#
#
# patch "cmd_automate.cc"
#  from [31490dcba1e859909b03f69fedfcc7ffe1ca0faa]
#    to [12ac852434d7da216115bcddac1c47986449fcc1]
# 
# patch "cmd_diff_log.cc"
#  from [509da14568d804c8e3fb741cc676f0979fe33e6f]
#    to [3c3f91765800b2dd861a997b400c4053fd6969a6]
# 
# patch "monotone.texi"
#  from [5e2bb7643436006b6bf4a7883eb6ac40eb4efdda]
#    to [49e39037ce032c7b65fdf42e5fde18b6fb911735]
# 
# patch "options_list.hh"
#  from [93e1285e0f6cd24e045a53bdb689af5739f94e9c]
#    to [be7e3a4c58245de8cdd8c88a1bfcb54ff5dc8821]
# 
# patch "tests/automate_content_diff/__driver__.lua"
#  from [49eb0b60c12eefb624af0e586d6bd860ac03cfb4]
#    to [274e9b78eab4715e2d793b1db848bc872b0ad173]
#
============================================================
--- cmd_automate.cc	31490dcba1e859909b03f69fedfcc7ffe1ca0faa
+++ cmd_automate.cc	12ac852434d7da216115bcddac1c47986449fcc1
@@ -68,7 +68,7 @@ namespace commands {
   }
 }
 
-static string const interface_version = "8.0";
+static string const interface_version = "8.1";
 // Major or minor number only increments once for each monotone release;
 // check the most recent release before incrementing this.
 
============================================================
--- cmd_diff_log.cc	509da14568d804c8e3fb741cc676f0979fe33e6f
+++ cmd_diff_log.cc	3c3f91765800b2dd861a997b400c4053fd6969a6
@@ -480,6 +480,33 @@ prepare_diff(app_state & app,
     revheader = header.str();
 }
 
+void dump_header(std::string const & revs,
+                 cset const & changes,
+                 std::ostream & out,
+                 bool show_if_empty)
+{
+  data summary;
+  write_cset(changes, summary);
+  if (summary().empty() && !show_if_empty)
+    return;
+
+  vector<string> lines;
+  split_into_lines(summary(), lines);
+  cout << "#\n";
+  if (!summary().empty())
+    {
+      out << revs << "#\n";
+      for (vector<string>::iterator i = lines.begin();
+           i != lines.end(); ++i)
+        out << "# " << *i << '\n';
+    }
+  else
+    {
+      out << "# " << _("no changes") << '\n';
+    }
+  out << "#\n";
+}
+
 CMD(diff, "diff", "di", CMD_REF(informative), N_("[PATH]..."),
     N_("Shows current differences"),
     N_("Compares the current tree with the files in the repository and "
@@ -503,24 +530,10 @@ CMD(diff, "diff", "di", CMD_REF(informat
 
   prepare_diff(app, db, included, args, new_is_archived, revs);
 
-  data summary;
-  write_cset(included, summary);
-
-  vector<string> lines;
-  split_into_lines(summary(), lines);
-  cout << "#\n";
-  if (!summary().empty())
+  if (!app.opts.without_header)
     {
-      cout << revs << "#\n";
-      for (vector<string>::iterator i = lines.begin();
-           i != lines.end(); ++i)
-        cout << "# " << *i << '\n';
+      dump_header(revs, included, cout, true);
     }
-  else
-    {
-      cout << "# " << _("no changes") << '\n';
-    }
-  cout << "#\n";
 
   if (app.opts.diff_format == external_diff)
     {
@@ -541,13 +554,13 @@ CMD(diff, "diff", "di", CMD_REF(informat
 // Added in: 4.0
 // Purpose: Availability of mtn diff as automate command.
 //
-// Output format: Like mtn diff, but with the header part omitted (as this is
-// doubles the output of automate get_revision). If no content changes happened,
-// the output is empty. All file operations beside mtn add are omitted,
-// as they don't change the content of the file.
+// Output format: Like mtn diff, but with the header part omitted by default.
+// If no content changes happened, the output is empty. All file operations
+// beside mtn add are omitted, as they don't change the content of the file.
 CMD_AUTOMATE(content_diff, N_("[FILE [...]]"),
              N_("Calculates diffs of files"),
              "",
+             options::opts::with_header | options::opts::without_header |
              options::opts::revision | options::opts::depth |
              options::opts::exclude)
 {
@@ -558,6 +571,12 @@ CMD_AUTOMATE(content_diff, N_("[FILE [..
 
   prepare_diff(app, db, included, args, new_is_archived, dummy_header);
 
+
+  if (app.opts.with_header)
+    {
+      dump_header(dummy_header, included, cout, false);
+    }
+
   dump_diffs(app.lua, db, included, output,
              app.opts.diff_format, new_is_archived, !app.opts.no_show_encloser);
 }
============================================================
--- monotone.texi	5e2bb7643436006b6bf4a7883eb6ac40eb4efdda
+++ monotone.texi	49e39037ce032c7b65fdf42e5fde18b6fb911735
@@ -7898,13 +7898,19 @@ @section Automation
 
 4.0
 
address@hidden Updated in:
+
+8.1
+
+Added @option{--with-header} option.
+
 @item Purpose:
 
 Prints the content changes between two revisions or a revision and the current
 workspace. This command differs from @command{mtn diff} in that way that it only
-outputs content changes and keeps quite on renames or drops, as the header of
address@hidden diff} is omitted (this is what @command{mtn automate get_revision}
-already provides).
+outputs content changes and keeps quiet on renames or drops by default, as the
+header of @command{mtn diff} is omitted unless @option{--with-header} is given
+and is omitted regardless if there are no changes.
 
 @item Sample output:
 
============================================================
--- options_list.hh	93e1285e0f6cd24e045a53bdb689af5739f94e9c
+++ options_list.hh	be7e3a4c58245de8cdd8c88a1bfcb54ff5dc8821
@@ -234,6 +234,25 @@ OPTION(diff_options, no_show_encloser, f
 }
 #endif
 
+OPTVAR(diff_options, bool, without_header, false);
+OPTVAR(diff_options, bool, with_header, false);
+OPTION(diff_options, without_header, false, "without-header",
+       gettext_noop("show the matching cset in the diff header"))
+#ifdef option_bodies
+{
+  with_header = false;
+  without_header = true;
+}
+#endif
+OPTION(diff_options, with_header, false, "with-header",
+       gettext_noop("do not show the matching cset in the diff header"))
+#ifdef option_bodies
+{
+  with_header = true;
+  without_header = false;
+}
+#endif
+
 OPT(diffs, "diffs", bool, false, gettext_noop("print diffs along with logs"))
 #ifdef option_bodies
 {
============================================================
--- tests/automate_content_diff/__driver__.lua	49eb0b60c12eefb624af0e586d6bd860ac03cfb4
+++ tests/automate_content_diff/__driver__.lua	274e9b78eab4715e2d793b1db848bc872b0ad173
@@ -4,6 +4,8 @@ check(fsize("stdout") == 0 and fsize("st
 -- check output if there are no changes
 check(mtn("automate", "content_diff"), 0, true, true)
 check(fsize("stdout") == 0 and fsize("stderr") == 0)
+check(mtn("automate", "content_diff", "--with-header"), 0, true, true)
+check(fsize("stdout") == 0 and fsize("stderr") == 0)
 
 -- check non-existing path
 check(mtn("automate", "content_diff", "non_existing"), 1, true, true)
@@ -30,6 +32,10 @@ check(fsize("stdout") ~= 0)
 check(fsize("stdout") ~= 0)
 check(mtn("automate", "content_diff", "-r", R1, "-r", R2), 0, true, true)
 check(fsize("stdout") ~= 0)
+check(not qgrep("# patch", "stdout"))
+check(mtn("automate", "content_diff", "-r", R1, "-r", R2, "--with-header"), 0, true, true)
+check(fsize("stdout") ~= 0)
+check(qgrep("# patch", "stdout"))
 
 -- three and more should not
 check(mtn("automate", "content_diff", "-r", R1, "-r", R2, "-r", R3), 1, true, true)