Index: /svn/local/subversion/include/svn_fs.h
==================================================================
@@ -1205,6 +1205,19 @@
                                       const char *path2,
                                       apr_pool_t *pool);
 
+/** Check if the text of two root/path combos have changed.
+ *
+ * Set @a *changed_p to 1 if the contents at @a path1 under @a root1 differ
+ * from those at @a path2 under @a root2, or set it to 0 if they are the
+ * same.  Both paths must exist under their respective roots, and both
+ * roots must be in the same filesystem. 
+ */
+svn_error_t *svn_fs_text_changed (svn_boolean_t *changed_p,
+                                  svn_fs_root_t *root1,
+                                  const char *path1,
+                                  svn_fs_root_t *root2,
+                                  const char *path2,
+                                  apr_pool_t *pool);
 
 
 /* Filesystem revisions.  */
Index: /svn/local/subversion/libsvn_fs/tree.c
==================================================================
@@ -3826,7 +3826,7 @@
   if ((svn_fs_root_fs (root1)) != (svn_fs_root_fs (root2)))
     return svn_error_create
       (SVN_ERR_FS_GENERAL, NULL,
-       "Asking props changed in two different filesystems.");
+       "Asking contents changed in two different filesystems.");
   
   /* Check that both paths are files. */
   {
@@ -3852,6 +3852,53 @@
 
   SVN_ERR (svn_fs__retry_txn (root1->fs, txn_body_contents_changed,
                               &args, pool));
+
+  return SVN_NO_ERROR;
+}
+
+svn_error_t *
+svn_fs_text_changed (svn_boolean_t *changed_p,
+                     svn_fs_root_t *root1,
+                     const char *path1,
+                     svn_fs_root_t *root2,
+                     const char *path2,
+                     apr_pool_t *pool)
+{
+  svn_filesize_t size1, size2;
+  SVN_ERR (svn_fs_contents_changed (changed_p, root1, path1,
+                                    root2, path2, pool));
+  if (!*changed_p)
+    return SVN_NO_ERROR;
+
+  SVN_ERR (svn_fs_file_length (&size1, root1, path1, pool));
+  SVN_ERR (svn_fs_file_length (&size2, root2, path2, pool));
+
+  if (size1 != size2)
+    *changed_p = TRUE;
+  else
+    {
+      svn_stream_t *stream1, *stream2;
+      char buf1[SVN_STREAM_CHUNK_SIZE], buf2[SVN_STREAM_CHUNK_SIZE];
+      apr_size_t len1, len2;
+
+      SVN_ERR (svn_fs_file_contents (&stream1, root1, path1, pool));
+      SVN_ERR (svn_fs_file_contents (&stream2, root2, path2, pool));
+
+      *changed_p = FALSE;
+      do
+        {
+          len1 = len2 = SVN_STREAM_CHUNK_SIZE;
+          SVN_ERR (svn_stream_read (stream1, buf1, &len1));
+          SVN_ERR (svn_stream_read (stream2, buf2, &len2));
+
+          if (len1 != len2 || memcmp (buf1, buf2, len1))
+            {
+              *changed_p = TRUE;
+              break;
+            }
+	}
+      while (len1 > 0);
+    }
 
   return SVN_NO_ERROR;
 }
Index: /svn/local/subversion/libsvn_repos/delta.c
==================================================================
@@ -679,10 +679,16 @@
   if (source_path)
     {
       /* Is this deltification worth our time? */
-      SVN_ERR (svn_fs_contents_changed (&changed, 
-                                        c->target_root, target_path,
-                                        c->source_root, source_path,
-                                        subpool));
+      if (c->ignore_ancestry)
+        SVN_ERR (svn_fs_text_changed (&changed, 
+                                      c->target_root, target_path,
+                                      c->source_root, source_path,
+                                      subpool));
+      else
+        SVN_ERR (svn_fs_contents_changed (&changed, 
+                                          c->target_root, target_path,
+                                          c->source_root, source_path,
+                                          subpool));
     }
   else
     {