[Emacs-diffs] master c204948: Avoid infloop due to Eshell's "smart" redisplay

[Eli Zaretskii]

branch: master
commit c2049489090141311bf8f460bf366d9784950861
Author: Eli Zaretskii <address@hidden>
Commit: Eli Zaretskii <address@hidden>

    Avoid infloop due to Eshell's "smart" redisplay
    
    * src/xdisp.c (pos_visible_p): Save and restore the window's
    mode-line and header-line height.  (Bug#27752)
---
 src/xdisp.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/xdisp.c b/src/xdisp.c
index a3bc5a5..c415bf2 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -1326,6 +1326,15 @@ pos_visible_p (struct window *w, ptrdiff_t charpos, int 
*x, int *y,
   if (charpos >= 0 && CHARPOS (top) > charpos)
     return visible_p;
 
+  /* Some Lisp hook could call us in the middle of redisplaying this
+     very window.  If, by some bad luck, we are retrying redisplay
+     because we found that the mode-line height and/or header-line
+     height needs to be updated, the assignment of mode_line_height
+     and header_line_height below could disrupt that, due to the
+     selected/nonselected window dance during mode-line display, and
+     we could infloop.  Avoid that.  */
+  int prev_mode_line_height = w->mode_line_height;
+  int prev_header_line_height = w->header_line_height;
   /* Compute exact mode line heights.  */
   if (window_wants_mode_line (w))
     {
@@ -1672,6 +1681,10 @@ pos_visible_p (struct window *w, ptrdiff_t charpos, int 
*x, int *y,
     fprintf (stderr, "-pv pt=%d vs=%d\n", charpos, w->vscroll);
 #endif
 
+  /* Restore potentially overwritten values.  */
+  w->mode_line_height = prev_mode_line_height;
+  w->header_line_height = prev_header_line_height;
+
   return visible_p;
 }