# HG changeset patch
# User John W. Eaton <jwe@octave.org>
# Date 1552577198 0
# Node ID ae9f8906e2cb98616946e7e8421aa9652eec9156
# Parent  075c4d3bf1de2d1fb448224f61dca96b9dc9de10
avoid possible cellfun and indexing errors in clf (bug #55921)

* clf.m: Handle possibility that allchild may return an empty array
when a figure has no children or that "get" may return a single value
instead of a cell array when a figure has only one child.

diff -r 075c4d3bf1de -r ae9f8906e2cb scripts/plot/util/clf.m
--- a/scripts/plot/util/clf.m	Thu Mar 14 08:00:59 2019 +0000
+++ b/scripts/plot/util/clf.m	Thu Mar 14 15:26:38 2019 +0000
@@ -72,16 +72,27 @@
   if (do_reset)
     ## Delete all the children, including the ones with hidden handles,
     ## except default menus and toolbar.
+
     kids = allchild (hfig);
-    ismenu = cellfun (@(s) strncmp (s, "__default_menu_", 15), ...
-                      get (kids, "tag"));
-    istoolbar = cellfun (@(s) strncmp (s, "__default_toolbar_menu_", 18), ...
-                         get (kids, "tag"));
-    delete (kids(! ismenu & ! istoolbar));
+
+    if (! isempty (kids))
+      tags = get (kids, "tag");
+      ## It's possible for a figure to have just one child and then get
+      ## will return a single value instead of a cell array.
+      if (! iscell (tags))
+        tags = {tags};
+      endif
+      ismenu = cellfun (@(s) strncmp (s, "__default_menu_", 15), tags);
+      istoolbar = cellfun (@(s) strncmp (s, "__default_toolbar_menu_", 18), tags);
+      delete (kids(! ismenu & ! istoolbar));
+    endif
+
     reset (hfig);
 
-    ## Recover figure listeners which have been deleted
-    __add_default_menu__ (hfig, kids(ismenu), kids(istoolbar));
+    if (! isempty (kids))
+      ## Recover figure listeners which have been deleted
+      __add_default_menu__ (hfig, kids(ismenu), kids(istoolbar));
+    endif
 
     __set_default_mouse_modes__ (hfig);
   else