--- a/mercurial/commands.py	Thu Mar 22 10:40:28 2007 -0700
+++ b/mercurial/commands.py	Thu Mar 22 10:44:59 2007 -0700
@@ -1477,15 +1477,21 @@
     text/plain body parts before first diff are added to commit
     message.
 
-    If imported patch was generated by hg export, user and description
+    If the imported patch was generated by hg export, user and description
     from patch override values from message headers and body.  Values
     given on command line with -m and -u override these.
 
+    If --exact is specified, import will set the working directory
+    to the parent of each patch before applying it, and will abort
+    if the resulting changeset has a different ID than the one
+    recorded in the patch. This may happen due to character set
+    problems or other deficiencies in the text patch format.
+
     To read a patch from standard input, use patch name "-".
     """
     patches = (patch1,) + patches
 
-    if not opts['force']:
+    if opts.get('exact') or not opts['force']:
         bail_if_changed(repo)
 
     d = opts["base"]
@@ -1499,10 +1505,10 @@
 
         if pf == '-':
             ui.status(_("applying patch from stdin\n"))
-            tmpname, message, user, date = patch.extract(ui, sys.stdin)
+            tmpname, message, user, date, nodeid, p1, p2 = patch.extract(ui, sys.stdin)
         else:
             ui.status(_("applying %s\n") % p)
-            tmpname, message, user, date = patch.extract(ui, file(pf))
+            tmpname, message, user, date, nodeid, p1, p2 = patch.extract(ui, file(pf))
 
         if tmpname is None:
             raise util.Abort(_('no diffs found'))
@@ -1521,12 +1527,27 @@
             ui.debug(_('message:\n%s\n') % message)
 
             files = {}
+            if opts.get('exact'):
+                if not nodeid or not p1:
+                    raise util.Abort(_('not a mercurial patch'))
+                p1 = repo.lookup(p1)
+                p2 = repo.lookup(p2 or hex(nullid))
+
+                wctx = repo.workingctx()
+                wp = repo.workingctx().parents()
+                if p1 != wp[0].node():
+                    hg.clean(repo, p1, wlock=wlock)
+                repo.dirstate.setparents(p1, p2)
             try:
                 fuzz = patch.patch(tmpname, ui, strip=strip, cwd=repo.root,
                                    files=files)
             finally:
                 files = patch.updatedir(ui, repo, files, wlock=wlock)
-            repo.commit(files, message, user, date, wlock=wlock, lock=lock)
+            n = repo.commit(files, message, user, date, wlock=wlock, lock=lock)
+            if opts.get('exact'):
+                if hex(n) != nodeid:
+                    repo.rollback()
+                    raise util.Abort(_('patch is damaged or loses information'))
         finally:
             os.unlink(tmpname)
 
@@ -2772,7 +2793,9 @@
              'meaning as the corresponding patch option')),
           ('b', 'base', '', _('base path')),
           ('f', 'force', None,
-           _('skip check for outstanding uncommitted changes'))] + commitopts,
+           _('skip check for outstanding uncommitted changes')),
+          ('', 'exact', None,
+           _('apply patch to the nodes from which it was generated'))] + commitopts,
          _('hg import [-p NUM] [-m MESSAGE] [-f] PATCH...')),
     "incoming|in": (incoming,
          [('M', 'no-merges', None, _('do not show merges')),

--- a/mercurial/patch.py	Thu Mar 22 10:40:28 2007 -0700
+++ b/mercurial/patch.py	Thu Mar 22 10:44:59 2007 -0700
@@ -33,11 +33,11 @@
 def extract(ui, fileobj):
     '''extract patch from data read from fileobj.
 
-    patch can be normal patch or contained in email message.
+    patch can be a normal patch or contained in an email message.
 
-    return tuple (filename, message, user, date). any item in returned
-    tuple can be None.  if filename is None, fileobj did not contain
-    patch. caller must unlink filename when done.'''
+    return tuple (filename, message, user, date, node, p1, p2).
+    Any item in the returned tuple can be None. If filename is None,
+    fileobj did not contain a patch. Caller must unlink filename when done.'''
 
     # attempt to detect the start of a patch
     # (this heuristic is borrowed from quilt)
@@ -54,6 +54,8 @@
         user = msg['From']
         # should try to parse msg['Date']
         date = None
+        nodeid = None
+        parents = []
 
         if message:
             if message.startswith('[PATCH'):
@@ -97,6 +99,10 @@
                             ui.debug('From: %s\n' % user)
                         elif line.startswith("# Date "):
                             date = line[7:]
+                        elif line.startswith("# Node ID "):
+                            nodeid = line[10:]
+                        elif line.startswith("# Parent "):
+                            parents.append(line[10:])
                     elif line == '---' and 'git-send-email' in msg['X-Mailer']:
                         ignoretext = True
                     if not line.startswith('# ') and not ignoretext:
@@ -117,8 +123,10 @@
     tmpfp.close()
     if not diffs_seen:
         os.unlink(tmpname)
-        return None, message, user, date
-    return tmpname, message, user, date
+        return None, message, user, date, None, None, None
+    p1 = parents and parents.pop(0) or None
+    p2 = parents and parents.pop(0) or None
+    return tmpname, message, user, date, nodeid, p1, p2
 
 GP_PATCH  = 1 << 0  # we have to run patch
 GP_FILTER = 1 << 1  # there's some copy/rename operation