v7-0002-Fix-returning-of-json-b-domains-in-JSON_VALUE.patch

From 8db33b187c1a032d2080b557327b8d7bc2cf2e5d Mon Sep 17 00:00:00 2001
From: Nikita Glukhov <n.gluhov@postgrespro.ru>
Date: Mon, 15 Aug 2022 20:18:11 +0300
Subject: [PATCH v7 2/4] Fix returning of json[b] domains in JSON_VALUE()

---
 src/backend/parser/parse_expr.c             |  52 ++++--
 src/include/executor/execExpr.h             |   3 +
 src/test/regress/expected/jsonb_sqljson.out | 181 +++++++++++++++++++-
 src/test/regress/sql/jsonb_sqljson.sql      |  63 ++++++-
 4 files changed, 287 insertions(+), 12 deletions(-)

diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c
index 3b82c0f3328..aff6fc1a1c4 100644
--- a/src/backend/parser/parse_expr.c
+++ b/src/backend/parser/parse_expr.c
@@ -4212,12 +4212,29 @@ coerceJsonExpr(ParseState *pstate, Node *expr,
 	return coercion;
 }
 
+/* Is it a json/jsonb type or its domain? */
+static bool
+isJsonType(Oid typid)
+{
+	Oid			basetypid;
+
+	if (typid == JSONOID || typid == JSONBOID)
+		return true;
+
+	basetypid = getBaseType(typid);
+
+	if (basetypid == JSONOID || basetypid == JSONBOID)
+		return true;
+
+	return false;
+}
+
 /*
  * Transform a JSON output clause of JSON_VALUE and JSON_QUERY.
  */
 static void
 transformJsonFuncExprOutput(ParseState *pstate, JsonFuncExpr *func,
-							JsonExpr *jsexpr)
+							JsonExpr *jsexpr, bool *returning_json)
 {
 	Node	   *expr = jsexpr->formatted_expr;
 
@@ -4234,11 +4251,19 @@ transformJsonFuncExprOutput(ParseState *pstate, JsonFuncExpr *func,
 	{
 		JsonReturning ret;
 
-		if (func->op == JSON_VALUE_OP &&
-			jsexpr->returning->typid != JSONOID &&
-			jsexpr->returning->typid != JSONBOID)
+		*returning_json = isJsonType(jsexpr->returning->typid);
+
+		if (func->op == JSON_VALUE_OP && !*returning_json)
 		{
-			/* Forced coercion via I/O for JSON_VALUE for non-JSON types */
+			/*
+			 * In JSON_VALUE result_coercion can only be used when
+			 * returning JSON types and for NULL values (resulting
+			 * item is JSON null or NULL behavior is used).
+			 * So there is no need to find a cast from json[b] to
+			 * output type when it is a non-JSON type, we only need to
+			 * check domains for NOT NULL, what can be done using I/O
+			 * coercion.
+			 */
 			jsexpr->result_coercion = makeNode(JsonCoercion);
 			jsexpr->result_coercion->ctype = JSON_COERCION_VIA_IO;
 			return;
@@ -4260,8 +4285,11 @@ transformJsonFuncExprOutput(ParseState *pstate, JsonFuncExpr *func,
 		}
 	}
 	else
+	{
 		assignDefaultJsonReturningType(jsexpr->formatted_expr, jsexpr->format,
 									   jsexpr->returning);
+		*returning_json = true;
+	}
 }
 
 /*
@@ -4371,13 +4399,14 @@ transformJsonFuncExpr(ParseState *pstate, JsonFuncExpr *func)
 	JsonExpr   *jsexpr = transformJsonExprCommon(pstate, func);
 	const char *func_name = NULL;
 	Node	   *contextItemExpr = jsexpr->formatted_expr;
+	bool		returning_json;
 
 	switch (func->op)
 	{
 		case JSON_VALUE_OP:
 			func_name = "JSON_VALUE";
 
-			transformJsonFuncExprOutput(pstate, func, jsexpr);
+			transformJsonFuncExprOutput(pstate, func, jsexpr, &returning_json);
 
 			jsexpr->returning->format->format_type = JS_FORMAT_DEFAULT;
 			jsexpr->returning->format->encoding = JS_ENC_DEFAULT;
@@ -4390,19 +4419,22 @@ transformJsonFuncExpr(ParseState *pstate, JsonFuncExpr *func)
 				coerceDefaultJsonExpr(pstate, jsexpr,
 									  jsexpr->on_error->default_expr);
 
-			if (jsexpr->returning->typid != JSONOID &&
-				jsexpr->returning->typid != JSONBOID)
+			/*
+			 * Don't initialize item coercions if returning one of JSON
+			 * types or their domains.  Coercion will be done using
+			 * "result_coercion".
+			 */
+			if (!returning_json)
 				jsexpr->coercions =
 					initJsonItemCoercions(pstate, jsexpr->returning,
 										  exprType(contextItemExpr));
 
-
 			break;
 
 		case JSON_QUERY_OP:
 			func_name = "JSON_QUERY";
 
-			transformJsonFuncExprOutput(pstate, func, jsexpr);
+			transformJsonFuncExprOutput(pstate, func, jsexpr, &returning_json);
 
 			jsexpr->on_empty->default_expr =
 				coerceDefaultJsonExpr(pstate, jsexpr,
diff --git a/src/include/executor/execExpr.h b/src/include/executor/execExpr.h
index 7dd96b8d5ba..51e8d93178e 100644
--- a/src/include/executor/execExpr.h
+++ b/src/include/executor/execExpr.h
@@ -789,6 +789,9 @@ typedef struct JsonExprState
 	/*
 	 * States for coercion of SQL/JSON items produced in JSON_VALUE
 	 * directly to the output type.
+	 *
+	 * `item_coercions == NULL` means output type is json[b] or its
+	 * domain and we use `result_coercion`.
 	 */
 	struct JsonItemsCoercionStates
 	{
diff --git a/src/test/regress/expected/jsonb_sqljson.out b/src/test/regress/expected/jsonb_sqljson.out
index ef496110af3..ee5e597909c 100644
--- a/src/test/regress/expected/jsonb_sqljson.out
+++ b/src/test/regress/expected/jsonb_sqljson.out
@@ -349,14 +349,193 @@ SELECT JSON_VALUE(jsonb '"2017-02-20"', '$' RETURNING date) + 9;
  03-01-2017
 (1 row)
 
--- Test NULL checks execution in domain types
+-- Test for domain types
 CREATE DOMAIN sqljsonb_int_not_null AS int NOT NULL;
+CREATE DOMAIN sqljsonb_json_not_null AS json NOT NULL CHECK (VALUE::text <> '0');
+CREATE DOMAIN sqljsonb_jsonb_not_null AS jsonb NOT NULL CHECK (VALUE <> '0');
+-- Test casting to json[b] domains (items casted as is, strings are not unquoted)
+SELECT JSON_VALUE(jsonb '"1"', '$' RETURNING sqljsonb_json_not_null);
+ json_value 
+------------
+ "1"
+(1 row)
+
+SELECT JSON_VALUE(jsonb '"1"', '$' RETURNING sqljsonb_jsonb_not_null);
+ json_value 
+------------
+ "1"
+(1 row)
+
+SELECT JSON_VALUE(jsonb '1', '$' RETURNING sqljsonb_json_not_null);
+ json_value 
+------------
+ 1
+(1 row)
+
+SELECT JSON_VALUE(jsonb '1', '$' RETURNING sqljsonb_jsonb_not_null);
+ json_value 
+------------
+ 1
+(1 row)
+
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_json_not_null);
+ERROR:  domain sqljsonb_json_not_null does not allow null values
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_jsonb_not_null);
+ERROR:  domain sqljsonb_jsonb_not_null does not allow null values
+SELECT JSON_VALUE(jsonb 'true', '$' RETURNING sqljsonb_json_not_null);
+ json_value 
+------------
+ true
+(1 row)
+
+SELECT JSON_VALUE(jsonb 'true', '$' RETURNING sqljsonb_jsonb_not_null);
+ json_value 
+------------
+ true
+(1 row)
+
+-- Test NULL checks execution in domain types
 SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_int_not_null);
 ERROR:  domain sqljsonb_int_not_null does not allow null values
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_int_not_null DEFAULT 2 ON EMPTY);
+ json_value 
+------------
+          2
+(1 row)
+
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_int_not_null DEFAULT NULL ON EMPTY);
+ERROR:  domain sqljsonb_int_not_null does not allow null values
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_int_not_null DEFAULT 2 ON ERROR);
+ json_value 
+------------
+          2
+(1 row)
+
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_int_not_null DEFAULT NULL ON EMPTY DEFAULT 2 ON ERROR);
+ json_value 
+------------
+          2
+(1 row)
+
 SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_int_not_null NULL ON ERROR);
 ERROR:  domain sqljsonb_int_not_null does not allow null values
 SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_int_not_null DEFAULT NULL ON ERROR);
 ERROR:  domain sqljsonb_int_not_null does not allow null values
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_json_not_null);
+ERROR:  domain sqljsonb_json_not_null does not allow null values
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_json_not_null DEFAULT '2' ON EMPTY);
+ json_value 
+------------
+ 2
+(1 row)
+
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_json_not_null DEFAULT NULL ON EMPTY);
+ERROR:  domain sqljsonb_json_not_null does not allow null values
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_json_not_null DEFAULT '2' ON ERROR);
+ json_value 
+------------
+ 2
+(1 row)
+
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_json_not_null DEFAULT NULL ON EMPTY DEFAULT '2' ON ERROR);
+ json_value 
+------------
+ 2
+(1 row)
+
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_json_not_null NULL ON ERROR);
+ERROR:  domain sqljsonb_json_not_null does not allow null values
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_json_not_null DEFAULT NULL ON ERROR);
+ERROR:  domain sqljsonb_json_not_null does not allow null values
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_jsonb_not_null);
+ERROR:  domain sqljsonb_jsonb_not_null does not allow null values
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_jsonb_not_null DEFAULT '2' ON EMPTY);
+ json_value 
+------------
+ 2
+(1 row)
+
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_jsonb_not_null DEFAULT NULL ON EMPTY);
+ERROR:  domain sqljsonb_jsonb_not_null does not allow null values
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_jsonb_not_null DEFAULT '2' ON ERROR);
+ json_value 
+------------
+ 2
+(1 row)
+
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_jsonb_not_null DEFAULT NULL ON EMPTY DEFAULT '2' ON ERROR);
+ json_value 
+------------
+ 2
+(1 row)
+
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_jsonb_not_null NULL ON ERROR);
+ERROR:  domain sqljsonb_jsonb_not_null does not allow null values
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_jsonb_not_null DEFAULT NULL ON ERROR);
+ERROR:  domain sqljsonb_jsonb_not_null does not allow null values
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_int_not_null);
+ERROR:  domain sqljsonb_int_not_null does not allow null values
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_int_not_null DEFAULT 2 ON EMPTY);
+ERROR:  domain sqljsonb_int_not_null does not allow null values
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_int_not_null DEFAULT 2 ON ERROR);
+ json_value 
+------------
+          2
+(1 row)
+
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_int_not_null NULL ON ERROR);
+ERROR:  domain sqljsonb_int_not_null does not allow null values
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_int_not_null DEFAULT NULL ON ERROR);
+ERROR:  domain sqljsonb_int_not_null does not allow null values
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_json_not_null);
+ERROR:  domain sqljsonb_json_not_null does not allow null values
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_json_not_null DEFAULT '2' ON EMPTY);
+ERROR:  domain sqljsonb_json_not_null does not allow null values
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_json_not_null DEFAULT '2' ON ERROR);
+ json_value 
+------------
+ 2
+(1 row)
+
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_json_not_null NULL ON ERROR);
+ERROR:  domain sqljsonb_json_not_null does not allow null values
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_json_not_null DEFAULT NULL ON ERROR);
+ERROR:  domain sqljsonb_json_not_null does not allow null values
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_jsonb_not_null);
+ERROR:  domain sqljsonb_jsonb_not_null does not allow null values
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_jsonb_not_null DEFAULT '2' ON EMPTY);
+ERROR:  domain sqljsonb_jsonb_not_null does not allow null values
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_jsonb_not_null DEFAULT '2' ON ERROR);
+ json_value 
+------------
+ 2
+(1 row)
+
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_jsonb_not_null NULL ON ERROR);
+ERROR:  domain sqljsonb_jsonb_not_null does not allow null values
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_jsonb_not_null DEFAULT NULL ON ERROR);
+ERROR:  domain sqljsonb_jsonb_not_null does not allow null values
+SELECT JSON_VALUE(jsonb '0', '$' RETURNING sqljsonb_json_not_null);
+ERROR:  domain sqljsonb_json_not_null does not allow null values
+SELECT JSON_VALUE(jsonb '0', '$' RETURNING sqljsonb_json_not_null ERROR ON ERROR);
+ERROR:  value for domain sqljsonb_json_not_null violates check constraint "sqljsonb_json_not_null_check"
+SELECT JSON_VALUE(jsonb '0', '$' RETURNING sqljsonb_json_not_null DEFAULT '2' ON ERROR);
+ json_value 
+------------
+ 2
+(1 row)
+
+SELECT JSON_VALUE(jsonb '0', '$' RETURNING sqljsonb_jsonb_not_null);
+ERROR:  domain sqljsonb_jsonb_not_null does not allow null values
+SELECT JSON_VALUE(jsonb '0', '$' RETURNING sqljsonb_jsonb_not_null ERROR ON ERROR);
+ERROR:  value for domain sqljsonb_jsonb_not_null violates check constraint "sqljsonb_jsonb_not_null_check"
+SELECT JSON_VALUE(jsonb '0', '$' RETURNING sqljsonb_jsonb_not_null DEFAULT '2' ON ERROR);
+ json_value 
+------------
+ 2
+(1 row)
+
+-- Test returning of non-scalar items
 SELECT JSON_VALUE(jsonb '[]', '$');
  json_value 
 ------------
diff --git a/src/test/regress/sql/jsonb_sqljson.sql b/src/test/regress/sql/jsonb_sqljson.sql
index fff25374808..d70104b70ef 100644
--- a/src/test/regress/sql/jsonb_sqljson.sql
+++ b/src/test/regress/sql/jsonb_sqljson.sql
@@ -82,12 +82,73 @@ SELECT JSON_VALUE(jsonb '"123"', '$' RETURNING int) + 234;
 
 SELECT JSON_VALUE(jsonb '"2017-02-20"', '$' RETURNING date) + 9;
 
--- Test NULL checks execution in domain types
+-- Test for domain types
 CREATE DOMAIN sqljsonb_int_not_null AS int NOT NULL;
+CREATE DOMAIN sqljsonb_json_not_null AS json NOT NULL CHECK (VALUE::text <> '0');
+CREATE DOMAIN sqljsonb_jsonb_not_null AS jsonb NOT NULL CHECK (VALUE <> '0');
+
+-- Test casting to json[b] domains (items casted as is, strings are not unquoted)
+SELECT JSON_VALUE(jsonb '"1"', '$' RETURNING sqljsonb_json_not_null);
+SELECT JSON_VALUE(jsonb '"1"', '$' RETURNING sqljsonb_jsonb_not_null);
+SELECT JSON_VALUE(jsonb '1', '$' RETURNING sqljsonb_json_not_null);
+SELECT JSON_VALUE(jsonb '1', '$' RETURNING sqljsonb_jsonb_not_null);
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_json_not_null);
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_jsonb_not_null);
+SELECT JSON_VALUE(jsonb 'true', '$' RETURNING sqljsonb_json_not_null);
+SELECT JSON_VALUE(jsonb 'true', '$' RETURNING sqljsonb_jsonb_not_null);
+
+-- Test NULL checks execution in domain types
 SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_int_not_null);
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_int_not_null DEFAULT 2 ON EMPTY);
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_int_not_null DEFAULT NULL ON EMPTY);
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_int_not_null DEFAULT 2 ON ERROR);
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_int_not_null DEFAULT NULL ON EMPTY DEFAULT 2 ON ERROR);
 SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_int_not_null NULL ON ERROR);
 SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_int_not_null DEFAULT NULL ON ERROR);
 
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_json_not_null);
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_json_not_null DEFAULT '2' ON EMPTY);
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_json_not_null DEFAULT NULL ON EMPTY);
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_json_not_null DEFAULT '2' ON ERROR);
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_json_not_null DEFAULT NULL ON EMPTY DEFAULT '2' ON ERROR);
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_json_not_null NULL ON ERROR);
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_json_not_null DEFAULT NULL ON ERROR);
+
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_jsonb_not_null);
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_jsonb_not_null DEFAULT '2' ON EMPTY);
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_jsonb_not_null DEFAULT NULL ON EMPTY);
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_jsonb_not_null DEFAULT '2' ON ERROR);
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_jsonb_not_null DEFAULT NULL ON EMPTY DEFAULT '2' ON ERROR);
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_jsonb_not_null NULL ON ERROR);
+SELECT JSON_VALUE(jsonb '1', '$.a' RETURNING sqljsonb_jsonb_not_null DEFAULT NULL ON ERROR);
+
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_int_not_null);
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_int_not_null DEFAULT 2 ON EMPTY);
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_int_not_null DEFAULT 2 ON ERROR);
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_int_not_null NULL ON ERROR);
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_int_not_null DEFAULT NULL ON ERROR);
+
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_json_not_null);
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_json_not_null DEFAULT '2' ON EMPTY);
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_json_not_null DEFAULT '2' ON ERROR);
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_json_not_null NULL ON ERROR);
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_json_not_null DEFAULT NULL ON ERROR);
+
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_jsonb_not_null);
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_jsonb_not_null DEFAULT '2' ON EMPTY);
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_jsonb_not_null DEFAULT '2' ON ERROR);
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_jsonb_not_null NULL ON ERROR);
+SELECT JSON_VALUE(jsonb 'null', '$' RETURNING sqljsonb_jsonb_not_null DEFAULT NULL ON ERROR);
+
+SELECT JSON_VALUE(jsonb '0', '$' RETURNING sqljsonb_json_not_null);
+SELECT JSON_VALUE(jsonb '0', '$' RETURNING sqljsonb_json_not_null ERROR ON ERROR);
+SELECT JSON_VALUE(jsonb '0', '$' RETURNING sqljsonb_json_not_null DEFAULT '2' ON ERROR);
+
+SELECT JSON_VALUE(jsonb '0', '$' RETURNING sqljsonb_jsonb_not_null);
+SELECT JSON_VALUE(jsonb '0', '$' RETURNING sqljsonb_jsonb_not_null ERROR ON ERROR);
+SELECT JSON_VALUE(jsonb '0', '$' RETURNING sqljsonb_jsonb_not_null DEFAULT '2' ON ERROR);
+
+-- Test returning of non-scalar items
 SELECT JSON_VALUE(jsonb '[]', '$');
 SELECT JSON_VALUE(jsonb '[]', '$' ERROR ON ERROR);
 SELECT JSON_VALUE(jsonb '{}', '$');
-- 
2.25.1