Index: mailer.py
===================================================================
--- mailer.py	(revision 35245)
+++ mailer.py	(working copy)
@@ -722,7 +722,7 @@
                         params, diffsels, diffurls, pool),
     other_diffs=other_diffs,
     )
-  renderer.render(data)
+  renderer.render(data,cfg,group,params)
 
 
 def generate_list(changekind, changelist, paths, in_paths):
@@ -1005,7 +1005,7 @@
   def __init__(self, output):
     self.output = output
 
-  def render(self, data):
+  def render(self, data,cfg,group,params):
     "Render the commit defined by 'data'."
 
     w = self.output.write
@@ -1038,11 +1038,11 @@
       else:
         w('and changes in other areas\n')
 
-    self._render_diffs(data.diffs, '')
+    self._render_diffs(data.diffs, '',cfg,group,params)
     if data.other_diffs:
       self._render_diffs(data.other_diffs,
                          '\nDiffs of changes in other areas also'
-                         ' in this revision:\n')
+                         ' in this revision:\n',cfg,group,params)
 
   def _render_list(self, header, data_list):
     if not data_list:
@@ -1073,15 +1073,27 @@
         w('      - copied%s from r%d, %s%s\n'
           % (text, d.base_rev, d.base_path, is_dir))
 
-  def _render_diffs(self, diffs, section_header):
+  def _render_diffs(self, diffs, section_header,cfg,group,params):
     """Render diffs. Write the SECTION_HEADER if there are actually
     any diffs to render."""
     if not diffs:
       return
     w = self.output.write
     section_header_printed = False
+    jnumber = cfg.get('max_number_of_diffs',group,params)
+    try:
+      max_number = int(jnumber)
+    except ValueError:
+      max_number = -1
+    i=0
 
     for diff in diffs:
+      i=i+1
+      if i > max_number and -1 != max_number:
+        w('\n\n================ MAX NUMBER OF FILES=%s' % max_number)
+	w(' IS REACHED, NO MORE DIFF ================\n\n')
+	break
+
       if not diff.diff and not diff.diff_url:
         continue
       if not section_header_printed:
Index: mailer.conf.example
===================================================================
--- mailer.conf.example	(revision 35245)
+++ mailer.conf.example	(working copy)
@@ -243,6 +243,10 @@
 # Set to 0 to turn off.
 #truncate_subject = 200
 
+# Maximal number of diffed files. To prevent really big emails.
+# 0 means no diffs included, below 0 means no limit
+# max_number_of_diffs = 128
+
 # --------------------------------------------------------------------------
 
 [maps]