Fix nested NOT operation cleanup in tsquery.

During normalization of tsquery tree it tries to simplify nested NOT
operations but there it's obvioulsy missed that subsequent node could be
a leaf node (value node)

Bug #14245: Segfault on weird to_tsquery
Reported by David Kellum.

src/backend/utils/adt/tsquery_cleanup.c

@@ -406,6 +406,8 @@ normalize_phrase_tree(NODE *node)
 
 	if (node->valnode->qoperator.oper == OP_NOT)
 	{
+		NODE *orignode = node;
+
 		/* eliminate NOT sequence */
 		while (node->valnode->type == QI_OPR &&
 		node->valnode->qoperator.oper == node->right->valnode->qoperator.oper)
@@ -413,7 +415,11 @@ normalize_phrase_tree(NODE *node)
 			node = node->right->right;
 		}
 
-		node->right = normalize_phrase_tree(node->right);
+		if (orignode != node)
+			/* current node isn't checked yet */
+			node = normalize_phrase_tree(node);
+		else
+			node->right = normalize_phrase_tree(node->right);
 	}
 	else if (node->valnode->qoperator.oper == OP_PHRASE)
 	{

src/test/regress/expected/tsearch.out

@@ -555,6 +555,18 @@ SELECT plainto_tsquery('english', 'foo bar') && 'asd | fg';
 (1 row)
 
 -- Check stop word deletion, a and s are stop-words
+SELECT to_tsquery('english', '!(a & !b) & c');
+ to_tsquery 
+------------
+ 'b' & 'c'
+(1 row)
+
+SELECT to_tsquery('english', '!(a & !b)');
+ to_tsquery 
+------------
+ 'b'
+(1 row)
+
 SELECT to_tsquery('english', '(1 <-> 2) <-> a');
  to_tsquery  
 -------------

src/test/regress/sql/tsearch.sql

@@ -130,6 +130,9 @@ SELECT plainto_tsquery('english', 'foo bar') || !!plainto_tsquery('english', 'as
 SELECT plainto_tsquery('english', 'foo bar') && 'asd | fg';
 
 -- Check stop word deletion, a and s are stop-words
+SELECT to_tsquery('english', '!(a & !b) & c');
+SELECT to_tsquery('english', '!(a & !b)');
+
 SELECT to_tsquery('english', '(1 <-> 2) <-> a');
 SELECT to_tsquery('english', '(1 <-> a) <-> 2');
 SELECT to_tsquery('english', '(a <-> 1) <-> 2');