commit cf619daa8e0ef9a335f27f65eb74e422a17d4f92
author Bram Moolenaar <Bram@vim.org> Tue Sep 01 20:53:24 2015 +0200
committer Bram Moolenaar <Bram@vim.org> Tue Sep 01 20:53:24 2015 +0200
tree f2008199197ac39cdfd884fda911039c01c9c7c3
parent ac360bf2ca293735fc7c6654dc2b3066f4c62488

patch 7.4.853
Problem:    "zt" in diff mode does not always work properly. (Gary Johnson)
Solution:   Don't count filler lines twice. (Christian Brabandt)

src/move.c

diff --git a/src/move.c b/src/move.c
index 0242fef..594f9ac 100644
--- a/src/move.c
+++ b/src/move.c
@@ -1732,7 +1732,7 @@
      * - at least 'scrolloff' lines above and below the cursor
      */
     validate_cheight();
-    used = curwin->w_cline_height;
+    used = curwin->w_cline_height; /* includes filler lines above */
     if (curwin->w_cursor.lnum < curwin->w_topline)
 	scrolled = used;
 
@@ -1751,10 +1751,12 @@
     new_topline = top + 1;
 
 #ifdef FEAT_DIFF
-    /* count filler lines of the cursor window as context */
-    i = diff_check_fill(curwin, curwin->w_cursor.lnum);
-    used += i;
-    extra += i;
+    /* used already contains the number of filler lines above, don't add it
+     * again.
+     * TODO: if filler lines above new top are to be considered as context for
+     * the current window, leave next statement commented, else hide filler
+     * lines above cursor line, by adding them to extra */
+    /* extra += diff_check_fill(curwin, curwin->w_cursor.lnum); */
 #endif
 
     /*

src/version.c

diff --git a/src/version.c b/src/version.c
index 2aa3807..7b0ad1b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -742,6 +742,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    853,
+/**/
     852,
 /**/
     851,