style: kill ersatz if-else ternary operators

Although Python supports `X = Y if COND else Z`, this was only
introduced in Python 2.5. Since we have to support Python 2.4, it was
a very common thing to write instead `X = COND and Y or Z`, which is a
bit obscure at a glance. It requires some intricate knowledge of
Python to understand how to parse these one-liners.

We change instead all of these one-liners to 4-liners. This was
executed with the following perlism:

    find -name "*.py" -exec perl -pi -e 's,(\s*)([\.\w]+) = \(?(\S+)\s+and\s+(\S*)\)?\s+or\s+(\S*)$,$1if $3:\n$1    $2 = $4\n$1else:\n$1    $2 = $5,' {} \;

I tweaked the following cases from the automatic Perl output:

    prev = (parents and parents[0]) or nullid
    port = (use_ssl and 443 or 80)
    cwd = (pats and repo.getcwd()) or ''
    rename = fctx and webutil.renamelink(fctx) or []
    ctx = fctx and fctx or ctx
    self.base = (mapfile and os.path.dirname(mapfile)) or ''

I also added some newlines wherever they seemd appropriate for readability

There are probably a few ersatz ternary operators still in the code
somewhere, lurking away from the power of a simple regex.

contrib/synthrepo.py

@@ -359,7 +359,10 b' def synthesize(ui, repo, descpath, **opt'
                             files.iterkeys(), filectxfn, ui.username(),
                             '%d %d' % util.makedate())
         initnode = mc.commit()
-        hexfn = ui.debugflag and hex or short
+        if ui.debugflag:
+            hexfn = hex
+        else:
+            hexfn = short
         ui.status(_('added commit %s with %d files\n')
                   % (hexfn(initnode), len(files)))
 
@@ -475,7 +478,10 b' def renamedirs(dirs, words):'
         if dirpath in replacements:
             return replacements[dirpath]
         head, _ = os.path.split(dirpath)
-        head = head and rename(head) or ''
+        if head:
+            head = rename(head)
+        else:
+            head = ''
         renamed = os.path.join(head, wordgen.next())
         replacements[dirpath] = renamed
         return renamed

hgext/convert/common.py

@@ -31,7 +31,10 b' class MissingTool(Exception):'
 def checktool(exe, name=None, abort=True):
     name = name or exe
     if not util.findexe(exe):
-        exc = abort and util.Abort or MissingTool
+        if abort:
+            exc = util.Abort
+        else:
+            exc = MissingTool
         raise exc(_('cannot find required "%s" tool') % name)
 
 class NoRepo(Exception):

hgext/convert/convcmd.py

@@ -515,7 +515,11 b' def convert(ui, src, dest=None, revmapfi'
     sortmode = [m for m in sortmodes if opts.get(m)]
     if len(sortmode) > 1:
         raise util.Abort(_('more than one sort mode specified'))
-    sortmode = sortmode and sortmode[0] or defaultsort
+    if sortmode:
+        sortmode = sortmode[0]
+    else:
+        sortmode = defaultsort
+
     if sortmode == 'sourcesort' and not srcc.hasnativeorder():
         raise util.Abort(_('--sourcesort is not supported by this data source'))
     if sortmode == 'closesort' and not srcc.hasnativeclose():

hgext/convert/gnuarch.py

@@ -209,7 +209,10 b' class gnuarch_source(converter_source, c'
         mode = os.lstat(os.path.join(self.tmppath, name)).st_mode
         if stat.S_ISLNK(mode):
             data = os.readlink(os.path.join(self.tmppath, name))
-            mode = mode and 'l' or ''
+            if mode:
+                mode = 'l'
+            else:
+                mode = ''
         else:
             data = open(os.path.join(self.tmppath, name), 'rb').read()
             mode = (mode & 0111) and 'x' or ''

hgext/convert/hg.py

@@ -87,7 +87,10 b' class mercurial_sink(converter_sink):'
         if not branch:
             branch = 'default'
         pbranches = [(b[0], b[1] and b[1] or 'default') for b in pbranches]
-        pbranch = pbranches and pbranches[0][1] or 'default'
+        if pbranches:
+            pbranch = pbranches[0][1]
+        else:
+            pbranch = 'default'
 
         branchpath = os.path.join(self.path, branch)
         if setbranch:

hgext/convert/subversion.py

@@ -871,8 +871,16 b' class svn_source(converter_source):'
             if self.ui.configbool('convert', 'localtimezone'):
                 date = makedatetimestamp(date[0])
 
-            log = message and self.recode(message) or ''
-            author = author and self.recode(author) or ''
+            if message:
+                log = self.recode(message)
+            else:
+                log = ''
+
+            if author:
+                author = self.recode(author)
+            else:
+                author = ''
+
             try:
                 branch = self.module.split("/")[-1]
                 if branch == self.trunkname:
@@ -1118,7 +1126,10 b' class svn_sink(converter_sink, commandli'
         self.opener = scmutil.opener(self.wc)
         self.wopener = scmutil.opener(self.wc)
         self.childmap = mapfile(ui, self.join('hg-childmap'))
-        self.is_exec = util.checkexec(self.wc) and util.isexec or None
+        if util.checkexec(self.wc):
+            self.is_exec = util.isexec
+        else:
+            self.is_exec = None
 
         if created:
             hook = os.path.join(created, 'hooks', 'pre-revprop-change')

hgext/hgcia.py

@@ -121,7 +121,10 b' class ciamsg(object):'
         return patch.diffstat(pbuf.lines) or ''
 
     def logmsg(self):
-        diffstat = self.cia.diffstat and self.diffstat() or ''
+        if self.cia.diffstat:
+            diffstat = self.diffstat()
+        else:
+            diffstat = ''
         self.cia.ui.pushbuffer()
         self.cia.templater.show(self.ctx, changes=self.ctx.changeset(),
                                 baseurl=self.cia.ui.config('web', 'baseurl'),
@@ -199,7 +202,10 b' class hgcia(object):'
         style = self.ui.config('cia', 'style')
         template = self.ui.config('cia', 'template')
         if not template:
-            template = self.diffstat and self.dstemplate or self.deftemplate
+            if self.diffstat:
+                template = self.dstemplate
+            else:
+                template = self.deftemplate
         template = templater.parsestring(template, quoted=False)
         t = cmdutil.changeset_templater(self.ui, self.repo, False, None,
                                         template, style, False)

hgext/keyword.py

@@ -506,7 +506,10 b' def files(ui, repo, *pats, **opts):'
     kwt = kwtools['templater']
     wctx = repo[None]
     status = _status(ui, repo, wctx, kwt, *pats, **opts)
-    cwd = pats and repo.getcwd() or ''
+    if pats:
+        cwd = repo.getcwd()
+    else:
+        cwd = ''
     files = []
     if not opts.get('unknown') or opts.get('all'):
         files = sorted(status.modified + status.added + status.clean)

hgext/mq.py

@@ -418,7 +418,10 b' class queue(object):'
             gitmode = ui.configbool('mq', 'git', None)
             if gitmode is None:
                 raise error.ConfigError
-            self.gitmode = gitmode and 'yes' or 'no'
+            if gitmode:
+                self.gitmode = 'yes'
+            else:
+                self.gitmode = 'no'
         except error.ConfigError:
             self.gitmode = ui.config('mq', 'git', 'auto').lower()
         self.plainmode = ui.configbool('mq', 'plain', False)
@@ -610,7 +613,11 b' class queue(object):'
         return True, ''
 
     def explainpushable(self, idx, all_patches=False):
-        write = all_patches and self.ui.write or self.ui.warn
+        if all_patches:
+            write = self.ui.write
+        else:
+            write = self.ui.warn
+
         if all_patches or self.ui.verbose:
             if isinstance(idx, str):
                 idx = self.series.index(idx)
@@ -1825,7 +1832,11 b' class queue(object):'
                 self.ui.write(pfx)
             if summary:
                 ph = patchheader(self.join(patchname), self.plainmode)
-                msg = ph.message and ph.message[0] or ''
+                if ph.message:
+                    msg = ph.message[0]
+                else:
+                    msg = ''
+
                 if self.ui.formatted():
                     width = self.ui.termwidth() - len(pfx) - len(patchname) - 2
                     if width > 0:
@@ -2228,7 +2239,10 b' def unapplied(ui, repo, patch=None, **op'
         ui.write(_("all patches applied\n"))
         return 1
 
-    length = opts.get('first') and 1 or None
+    if opts.get('first'):
+        length = 1
+    else:
+        length = None
     q.qseries(repo, start=start, length=length, status='U',
               summary=opts.get('summary'))
 
@@ -2454,7 +2468,11 b' def top(ui, repo, **opts):'
 
     Returns 0 on success."""
     q = repo.mq
-    t = q.applied and q.seriesend(True) or 0
+    if q.applied:
+        t = q.seriesend(True)
+    else:
+        t = 0
+
     if t:
         q.qseries(repo, start=t - 1, length=1, status='A',
                   summary=opts.get('summary'))

hgext/notify.py

@@ -340,7 +340,10 b' class notifier(object):'
 
         maxdiff = int(self.ui.config('notify', 'maxdiff', 300))
         prev = ctx.p1().node()
-        ref = ref and ref.node() or ctx.node()
+        if ref:
+            ref = ref.node()
+        else:
+            ref = ctx.node()
         chunks = patch.diff(self.repo, prev, ref,
                             opts=patch.diffallopts(self.ui))
         difflines = ''.join(chunks).splitlines()

hgext/patchbomb.py

@@ -489,7 +489,10 b' def patchbomb(ui, repo, *revs, **opts):'
     if outgoing or bundle:
         if len(revs) > 1:
             raise util.Abort(_("too many destinations"))
-        dest = revs and revs[0] or None
+        if revs:
+            dest = revs[0]
+        else:
+            dest = None
         revs = []
 
     if rev:

i18n/polib.py

@@ -437,8 +437,15 b' class _BaseFile(list):'
         # the keys are sorted in the .mo file
         def cmp(_self, other):
             # msgfmt compares entries with msgctxt if it exists
-            self_msgid = _self.msgctxt and _self.msgctxt or _self.msgid
-            other_msgid = other.msgctxt and other.msgctxt or other.msgid
+            if _self.msgctxt:
+                self_msgid = _self.msgctxt
+            else:
+                self_msgid = _self.msgid
+
+            if other.msgctxt:
+                other_msgid = other.msgctxt
+            else:
+                other_msgid = other.msgid
             if self_msgid > other_msgid:
                 return 1
             elif self_msgid < other_msgid:

mercurial/bookmarks.py

@@ -435,7 +435,10 b' def diff(ui, dst, src):'
 
     diff = sorted(set(smarks) - set(dmarks))
     for k in diff:
-        mark = ui.debugflag and smarks[k] or smarks[k][:12]
+        if ui.debugflag:
+            mark = smarks[k]
+        else:
+            mark = smarks[k][:12]
         ui.write("   %-25s %s\n" % (k, mark))
 
     if len(diff) <= 0:

mercurial/bundlerepo.py

@@ -426,7 +426,10 b' def getremotechanges(ui, repo, other, on'
             rheads = None
         else:
             cg = other.changegroupsubset(incoming, rheads, 'incoming')
-        bundletype = localrepo and "HG10BZ" or "HG10UN"
+        if localrepo:
+            bundletype = "HG10BZ"
+        else:
+            bundletype = "HG10UN"
         fname = bundle = changegroup.writebundle(ui, cg, bundlename, bundletype)
         # keep written bundle?
         if bundlename:

mercurial/byterange.py

@@ -274,7 +274,11 b' class FTPRangeHandler(urllib2.FTPHandler'
             dirs = dirs[1:]
         try:
             fw = self.connect_ftp(user, passwd, host, port, dirs)
-            type = file and 'I' or 'D'
+            if file:
+                type = 'I'
+            else:
+                type = 'D'
+
             for attr in attrs:
                 attr, value = splitattr(attr)
                 if attr.lower() == 'type' and \

mercurial/cmdutil.py

@@ -398,7 +398,10 b' def makefileobj(repo, pat, node=None, de'
     writable = mode not in ('r', 'rb')
 
     if not pat or pat == '-':
-        fp = writable and repo.ui.fout or repo.ui.fin
+        if writable:
+            fp = repo.ui.fout
+        else:
+            fp = repo.ui.fin
         if util.safehasattr(fp, 'fileno'):
             return os.fdopen(os.dup(fp.fileno()), mode)
         else:
@@ -474,7 +477,10 b' def copy(ui, repo, pats, opts, rename=Fa'
 
     def walkpat(pat):
         srcs = []
-        badstates = after and '?' or '?r'
+        if after:
+            badstates = '?'
+        else:
+            badstates = '?r'
         m = scmutil.match(repo[None], [pat], opts, globbed=True)
         for abs in repo.walk(m):
             state = repo.dirstate[abs]
@@ -693,7 +699,10 b' def service(opts, parentfn=None, initfn='
 
     def writepid(pid):
         if opts['pid_file']:
-            mode = appendpid and 'a' or 'w'
+            if appendpid:
+                mode = 'a'
+            else:
+                mode = 'w'
             fp = open(opts['pid_file'], mode)
             fp.write(str(pid) + '\n')
             fp.close()
@@ -929,7 +938,11 b" def export(repo, revs, template='hg-%h.p"
         branch = ctx.branch()
         if switch_parent:
             parents.reverse()
-        prev = (parents and parents[0]) or nullid
+
+        if parents:
+            prev = parents[0]
+        else:
+            prev = nullid
 
         shouldclose = False
         if not fp and len(template) > 0:
@@ -1067,7 +1080,10 b' class changeset_printer(object):'
         log = self.repo.changelog
         date = util.datestr(ctx.date())
 
-        hexfunc = self.ui.debugflag and hex or short
+        if self.ui.debugflag:
+            hexfunc = hex
+        else:
+            hexfunc = short
 
         parents = [(p, hexfunc(log.node(p)))
                    for p in self._meaningful_parentrevs(log, rev)]
@@ -1866,7 +1882,10 b' def _makelogrevset(repo, pats, opts, rev'
     opts = dict(opts)
     # follow or not follow?
     follow = opts.get('follow') or opts.get('follow_first')
-    followfirst = opts.get('follow_first') and 1 or 0
+    if opts.get('follow_first'):
+        followfirst = 1
+    else:
+        followfirst = 0
     # --follow with FILE behaviour depends on revs...
     it = iter(revs)
     startrev = it.next()

mercurial/commands.py

@@ -277,7 +277,10 b' def annotate(ui, repo, *pats, **opts):'
         opts['file'] = True
 
     fm = ui.formatter('annotate', opts)
-    datefunc = ui.quiet and util.shortdate or util.datestr
+    if ui.quiet:
+        datefunc = util.shortdate
+    else:
+        datefunc = util.datestr
     hexfn = fm.hexfunc
 
     opmap = [('user', ' ', lambda x: x[0].user(), ui.shortuser),
@@ -664,7 +667,10 b' def bisect(ui, repo, rev=None, extra=Non'
         # one of the parent was not checked.
         parents = repo[nodes[0]].parents()
         if len(parents) > 1:
-            side = good and state['bad'] or state['good']
+            if good:
+                side = state['bad']
+            else:
+                side = state['good']
             num = len(set(i.node() for i in parents) & set(side))
             if num == 1:
                 return parents[0].ancestor(parents[1])
@@ -3670,7 +3676,10 b' def grep(ui, repo, pattern, *pats, **opt'
 
     def display(fn, ctx, pstates, states):
         rev = ctx.rev()
-        datefunc = ui.quiet and util.shortdate or util.datestr
+        if ui.quiet:
+            datefunc = util.shortdate
+        else:
+            datefunc = util.datestr
         found = False
         @util.cachefunc
         def binary():
@@ -3946,7 +3955,10 b' def identify(ui, repo, source=None, rev='
         raise util.Abort(_("there is no Mercurial repository here "
                            "(.hg not found)"))
 
-    hexfunc = ui.debugflag and hex or short
+    if ui.debugflag:
+        hexfunc = hex
+    else:
+        hexfunc = short
     default = not (num or id or branch or tags or bookmarks)
     output = []
     revs = []
@@ -4342,7 +4354,10 b' def locate(ui, repo, *pats, **opts):'
 
     Returns 0 if a match is found, 1 otherwise.
     """
-    end = opts.get('print0') and '\0' or '\n'
+    if opts.get('print0'):
+        end = '\0'
+    else:
+        end = '\n'
     rev = scmutil.revsingle(repo, opts.get('rev'), None).node()
 
     ret = 1
@@ -4506,7 +4521,10 b' def log(ui, repo, *pats, **opts):'
                 rename = getrenamed(fn, rev)
                 if rename:
                     copies.append((fn, rename[0]))
-        revmatchfn = filematcher and filematcher(ctx.rev()) or None
+        if filematcher:
+            revmatchfn = filematcher(ctx.rev())
+        else:
+            revmatchfn = None
         displayer.show(ctx, copies=copies, matchfn=revmatchfn)
         if displayer.flush(rev):
             count += 1
@@ -5550,7 +5568,10 b' def serve(ui, repo, **opts):'
     if opts.get('port'):
         opts['port'] = util.getport(opts.get('port'))
 
-    baseui = repo and repo.baseui or ui
+    if repo:
+        baseui = repo.baseui
+    else:
+        baseui = ui
     optlist = ("name templates style address port prefix ipv6"
                " accesslog errorlog certificate encoding")
     for o in optlist.split():
@@ -5700,15 +5721,25 b' def status(ui, repo, *pats, **opts):'
     else:
         node1, node2 = scmutil.revpair(repo, revs)
 
-    cwd = (pats and repo.getcwd()) or ''
-    end = opts.get('print0') and '\0' or '\n'
+    if pats:
+        cwd = repo.getcwd()
+    else:
+        cwd = ''
+
+    if opts.get('print0'):
+        end = '\0'
+    else:
+        end = '\n'
     copy = {}
     states = 'modified added removed deleted unknown ignored clean'.split()
     show = [k for k in states if opts.get(k)]
     if opts.get('all'):
         show += ui.quiet and (states[:4] + ['clean']) or states
     if not show:
-        show = ui.quiet and states[:4] or states[:5]
+        if ui.quiet:
+            show = states[:4]
+        else:
+            show = states[:5]
 
     stat = repo.status(node1, node2, scmutil.match(repo[node2], pats, opts),
                        'ignored' in show, 'clean' in show, 'unknown' in show,
@@ -6029,7 +6060,11 b' def tag(ui, repo, name1, *names, **opts)'
             rev_ = opts['rev']
         message = opts.get('message')
         if opts.get('remove'):
-            expectedtype = opts.get('local') and 'local' or 'global'
+            if opts.get('local'):
+                expectedtype = 'local'
+            else:
+                expectedtype = 'global'
+
             for n in names:
                 if not repo.tagtype(n):
                     raise util.Abort(_("tag '%s' does not exist") % n)

mercurial/context.py

@@ -963,7 +963,11 b' class basefilectx(object):'
     def ancestors(self, followfirst=False):
         visit = {}
         c = self
-        cut = followfirst and 1 or None
+        if followfirst:
+            cut = 1
+        else:
+            cut = None
+
         while True:
             for parent in c.parents()[:cut]:
                 visit[(parent.linkrev(), parent.filenode())] = parent
@@ -1755,7 +1759,11 b' class memctx(committablectx):'
             # "filectxfn" for performance (e.g. converting from another VCS)
             self._filectxfn = util.cachefunc(filectxfn)
 
-        self._extra = extra and extra.copy() or {}
+        if extra:
+            self._extra = extra.copy()
+        else:
+            self._extra = {}
+
         if self._extra.get('branch', '') == '':
             self._extra['branch'] = 'default'
 

mercurial/dagutil.py

@@ -88,7 +88,10 b' class genericdag(basedag):'
     '''generic implementations for DAGs'''
 
     def ancestorset(self, starts, stops=None):
-        stops = stops and set(stops) or set()
+        if stops:
+            stops = set(stops)
+        else:
+            stops = set()
         seen = set()
         pending = list(starts)
         while pending:
@@ -179,7 +182,10 b' class revlogdag(revlogbaseddag):'
     def ancestorset(self, starts, stops=None):
         rlog = self._revlog
         idx = rlog.index
-        stops = stops and set(stops) or set()
+        if stops:
+            stops = set(stops)
+        else:
+            stops = set()
         seen = set()
         pending = list(starts)
         while pending:

mercurial/discovery.py

@@ -218,7 +218,10 b' def _oldheadssummary(repo, remoteheads, '
     r = repo.set('heads(%ln + %ln)', oldheads, outgoing.missing)
     newheads = list(c.node() for c in r)
     # set some unsynced head to issue the "unsynced changes" warning
-    unsynced = inc and set([None]) or set()
+    if inc:
+        unsynced = set([None])
+    else:
+        unsynced = set()
     return {None: (oldheads, newheads, unsynced)}
 
 def checkheads(repo, remote, outgoing, remoteheads, newbranch=False, inc=False,

mercurial/hg.py

@@ -34,7 +34,11 b' def addbranchrevs(lrepo, other, branches'
         else:
             y = None
         return x, y
-    revs = revs and list(revs) or []
+    if revs:
+        revs = list(revs)
+    else:
+        revs = []
+
     if not peer.capable('branchmap'):
         if branches:
             raise util.Abort(_("remote branch lookup not supported"))

mercurial/hgweb/webcommands.py

@@ -90,7 +90,10 b' def rawfile(web, req, tmpl):'
     if guessmime:
         mt = mimetypes.guess_type(path)[0]
         if mt is None:
-            mt = util.binary(text) and 'application/binary' or 'text/plain'
+            if util.binary(text):
+                mt = 'application/binary'
+            else:
+                mt = 'text/plain'
     if mt.startswith('text/'):
         mt += '; charset="%s"' % encoding.encoding
 
@@ -365,7 +368,11 b' def changelog(web, req, tmpl, shortlog=F'
             entry['parity'] = parity.next()
             yield entry
 
-    revcount = shortlog and web.maxshortchanges or web.maxchanges
+    if shortlog:
+        revcount = web.maxshortchanges
+    else:
+        revcount = web.maxchanges
+
     if 'revcount' in req.form:
         try:
             revcount = int(req.form.get('revcount', [revcount])[0])
@@ -783,8 +790,12 b' def filediff(web, req, tmpl):'
         style = req.form['style'][0]
 
     diffs = webutil.diffs(web.repo, tmpl, ctx, None, [path], parity, style)
-    rename = fctx and webutil.renamelink(fctx) or []
-    ctx = fctx and fctx or ctx
+    if fctx:
+        rename = webutil.renamelink(fctx)
+        ctx = fctx
+    else:
+        rename = []
+        ctx = ctx
     return tmpl("filediff",
                 file=path,
                 node=hex(n),

mercurial/hgweb/webutil.py

@@ -373,7 +373,10 b' def diffs(repo, tmpl, ctx, basectx, file'
     diffopts = patch.diffopts(repo.ui, untrusted=True)
     if basectx is None:
         parents = ctx.parents()
-        node1 = parents and parents[0].node() or nullid
+        if parents:
+            node1 = parents[0].node()
+        else:
+            node1 = nullid
     else:
         node1 = basectx.node()
     node2 = ctx.node()

mercurial/httpclient/__init__.py

@@ -330,7 +330,10 b' class HTTPConnection(object):'
         elif use_ssl is None:
             use_ssl = (port == 443)
         elif port is None:
-            port = (use_ssl and 443 or 80)
+            if use_ssl:
+                port = 443
+            else:
+                port = 80
         self.port = port
         if use_ssl and not socketutil.have_ssl:
             raise Exception('ssl requested but unavailable on this Python')

mercurial/localrepo.py

@@ -523,7 +523,11 b' class localrepository(object):'
             if prevtags and prevtags[-1] != '\n':
                 fp.write('\n')
             for name in names:
-                m = munge and munge(name) or name
+                if munge:
+                    m = munge(name)
+                else:
+                    m = name
+
                 if (self._tagscache.tagtypes and
                     name in self._tagscache.tagtypes):
                     old = self.tags().get(name, nullid)
@@ -893,7 +897,11 b' class localrepository(object):'
 
     def currenttransaction(self):
         """return the current transaction or None if non exists"""
-        tr = self._transref and self._transref() or None
+        if self._transref:
+            tr = self._transref()
+        else:
+            tr = None
+
         if tr and tr.running():
             return tr
         return None
@@ -913,7 +921,10 b' class localrepository(object):'
 
         self._writejournal(desc)
         renames = [(vfs, x, undoname(x)) for vfs, x in self._journalfiles()]
-        rp = report and report or self.ui.warn
+        if report:
+            rp = report
+        else:
+            rp = self.ui.warn
         vfsmap = {'plain': self.vfs} # root of .hg/
         # we must avoid cyclic reference between repo and transaction.
         reporef = weakref.ref(self)

mercurial/patch.py

@@ -259,8 +259,17 b' def extract(ui, fileobj):'
     if not diffs_seen:
         os.unlink(tmpname)
         return None, message, user, date, branch, None, None, None
-    p1 = parents and parents.pop(0) or None
-    p2 = parents and parents.pop(0) or None
+
+    if parents:
+        p1 = parents.pop(0)
+    else:
+        p1 = None
+
+    if parents:
+        p2 = parents.pop(0)
+    else:
+        p2 = None
+
     return tmpname, message, user, date, branch, nodeid, p1, p2
 
 class patchmeta(object):
@@ -1489,13 +1498,19 b' def makepatchmeta(backend, afile_orig, b'
     fname = None
     if not missing:
         if gooda and goodb:
-            fname = isbackup and afile or bfile
+            if isbackup:
+                fname = afile
+            else:
+                fname = bfile
         elif gooda:
             fname = afile
 
     if not fname:
         if not nullb:
-            fname = isbackup and afile or bfile
+            if isbackup:
+                fname = afile
+            else:
+                fname = bfile
         elif not nulla:
             fname = afile
         else:
@@ -2070,7 +2085,10 b' def diff(repo, node1=None, node2=None, m'
     if not modified and not added and not removed:
         return []
 
-    hexfunc = repo.ui.debugflag and hex or short
+    if repo.ui.debugflag:
+        hexfunc = hex
+    else:
+        hexfunc = short
     revs = [hexfunc(node) for node in [ctx1.node(), ctx2.node()] if node]
 
     copy = {}

mercurial/revset.py

@@ -18,7 +18,10 b' import repoview'
 
 def _revancestors(repo, revs, followfirst):
     """Like revlog.ancestors(), but supports followfirst."""
-    cut = followfirst and 1 or None
+    if followfirst:
+        cut = 1
+    else:
+        cut = None
     cl = repo.changelog
 
     def iterate():
@@ -49,7 +52,10 b' def _revancestors(repo, revs, followfirs'
 
 def _revdescendants(repo, revs, followfirst):
     """Like revlog.descendants() but supports followfirst."""
-    cut = followfirst and 1 or None
+    if followfirst:
+        cut = 1
+    else:
+        cut = None
 
     def iterate():
         cl = repo.changelog

mercurial/templater.py

@@ -656,7 +656,10 b' class templater(object):'
         self.mapfile = mapfile or 'template'
         self.cache = cache.copy()
         self.map = {}
-        self.base = (mapfile and os.path.dirname(mapfile)) or ''
+        if mapfile:
+            self.base = os.path.dirname(mapfile)
+        else:
+            self.base = ''
         self.filters = templatefilters.filters.copy()
         self.filters.update(filters)
         self.defaults = defaults

tests/run-tests.py

@@ -1836,7 +1836,10 b' class TestRunner(object):'
         compiler = ''
         if self.options.compiler:
             compiler = '--compiler ' + self.options.compiler
-        pure = self.options.pure and "--pure" or ""
+        if self.options.pure:
+            pure = "--pure"
+        else:
+            pure = ""
         py3 = ''
         if sys.version_info[0] == 3:
             py3 = '--c2to3'