don't exist locally
    finally:
        if proc:
            proc.communicate()
        if src:
            src.close()
    if proc and proc.returncode != 0:
        raise error.Abort(_("extdata command '%s' failed: %s")
                          % (cmd, util.explainexit(proc.returncode)[0]))

    return data

def _locksub(repo, lock, envvar, cmd, environ=None, *args, **kwargs):
    if lock is None:
        raise error.LockInheritanceContractViolation(
            'lock can only be inherited while held')
    if environ is None:
        environ = {}
    with lock.inherit() as locker:
        environ[envvar] = locker
        return repo.ui.system(cmd, environ=environ, *args, **kwargs)

def wlocksub(repo, cmd, *args, **kwargs):
    """run cmd as a subprocess that allows inheriting repo's wlock

    This can only be called while the wlock is held. This takes all the
    arguments that ui.system does, and returns the exit code of the
    subprocess."""
    return _locksub(repo, repo.currentwlock(), 'HG_WLOCK_LOCKER', cmd, *args,
                    **kwargs)

def gdinitconfig(ui):
    """helper function to know if a repo should be created as general delta
    """
    # experimental config: format.generaldelta
    return (ui.configbool('format', 'generaldelta')
            or ui.configbool('format', 'usegeneraldelta'))

def gddeltaconfig(ui):
    """helper function to know if incoming delta should be optimised
    """
    # experimental config: format.generaldelta
    return ui.configbool('format', 'generaldelta')

class simplekeyvaluefile(object):
    """A simple file with key=value lines

    Keys must be alphanumerics and start with a letter, values must not
    contain '\n' characters"""
    firstlinekey = '__firstline'

    def __init__(self, vfs, path, keys=None):
        self.vfs = vfs
        self.path = path

    def read(self, firstlinenonkeyval=False):
        """Read the contents of a simple key-value file

        'firstlinenonkeyval' indicates whether the first line of file should
        be treated as a key-value pair or reuturned fully under the
        __firstline key."""
        lines = self.vfs.readlines(self.path)
        d = {}
        if firstlinenonkeyval:
            if not lines:
                e = _("empty simplekeyvalue file")
                raise error.CorruptedState(e)
            # we don't want to include '\n' in the __firstline
            d[self.firstlinekey] = lines[0][:-1]
            del lines[0]

        try:
            # the 'if line.strip()' part prevents us from failing on empty
            # lines which only contain '\n' therefore are not skipped
            # by 'if line'
            updatedict = dict(line[:-1].split('=', 1) for line in lines
                                                      if line.strip())
            if self.firstlinekey in updatedict:
                e = _("%r can't be used as a key")
                raise error.CorruptedState(e % self.firstlinekey)
            d.update(updatedict)
        except ValueError as e:
            raise error.CorruptedState(str(e))
        return d

    def write(self, data, firstline=None):
        """Write key=>value mapping to a file
        data is a dict. Keys must be alphanumerical and start with a letter.
        Values must not contain newline characters.

        If 'firstline' is not None, it is written to file before
        everything else, as it is, not in a key=value form"""
        lines = []
        if firstline is not None:
            lines.append('%s\n' % firstline)

        for k, v in data.items():
            if k == self.firstlinekey:
                e = "key name '%s' is reserved" % self.firstlinekey
                raise error.ProgrammingError(e)
            if not k[0].isalpha():
                e = "keys must start with a letter in a key-value file"
                raise error.ProgrammingError(e)
            if not k.isalnum():
                e = "invalid key name in a simple key-value file"
                raise error.ProgrammingError(e)
            if '\n' in v:
                e = "invalid value in a simple key-value file"
                raise error.ProgrammingError(e)
            lines.append("%s=%s\n" % (k, v))
        with self.vfs(self.path, mode='wb', atomictemp=True) as fp:
            fp.write(''.join(lines))

_reportobsoletedsource = [
    'debugobsolete',
    'pull',
    'push',
    'serve',
    'unbundle',
]

_reportnewcssource = [
    'pull',
    'unbundle',
]

# A marker that tells the evolve extension to suppress its own reporting
_reportstroubledchangesets = True

def registersummarycallback(repo, otr, txnname=''):
    """register a callback to issue a summary after the transaction is closed
    """
    def txmatch(sources):
        return any(txnname.startswith(source) for source in sources)

    categories = []

    def reportsummary(func):
        """decorator for report callbacks."""
        # The repoview life cycle is shorter than the one of the actual
        # underlying repository. So the filtered object can die before the
        # weakref is used leading to troubles. We keep a reference to the
        # unfiltered object and restore the filtering when retrieving the
        # repository through the weakref.
        filtername = repo.filtername
        reporef = weakref.ref(repo.unfiltered())
        def wrapped(tr):
            repo = reporef()
            if filtername:
                repo = repo.filtered(filtername)
            func(repo, tr)
        newcat = '%02i-txnreport' % len(categories)
        otr.addpostclose(newcat, wrapped)
        categories.append(newcat)
        return wrapped

    if txmatch(_reportobsoletedsource):
        @reportsummary
        def reportobsoleted(repo, tr):
            obsoleted = obsutil.getobsoleted(repo, tr)
            if obsoleted:
                repo.ui.status(_('obsoleted %i changesets\n')
                               % len(obsoleted))

    if (obsolete.isenabled(repo, obsolete.createmarkersopt) and
        repo.ui.configbool('experimental', 'evolution.report-instabilities')):
        instabilitytypes = [
            ('orphan', 'orphan'),
            ('phase-divergent', 'phasedivergent'),
            ('content-divergent', 'contentdivergent'),
        ]

        def getinstabilitycounts(repo):
            filtered = repo.changelog.filteredrevs
            counts = {}
            for instability, revset in instabilitytypes:
                counts[instability] = len(set(obsolete.getrevs(repo, revset)) -
                                          filtered)
            return counts

        oldinstabilitycounts = getinstabilitycounts(repo)
        @reportsummary
        def reportnewinstabilities(repo, tr):
            newinstabilitycounts = getinstabilitycounts(repo)
            for instability, revset in instabilitytypes:
                delta = (newinstabilitycounts[instability] -
                         oldinstabilitycounts[instability])
                if delta > 0:
                    repo.ui.warn(_('%i new %s changesets\n') %
                                 (delta, instability))

    if txmatch(_reportnewcssource):
        @reportsummary
        def reportnewcs(repo, tr):
            """Report the range of new revisions pulled/unbundled."""
            newrevs = tr.changes.get('revs', xrange(0, 0))
            if not newrevs:
                return

            # Compute the bounds of new revisions' range, excluding obsoletes.
            unfi = repo.unfiltered()
            revs = unfi.revs('%ld and not obsolete()', newrevs)
            if not revs:
                # Got only obsoletes.
                return
            minrev, maxrev = repo[revs.min()], repo[revs.max()]

            if minrev == maxrev:
                revrange = minrev
            else:
                revrange = '%s:%s' % (minrev, maxrev)
            repo.ui.status(_('new changesets %s\n') % revrange)

def nodesummaries(repo, nodes, maxnumnodes=4):
    if len(nodes) <= maxnumnodes or repo.ui.verbose:
        return ' '.join(short(h) for h in nodes)
    first = ' '.join(short(h) for h in nodes[:maxnumnodes])
    return _("%s and %d others") % (first, len(nodes) - maxnumnodes)

def enforcesinglehead(repo, tr, desc):
    """check that no named branch has multiple heads"""
    if desc in ('strip', 'repair'):
        # skip the logic during strip
        return
    visible = repo.filtered('visible')
    # possible improvement: we could restrict the check to affected branch
    for name, heads in visible.branchmap().iteritems():
        if len(heads) > 1:
            msg = _('rejecting multiple heads on branch "%s"')
            msg %= name
            hint = _('%d heads: %s')
            hint %= (len(heads), nodesummaries(repo, heads))
            raise error.Abort(msg, hint=hint)

def wrapconvertsink(sink):
    """Allow extensions to wrap the sink returned by convcmd.convertsink()
    before it is used, whether or not the convert extension was formally loaded.
    """
    return sink

def unhidehashlikerevs(repo, specs, hiddentype):
    """parse the user specs and unhide changesets whose hash or revision number
    is passed.

    hiddentype can be: 1) 'warn': warn while unhiding changesets
                       2) 'nowarn': don't warn while unhiding changesets

    returns a repo object with the required changesets unhidden
    """
    if not repo.filtername or not repo.ui.configbool('experimental',
                                                     'directaccess'):
        return repo

    if repo.filtername not in ('visible', 'visible-hidden'):
        return repo

    symbols = set()
    for spec in specs:
        try:
            tree = revsetlang.parse(spec)
        except error.ParseError: # will be reported by scmutil.revrange()
            continue

        symbols.update(revsetlang.gethashlikesymbols(tree))

    if not symbols:
        return repo

    revs = _getrevsfromsymbols(repo, symbols)

    if not revs:
        return repo

    if hiddentype == 'warn':
        unfi = repo.unfiltered()
        revstr = ", ".join([pycompat.bytestr(unfi[l]) for l in revs])
        repo.ui.warn(_("warning: accessing hidden changesets for write "
                       "operation: %s\n") % revstr)

    # we have to use new filtername to separate branch/tags cache until we can
    # disbale these cache when revisions are dynamically pinned.
    return repo.filtered('visible-hidden', revs)

def _getrevsfromsymbols(repo, symbols):
    """parse the list of symbols and returns a set of revision numbers of hidden
    changesets present in symbols"""
    revs = set()
    unfi = repo.unfiltered()
    unficl = unfi.changelog
    cl = repo.changelog
    tiprev = len(unficl)
    pmatch = unficl._partialmatch
    allowrevnums = repo.ui.configbool('experimental', 'directaccess.revnums')
    for s in symbols:
        try:
            n = int(s)
            if n <= tiprev:
                if not allowrevnums:
                    continue
                else:
                    if n not in cl:
                        revs.add(n)
                    continue
        except ValueError:
            pass

        try:
            s = pmatch(s)
        except error.LookupError:
            s = None

        if s is not None:
            rev = unficl.rev(s)
            if rev not in cl:
                revs.add(rev)

    return revs