[gtk/wip/ebassi/constraint-layout: 48/69] constraint solver: Fix repeat suggestions

[Emmanuele Bassi <ebassi src gnome org>]

commit 3d3a672deb22899d94e22b10939341c418e7bb5d
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Jun 28 16:59:39 2019 +0000

    constraint solver: Fix repeat suggestions
    
    We were not storing the previous value, causing
    the first two suggestions to work, but not later
    ones.
    
    Fixes the test added in the previous commit.

 gtk/gtkconstraintsolver.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtkconstraintsolver.c b/gtk/gtkconstraintsolver.c
index 3c3a5289f3..8c0fe08669 100644
--- a/gtk/gtkconstraintsolver.c
+++ b/gtk/gtkconstraintsolver.c
@@ -1971,6 +1971,7 @@ gtk_constraint_solver_suggest_value (GtkConstraintSolver *self,
                                      double value)
 {
   EditInfo *ei = g_hash_table_lookup (self->edit_var_map, variable);
+  double delta;
   if (ei == NULL)
     {
       g_critical ("Suggesting value '%g' but variable %p is not editable",
@@ -1986,9 +1987,10 @@ gtk_constraint_solver_suggest_value (GtkConstraintSolver *self,
       return;
     }
 
-  ei->prev_constant = value - ei->prev_constant;
+  delta = value - ei->prev_constant;
+  ei->prev_constant = value;
 
-  gtk_constraint_solver_delta_edit_constant (self, ei->prev_constant, ei->eplus, ei->eminus);
+  gtk_constraint_solver_delta_edit_constant (self, delta, ei->eplus, ei->eminus);
 }
 
 /*< private >