MDEV-24739: Assertion `root->weight >= ...' failed in SEL_ARG::tree_delete

Also update the SEL_ARG graph weight in:
- sel_add()
- SEL_ARG::clone()

Make key_{and,or}_with_limit() to also verify weight for the arguments
(There is no single point to verify SEL_ARG graphs constructed from
conditions that are not AND-OR formulas, so we hope that those are
connected with AND/OR and do it here).

mysql-test/main/range_notembedded.result

@@ -214,3 +214,14 @@ left(@json, 1500)
 set optimizer_max_sel_arg_weight= @tmp9750_weight;
 set optimizer_trace=@tmp_9750;
 drop table t1;
+#
+# MDEV-24739: Assertion `root->weight >= ...' failed in SEL_ARG::tree_delete
+#
+SELECT *
+FROM mysql.help_relation
+WHERE NOT (help_topic_id != 8 AND help_keyword_id != 0 OR help_keyword_id = 2 OR help_topic_id < 1900);
+help_topic_id	help_keyword_id
+SELECT *
+FROM mysql.help_relation ignore index (help_topic_id)
+WHERE (help_topic_id = 8 OR help_keyword_id = 0) AND help_keyword_id != 2 AND help_topic_id >= 1900;
+help_topic_id	help_keyword_id

mysql-test/main/range_notembedded.test

@@ -96,4 +96,17 @@ select left(@json, 1500);
 
 set optimizer_max_sel_arg_weight= @tmp9750_weight;
 set optimizer_trace=@tmp_9750;
+
 drop table t1;
+
+--echo #
+--echo # MDEV-24739: Assertion `root->weight >= ...' failed in SEL_ARG::tree_delete
+--echo #
+SELECT *
+FROM mysql.help_relation
+WHERE NOT (help_topic_id != 8 AND help_keyword_id != 0 OR help_keyword_id = 2 OR help_topic_id < 1900);
+
+SELECT *
+FROM mysql.help_relation ignore index (help_topic_id)
+WHERE (help_topic_id = 8 OR help_keyword_id = 0) AND help_keyword_id != 2 AND help_topic_id >= 1900;
+

sql/opt_range.cc

@@ -2079,6 +2079,7 @@ SEL_ARG *SEL_ARG::clone(RANGE_OPT_PARAM *param, SEL_ARG *new_parent,
   tmp->color= color;
   tmp->elements= this->elements;
   tmp->max_part_no= max_part_no;
+  tmp->weight= weight;
   return tmp;
 }
 
@@ -9035,6 +9036,19 @@ SEL_ARG *Field::stored_field_make_mm_leaf_exact(RANGE_OPT_PARAM *param,
 ** KEY_RANGE:	 Condition uses a key
 ******************************************************************************/
 
+/*
+  Update weights for SEL_ARG graph that is connected only via next_key_part
+  (and not left/right) links
+*/
+static uint update_weight_for_single_arg(SEL_ARG *arg)
+{
+  if (arg->next_key_part)
+    return (arg->weight= 1 + update_weight_for_single_arg(arg->next_key_part));
+  else
+    return (arg->weight= 1);
+}
+
+
 /*
   Add a new key test to a key when scanning through all keys
   This will never be called for same key parts.
@@ -9067,6 +9081,8 @@ sel_add(SEL_ARG *key1,SEL_ARG *key2)
     }
   }
   *key_link=key1 ? key1 : key2;
+
+  update_weight_for_single_arg(root);
   return root;
 }
 
@@ -10020,6 +10036,13 @@ static
 SEL_ARG *key_or_with_limit(RANGE_OPT_PARAM *param, uint keyno,
                            SEL_ARG *key1, SEL_ARG *key2)
 {
+#ifndef DBUG_OFF
+  if (key1)
+    key1->verify_weight();
+  if (key2)
+    key2->verify_weight();
+#endif
+
   SEL_ARG *res= key_or(param, key1, key2);
   res= enforce_sel_arg_weight_limit(param, keyno, res);
 #ifndef DBUG_OFF
@@ -10034,6 +10057,12 @@ static
 SEL_ARG *key_and_with_limit(RANGE_OPT_PARAM *param, uint keyno,
                             SEL_ARG *key1, SEL_ARG *key2, uint clone_flag)
 {
+#ifndef DBUG_OFF
+  if (key1)
+    key1->verify_weight();
+  if (key2)
+    key2->verify_weight();
+#endif
   SEL_ARG *res= key_and(param, key1, key2, clone_flag);
   res= enforce_sel_arg_weight_limit(param, keyno, res);
 #ifndef DBUG_OFF