809 

   810 def rewrite(repo, old, updates, head, newbases, commitopts):

   811     """Return (nodeid, created) where nodeid is the identifier of the

   812     changeset generated by the rewrite process, and created is True if

   813     nodeid was actually created. If created is False, nodeid

   814     references a changeset existing before the rewrite call.

   815     """

   816     wlock = lock = tr = None

   817     try:

   818         wlock = repo.wlock()

   819         lock = repo.lock()

   820         tr = repo.transaction('rewrite')

   821         if len(old.parents()) > 1: # XXX remove this unnecessary limitation.

   822             raise error.Abort(_('cannot amend merge changesets'))

   823         base = old.p1()

   824         updatebookmarks = _bookmarksupdater(repo, old.node(), tr)

   825 

   826         # commit a new version of the old changeset, including the update

   827         # collect all files which might be affected

   828         files = set(old.files())

   829         for u in updates:

   830             files.update(u.files())

   831 

   832         # Recompute copies (avoid recording a -> b -> a)

   833         copied = copies.pathcopies(base, head)

   834 

   835         # prune files which were reverted by the updates

   836         def samefile(f):

   837             if f in head.manifest():

   838                 a = head.filectx(f)

   839                 if f in base.manifest():

   840                     b = base.filectx(f)

   841                     return (a.data() == b.data()

   842                             and a.flags() == b.flags())

   843                 else:

   844                     return False

   845             else:

   846                 return f not in base.manifest()

   847         files = [f for f in files if not samefile(f)]

   848         # commit version of these files as defined by head

   849         headmf = head.manifest()

   850 

   851         def filectxfn(repo, ctx, path):

   852             if path in headmf:

   853                 fctx = head[path]

   854                 flags = fctx.flags()

   855                 mctx = context.memfilectx(repo, fctx.path(), fctx.data(),

   856                                           islink='l' in flags,

   857                                           isexec='x' in flags,

   858                                           copied=copied.get(path))

   859                 return mctx

   860             return None

   861 

   862         message = cmdutil.logmessage(repo.ui, commitopts)

   863         if not message:

   864             message = old.description()

   865 

   866         user = commitopts.get('user') or old.user()

   867         # TODO: In case not date is given, we should take the old commit date

   868         # if we are working one one changeset or mimic the fold behavior about

   869         # date

   870         date = commitopts.get('date') or None

   871         extra = dict(commitopts.get('extra', old.extra()))

   872         extra['branch'] = head.branch()

   873 

   874         new = context.memctx(repo,

   875                              parents=newbases,

   876                              text=message,

   877                              files=files,

   878                              filectxfn=filectxfn,

   879                              user=user,

   880                              date=date,

   881                              extra=extra)

   882 

   883         if commitopts.get('edit'):

   884             new._text = cmdutil.commitforceeditor(repo, new, [])

   885         revcount = len(repo)

   886         newid = repo.commitctx(new)

   887         new = repo[newid]

   888         created = len(repo) != revcount

   889         updatebookmarks(newid)

   890 

   891         tr.close()

   892         return newid, created

   893     finally:

   894         lockmod.release(tr, lock, wlock)