boxlayout: Do not infloop

if the loop for determining max width grows too big, print an error and
abort assuming that a satisfactory value was reached.

This will cause wrong layout and might cause widgets to overlap, but it
will not infloop.

It actually works around and doesn't really fix the primary cause of the
following bugs, but good enough to close them:

Fixes: #4252
Fixes: #4517

1 files changed, 41 insertions, 2 deletions

diff --git a/gtk/gtkboxlayout.c b/gtk/gtkboxlayout.c
index e79c5e202a..5d1b63169d 100644
--- a/gtk/gtkboxlayout.c
+++ b/gtk/gtkboxlayout.c
@@ -288,6 +288,12 @@ gtk_box_layout_compute_opposite_size (GtkBoxLayout *self,
   *natural = largest_nat;
 }
 
+/* if widgets haven't reached their min opposite size at this
+ * huge value, things went massively wrong and we need to bail to not
+ * cause an infinite loop.
+ */
+#define MAX_ALLOWED_SIZE (1 << 20)
+
 static int
 distribute_remaining_size (GtkRequestedSize *sizes,
                            gsize             n_sizes,
@@ -321,7 +327,40 @@ distribute_remaining_size (GtkRequestedSize *sizes,
     {
       int test;
 
-      if (max == G_MAXINT)
+      if (min > MAX_ALLOWED_SIZE)
+        {
+          /* sanity check! */
+          for (i = 0; i < n_sizes; i++)
+            {
+              int check_min, check_nat;
+              gtk_widget_measure (sizes[i].data,
+                                  orientation,
+                                  MAX_ALLOWED_SIZE,
+                                  &sizes[i].minimum_size, &sizes[i].natural_size,
+                                  NULL, NULL);
+              gtk_widget_measure (sizes[i].data,
+                                  orientation,
+                                  -1,
+                                  &check_min, &check_nat,
+                                  NULL, NULL);
+              if (check_min < sizes[i].minimum_size)
+                {
+                  g_critical ("%s %p reports a minimum %s of %u, but minimum %s for %s of %u is %u. Expect overlapping widgets.",
+                              G_OBJECT_TYPE_NAME (sizes[i].data), sizes[i].data,
+                              orientation == GTK_ORIENTATION_HORIZONTAL ? "width" : "height",
+                              check_min,
+                              orientation == GTK_ORIENTATION_HORIZONTAL ? "width" : "height",
+                              orientation == GTK_ORIENTATION_HORIZONTAL ? "height" : "width",
+                              MAX_ALLOWED_SIZE, sizes[i].minimum_size);
+                  sizes[i].minimum_size = check_min;
+                  sizes[i].natural_size = check_nat;
+                }
+              total_size += sizes[i].minimum_size;
+            }
+          return MAX (0, available - total_size);
+        }
+
+      if (max == MAX_ALLOWED_SIZE)
         test = min * 2;
       else
         test = (min + max) / 2;
@@ -465,7 +504,7 @@ gtk_box_layout_compute_opposite_size_for_size (GtkBoxLayout *self,
                                              self->orientation,
                                              available,
                                              min_size,
-                                             G_MAXINT);
+                                             MAX_ALLOWED_SIZE);
 
       /* Bring children up to size first */
       available = gtk_distribute_natural_allocation (available, nvis_children, sizes);