proper fix for the crash when closing one of the many concurrently open root patches

pd/src/g_canvas.c

@@ -884,6 +884,7 @@ void canvas_free(t_canvas *x)
     if (x->gl_magic_glass) {
       	//magicGlass_free(x->gl_magic_glass);
 		pd_free(&x->gl_magic_glass->x_obj.te_g.g_pd);
+		x->gl_magic_glass = NULL;
 	}
 
     //canvas_noundo(x);
@@ -911,11 +912,11 @@ void canvas_free(t_canvas *x)
         freebytes(x->gl_env->ce_argv, x->gl_env->ce_argc * sizeof(t_atom));
         freebytes(x->gl_env, sizeof(*x->gl_env));
     }
+    canvas_resume_dsp(dspstate);
     glist_cleanup(x);
     gfxstub_deleteforkey(x);        /* probably unnecessary */
     if (!x->gl_owner)
         canvas_takeofflist(x);
-    canvas_resume_dsp(dspstate);
 }
 
 /* ----------------- lines ---------- */
@@ -1376,8 +1377,8 @@ static void canvas_dodsp(t_canvas *x, int toplevel, t_signal **sp)
         /* find all the "dsp" boxes and add them to the graph */
 
     ob = &x->gl_magic_glass->x_obj;
-    if (ob && x->gl_magic_glass->x_connectedObj) {
-		//fprintf(stderr,"adding cord inspector to dsp\n");
+    if (ob && magicGlass_bound(x->gl_magic_glass)) {
+		//fprintf(stderr,"adding cord inspector to dsp %d\n", magicGlass_bound(x->gl_magic_glass));
 		ugen_add(dc, ob);  // this t_canvas could be an array, hence no gl_magic_glass
 	}
     

pd/src/g_magicglass.c

@@ -18,7 +18,7 @@ void magicGlass_clearText(t_magicGlass *x);
 
 void magicGlass_bind(t_magicGlass *x, t_object *obj, int outno)
 {
-	//fprintf(stderr,"magicglass_bind\n");
+	//fprintf(stderr,"magicglass_bind %lx\n", (t_int)x);
     if (x->x_connectedObj != obj)
     {
         if (x->x_connectedObj)
@@ -38,7 +38,7 @@ void magicGlass_bind(t_magicGlass *x, t_object *obj, int outno)
 
 void magicGlass_unbind(t_magicGlass *x)
 {
-	//fprintf(stderr,"magicglass_unbind\n");
+	//fprintf(stderr,"magicglass_unbind %lx\n", (t_int)x);
     if (x->x_connectedObj)
     {
         obj_disconnect(x->x_connectedObj,
@@ -285,7 +285,7 @@ void magicGlass_moveText(t_magicGlass *x, int pX, int pY)
 int magicGlass_bound(t_magicGlass *x)
 {
 	//fprintf(stderr,"magicglass_bound\n");
-    if (x->x_connectedObj)
+    if (x->x_connectedObj != NULL)
         return 1;
     else
         return 0;
@@ -378,7 +378,7 @@ void *magicGlass_new(t_glist *c)
 {
 	//fprintf(stderr,"magicglass_new\n");
     t_magicGlass *x = (t_magicGlass *)pd_new(magicGlass_class);
-    x->x_connectedObj= NULL;
+    x->x_connectedObj = NULL;
     x->x_connectedOutno = 0;
     x->x_visible = 0;
     x->x_c = c;
@@ -397,7 +397,7 @@ void *magicGlass_new(t_glist *c)
 
 void magicGlass_free(t_magicGlass *x)
 {
-	//fprintf(stderr,"magicglass_free\n");
+	//fprintf(stderr,"magicglass_free %lx\n", (t_int)x);
 	magicGlass_unbind(x);
     x->x_dspOn = 0;
     clock_free(x->x_clearClock);