#
#
# add_dir "tests/diff_reverse"
# 
# add_file "tests/diff_reverse/__driver__.lua"
#  content [e174ee4ebe94c2af95edf48fd2f30029f95a8958]
# 
# patch "cmd_diff_log.cc"
#  from [ddcd0dfc3c690b04ce83cb0fb68b8cce2795137e]
#    to [1595b889561fe5cd2f14fb0ad37acfa1483949a0]
# 
# patch "monotone.texi"
#  from [b788c4a30206f2eacd2011dac65f79584488bd1a]
#    to [faf359c7d44bb4922b5487495cda7da5d784e2bf]
# 
# patch "options_list.hh"
#  from [fe3b7714d2c58e05d75fefc8d28bbe5935d22051]
#    to [9c3cd1b82269f3c1261a687ff327335b3e7b9fbf]
# 
# patch "txt2c.cc"
#  from [b23798126943239eaff66187b8828e153ec2c8d8]
#    to [ce222c5c631cce47040a85f23f6256fe18387cd1]
#
============================================================
--- tests/diff_reverse/__driver__.lua	e174ee4ebe94c2af95edf48fd2f30029f95a8958
+++ tests/diff_reverse/__driver__.lua	e174ee4ebe94c2af95edf48fd2f30029f95a8958
@@ -0,0 +1,28 @@
+-- Test --reverse option for diff
+
+mtn_setup()
+
+addfile("file1", "1: data 1\n")
+commit()
+rev = base_revision()
+
+writefile("file1", "1: data 2\n")
+
+-- illegal --reverse option
+check(mtn("diff", "--reverse"), 1, false, true)
+check(qgrep("--reverse only allowed with exactly one revision", "stderr"))
+
+check(mtn("diff", "--reverse", rev, rev), 1, false, true)
+check(qgrep("--reverse only allowed with exactly one revision", "stderr"))
+
+-- no --reverse option
+check(mtn("diff", "--revision=" .. rev), 0, true, false)
+check(qgrep("from \\[614d24f144edd2ef92ad9f8bc6d25bcf77e04101\\]", "stdout"))
+check(qgrep("to \\[50812c5d2dcc96a92cea9c1c6ee7fd093774a4ea\\]", "stdout"))
+
+check(mtn("diff", "--reverse", "--revision=" .. rev), 0, true, false)
+check(qgrep("to \\[614d24f144edd2ef92ad9f8bc6d25bcf77e04101\\]", "stdout"))
+check(qgrep("from \\[50812c5d2dcc96a92cea9c1c6ee7fd093774a4ea\\]", "stdout"))
+
+
+-- end of file
============================================================
--- cmd_diff_log.cc	ddcd0dfc3c690b04ce83cb0fb68b8cce2795137e
+++ cmd_diff_log.cc	1595b889561fe5cd2f14fb0ad37acfa1483949a0
@@ -1,4 +1,5 @@
-// Copyright (C) 2002 Graydon Hoare <address@hidden>
+// Copyright (C) 2009 Stephen Leake <address@hidden>
+// Copyright (C) 2002, 2009 Graydon Hoare <address@hidden>
 //
 // This program is made available under the GNU GPL version 2.0 or
 // greater. See the accompanying file COPYING for details.
@@ -361,12 +362,18 @@ prepare_diff(app_state & app,
   ostringstream header;
   cset excluded;
 
+  // The resulting diff is output in 'included'. Not clear what 'excluded'
+  // is for.
+
   // initialize before transaction so we have a database to work with.
   project_t project(db);
 
   E(app.opts.revision_selectors.size() <= 2, origin::user,
     F("more than two revisions given"));
 
+  E(!app.opts.reverse || app.opts.revision_selectors.size() == 1, origin::user,
+    F("--reverse only allowed with exactly one revision"));
+
   if (app.opts.revision_selectors.empty())
     {
       roster_t old_roster, restricted_roster, new_roster;
@@ -422,8 +429,17 @@ prepare_diff(app_state & app,
       make_restricted_roster(old_roster, new_roster, restricted_roster,
                              mask);
 
-      make_cset(old_roster, restricted_roster, included);
-      make_cset(restricted_roster, new_roster, excluded);
+      if (app.opts.reverse)
+        {
+          // FIXME: this breaks something in graph.cc
+          make_cset(new_roster, restricted_roster, excluded);
+          make_cset(restricted_roster, old_roster, included);
+        }
+      else
+        {
+          make_cset(old_roster, restricted_roster, included);
+          make_cset(restricted_roster, new_roster, excluded);
+        }
 
       new_is_archived = false;
       header << "# old_revision [" << r_old_id << "]\n";
============================================================
--- monotone.texi	b788c4a30206f2eacd2011dac65f79584488bd1a
+++ monotone.texi	faf359c7d44bb4922b5487495cda7da5d784e2bf
@@ -5498,22 +5498,26 @@ @section Informative
 @itemx mtn diff --context [--no-show-encloser]
 @itemx mtn diff --external address@hidden
 @itemx mtn diff @var{pathname...}
address@hidden mtn diff address@hidden
address@hidden mtn diff [--reverse] address@hidden
 @itemx mtn diff address@hidden @var{pathname...}
 @itemx mtn diff address@hidden address@hidden
 @itemx mtn diff address@hidden address@hidden @var{pathname...}
 
 These commands print out GNU ``unified diff format'' textual difference
 listings between various manifest versions. With no @option{--revision}
-options, @command{diff} will print the differences between the
-base revision and the current revision in the workspace.
+options, @command{diff} will print the difference from the
+base revision to the current revision in the workspace.
 
 With one @option{--revision} option, @command{diff} will print the
-differences between the revision @var{id} and the current revision in
-the workspace.  With two @option{--revision} options @command{diff}
-will print the differences between revisions @var{id1} and @var{id2},
-ignoring any workspace.
+difference from the revision @var{id} to the current revision in the
+workspace. If @option{--reverse} is given, the order of the diff is
+reversed.
 
+With two @option{--revision} options @command{diff} will print the
+difference from revision @var{id1} to @var{id2}, ignoring any
+workspace.
+
+
 In all cases, monotone will print a textual summary -- identical to
 the summary presented by @command{mtn status} -- of the logical
 differences between revisions in lines proceeding the diff. These
============================================================
--- options_list.hh	fe3b7714d2c58e05d75fefc8d28bbe5935d22051
+++ options_list.hh	9c3cd1b82269f3c1261a687ff327335b3e7b9fbf
@@ -1,5 +1,5 @@
 // Copyright (C) 2006 Timothy Brownawell <address@hidden>
-//               2008 Stephen Leake <address@hidden>
+//               2008-2009 Stephen Leake <address@hidden>
 //
 // This program is made available under the GNU GPL version 2.0 or
 // greater. See the accompanying file COPYING for details.
@@ -217,6 +217,14 @@ OPTION(diff_options, external_diff_args,
 }
 #endif
 
+OPTVAR(diff_options, bool, reverse, false)
+OPTION(diff_options, reverse, false, "reverse",
+        gettext_noop("reverse order of diff"))
+#ifdef option_bodies
+{
+  reverse = true;
+}
+#endif
 OPTVAR(diff_options, diff_type, diff_format, unified_diff)
 OPTION(diff_options, diff_context, false, "context",
         gettext_noop("use context diff format"))
============================================================
--- txt2c.cc	b23798126943239eaff66187b8828e153ec2c8d8
+++ txt2c.cc	ce222c5c631cce47040a85f23f6256fe18387cd1
@@ -150,6 +150,9 @@ atomic_update_if_changed(char const *ofn
       throw ioerror(tfname, "write");
   }
 
+  if (remove(ofname))
+      throw ioerror(ofname, "remove");
+
   if (rename(tfname.c_str(), ofname))
     throw ioerror(ofname, "rename");
 }