aboutsummaryrefslogtreecommitdiffstats
path: root/libbe/bug.py
blob: fecb9b70db6da1c921e30685eeaeba00a0977e3b (plain) (blame)
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
# Copyright (C) 2008-2009 Gianluca Montecchi <gian@grys.it>
#                         Thomas Habets <thomas@habets.pp.se>
#                         W. Trevor King <wking@drexel.edu>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

"""
Define the Bug class for representing bugs.
"""

import os
import os.path
import errno
import time
import types
try: # import core module, Python >= 2.5
    from xml.etree import ElementTree
except ImportError: # look for non-core module
    from elementtree import ElementTree
import xml.sax.saxutils
import doctest

from beuuid import uuid_gen
from properties import Property, doc_property, local_property, \
    defaulting_property, checked_property, cached_property, \
    primed_property, change_hook_property, settings_property
import settings_object
import mapfile
import comment
import utility


class DiskAccessRequired (Exception):
    def __init__(self, goal):
        msg = "Cannot %s without accessing the disk" % goal
        Exception.__init__(self, msg)

### Define and describe valid bug categories
# Use a tuple of (category, description) tuples since we don't have
# ordered dicts in Python yet http://www.python.org/dev/peps/pep-0372/

# in order of increasing severity.  (name, description) pairs
severity_def = (
  ("wishlist","A feature that could improve usefulness, but not a bug."),
  ("minor","The standard bug level."),
  ("serious","A bug that requires workarounds."),
  ("critical","A bug that prevents some features from working at all."),
  ("fatal","A bug that makes the package unusable."))

# in order of increasing resolution
# roughly following http://www.bugzilla.org/docs/3.2/en/html/lifecycle.html
active_status_def = (
  ("unconfirmed","A possible bug which lacks independent existance confirmation."),
  ("open","A working bug that has not been assigned to a developer."),
  ("assigned","A working bug that has been assigned to a developer."),
  ("test","The code has been adjusted, but the fix is still being tested."))
inactive_status_def = (
  ("closed", "The bug is no longer relevant."),
  ("fixed", "The bug should no longer occur."),
  ("wontfix","It's not a bug, it's a feature."))


### Convert the description tuples to more useful formats

severity_values = ()
severity_description = {}
severity_index = {}
def load_severities(severity_def):
    global severity_values
    global severity_description
    global severity_index
    if severity_def == None:
        return
    severity_values = tuple([val for val,description in severity_def])
    severity_description = dict(severity_def)
    severity_index = {}
    for i,severity in enumerate(severity_values):
        severity_index[severity] = i
load_severities(severity_def)

active_status_values = []
inactive_status_values = []
status_values = []
status_description = {}
status_index = {}
def load_status(active_status_def, inactive_status_def):
    global active_status_values
    global inactive_status_values
    global status_values
    global status_description
    global status_index
    if active_status_def == None:
        active_status_def = globals()["active_status_def"]
    if inactive_status_def == None:
        inactive_status_def = globals()["inactive_status_def"]
    active_status_values = tuple([val for val,description in active_status_def])
    inactive_status_values = tuple([val for val,description in inactive_status_def])
    status_values = active_status_values + inactive_status_values
    status_description = dict(tuple(active_status_def) + tuple(inactive_status_def))
    status_index = {}
    for i,status in enumerate(status_values):
        status_index[status] = i
load_status(active_status_def, inactive_status_def)


class Bug(settings_object.SavedSettingsObject):
    """
    >>> b = Bug()
    >>> print b.status
    open
    >>> print b.severity
    minor

    There are two formats for time, int and string.  Setting either
    one will adjust the other appropriately.  The string form is the
    one stored in the bug's settings file on disk.
    >>> print type(b.time)
    <type 'int'>
    >>> print type(b.time_string)
    <type 'str'>
    >>> b.time = 0
    >>> print b.time_string
    Thu, 01 Jan 1970 00:00:00 +0000
    >>> b.time_string="Thu, 01 Jan 1970 00:01:00 +0000"
    >>> b.time
    60
    >>> print b.settings["time"]
    Thu, 01 Jan 1970 00:01:00 +0000
    """
    settings_properties = []
    required_saved_properties = []
    _prop_save_settings = settings_object.prop_save_settings
    _prop_load_settings = settings_object.prop_load_settings
    def _versioned_property(settings_properties=settings_properties,
                            required_saved_properties=required_saved_properties,
                            **kwargs):
        if "settings_properties" not in kwargs:
            kwargs["settings_properties"] = settings_properties
        if "required_saved_properties" not in kwargs:
            kwargs["required_saved_properties"]=required_saved_properties
        return settings_object.versioned_property(**kwargs)

    @_versioned_property(name="severity",
                         doc="A measure of the bug's importance",
                         default="minor",
                         check_fn=lambda s: s in severity_values,
                         require_save=True)
    def severity(): return {}

    @_versioned_property(name="status",
                         doc="The bug's current status",
                         default="open",
                         check_fn=lambda s: s in status_values,
                         require_save=True)
    def status(): return {}
    
    @property
    def active(self):
        return self.status in active_status_values

    @_versioned_property(name="target",
                         doc="The deadline for fixing this bug")
    def target(): return {}

    @_versioned_property(name="creator",
                         doc="The user who entered the bug into the system")
    def creator(): return {}

    @_versioned_property(name="reporter",
                         doc="The user who reported the bug")
    def reporter(): return {}

    @_versioned_property(name="assigned",
                         doc="The developer in charge of the bug")
    def assigned(): return {}

    @_versioned_property(name="time",
                         doc="An RFC 2822 timestamp for bug creation")
    def time_string(): return {}

    def _get_time(self):
        if self.time_string == None:
            return None
        return utility.str_to_time(self.time_string)
    def _set_time(self, value):
        self.time_string = utility.time_to_str(value)
    time = property(fget=_get_time,
                    fset=_set_time,
                    doc="An integer version of .time_string")

    def _extra_strings_check_fn(value):
        return utility.iterable_full_of_strings(value, \
                         alternative=settings_object.EMPTY)
    def _extra_strings_change_hook(self, old, new):
        self.extra_strings.sort() # to make merging easier
        self._prop_save_settings(old, new)
    @_versioned_property(name="extra_strings",
                         doc="Space for an array of extra strings.  Useful for storing state for functionality implemented purely in becommands/<some_function>.py.",
                         default=[],
                         check_fn=_extra_strings_check_fn,
                         change_hook=_extra_strings_change_hook,
                         mutable=True)
    def extra_strings(): return {}

    @_versioned_property(name="summary",
                         doc="A one-line bug description")
    def summary(): return {}

    def _get_comment_root(self, load_full=False):
        if self.sync_with_disk:
            return comment.loadComments(self, load_full=load_full)
        else:
            return comment.Comment(self, uuid=comment.INVALID_UUID)

    @Property
    @cached_property(generator=_get_comment_root)
    @local_property("comment_root")
    @doc_property(doc="The trunk of the comment tree")
    def comment_root(): return {}

    def _get_vcs(self):
        if hasattr(self.bugdir, "vcs"):
            return self.bugdir.vcs

    @Property
    @cached_property(generator=_get_vcs)
    @local_property("vcs")
    @doc_property(doc="A revision control system instance.")
    def vcs(): return {}

    def __init__(self, bugdir=None, uuid=None, from_disk=False,
                 load_comments=False, summary=None):
        settings_object.SavedSettingsObject.__init__(self)
        self.bugdir = bugdir
        self.uuid = uuid
        if from_disk == True:
            self.sync_with_disk = True
        else:
            self.sync_with_disk = False
            if uuid == None:
                self.uuid = uuid_gen()
            self.time = int(time.time()) # only save to second precision
            if self.vcs != None:
                self.creator = self.vcs.get_user_id()
            self.summary = summary

    def __repr__(self):
        return "Bug(uuid=%r)" % self.uuid

    def __str__(self):
        return self.string(shortlist=True)

    def __cmp__(self, other):
        return cmp_full(self, other)

    # serializing methods

    def _setting_attr_string(self, setting):
        value = getattr(self, setting)
        if value == None:
            return ""
        if type(value) not in types.StringTypes:
            return str(value)
        return value

    def xml(self, indent=0, shortname=None, show_comments=False):
        if shortname == None:
            if self.bugdir == None:
                shortname = self.uuid
            else:
                shortname = self.bugdir.bug_shortname(self)

        if self.time == None:
            timestring = ""
        else:
            timestring = utility.time_to_str(self.time)

        info = [('uuid', self.uuid),
                ('short-name', shortname),
                ('severity', self.severity),
                ('status', self.status),
                ('assigned', self.assigned),
                ('target', self.target),
                ('reporter', self.reporter),
                ('creator', self.creator),
                ('created', timestring),
                ('summary', self.summary)]
        lines = ['<bug>']
        for (k,v) in info:
            if v is not None:
                lines.append('  <%s>%s</%s>' % (k,xml.sax.saxutils.escape(v),k))
        for estr in self.extra_strings:
            lines.append('  <extra-string>%s</extra-string>\n' % estr)
        if show_comments == True:
            comout = self.comment_root.xml_thread(indent=indent+2,
                                                  auto_name_map=True,
                                                  bug_shortname=shortname)
            if len(comout) > 0:
                lines.append(comout)
        lines.append('</bug>')
        istring = ' '*indent
        sep = '\n' + istring
        return istring + sep.join(lines).rstrip('\n')

    def from_xml(self, xml_string, verbose=True):
        """
        Note: If a bug uuid is given, set .alt_id to it's value.
        >>> bugA = Bug(uuid="0123", summary="Need to test Bug.from_xml()")
        >>> bugA.date = "Thu, 01 Jan 1970 00:00:00 +0000"
        >>> bugA.creator = u'Fran\xe7ois'
        >>> bugA.extra_strings += ['TAG: very helpful']
        >>> commA = bugA.comment_root.new_reply(body='comment A')
        >>> commB = bugA.comment_root.new_reply(body='comment B')
        >>> commC = commA.new_reply(body='comment C')
        >>> xml = bugA.xml(shortname="bug-1")
        >>> bugB = Bug()
        >>> bugB.from_xml(xml, verbose=True)
        >>> bugB.xml(shortname="bug-1") == xml
        False
        >>> bugB.uuid = bugB.alt_id
        >>> bugB.xml(shortname="bug-1") == xml
        True
        """
        if type(xml_string) == types.UnicodeType:
            xml_string = xml_string.strip().encode('unicode_escape')
        bug = ElementTree.XML(xml_string)
        if bug.tag != 'bug':
            raise utility.InvalidXML( \
                'bug', bug, 'root element must be <comment>')
        tags=['uuid','short-name','severity','status','assigned','target',
              'reporter', 'creator', 'created', 'summary', 'extra-string',
              'comment']
        uuid = None
        estrs = []
        for child in bug.getchildren():
            if child.tag == 'short-name':
                pass
            elif child.tag in tags:
                if child.text == None or len(child.text) == 0:
                    text = settings_object.EMPTY
                else:
                    text = xml.sax.saxutils.unescape(child.text)
                    text = text.decode('unicode_escape').strip()
                if child.tag == "uuid":
                    uuid = text
                    continue # don't set the bug's uuid tag.
                if child.tag == 'extra-string':
                    estrs.append(text)
                    continue # don't set the bug's extra_string yet.
                else:
                    attr_name = child.tag.replace('-','_')
                setattr(self, attr_name, text)
            elif verbose == True:
                print >> sys.stderr, "Ignoring unknown tag %s in %s" \
                    % (child.tag, comment.tag)
        if uuid not in [None, self.uuid]:
            if not hasattr(self, 'alt_id') or self.alt_id == None:
                self.alt_id = uuid
        self.extra_strings = estrs

    def string(self, shortlist=False, show_comments=False):
        if self.bugdir == None:
            shortname = self.uuid
        else:
            shortname = self.bugdir.bug_shortname(self)
        if shortlist == False:
            if self.time == None:
                timestring = ""
            else:
                htime = utility.handy_time(self.time)
                timestring = "%s (%s)" % (htime, self.time_string)
            info = [("ID", self.uuid),
                    ("Short name", shortname),
                    ("Severity", self.severity),
                    ("Status", self.status),
                    ("Assigned", self._setting_attr_string("assigned")),
                    ("Target", self._setting_attr_string("target")),
                    ("Reporter", self._setting_attr_string("reporter")),
                    ("Creator", self._setting_attr_string("creator")),
                    ("Created", timestring)]
            longest_key_len = max([len(k) for k,v in info])
            infolines = ["  %*s : %s\n" %(longest_key_len,k,v) for k,v in info]
            bugout = "".join(infolines) + "%s" % self.summary.rstrip('\n')
        else:
            statuschar = self.status[0]
            severitychar = self.severity[0]
            chars = "%c%c" % (statuschar, severitychar)
            bugout = "%s:%s: %s" % (shortname,chars,self.summary.rstrip('\n'))
        
        if show_comments == True:
            # take advantage of the string_thread(auto_name_map=True)
            # SIDE-EFFECT of sorting by comment time.
            comout = self.comment_root.string_thread(flatten=False,
                                                     auto_name_map=True,
                                                     bug_shortname=shortname)
            output = bugout + '\n' + comout.rstrip('\n')
        else :
            output = bugout
        return output

    # methods for saving/loading/acessing settings and properties.

    def get_path(self, *args):
        dir = os.path.join(self.bugdir.get_path("bugs"), self.uuid)
        if len(args) == 0:
            return dir
        assert args[0] in ["values", "comments"], str(args)
        return os.path.join(dir, *args)

    def set_sync_with_disk(self, value):
        self.sync_with_disk = value
        for comment in self.comments():
            comment.set_sync_with_disk(value)

    def load_settings(self):
        if self.sync_with_disk == False:
            raise DiskAccessRequired("load settings")
        self.settings = mapfile.map_load(self.vcs, self.get_path("values"))
        self._setup_saved_settings()

    def save_settings(self):
        if self.sync_with_disk == False:
            raise DiskAccessRequired("save settings")
        assert self.summary != None, "Can't save blank bug"
        self.vcs.mkdir(self.get_path())
        path = self.get_path("values")
        mapfile.map_save(self.vcs, path, self._get_saved_settings())

    def save(self):
        """
        Save any loaded contents to disk.  Because of lazy loading of
        comments, this is actually not too inefficient.
        
        However, if self.sync_with_disk = True, then any changes are
        automatically written to disk as soon as they happen, so
        calling this method will just waste time (unless something
        else has been messing with your on-disk files).
        """
        sync_with_disk = self.sync_with_disk
        if sync_with_disk == False:
            self.set_sync_with_disk(True)
        self.save_settings()
        if len(self.comment_root) > 0:
            comment.saveComments(self)
        if sync_with_disk == False:
            self.set_sync_with_disk(False)

    def load_comments(self, load_full=True):
        if self.sync_with_disk == False:
            raise DiskAccessRequired("load comments")
        if load_full == True:
            # Force a complete load of the whole comment tree
            self.comment_root = self._get_comment_root(load_full=True)
        else:
            # Setup for fresh lazy-loading.  Clear _comment_root, so
            # _get_comment_root returns a fresh version.  Turn of
            # syncing temporarily so we don't write our blank comment
            # tree to disk.
            self.sync_with_disk = False
            self.comment_root = None
            self.sync_with_disk = True

    def remove(self):
        if self.sync_with_disk == False:
            raise DiskAccessRequired("remove")
        self.comment_root.remove()
        path = self.get_path()
        self.vcs.recursive_remove(path)
    
    # methods for managing comments

    def comments(self):
        for comment in self.comment_root.traverse():
            yield comment

    def new_comment(self, body=None):
        comm = self.comment_root.new_reply(body=body)
        return comm

    def comment_from_shortname(self, shortname, *args, **kwargs):
        return self.comment_root.comment_from_shortname(shortname,
                                                        *args, **kwargs)

    def comment_from_uuid(self, uuid):
        return self.comment_root.comment_from_uuid(uuid)

    def comment_shortnames(self, shortname=None):
        """
        SIDE-EFFECT : Comment.comment_shortnames will sort the comment
        tree by comment.time
        """
        for id, comment in self.comment_root.comment_shortnames(shortname):
            yield (id, comment)


# The general rule for bug sorting is that "more important" bugs are
# less than "less important" bugs.  This way sorting a list of bugs
# will put the most important bugs first in the list.  When relative
# importance is unclear, the sorting follows some arbitrary convention
# (i.e. dictionary order).

def cmp_severity(bug_1, bug_2):
    """
    Compare the severity levels of two bugs, with more severe bugs
    comparing as less.
    >>> bugA = Bug()
    >>> bugB = Bug()
    >>> bugA.severity = bugB.severity = "wishlist"
    >>> cmp_severity(bugA, bugB) == 0
    True
    >>> bugB.severity = "minor"
    >>> cmp_severity(bugA, bugB) > 0
    True
    >>> bugA.severity = "critical"
    >>> cmp_severity(bugA, bugB) < 0
    True
    """
    if not hasattr(bug_2, "severity") :
        return 1
    return -cmp(severity_index[bug_1.severity], severity_index[bug_2.severity])

def cmp_status(bug_1, bug_2):
    """
    Compare the status levels of two bugs, with more 'open' bugs
    comparing as less.
    >>> bugA = Bug()
    >>> bugB = Bug()
    >>> bugA.status = bugB.status = "open"
    >>> cmp_status(bugA, bugB) == 0
    True
    >>> bugB.status = "closed"
    >>> cmp_status(bugA, bugB) < 0
    True
    >>> bugA.status = "fixed"
    >>> cmp_status(bugA, bugB) > 0
    True
    """
    if not hasattr(bug_2, "status") :
        return 1
    val_2 = status_index[bug_2.status]
    return cmp(status_index[bug_1.status], status_index[bug_2.status])

def cmp_attr(bug_1, bug_2, attr, invert=False):
    """
    Compare a general attribute between two bugs using the conventional
    comparison rule for that attribute type.  If invert == True, sort
    *against* that convention.
    >>> attr="severity"
    >>> bugA = Bug()
    >>> bugB = Bug()
    >>> bugA.severity = "critical"
    >>> bugB.severity = "wishlist"
    >>> cmp_attr(bugA, bugB, attr) < 0
    True
    >>> cmp_attr(bugA, bugB, attr, invert=True) > 0
    True
    >>> bugB.severity = "critical"
    >>> cmp_attr(bugA, bugB, attr) == 0
    True
    """
    if not hasattr(bug_2, attr) :
        return 1
    val_1 = getattr(bug_1, attr)
    val_2 = getattr(bug_2, attr)
    if val_1 == None: val_1 = None
    if val_2 == None: val_2 = None
    
    if invert == True :
        return -cmp(val_1, val_2)
    else :
        return cmp(val_1, val_2)

# alphabetical rankings (a < z)
cmp_uuid = lambda bug_1, bug_2 : cmp_attr(bug_1, bug_2, "uuid")
cmp_creator = lambda bug_1, bug_2 : cmp_attr(bug_1, bug_2, "creator")
cmp_assigned = lambda bug_1, bug_2 : cmp_attr(bug_1, bug_2, "assigned")
cmp_target = lambda bug_1, bug_2 : cmp_attr(bug_1, bug_2, "target")
cmp_reporter = lambda bug_1, bug_2 : cmp_attr(bug_1, bug_2, "reporter")
cmp_summary = lambda bug_1, bug_2 : cmp_attr(bug_1, bug_2, "summary")
cmp_extra_strings = lambda bug_1, bug_2 : cmp_attr(bug_1, bug_2, "extra_strings")
# chronological rankings (newer < older)
cmp_time = lambda bug_1, bug_2 : cmp_attr(bug_1, bug_2, "time", invert=True)

def cmp_comments(bug_1, bug_2):
    """
    Compare two bugs' comments lists.  Doesn't load any new comments,
    so you should call each bug's .load_comments() first if you want a
    full comparison.
    """
    comms_1 = sorted(bug_1.comments(), key = lambda comm : comm.uuid)
    comms_2 = sorted(bug_2.comments(), key = lambda comm : comm.uuid)
    result = cmp(len(comms_1), len(comms_2))
    if result != 0:
        return result
    for c_1,c_2 in zip(comms_1, comms_2):
        result = cmp(c_1, c_2)
        if result != 0:
            return result
    return 0

DEFAULT_CMP_FULL_CMP_LIST = \
    (cmp_status, cmp_severity, cmp_assigned, cmp_time, cmp_creator,
     cmp_reporter, cmp_target, cmp_comments, cmp_summary, cmp_uuid,
     cmp_extra_strings)

class BugCompoundComparator (object):
    def __init__(self, cmp_list=DEFAULT_CMP_FULL_CMP_LIST):
        self.cmp_list = cmp_list
    def __call__(self, bug_1, bug_2):
        for comparison in self.cmp_list :
            val = comparison(bug_1, bug_2)
            if val != 0 :
                return val
        return 0
        
cmp_full = BugCompoundComparator()


# define some bonus cmp_* functions
def cmp_last_modified(bug_1, bug_2):
    """
    Like cmp_time(), but use most recent comment instead of bug
    creation for the timestamp.
    """
    def last_modified(bug):
        time = bug.time
        for comment in bug.comment_root.traverse():
            if comment.time > time:
                time = comment.time
        return time
    val_1 = last_modified(bug_1)
    val_2 = last_modified(bug_2)
    return -cmp(val_1, val_2)


suite = doctest.DocTestSuite()