Add command qheader to display the header of a given patch.

hgext/mq.py

@@ -1,1517 +1,1534 b''
 # queue.py - patch queues for mercurial
 #
 # Copyright 2005 Chris Mason <[e-mail]>
 #
 # This software may be used and distributed according to the terms
 # of the GNU General Public License, incorporated herein by reference.
 
 '''patch management and development
 
 This extension lets you work with a stack of patches in a Mercurial
 repository.  It manages two stacks of patches - all known patches, and
 applied patches (subset of known patches).
 
 Known patches are represented as patch files in the .hg/patches
 directory.  Applied patches are both patch files and changesets.
 
 Common tasks (use "hg help command" for more details):
 
 prepare repository to work with patches   qinit
 create new patch                          qnew
 import existing patch                     qimport
 
 print patch series                        qseries
 print applied patches                     qapplied
 print name of top applied patch           qtop
 
 add known patch to applied stack          qpush
 remove patch from applied stack           qpop
 refresh contents of top applied patch     qrefresh
 '''
 
 from mercurial.demandload import *
 demandload(globals(), "os sys re struct traceback errno bz2")
 from mercurial.i18n import gettext as _
 from mercurial import ui, hg, revlog, commands, util
 
 versionstr = "0.45"
 
 commands.norepo += " qclone qversion"
 
 class queue:
     def __init__(self, ui, path, patchdir=None):
         self.basepath = path
         if patchdir:
             self.path = patchdir
         else:
             self.path = os.path.join(path, "patches")
         self.opener = util.opener(self.path)
         self.ui = ui
         self.applied = []
         self.full_series = []
         self.applied_dirty = 0
         self.series_dirty = 0
         self.series_path = "series"
         self.status_path = "status"
 
         if os.path.exists(os.path.join(self.path, self.series_path)):
             self.full_series = self.opener(self.series_path).read().splitlines()
         self.read_series(self.full_series)
 
         if os.path.exists(os.path.join(self.path, self.status_path)):
             self.applied = self.opener(self.status_path).read().splitlines()
 
     def find_series(self, patch):
         pre = re.compile("(\s*)([^#]+)")
         index = 0
         for l in self.full_series:
             m = pre.match(l)
             if m:
                 s = m.group(2)
                 s = s.rstrip()
                 if s == patch:
                     return index
             index += 1
         return None
 
     def read_series(self, list):
         def matcher(list):
             pre = re.compile("(\s*)([^#]+)")
             for l in list:
                 m = pre.match(l)
                 if m:
                     s = m.group(2)
                     s = s.rstrip()
                     if len(s) > 0:
                         yield s
         self.series = []
         self.series = [ x for x in matcher(list) ]
 
     def save_dirty(self):
         if self.applied_dirty:
             if len(self.applied) > 0:
                 nl = "\n"
             else:
                 nl = ""
             f = self.opener(self.status_path, "w")
             f.write("\n".join(self.applied) + nl)
         if self.series_dirty:
             if len(self.full_series) > 0:
                 nl = "\n"
             else:
                 nl = ""
             f = self.opener(self.series_path, "w")
             f.write("\n".join(self.full_series) + nl)
 
     def readheaders(self, patch):
         def eatdiff(lines):
             while lines:
                 l = lines[-1]
                 if (l.startswith("diff -") or
                     l.startswith("Index:") or
                     l.startswith("===========")):
                     del lines[-1]
                 else:
                     break
         def eatempty(lines):
             while lines:
                 l = lines[-1]
                 if re.match('\s*$', l):
                     del lines[-1]
                 else:
                     break
 
         pf = os.path.join(self.path, patch)
         message = []
         comments = []
         user = None
         date = None
         format = None
         subject = None
         diffstart = 0
 
         for line in file(pf):
             line = line.rstrip()
             if diffstart:
                 if line.startswith('+++ '):
                     diffstart = 2
                 break
             if line.startswith("--- "):
                 diffstart = 1
                 continue
             elif format == "hgpatch":
                 # parse values when importing the result of an hg export
                 if line.startswith("# User "):
                     user = line[7:]
                 elif line.startswith("# Date "):
                     date = line[7:]
                 elif not line.startswith("# ") and line:
                     message.append(line)
                     format = None
             elif line == '# HG changeset patch':
                 format = "hgpatch"
             elif (format != "tagdone" and (line.startswith("Subject: ") or
                                            line.startswith("subject: "))):
                 subject = line[9:]
                 format = "tag"
             elif (format != "tagdone" and (line.startswith("From: ") or
                                            line.startswith("from: "))):
                 user = line[6:]
                 format = "tag"
             elif format == "tag" and line == "":
                 # when looking for tags (subject: from: etc) they
                 # end once you find a blank line in the source
                 format = "tagdone"
             elif message or line:
                 message.append(line)
             comments.append(line)
 
         eatdiff(message)
         eatdiff(comments)
         eatempty(message)
         eatempty(comments)
 
         # make sure message isn't empty
         if format and format.startswith("tag") and subject:
             message.insert(0, "")
             message.insert(0, subject)
         return (message, comments, user, date, diffstart > 1)
 
     def mergeone(self, repo, mergeq, head, patch, rev, wlock):
         # first try just applying the patch
         (err, n) = self.apply(repo, [ patch ], update_status=False,
                               strict=True, merge=rev, wlock=wlock)
 
         if err == 0:
             return (err, n)
 
         if n is None:
             raise util.Abort(_("apply failed for patch %s") % patch)
 
         self.ui.warn("patch didn't work out, merging %s\n" % patch)
 
         # apply failed, strip away that rev and merge.
         repo.update(head, allow=False, force=True, wlock=wlock)
         self.strip(repo, n, update=False, backup='strip', wlock=wlock)
 
         c = repo.changelog.read(rev)
         ret = repo.update(rev, allow=True, wlock=wlock)
         if ret:
             raise util.Abort(_("update returned %d") % ret)
         n = repo.commit(None, c[4], c[1], force=1, wlock=wlock)
         if n == None:
             raise util.Abort(_("repo commit failed"))
         try:
             message, comments, user, date, patchfound = mergeq.readheaders(patch)
         except:
             raise util.Abort(_("unable to read %s") % patch)
 
         patchf = self.opener(patch, "w")
         if comments:
             comments = "\n".join(comments) + '\n\n'
             patchf.write(comments)
         commands.dodiff(patchf, self.ui, repo, head, n)
         patchf.close()
         return (0, n)
 
     def qparents(self, repo, rev=None):
         if rev is None:
             (p1, p2) = repo.dirstate.parents()
             if p2 == revlog.nullid:
                 return p1
             if len(self.applied) == 0:
                 return None
             (top, patch) = self.applied[-1].split(':')
             top = revlog.bin(top)
             return top
         pp = repo.changelog.parents(rev)
         if pp[1] != revlog.nullid:
             arevs = [ x.split(':')[0] for x in self.applied ]
             p0 = revlog.hex(pp[0])
             p1 = revlog.hex(pp[1])
             if p0 in arevs:
                 return pp[0]
             if p1 in arevs:
                 return pp[1]
         return pp[0]
 
     def mergepatch(self, repo, mergeq, series, wlock):
         if len(self.applied) == 0:
             # each of the patches merged in will have two parents.  This
             # can confuse the qrefresh, qdiff, and strip code because it
             # needs to know which parent is actually in the patch queue.
             # so, we insert a merge marker with only one parent.  This way
             # the first patch in the queue is never a merge patch
             #
             pname = ".hg.patches.merge.marker"
             n = repo.commit(None, '[mq]: merge marker', user=None, force=1,
                             wlock=wlock)
             self.applied.append(revlog.hex(n) + ":" + pname)
             self.applied_dirty = 1
 
         head = self.qparents(repo)
 
         for patch in series:
             patch = mergeq.lookup(patch, strict=True)
             if not patch:
                 self.ui.warn("patch %s does not exist\n" % patch)
                 return (1, None)
 
             info = mergeq.isapplied(patch)
             if not info:
                 self.ui.warn("patch %s is not applied\n" % patch)
                 return (1, None)
             rev = revlog.bin(info[1])
             (err, head) = self.mergeone(repo, mergeq, head, patch, rev, wlock)
             if head:
                 self.applied.append(revlog.hex(head) + ":" + patch)
                 self.applied_dirty = 1
             if err:
                 return (err, head)
         return (0, head)
 
     def apply(self, repo, series, list=False, update_status=True,
               strict=False, patchdir=None, merge=None, wlock=None):
         # TODO unify with commands.py
         if not patchdir:
             patchdir = self.path
         err = 0
         if not wlock:
             wlock = repo.wlock()
         lock = repo.lock()
         tr = repo.transaction()
         n = None
         for patch in series:
             self.ui.warn("applying %s\n" % patch)
             pf = os.path.join(patchdir, patch)
 
             try:
                 message, comments, user, date, patchfound = self.readheaders(patch)
             except:
                 self.ui.warn("Unable to read %s\n" % pf)
                 err = 1
                 break
 
             if not message:
                 message = "imported patch %s\n" % patch
             else:
                 if list:
                     message.append("\nimported patch %s" % patch)
                 message = '\n'.join(message)
 
             try:
                 pp = util.find_in_path('gpatch', os.environ.get('PATH', ''), 'patch')
                 f = os.popen("%s -d '%s' -p1 --no-backup-if-mismatch < '%s'" %
                              (pp, repo.root, pf))
             except:
                 self.ui.warn("patch failed, unable to continue (try -v)\n")
                 err = 1
                 break
             files = []
             fuzz = False
             for l in f:
                 l = l.rstrip('\r\n');
                 if self.ui.verbose:
                     self.ui.warn(l + "\n")
                 if l[:14] == 'patching file ':
                     pf = os.path.normpath(l[14:])
                     # when patch finds a space in the file name, it puts
                     # single quotes around the filename.  strip them off
                     if pf[0] == "'" and pf[-1] == "'":
                         pf = pf[1:-1]
                     if pf not in files:
                         files.append(pf)
                     printed_file = False
                     file_str = l
                 elif l.find('with fuzz') >= 0:
                     if not printed_file:
                         self.ui.warn(file_str + '\n')
                         printed_file = True
                     self.ui.warn(l + '\n')
                     fuzz = True
                 elif l.find('saving rejects to file') >= 0:
                     self.ui.warn(l + '\n')
                 elif l.find('FAILED') >= 0:
                     if not printed_file:
                         self.ui.warn(file_str + '\n')
                         printed_file = True
                     self.ui.warn(l + '\n')
             patcherr = f.close()
 
             if merge and len(files) > 0:
                 # Mark as merged and update dirstate parent info
                 repo.dirstate.update(repo.dirstate.filterfiles(files), 'm')
                 p1, p2 = repo.dirstate.parents()
                 repo.dirstate.setparents(p1, merge)
             if len(files) > 0:
                 cwd = repo.getcwd()
                 cfiles = files
                 if cwd:
                     cfiles = [util.pathto(cwd, f) for f in files]
                 commands.addremove_lock(self.ui, repo, cfiles,
                                         opts={}, wlock=wlock)
             n = repo.commit(files, message, user, date, force=1, lock=lock,
                             wlock=wlock)
 
             if n == None:
                 raise util.Abort(_("repo commit failed"))
 
             if update_status:
                 self.applied.append(revlog.hex(n) + ":" + patch)
 
             if patcherr:
                 if not patchfound:
                     self.ui.warn("patch %s is empty\n" % patch)
                     err = 0
                 else:
                     self.ui.warn("patch failed, rejects left in working dir\n")
                     err = 1
                 break
 
             if fuzz and strict:
                 self.ui.warn("fuzz found when applying patch, stopping\n")
                 err = 1
                 break
         tr.close()
         return (err, n)
 
     def delete(self, repo, patch):
         patch = self.lookup(patch, strict=True)
         info = self.isapplied(patch)
         if info:
             raise util.Abort(_("cannot delete applied patch %s") % patch)
         if patch not in self.series:
             raise util.Abort(_("patch %s not in series file") % patch)
         i = self.find_series(patch)
         del self.full_series[i]
         self.read_series(self.full_series)
         self.series_dirty = 1
 
     def check_toppatch(self, repo):
         if len(self.applied) > 0:
             (top, patch) = self.applied[-1].split(':')
             top = revlog.bin(top)
             pp = repo.dirstate.parents()
             if top not in pp:
                 raise util.Abort(_("queue top not at same revision as working directory"))
             return top
         return None
     def check_localchanges(self, repo):
         (c, a, r, d, u) = repo.changes(None, None)
         if c or a or d or r:
             raise util.Abort(_("local changes found, refresh first"))
     def new(self, repo, patch, msg=None, force=None):
         if os.path.exists(os.path.join(self.path, patch)):
             raise util.Abort(_('patch "%s" already exists') % patch)
         commitfiles = []
         (c, a, r, d, u) = repo.changes(None, None)
         if c or a or d or r:
             if not force:
                 raise util.Abort(_("local changes found, refresh first"))
             commitfiles = c + a + r
         self.check_toppatch(repo)
         wlock = repo.wlock()
         insert = self.full_series_end()
         if msg:
             n = repo.commit(commitfiles, "[mq]: %s" % msg, force=True,
                             wlock=wlock)
         else:
             n = repo.commit(commitfiles,
                             "New patch: %s" % patch, force=True, wlock=wlock)
         if n == None:
             raise util.Abort(_("repo commit failed"))
         self.full_series[insert:insert] = [patch]
         self.applied.append(revlog.hex(n) + ":" + patch)
         self.read_series(self.full_series)
         self.series_dirty = 1
         self.applied_dirty = 1
         p = self.opener(patch, "w")
         if msg:
             msg = msg + "\n"
             p.write(msg)
         p.close()
         wlock = None
         r = self.qrepo()
         if r: r.add([patch])
         if commitfiles:
             self.refresh(repo, msg=None, short=True)
 
     def strip(self, repo, rev, update=True, backup="all", wlock=None):
         def limitheads(chlog, stop):
             """return the list of all nodes that have no children"""
             p = {}
             h = []
             stoprev = 0
             if stop in chlog.nodemap:
                 stoprev = chlog.rev(stop)
 
             for r in range(chlog.count() - 1, -1, -1):
                 n = chlog.node(r)
                 if n not in p:
                     h.append(n)
                 if n == stop:
                     break
                 if r < stoprev:
                     break
                 for pn in chlog.parents(n):
                     p[pn] = 1
             return h
 
         def bundle(cg):
             backupdir = repo.join("strip-backup")
             if not os.path.isdir(backupdir):
                 os.mkdir(backupdir)
             name = os.path.join(backupdir, "%s" % revlog.short(rev))
             name = savename(name)
             self.ui.warn("saving bundle to %s\n" % name)
             # TODO, exclusive open
             f = open(name, "wb")
             try:
                 f.write("HG10")
                 z = bz2.BZ2Compressor(9)
                 while 1:
                     chunk = cg.read(4096)
                     if not chunk:
                         break
                     f.write(z.compress(chunk))
                 f.write(z.flush())
             except:
                 os.unlink(name)
                 raise
             f.close()
             return name
 
         def stripall(rev, revnum):
             cl = repo.changelog
             c = cl.read(rev)
             mm = repo.manifest.read(c[0])
             seen = {}
 
             for x in xrange(revnum, cl.count()):
                 c = cl.read(cl.node(x))
                 for f in c[3]:
                     if f in seen:
                         continue
                     seen[f] = 1
                     if f in mm:
                         filerev = mm[f]
                     else:
                         filerev = 0
                     seen[f] = filerev
             # we go in two steps here so the strip loop happens in a
             # sensible order.  When stripping many files, this helps keep
             # our disk access patterns under control.
             list = seen.keys()
             list.sort()
             for f in list:
                 ff = repo.file(f)
                 filerev = seen[f]
                 if filerev != 0:
                     if filerev in ff.nodemap:
                         filerev = ff.rev(filerev)
                     else:
                         filerev = 0
                 ff.strip(filerev, revnum)
 
         if not wlock:
             wlock = repo.wlock()
         lock = repo.lock()
         chlog = repo.changelog
         # TODO delete the undo files, and handle undo of merge sets
         pp = chlog.parents(rev)
         revnum = chlog.rev(rev)
 
         if update:
             (c, a, r, d, u) = repo.changes(None, None)
             if c or a or d or r:
                 raise util.Abort(_("local changes found"))
             urev = self.qparents(repo, rev)
             repo.update(urev, allow=False, force=True, wlock=wlock)
             repo.dirstate.write()
 
         # save is a list of all the branches we are truncating away
         # that we actually want to keep.  changegroup will be used
         # to preserve them and add them back after the truncate
         saveheads = []
         savebases = {}
 
         tip = chlog.tip()
         heads = limitheads(chlog, rev)
         seen = {}
 
         # search through all the heads, finding those where the revision
         # we want to strip away is an ancestor.  Also look for merges
         # that might be turned into new heads by the strip.
         while heads:
             h = heads.pop()
             n = h
             while True:
                 seen[n] = 1
                 pp = chlog.parents(n)
                 if pp[1] != revlog.nullid and chlog.rev(pp[1]) > revnum:
                     if pp[1] not in seen:
                         heads.append(pp[1])
                 if pp[0] == revlog.nullid:
                     break
                 if chlog.rev(pp[0]) < revnum:
                     break
                 n = pp[0]
                 if n == rev:
                     break
             r = chlog.reachable(h, rev)
             if rev not in r:
                 saveheads.append(h)
                 for x in r:
                     if chlog.rev(x) > revnum:
                         savebases[x] = 1
 
         # create a changegroup for all the branches we need to keep
         if backup is "all":
             backupch = repo.changegroupsubset([rev], chlog.heads(), 'strip')
             bundle(backupch)
         if saveheads:
             backupch = repo.changegroupsubset(savebases.keys(), saveheads, 'strip')
             chgrpfile = bundle(backupch)
 
         stripall(rev, revnum)
 
         change = chlog.read(rev)
         repo.manifest.strip(repo.manifest.rev(change[0]), revnum)
         chlog.strip(revnum, revnum)
         if saveheads:
             self.ui.status("adding branch\n")
             commands.unbundle(self.ui, repo, chgrpfile, update=False)
             if backup is not "strip":
                 os.unlink(chgrpfile)
 
     def isapplied(self, patch):
         """returns (index, rev, patch)"""
         for i in xrange(len(self.applied)):
             p = self.applied[i]
             a = p.split(':')
             if a[1] == patch:
                 return (i, a[0], a[1])
         return None
 
     # if the exact patch name does not exist, we try a few 
     # variations.  If strict is passed, we try only #1
     #
     # 1) a number to indicate an offset in the series file
     # 2) a unique substring of the patch name was given
     # 3) patchname[-+]num to indicate an offset in the series file
     def lookup(self, patch, strict=False):
         def partial_name(s):
             count = 0
             if s in self.series:
                 return s
             for x in self.series:
                 if s in x:
                     count += 1
                     last = x
                 if count > 1:
                     return None
             if count:
                 return last
             if len(self.series) > 0 and len(self.applied) > 0:
                 if s == 'qtip':
                     return self.series[self.series_end()-1]
                 if s == 'qbase':
                     return self.series[0]
             return None
         if patch == None:
             return None
 
         # we don't want to return a partial match until we make
         # sure the file name passed in does not exist (checked below)
         res = partial_name(patch)
         if res and res == patch:
             return res
 
         if not os.path.isfile(os.path.join(self.path, patch)):
             try:
                 sno = int(patch)
             except(ValueError, OverflowError):
                 pass
             else:
                 if sno < len(self.series):
                     patch = self.series[sno]
                     return patch
             if not strict:
                 # return any partial match made above
                 if res:
                     return res
                 minus = patch.rsplit('-', 1)
                 if len(minus) > 1:
                     res = partial_name(minus[0])
                     if res:
                         i = self.series.index(res)
                         try:
                             off = int(minus[1] or 1)
                         except(ValueError, OverflowError):
                             pass
                         else:
                             if i - off >= 0:
                                 return self.series[i - off]
                 plus = patch.rsplit('+', 1)
                 if len(plus) > 1:
                     res = partial_name(plus[0])
                     if res:
                         i = self.series.index(res)
                         try:
                             off = int(plus[1] or 1)
                         except(ValueError, OverflowError):
                             pass
                         else:
                             if i + off < len(self.series):
                                 return self.series[i + off]
         raise util.Abort(_("patch %s not in series") % patch)
 
     def push(self, repo, patch=None, force=False, list=False,
              mergeq=None, wlock=None):
         if not wlock:
             wlock = repo.wlock()
         patch = self.lookup(patch)
         if patch and self.isapplied(patch):
             self.ui.warn(_("patch %s is already applied\n") % patch)
             sys.exit(1)
         if self.series_end() == len(self.series):
             self.ui.warn(_("patch series fully applied\n"))
             sys.exit(1)
         if not force:
             self.check_localchanges(repo)
 
         self.applied_dirty = 1;
         start = self.series_end()
         if start > 0:
             self.check_toppatch(repo)
         if not patch:
             patch = self.series[start]
             end = start + 1
         else:
             end = self.series.index(patch, start) + 1
         s = self.series[start:end]
         if mergeq:
             ret = self.mergepatch(repo, mergeq, s, wlock)
         else:
             ret = self.apply(repo, s, list, wlock=wlock)
         top = self.applied[-1].split(':')[1]
         if ret[0]:
             self.ui.write("Errors during apply, please fix and refresh %s\n" %
                           top)
         else:
             self.ui.write("Now at: %s\n" % top)
         return ret[0]
 
     def pop(self, repo, patch=None, force=False, update=True, all=False,
             wlock=None):
         def getfile(f, rev):
             t = repo.file(f).read(rev)
             try:
                 repo.wfile(f, "w").write(t)
             except IOError:
                 try:
                     os.makedirs(os.path.dirname(repo.wjoin(f)))
                 except OSError, err:
                     if err.errno != errno.EEXIST: raise
                 repo.wfile(f, "w").write(t)
 
         if not wlock:
             wlock = repo.wlock()
         if patch:
             # index, rev, patch
             info = self.isapplied(patch)
             if not info:
                 patch = self.lookup(patch)
             info = self.isapplied(patch)
             if not info:
                 raise util.Abort(_("patch %s is not applied") % patch)
         if len(self.applied) == 0:
             self.ui.warn(_("no patches applied\n"))
             sys.exit(1)
 
         if not update:
             parents = repo.dirstate.parents()
             rr = [ revlog.bin(x.split(':')[0]) for x in self.applied ]
             for p in parents:
                 if p in rr:
                     self.ui.warn("qpop: forcing dirstate update\n")
                     update = True
 
         if not force and update:
             self.check_localchanges(repo)
 
         self.applied_dirty = 1;
         end = len(self.applied)
         if not patch:
             if all:
                 popi = 0
             else:
                 popi = len(self.applied) - 1
         else:
             popi = info[0] + 1
             if popi >= end:
                 self.ui.warn("qpop: %s is already at the top\n" % patch)
                 return
         info = [ popi ] + self.applied[popi].split(':')
 
         start = info[0]
         rev = revlog.bin(info[1])
 
         # we know there are no local changes, so we can make a simplified
         # form of hg.update.
         if update:
             top = self.check_toppatch(repo)
             qp = self.qparents(repo, rev)
             changes = repo.changelog.read(qp)
             mf1 = repo.manifest.readflags(changes[0])
             mmap = repo.manifest.read(changes[0])
             (c, a, r, d, u) = repo.changes(qp, top)
             if d:
                 raise util.Abort("deletions found between repo revs")
             for f in c:
                 getfile(f, mmap[f])
             for f in r:
                 getfile(f, mmap[f])
                 util.set_exec(repo.wjoin(f), mf1[f])
             repo.dirstate.update(c + r, 'n')
             for f in a:
                 try: os.unlink(repo.wjoin(f))
                 except: raise
                 try: os.removedirs(os.path.dirname(repo.wjoin(f)))
                 except: pass
             if a:
                 repo.dirstate.forget(a)
             repo.dirstate.setparents(qp, revlog.nullid)
         self.strip(repo, rev, update=False, backup='strip', wlock=wlock)
         del self.applied[start:end]
         if len(self.applied):
             self.ui.write("Now at: %s\n" % self.applied[-1].split(':')[1])
         else:
             self.ui.write("Patch queue now empty\n")
 
     def diff(self, repo, files):
         top = self.check_toppatch(repo)
         if not top:
             self.ui.write("No patches applied\n")
             return
         qp = self.qparents(repo, top)
         commands.dodiff(sys.stdout, self.ui, repo, qp, None, files)
 
     def refresh(self, repo, msg=None, short=False):
         if len(self.applied) == 0:
             self.ui.write("No patches applied\n")
             return
         wlock = repo.wlock()
         self.check_toppatch(repo)
         qp = self.qparents(repo)
         (top, patch) = self.applied[-1].split(':')
         top = revlog.bin(top)
         cparents = repo.changelog.parents(top)
         patchparent = self.qparents(repo, top)
         message, comments, user, date, patchfound = self.readheaders(patch)
 
         patchf = self.opener(patch, "w")
         msg = msg.rstrip()
         if msg:
             if comments:
                 # Remove existing message.
                 ci = 0
                 for mi in range(len(message)):
                     while message[mi] != comments[ci]:
                         ci += 1
                     del comments[ci]
             comments.append(msg)
         if comments:
             comments = "\n".join(comments) + '\n\n'
             patchf.write(comments)
 
         tip = repo.changelog.tip()
         if top == tip:
             # if the top of our patch queue is also the tip, there is an
             # optimization here.  We update the dirstate in place and strip
             # off the tip commit.  Then just commit the current directory
             # tree.  We can also send repo.commit the list of files
             # changed to speed up the diff
             #
             # in short mode, we only diff the files included in the
             # patch already
             #
             # this should really read:
             #(cc, dd, aa, aa2, uu) = repo.changes(tip, patchparent)
             # but we do it backwards to take advantage of manifest/chlog
             # caching against the next repo.changes call
             #
             (cc, aa, dd, aa2, uu) = repo.changes(patchparent, tip)
             if short:
                 filelist = cc + aa + dd
             else:
                 filelist = None
             (c, a, r, d, u) = repo.changes(None, None, filelist)
 
             # we might end up with files that were added between tip and
             # the dirstate parent, but then changed in the local dirstate.
             # in this case, we want them to only show up in the added section
             for x in c:
                 if x not in aa:
                     cc.append(x)
             # we might end up with files added by the local dirstate that
             # were deleted by the patch.  In this case, they should only
             # show up in the changed section.
             for x in a:
                 if x in dd:
                     del dd[dd.index(x)]
                     cc.append(x)
                 else:
                     aa.append(x)
             # make sure any files deleted in the local dirstate
             # are not in the add or change column of the patch
             forget = []
             for x in d + r:
                 if x in aa:
                     del aa[aa.index(x)]
                     forget.append(x)
                     continue
                 elif x in cc:
                     del cc[cc.index(x)]
                 dd.append(x)
 
             c = list(util.unique(cc))
             r = list(util.unique(dd))
             a = list(util.unique(aa))
             filelist = list(util.unique(c + r + a ))
             commands.dodiff(patchf, self.ui, repo, patchparent, None,
                             filelist, changes=(c, a, r, [], u))
             patchf.close()
 
             changes = repo.changelog.read(tip)
             repo.dirstate.setparents(*cparents)
             repo.dirstate.update(a, 'a')
             repo.dirstate.update(r, 'r')
             repo.dirstate.update(c, 'n')
             repo.dirstate.forget(forget)
 
             if not msg:
                 if not message:
                     message = "patch queue: %s\n" % patch
                 else:
                     message = "\n".join(message)
             else:
                 message = msg
 
             self.strip(repo, top, update=False, backup='strip', wlock=wlock)
             n = repo.commit(filelist, message, changes[1], force=1, wlock=wlock)
             self.applied[-1] = revlog.hex(n) + ':' + patch
             self.applied_dirty = 1
         else:
             commands.dodiff(patchf, self.ui, repo, patchparent, None)
             patchf.close()
             self.pop(repo, force=True, wlock=wlock)
             self.push(repo, force=True, wlock=wlock)
 
     def init(self, repo, create=False):
         if os.path.isdir(self.path):
             raise util.Abort(_("patch queue directory already exists"))
         os.mkdir(self.path)
         if create:
             return self.qrepo(create=True)
 
     def unapplied(self, repo, patch=None):
         if patch and patch not in self.series:
             raise util.Abort(_("patch %s is not in series file") % patch)
         if not patch:
             start = self.series_end()
         else:
             start = self.series.index(patch) + 1
         for p in self.series[start:]:
             if self.ui.verbose:
                 self.ui.write("%d " % self.series.index(p))
             self.ui.write("%s\n" % p)
 
     def qseries(self, repo, missing=None):
         start = self.series_end()
         if not missing:
             for p in self.series[:start]:
                 if self.ui.verbose:
                     self.ui.write("%d A " % self.series.index(p))
                 self.ui.write("%s\n" % p)
             for p in self.series[start:]:
                 if self.ui.verbose:
                     self.ui.write("%d U " % self.series.index(p))
                 self.ui.write("%s\n" %  p)
         else:
             list = []
             for root, dirs, files in os.walk(self.path):
                 d = root[len(self.path) + 1:]
                 for f in files:
                     fl = os.path.join(d, f)
                     if (fl not in self.series and
                         fl not in (self.status_path, self.series_path)
                         and not fl.startswith('.')):
                         list.append(fl)
             list.sort()
             if list:
                 for x in list:
                     if self.ui.verbose:
                         self.ui.write("D ")
                     self.ui.write("%s\n" % x)
 
     def issaveline(self, l):
         name = l.split(':')[1]
         if name == '.hg.patches.save.line':
             return True
 
     def qrepo(self, create=False):
         if create or os.path.isdir(os.path.join(self.path, ".hg")):
             return hg.repository(self.ui, path=self.path, create=create)
 
     def restore(self, repo, rev, delete=None, qupdate=None):
         c = repo.changelog.read(rev)
         desc = c[4].strip()
         lines = desc.splitlines()
         i = 0
         datastart = None
         series = []
         applied = []
         qpp = None
         for i in xrange(0, len(lines)):
             if lines[i] == 'Patch Data:':
                 datastart = i + 1
             elif lines[i].startswith('Dirstate:'):
                 l = lines[i].rstrip()
                 l = l[10:].split(' ')
                 qpp = [ hg.bin(x) for x in l ]
             elif datastart != None:
                 l = lines[i].rstrip()
                 index = l.index(':')
                 id = l[:index]
                 file = l[index + 1:]
                 if id:
                     applied.append(l)
                 series.append(file)
         if datastart == None:
             self.ui.warn("No saved patch data found\n")
             return 1
         self.ui.warn("restoring status: %s\n" % lines[0])
         self.full_series = series
         self.applied = applied
         self.read_series(self.full_series)
         self.series_dirty = 1
         self.applied_dirty = 1
         heads = repo.changelog.heads()
         if delete:
             if rev not in heads:
                 self.ui.warn("save entry has children, leaving it alone\n")
             else:
                 self.ui.warn("removing save entry %s\n" % hg.short(rev))
                 pp = repo.dirstate.parents()
                 if rev in pp:
                     update = True
                 else:
                     update = False
                 self.strip(repo, rev, update=update, backup='strip')
         if qpp:
             self.ui.warn("saved queue repository parents: %s %s\n" %
                          (hg.short(qpp[0]), hg.short(qpp[1])))
             if qupdate:
                 print "queue directory updating"
                 r = self.qrepo()
                 if not r:
                     self.ui.warn("Unable to load queue repository\n")
                     return 1
                 r.update(qpp[0], allow=False, force=True)
 
     def save(self, repo, msg=None):
         if len(self.applied) == 0:
             self.ui.warn("save: no patches applied, exiting\n")
             return 1
         if self.issaveline(self.applied[-1]):
             self.ui.warn("status is already saved\n")
             return 1
 
         ar = [ ':' + x for x in self.full_series ]
         if not msg:
             msg = "hg patches saved state"
         else:
             msg = "hg patches: " + msg.rstrip('\r\n')
         r = self.qrepo()
         if r:
             pp = r.dirstate.parents()
             msg += "\nDirstate: %s %s" % (hg.hex(pp[0]), hg.hex(pp[1]))
         msg += "\n\nPatch Data:\n"
         text = msg + "\n".join(self.applied) + '\n' + (ar and "\n".join(ar)
                                                        + '\n' or "")
         n = repo.commit(None, text, user=None, force=1)
         if not n:
             self.ui.warn("repo commit failed\n")
             return 1
         self.applied.append(revlog.hex(n) + ":" + '.hg.patches.save.line')
         self.applied_dirty = 1
 
     def full_series_end(self):
         if len(self.applied) > 0:
             (top, p) = self.applied[-1].split(':')
             end = self.find_series(p)
             if end == None:
                 return len(self.full_series)
             return end + 1
         return 0
 
     def series_end(self):
         end = 0
         if len(self.applied) > 0:
             (top, p) = self.applied[-1].split(':')
             try:
                 end = self.series.index(p)
             except ValueError:
                 return 0
             return end + 1
         return end
 
     def qapplied(self, repo, patch=None):
         if patch and patch not in self.series:
             raise util.Abort(_("patch %s is not in series file") % patch)
         if not patch:
             end = len(self.applied)
         else:
             end = self.series.index(patch) + 1
         for x in xrange(end):
             p = self.appliedname(x)
             self.ui.write("%s\n" % p)
 
     def appliedname(self, index):
         p = self.applied[index]
         pname = p.split(':')[1]
         if not self.ui.verbose:
             p = pname
         else:
             p = str(self.series.index(pname)) + " " + p
         return p
 
     def top(self, repo):
         if len(self.applied):
             p = self.appliedname(-1)
             self.ui.write(p + '\n')
         else:
             self.ui.write("No patches applied\n")
 
     def next(self, repo):
         end = self.series_end()
         if end == len(self.series):
             self.ui.write("All patches applied\n")
         else:
             p = self.series[end]
             if self.ui.verbose:
                 self.ui.write("%d " % self.series.index(p))
             self.ui.write(p + '\n')
 
     def prev(self, repo):
         if len(self.applied) > 1:
             p = self.appliedname(-2)
             self.ui.write(p + '\n')
         elif len(self.applied) == 1:
             self.ui.write("Only one patch applied\n")
         else:
             self.ui.write("No patches applied\n")
 
     def qimport(self, repo, files, patch=None, existing=None, force=None):
         if len(files) > 1 and patch:
             raise util.Abort(_('option "-n" not valid when importing multiple '
                                'files'))
         i = 0
         added = []
         for filename in files:
             if existing:
                 if not patch:
                     patch = filename
                 if not os.path.isfile(os.path.join(self.path, patch)):
                     raise util.Abort(_("patch %s does not exist") % patch)
             else:
                 try:
                     text = file(filename).read()
                 except IOError:
                     raise util.Abort(_("unable to read %s") % patch)
                 if not patch:
                     patch = os.path.split(filename)[1]
                 if not force and os.path.exists(os.path.join(self.path, patch)):
                     raise util.Abort(_('patch "%s" already exists') % patch)
                 patchf = self.opener(patch, "w")
                 patchf.write(text)
             if patch in self.series:
                 raise util.Abort(_('patch %s is already in the series file')
                                  % patch)
             index = self.full_series_end() + i
             self.full_series[index:index] = [patch]
             self.read_series(self.full_series)
             self.ui.warn("adding %s to series file\n" % patch)
             i += 1
             added.append(patch)
             patch = None
         self.series_dirty = 1
         qrepo = self.qrepo()
         if qrepo:
             qrepo.add(added)
 
 def delete(ui, repo, patch, **opts):
     """remove a patch from the series file"""
     q = repo.mq
     q.delete(repo, patch)
     q.save_dirty()
     return 0
 
 def applied(ui, repo, patch=None, **opts):
     """print the patches already applied"""
     repo.mq.qapplied(repo, patch)
     return 0
 
 def unapplied(ui, repo, patch=None, **opts):
     """print the patches not yet applied"""
     repo.mq.unapplied(repo, patch)
     return 0
 
 def qimport(ui, repo, *filename, **opts):
     """import a patch"""
     q = repo.mq
     q.qimport(repo, filename, patch=opts['name'],
               existing=opts['existing'], force=opts['force'])
     q.save_dirty()
     return 0
 
 def init(ui, repo, **opts):
     """init a new queue repository"""
     q = repo.mq
     r = q.init(repo, create=opts['create_repo'])
     q.save_dirty()
     if r:
         fp = r.wopener('.hgignore', 'w')
         print >> fp, 'syntax: glob'
         print >> fp, 'status'
         fp.close()
         r.wopener('series', 'w').close()
         r.add(['.hgignore', 'series'])
     return 0
 
 def clone(ui, source, dest=None, **opts):
     '''clone main and patch repository at same time
 
     If source is local, destination will have no patches applied.  If
     source is remote, this command can not check if patches are
     applied in source, so cannot guarantee that patches are not
     applied in destination.  If you clone remote repository, be sure
     before that it has no patches applied.
 
     Source patch repository is looked for in <src>/.hg/patches by
     default.  Use -p <url> to change.
     '''
     commands.setremoteconfig(**opts)
     if dest is None:
         dest = hg.defaultdest(source)
     sr = hg.repository(ui, ui.expandpath(source))
     qbase, destrev = None, None
     if sr.local():
         reposetup(ui, sr)
         if sr.mq.applied:
             qbase = revlog.bin(sr.mq.applied[0].split(':')[0])
             if not hg.islocal(dest):
                 destrev = sr.parents(qbase)[0]
     ui.note(_('cloning main repo\n'))
     sr, dr = hg.clone(ui, sr, dest,
                       pull=opts['pull'],
                       rev=destrev,
                       update=False,
                       stream=opts['uncompressed'])
     ui.note(_('cloning patch repo\n'))
     spr, dpr = hg.clone(ui, opts['patches'] or (sr.url() + '/.hg/patches'),
                         dr.url() + '/.hg/patches',
                         pull=opts['pull'],
                         update=not opts['noupdate'],
                         stream=opts['uncompressed'])
     if dr.local():
         if qbase:
             ui.note(_('stripping applied patches from destination repo\n'))
             reposetup(ui, dr)
             dr.mq.strip(dr, qbase, update=False, backup=None)
         if not opts['noupdate']:
             ui.note(_('updating destination repo\n'))
             dr.update(dr.changelog.tip())
 
 def commit(ui, repo, *pats, **opts):
     """commit changes in the queue repository"""
     q = repo.mq
     r = q.qrepo()
     if not r: raise util.Abort('no queue repository')
     commands.commit(r.ui, r, *pats, **opts)
 
 def series(ui, repo, **opts):
     """print the entire series file"""
     repo.mq.qseries(repo, missing=opts['missing'])
     return 0
 
 def top(ui, repo, **opts):
     """print the name of the current patch"""
     repo.mq.top(repo)
     return 0
 
 def next(ui, repo, **opts):
     """print the name of the next patch"""
     repo.mq.next(repo)
     return 0
 
 def prev(ui, repo, **opts):
     """print the name of the previous patch"""
     repo.mq.prev(repo)
     return 0
 
 def new(ui, repo, patch, **opts):
     """create a new patch"""
     q = repo.mq
     message=commands.logmessage(**opts)
     q.new(repo, patch, msg=message, force=opts['force'])
     q.save_dirty()
     return 0
 
 def refresh(ui, repo, **opts):
     """update the current patch"""
     q = repo.mq
     message=commands.logmessage(**opts)
     if opts['edit']:
         if message:
             raise util.Abort(_('option "-e" incompatible with "-m" or "-l"'))
         patch = q.applied[-1].split(':')[1]
         (message, comment, user, date, hasdiff) = q.readheaders(patch)
         message = ui.edit('\n'.join(message), user or ui.username())
     q.refresh(repo, msg=message, short=opts['short'])
     q.save_dirty()
     return 0
 
 def diff(ui, repo, *files, **opts):
     """diff of the current patch"""
     # deep in the dirstate code, the walkhelper method wants a list, not a tuple
     repo.mq.diff(repo, list(files))
     return 0
 
+def header(ui, repo, patch=None):
+    """Print the header of the topmost or specified patch"""
+    q = repo.mq
+
+    if patch:
+        patch = q.lookup(patch)
+    else:
+        if not q.applied:
+            ui.write('No patches applied\n')
+            return
+        patch = q.lookup('qtip')
+    message = repo.mq.readheaders(patch)[0]
+
+    ui.write('\n'.join(message) + '\n')
+
 def lastsavename(path):
     (dir, base) = os.path.split(path)
     names = os.listdir(dir)
     namere = re.compile("%s.([0-9]+)" % base)
     max = None
     maxname = None
     for f in names:
         m = namere.match(f)
         if m:
             index = int(m.group(1))
             if max == None or index > max:
                 max = index
                 maxname = f
     if maxname:
         return (os.path.join(dir, maxname), max)
     return (None, None)
 
 def savename(path):
     (last, index) = lastsavename(path)
     if last is None:
         index = 0
     newpath = path + ".%d" % (index + 1)
     return newpath
 
 def push(ui, repo, patch=None, **opts):
     """push the next patch onto the stack"""
     q = repo.mq
     mergeq = None
 
     if opts['all']:
         patch = q.series[-1]
     if opts['merge']:
         if opts['name']:
             newpath = opts['name']
         else:
             newpath, i = lastsavename(q.path)
         if not newpath:
             ui.warn("no saved queues found, please use -n\n")
             return 1
         mergeq = queue(ui, repo.join(""), newpath)
         ui.warn("merging with queue at: %s\n" % mergeq.path)
     ret = q.push(repo, patch, force=opts['force'], list=opts['list'],
                  mergeq=mergeq)
     q.save_dirty()
     return ret
 
 def pop(ui, repo, patch=None, **opts):
     """pop the current patch off the stack"""
     localupdate = True
     if opts['name']:
         q = queue(ui, repo.join(""), repo.join(opts['name']))
         ui.warn('using patch queue: %s\n' % q.path)
         localupdate = False
     else:
         q = repo.mq
     q.pop(repo, patch, force=opts['force'], update=localupdate, all=opts['all'])
     q.save_dirty()
     return 0
 
 def restore(ui, repo, rev, **opts):
     """restore the queue state saved by a rev"""
     rev = repo.lookup(rev)
     q = repo.mq
     q.restore(repo, rev, delete=opts['delete'],
               qupdate=opts['update'])
     q.save_dirty()
     return 0
 
 def save(ui, repo, **opts):
     """save current queue state"""
     q = repo.mq
     message=commands.logmessage(**opts)
     ret = q.save(repo, msg=message)
     if ret:
         return ret
     q.save_dirty()
     if opts['copy']:
         path = q.path
         if opts['name']:
             newpath = os.path.join(q.basepath, opts['name'])
             if os.path.exists(newpath):
                 if not os.path.isdir(newpath):
                     raise util.Abort(_('destination %s exists and is not '
                                        'a directory') % newpath)
                 if not opts['force']:
                     raise util.Abort(_('destination %s exists, '
                                        'use -f to force') % newpath)
         else:
             newpath = savename(path)
         ui.warn("copy %s to %s\n" % (path, newpath))
         util.copyfiles(path, newpath)
     if opts['empty']:
         try:
             os.unlink(os.path.join(q.path, q.status_path))
         except:
             pass
     return 0
 
 def strip(ui, repo, rev, **opts):
     """strip a revision and all later revs on the same branch"""
     rev = repo.lookup(rev)
     backup = 'all'
     if opts['backup']:
         backup = 'strip'
     elif opts['nobackup']:
         backup = 'none'
     repo.mq.strip(repo, rev, backup=backup)
     return 0
 
 def version(ui, q=None):
     """print the version number"""
     ui.write("mq version %s\n" % versionstr)
     return 0
 
 def reposetup(ui, repo):
     class MqRepo(repo.__class__):
         def tags(self):
             if self.tagscache:
                 return self.tagscache
 
             tagscache = super(MqRepo, self).tags()
 
             q = self.mq
             if not q.applied:
                 return tagscache
 
             mqtags = [patch.split(':') for patch in q.applied]
             mqtags.append((mqtags[-1][0], 'qtip'))
             mqtags.append((mqtags[0][0], 'qbase'))
             for patch in mqtags:
                 if patch[1] in tagscache:
                     self.ui.warn('Tag %s overrides mq patch of the same name\n' % patch[1])
                 else:
                     tagscache[patch[1]] = revlog.bin(patch[0])
 
             return tagscache
 
     repo.__class__ = MqRepo
     repo.mq = queue(ui, repo.join(""))
 
 cmdtable = {
     "qapplied": (applied, [], 'hg qapplied [PATCH]'),
     "qclone": (clone,
                [('', 'pull', None, _('use pull protocol to copy metadata')),
                 ('U', 'noupdate', None, _('do not update the new working directories')),
                 ('', 'uncompressed', None,
                  _('use uncompressed transfer (fast over LAN)')),
                 ('e', 'ssh', '', _('specify ssh command to use')),
                 ('p', 'patches', '', _('location of source patch repo')),
                 ('', 'remotecmd', '',
                  _('specify hg command to run on the remote side'))],
                'hg qclone [OPTION]... SOURCE [DEST]'),
     "qcommit|qci":
         (commit,
          commands.table["^commit|ci"][1],
          'hg qcommit [OPTION]... [FILE]...'),
     "^qdiff": (diff, [], 'hg qdiff [FILE]...'),
     "qdelete": (delete, [], 'hg qdelete PATCH'),
+    'qheader': (header, [],
+                _('hg qheader [PATCH]')),
     "^qimport":
         (qimport,
          [('e', 'existing', None, 'import file in patch dir'),
           ('n', 'name', '', 'patch file name'),
           ('f', 'force', None, 'overwrite existing files')],
          'hg qimport [-e] [-n NAME] [-f] FILE...'),
     "^qinit":
         (init,
          [('c', 'create-repo', None, 'create queue repository')],
          'hg qinit [-c]'),
     "qnew":
         (new,
          [('m', 'message', '', _('use <text> as commit message')),
           ('l', 'logfile', '', _('read the commit message from <file>')),
           ('f', 'force', None, 'force')],
          'hg qnew [-m TEXT] [-l FILE] [-f] PATCH'),
     "qnext": (next, [], 'hg qnext'),
     "qprev": (prev, [], 'hg qprev'),
     "^qpop":
         (pop,
          [('a', 'all', None, 'pop all patches'),
           ('n', 'name', '', 'queue name to pop'),
           ('f', 'force', None, 'forget any local changes')],
          'hg qpop [-a] [-n NAME] [-f] [PATCH | INDEX]'),
     "^qpush":
         (push,
          [('f', 'force', None, 'apply if the patch has rejects'),
           ('l', 'list', None, 'list patch name in commit text'),
           ('a', 'all', None, 'apply all patches'),
           ('m', 'merge', None, 'merge from another queue'),
           ('n', 'name', '', 'merge queue name')],
          'hg qpush [-f] [-l] [-a] [-m] [-n NAME] [PATCH | INDEX]'),
     "^qrefresh":
         (refresh,
          [('e', 'edit', None, _('edit commit message')),
           ('m', 'message', '', _('change commit message with <text>')),
           ('l', 'logfile', '', _('change commit message with <file> content')),
           ('s', 'short', None, 'short refresh')],
          'hg qrefresh [-e] [-m TEXT] [-l FILE] [-s]'),
     "qrestore":
         (restore,
          [('d', 'delete', None, 'delete save entry'),
           ('u', 'update', None, 'update queue working dir')],
          'hg qrestore [-d] [-u] REV'),
     "qsave":
         (save,
          [('m', 'message', '', _('use <text> as commit message')),
           ('l', 'logfile', '', _('read the commit message from <file>')),
           ('c', 'copy', None, 'copy patch directory'),
           ('n', 'name', '', 'copy directory name'),
           ('e', 'empty', None, 'clear queue status file'),
           ('f', 'force', None, 'force copy')],
          'hg qsave [-m TEXT] [-l FILE] [-c] [-n NAME] [-e] [-f]'),
     "qseries":
         (series,
          [('m', 'missing', None, 'print patches not in series')],
          'hg qseries [-m]'),
     "^strip":
         (strip,
          [('f', 'force', None, 'force multi-head removal'),
           ('b', 'backup', None, 'bundle unrelated changesets'),
           ('n', 'nobackup', None, 'no backups')],
          'hg strip [-f] [-b] [-n] REV'),
     "qtop": (top, [], 'hg qtop'),
     "qunapplied": (unapplied, [], 'hg qunapplied [PATCH]'),
     "qversion": (version, [], 'hg qversion')
 }
 

tests/test-mq.out

@@ -1,111 +1,112 b''
 % help
 mq extension - patch management and development
 
 This extension lets you work with a stack of patches in a Mercurial
 repository.  It manages two stacks of patches - all known patches, and
 applied patches (subset of known patches).
 
 Known patches are represented as patch files in the .hg/patches
 directory.  Applied patches are both patch files and changesets.
 
 Common tasks (use "hg help command" for more details):
 
 prepare repository to work with patches   qinit
 create new patch                          qnew
 import existing patch                     qimport
 
 print patch series                        qseries
 print applied patches                     qapplied
 print name of top applied patch           qtop
 
 add known patch to applied stack          qpush
 remove patch from applied stack           qpop
 refresh contents of top applied patch     qrefresh
 
 list of commands (use "hg help -v mq" to show aliases and global options):
 
  qapplied     print the patches already applied
  qclone       clone main and patch repository at same time
  qcommit      commit changes in the queue repository
  qdelete      remove a patch from the series file
  qdiff        diff of the current patch
+ qheader      Print the header of the topmost or specified patch
  qimport      import a patch
  qinit        init a new queue repository
  qnew         create a new patch
  qnext        print the name of the next patch
  qpop         pop the current patch off the stack
  qprev        print the name of the previous patch
  qpush        push the next patch onto the stack
  qrefresh     update the current patch
  qrestore     restore the queue state saved by a rev
  qsave        save current queue state
  qseries      print the entire series file
  qtop         print the name of the current patch
  qunapplied   print the patches not yet applied
  qversion     print the version number
  strip        strip a revision and all later revs on the same branch
 adding a
 adding b/z
 % qinit
 % -R qinit
 % qinit -c
 A .hgignore
 A series
 % qnew implies add
 A .hgignore
 A series
 A test.patch
 % qnew -m
 foo bar
 % qrefresh
 foo bar
 
 diff -r  xa
 --- a/a
 +++ b/a
 @@ -1,1 +1,2 @@ a
  a
 +a
 % qpop
 Patch queue now empty
 % qpush
 applying test.patch
 Now at: test.patch
 % pop/push outside repo
 Patch queue now empty
 applying test.patch
 Now at: test.patch
 % qrefresh in subdir
 % pop/push -a in subdir
 Patch queue now empty
 applying test.patch
 applying test2.patch
 Now at: test2.patch
 % qseries
 test.patch
 test2.patch
 % qapplied
 test.patch
 test2.patch
 % qtop
 test2.patch
 % qprev
 test.patch
 % qnext
 All patches applied
 % pop, qnext, qprev, qapplied
 Now at: test.patch
 test2.patch
 Only one patch applied
 test.patch
 % qunapplied
 test2.patch
 % strip
 adding x
 0 files updated, 0 files merged, 1 files removed, 0 files unresolved
 saving bundle to 
 adding changesets
 adding manifests
 adding file changes
 added 1 changesets with 1 changes to 1 files
 (run 'hg update' to get a working copy)