SQL/JSON: Always coerce JsonExpr result at runtime

Instead of looking up casts at parse time for converting the result
of JsonPath* query functions to the specified or the default
RETURNING type, always perform the conversion at runtime using either
the target type's input function or the function
json_populate_type().

There are two motivations for this change:

1. json_populate_type() coerces to types with typmod such that any
   string values that exceed length limit cause an error instead of
   silent truncation, which is necessary to be standard-conforming.

2. It was possible to end up with a cast expression that doesn't
   support soft handling of errors causing bugs in the of handling
   ON ERROR clause.

JsonExpr.coercion_expr which would store the cast expression is no
longer necessary, so remove.

Bump catversion because stored rules change because of the above
removal.

Reported-by: Alvaro Herrera <alvherre@alvh.no-ip.org>
Reviewed-by: Jian He <jian.universality@gmail.com>
Discussion: Discussion: https://postgr.es/m/202405271326.5a5rprki64aw%40alvherre.pgsql

src/backend/executor/execExpr.c

@@ -92,7 +92,7 @@ static void ExecInitJsonExpr(JsonExpr *jsexpr, ExprState *state,
 							 Datum *resv, bool *resnull,
 							 ExprEvalStep *scratch);
 static void ExecInitJsonCoercion(ExprState *state, JsonReturning *returning,
-								 ErrorSaveContext *escontext,
+								 ErrorSaveContext *escontext, bool omit_quotes,
 								 Datum *resv, bool *resnull);
 
 
@@ -4313,13 +4313,15 @@ ExecInitJsonExpr(JsonExpr *jsexpr, ExprState *state,
 	ExprEvalPushStep(state, scratch);
 
 	/*
-	 * Jump to coerce the NULL using coercion_expr if present.  Coercing NULL
-	 * is only interesting when the RETURNING type is a domain whose
-	 * constraints must be checked.  jsexpr->coercion_expr containing a
-	 * CoerceToDomain node must have been set in that case.
+	 * Jump to coerce the NULL using json_populate_type() if needed.  Coercing
+	 * NULL is only interesting when the RETURNING type is a domain whose
+	 * constraints must be checked.  jsexpr->use_json_coercion must have been
+	 * set in that case.
 	 */
-	if (jsexpr->coercion_expr)
+	if (get_typtype(jsexpr->returning->typid) == TYPTYPE_DOMAIN &&
+		DomainHasConstraints(jsexpr->returning->typid))
 	{
+		Assert(jsexpr->use_json_coercion);
 		scratch->opcode = EEOP_JUMP;
 		scratch->d.jump.jumpdone = state->steps_len + 1;
 		ExprEvalPushStep(state, scratch);
@@ -4337,33 +4339,12 @@ ExecInitJsonExpr(JsonExpr *jsexpr, ExprState *state,
 	 * NULL returned on NULL input as described above.
 	 */
 	jsestate->jump_eval_coercion = -1;
-	if (jsexpr->coercion_expr)
-	{
-		Datum	   *save_innermost_caseval;
-		bool	   *save_innermost_casenull;
-		ErrorSaveContext *save_escontext;
-
-		jsestate->jump_eval_coercion = state->steps_len;
-
-		save_innermost_caseval = state->innermost_caseval;
-		save_innermost_casenull = state->innermost_casenull;
-		save_escontext = state->escontext;
-
-		state->innermost_caseval = resv;
-		state->innermost_casenull = resnull;
-		state->escontext = escontext;
-
-		ExecInitExprRec((Expr *) jsexpr->coercion_expr, state, resv, resnull);
-
-		state->innermost_caseval = save_innermost_caseval;
-		state->innermost_casenull = save_innermost_casenull;
-		state->escontext = save_escontext;
-	}
-	else if (jsexpr->use_json_coercion)
+	if (jsexpr->use_json_coercion)
 	{
 		jsestate->jump_eval_coercion = state->steps_len;
 
-		ExecInitJsonCoercion(state, jsexpr->returning, escontext, resv, resnull);
+		ExecInitJsonCoercion(state, jsexpr->returning, escontext,
+							 jsexpr->omit_quotes, resv, resnull);
 	}
 	else if (jsexpr->use_io_coercion)
 	{
@@ -4435,8 +4416,8 @@ ExecInitJsonExpr(JsonExpr *jsexpr, ExprState *state,
 
 		/* Step to coerce the ON ERROR expression if needed */
 		if (jsexpr->on_error->coerce)
-			ExecInitJsonCoercion(state, jsexpr->returning, escontext, resv,
-								 resnull);
+			ExecInitJsonCoercion(state, jsexpr->returning, escontext,
+								 jsexpr->omit_quotes, resv, resnull);
 
 		/* JUMP to end to skip the ON EMPTY steps added below. */
 		jumps_to_end = lappend_int(jumps_to_end, state->steps_len);
@@ -4468,8 +4449,8 @@ ExecInitJsonExpr(JsonExpr *jsexpr, ExprState *state,
 
 		/* Step to coerce the ON EMPTY expression if needed */
 		if (jsexpr->on_empty->coerce)
-			ExecInitJsonCoercion(state, jsexpr->returning, escontext, resv,
-								 resnull);
+			ExecInitJsonCoercion(state, jsexpr->returning, escontext,
+								 jsexpr->omit_quotes, resv, resnull);
 	}
 
 	foreach(lc, jumps_to_end)
@@ -4488,7 +4469,7 @@ ExecInitJsonExpr(JsonExpr *jsexpr, ExprState *state,
  */
 static void
 ExecInitJsonCoercion(ExprState *state, JsonReturning *returning,
-					 ErrorSaveContext *escontext,
+					 ErrorSaveContext *escontext, bool omit_quotes,
 					 Datum *resv, bool *resnull)
 {
 	ExprEvalStep scratch = {0};
@@ -4501,5 +4482,6 @@ ExecInitJsonCoercion(ExprState *state, JsonReturning *returning,
 	scratch.d.jsonexpr_coercion.targettypmod = returning->typmod;
 	scratch.d.jsonexpr_coercion.json_populate_type_cache = NULL;
 	scratch.d.jsonexpr_coercion.escontext = escontext;
+	scratch.d.jsonexpr_coercion.omit_quotes = omit_quotes;
 	ExprEvalPushStep(state, &scratch);
 }

src/backend/executor/execExprInterp.c

@@ -4303,8 +4303,14 @@ ExecEvalJsonExprPath(ExprState *state, ExprEvalStep *op,
 
 				if (!error)
 				{
-					*op->resvalue = BoolGetDatum(exists);
 					*op->resnull = false;
+					if (jsexpr->use_json_coercion)
+						*op->resvalue = DirectFunctionCall1(jsonb_in,
+															BoolGetDatum(exists) ?
+															CStringGetDatum("true") :
+															CStringGetDatum("false"));
+					else
+						*op->resvalue = BoolGetDatum(exists);
 				}
 			}
 			break;
@@ -4316,22 +4322,6 @@ ExecEvalJsonExprPath(ExprState *state, ExprEvalStep *op,
 										  jsexpr->column_name);
 
 			*op->resnull = (DatumGetPointer(*op->resvalue) == NULL);
-
-			/* Handle OMIT QUOTES. */
-			if (!*op->resnull && jsexpr->omit_quotes)
-			{
-				val_string = JsonbUnquote(DatumGetJsonbP(*op->resvalue));
-
-				/*
-				 * Pass the string as a text value to the cast expression if
-				 * one present.  If not, use the input function call below to
-				 * do the coercion.
-				 */
-				if (jump_eval_coercion >= 0)
-					*op->resvalue =
-						DirectFunctionCall1(textin,
-											PointerGetDatum(val_string));
-			}
 			break;
 
 		case JSON_VALUE_OP:
@@ -4343,7 +4333,7 @@ ExecEvalJsonExprPath(ExprState *state, ExprEvalStep *op,
 
 				if (jbv == NULL)
 				{
-					/* Will be coerced with coercion_expr, if any. */
+					/* Will be coerced with json_populate_type(), if needed. */
 					*op->resvalue = (Datum) 0;
 					*op->resnull = true;
 				}
@@ -4355,18 +4345,22 @@ ExecEvalJsonExprPath(ExprState *state, ExprEvalStep *op,
 						val_string = DatumGetCString(DirectFunctionCall1(jsonb_out,
 																		 JsonbPGetDatum(JsonbValueToJsonb(jbv))));
 					}
+					else if (jsexpr->use_json_coercion)
+					{
+						*op->resvalue = JsonbPGetDatum(JsonbValueToJsonb(jbv));
+						*op->resnull = false;
+					}
 					else
 					{
 						val_string = ExecGetJsonValueItemString(jbv, op->resnull);
 
 						/*
-						 * Pass the string as a text value to the cast
-						 * expression if one present.  If not, use the input
-						 * function call below to do the coercion.
+						 * Simply convert to the default RETURNING type (text)
+						 * if no coercion needed.
 						 */
-						*op->resvalue = PointerGetDatum(val_string);
-						if (jump_eval_coercion >= 0)
-							*op->resvalue = DirectFunctionCall1(textin, *op->resvalue);
+						if (!jsexpr->use_io_coercion)
+							*op->resvalue = DirectFunctionCall1(textin,
+																CStringGetDatum(val_string));
 					}
 				}
 				break;
@@ -4545,13 +4539,14 @@ ExecEvalJsonCoercion(ExprState *state, ExprEvalStep *op,
 									   op->d.jsonexpr_coercion.targettypmod,
 									   &op->d.jsonexpr_coercion.json_populate_type_cache,
 									   econtext->ecxt_per_query_memory,
-									   op->resnull, (Node *) escontext);
+									   op->resnull,
+									   op->d.jsonexpr_coercion.omit_quotes,
+									   (Node *) escontext);
 }
 
 /*
- * Checks if an error occurred either when evaluating JsonExpr.coercion_expr or
- * in ExecEvalJsonCoercion().  If so, this sets JsonExprState.error to trigger
- * the ON ERROR handling steps.
+ * Checks if an error occurred in ExecEvalJsonCoercion().  If so, this sets
+ * JsonExprState.error to trigger the ON ERROR handling steps.
  */
 void
 ExecEvalJsonCoercionFinish(ExprState *state, ExprEvalStep *op)

src/backend/jit/llvm/llvmjit_expr.c

@@ -2010,7 +2010,7 @@ llvm_compile_expr(ExprState *state)
 							v_jump_coercion = l_int32_const(lc, jsestate->jump_eval_coercion);
 							LLVMAddCase(v_switch, v_jump_coercion, b_coercion);
 						}
-						/* coercion_expr code */
+						/* jump_eval_coercion code */
 						LLVMPositionBuilderAtEnd(b, b_coercion);
 						if (jsestate->jump_eval_coercion >= 0)
 							LLVMBuildBr(b, opblocks[jsestate->jump_eval_coercion]);

src/backend/nodes/nodeFuncs.c

@@ -1006,10 +1006,7 @@ exprCollation(const Node *expr)
 			{
 				const JsonExpr *jsexpr = (JsonExpr *) expr;
 
-				if (jsexpr->coercion_expr)
-					coll = exprCollation(jsexpr->coercion_expr);
-				else
-					coll = jsexpr->collation;
+				coll = jsexpr->collation;
 			}
 			break;
 		case T_JsonBehavior:
@@ -1265,10 +1262,7 @@ exprSetCollation(Node *expr, Oid collation)
 			{
 				JsonExpr   *jexpr = (JsonExpr *) expr;
 
-				if (jexpr->coercion_expr)
-					exprSetCollation((Node *) jexpr->coercion_expr, collation);
-				else
-					jexpr->collation = collation;
+				jexpr->collation = collation;
 			}
 			break;
 		case T_JsonBehavior:
@@ -2368,8 +2362,6 @@ expression_tree_walker_impl(Node *node,
 					return true;
 				if (WALK(jexpr->path_spec))
 					return true;
-				if (WALK(jexpr->coercion_expr))
-					return true;
 				if (WALK(jexpr->passing_values))
 					return true;
 				/* we assume walker doesn't care about passing_names */
@@ -3411,7 +3403,6 @@ expression_tree_mutator_impl(Node *node,
 				FLATCOPY(newnode, jexpr, JsonExpr);
 				MUTATE(newnode->formatted_expr, jexpr->formatted_expr, Node *);
 				MUTATE(newnode->path_spec, jexpr->path_spec, Node *);
-				MUTATE(newnode->coercion_expr, jexpr->coercion_expr, Node *);
 				MUTATE(newnode->passing_values, jexpr->passing_values, List *);
 				/* assume mutator does not care about passing_names */
 				MUTATE(newnode->on_empty, jexpr->on_empty, JsonBehavior *);

src/backend/parser/parse_expr.c

@@ -96,7 +96,6 @@ static Node *transformJsonFuncExpr(ParseState *pstate, JsonFuncExpr *func);
 static void transformJsonPassingArgs(ParseState *pstate, const char *constructName,
 									 JsonFormatType format, List *args,
 									 List **passing_values, List **passing_names);
-static void coerceJsonExprOutput(ParseState *pstate, JsonExpr *jsexpr);
 static JsonBehavior *transformJsonBehavior(ParseState *pstate, JsonBehavior *behavior,
 										   JsonBehaviorType default_behavior,
 										   JsonReturning *returning);
@@ -4492,39 +4491,7 @@ transformJsonFuncExpr(ParseState *pstate, JsonFuncExpr *func)
 
 			/* JSON_TABLE() COLUMNS can specify a non-boolean type. */
 			if (jsexpr->returning->typid != BOOLOID)
-			{
-				Node	   *coercion_expr;
-				CaseTestExpr *placeholder = makeNode(CaseTestExpr);
-				int			location = exprLocation((Node *) jsexpr);
-
-				/*
-				 * We abuse CaseTestExpr here as placeholder to pass the
-				 * result of evaluating JSON_EXISTS to the coercion
-				 * expression.
-				 */
-				placeholder->typeId = BOOLOID;
-				placeholder->typeMod = -1;
-				placeholder->collation = InvalidOid;
-
-				coercion_expr =
-					coerce_to_target_type(pstate, (Node *) placeholder, BOOLOID,
-										  jsexpr->returning->typid,
-										  jsexpr->returning->typmod,
-										  COERCION_EXPLICIT,
-										  COERCE_IMPLICIT_CAST,
-										  location);
-
-				if (coercion_expr == NULL)
-					ereport(ERROR,
-							(errcode(ERRCODE_CANNOT_COERCE),
-							 errmsg("cannot cast type %s to %s",
-									format_type_be(BOOLOID),
-									format_type_be(jsexpr->returning->typid)),
-							 parser_coercion_errposition(pstate, location, (Node *) jsexpr)));
-
-				if (coercion_expr != (Node *) placeholder)
-					jsexpr->coercion_expr = coercion_expr;
-			}
+				jsexpr->use_json_coercion = true;
 
 			jsexpr->on_error = transformJsonBehavior(pstate, func->on_error,
 													 JSON_BEHAVIOR_FALSE,
@@ -4548,7 +4515,13 @@ transformJsonFuncExpr(ParseState *pstate, JsonFuncExpr *func)
 			jsexpr->omit_quotes = (func->quotes == JS_QUOTES_OMIT);
 			jsexpr->wrapper = func->wrapper;
 
-			coerceJsonExprOutput(pstate, jsexpr);
+			/*
+			 * Set up to coerce the result value of JsonPathValue() to the
+			 * RETURNING type (default or user-specified), if needed.  Also if
+			 * OMIT QUOTES is specified.
+			 */
+			if (jsexpr->returning->typid != JSONBOID || jsexpr->omit_quotes)
+				jsexpr->use_json_coercion = true;
 
 			/* Assume NULL ON EMPTY when ON EMPTY is not specified. */
 			jsexpr->on_empty = transformJsonBehavior(pstate, func->on_empty,
@@ -4578,7 +4551,18 @@ transformJsonFuncExpr(ParseState *pstate, JsonFuncExpr *func)
 			/* Always omit quotes from scalar strings. */
 			jsexpr->omit_quotes = true;
 
-			coerceJsonExprOutput(pstate, jsexpr);
+			/*
+			 * Set up to coerce the result value of JsonPathValue() to the
+			 * RETURNING type (default or user-specified), if needed.
+			 */
+			if (jsexpr->returning->typid != TEXTOID)
+			{
+				if (get_typtype(jsexpr->returning->typid) == TYPTYPE_DOMAIN &&
+					DomainHasConstraints(jsexpr->returning->typid))
+					jsexpr->use_json_coercion = true;
+				else
+					jsexpr->use_io_coercion = true;
+			}
 
 			/* Assume NULL ON EMPTY when ON EMPTY is not specified. */
 			jsexpr->on_empty = transformJsonBehavior(pstate, func->on_empty,
@@ -4641,121 +4625,6 @@ transformJsonPassingArgs(ParseState *pstate, const char *constructName,
 	}
 }
 
-/*
- * Set up to coerce the result value of JSON_VALUE() / JSON_QUERY() to the
- * RETURNING type (default or user-specified), if needed.
- */
-static void
-coerceJsonExprOutput(ParseState *pstate, JsonExpr *jsexpr)
-{
-	JsonReturning *returning = jsexpr->returning;
-	Node	   *context_item = jsexpr->formatted_expr;
-	int			default_typmod;
-	Oid			default_typid;
-	bool		omit_quotes =
-		jsexpr->op == JSON_QUERY_OP && jsexpr->omit_quotes;
-	Node	   *coercion_expr = NULL;
-
-	Assert(returning);
-
-	/*
-	 * Check for cases where the coercion should be handled at runtime, that
-	 * is, without using a cast expression.
-	 */
-	if (jsexpr->op == JSON_VALUE_OP)
-	{
-		/*
-		 * Use cast expressions for types with typmod and domain types.
-		 */
-		if (returning->typmod == -1 &&
-			get_typtype(returning->typid) != TYPTYPE_DOMAIN)
-		{
-			jsexpr->use_io_coercion = true;
-			return;
-		}
-	}
-	else if (jsexpr->op == JSON_QUERY_OP)
-	{
-		/*
-		 * Cast functions from jsonb to the following types (jsonb_bool() et
-		 * al) don't handle errors softly, so coerce either by calling
-		 * json_populate_type() or the type's input function so that any
-		 * errors are handled appropriately. The latter only if OMIT QUOTES is
-		 * true.
-		 */
-		switch (returning->typid)
-		{
-			case BOOLOID:
-			case NUMERICOID:
-			case INT2OID:
-			case INT4OID:
-			case INT8OID:
-			case FLOAT4OID:
-			case FLOAT8OID:
-				if (jsexpr->omit_quotes)
-					jsexpr->use_io_coercion = true;
-				else
-					jsexpr->use_json_coercion = true;
-				return;
-			default:
-				break;
-		}
-	}
-
-	/* Look up a cast expression. */
-
-	/*
-	 * For JSON_VALUE() and for JSON_QUERY() when OMIT QUOTES is true,
-	 * ExecEvalJsonExprPath() will convert a quote-stripped source value to
-	 * its text representation, so use TEXTOID as the source type.
-	 */
-	if (omit_quotes || jsexpr->op == JSON_VALUE_OP)
-	{
-		default_typid = TEXTOID;
-		default_typmod = -1;
-	}
-	else
-	{
-		default_typid = exprType(context_item);
-		default_typmod = exprTypmod(context_item);
-	}
-
-	if (returning->typid != default_typid ||
-		returning->typmod != default_typmod)
-	{
-		/*
-		 * We abuse CaseTestExpr here as placeholder to pass the result of
-		 * jsonpath evaluation as input to the coercion expression.
-		 */
-		CaseTestExpr *placeholder = makeNode(CaseTestExpr);
-
-		placeholder->typeId = default_typid;
-		placeholder->typeMod = default_typmod;
-
-		coercion_expr = coerceJsonFuncExpr(pstate, (Node *) placeholder,
-										   returning, false);
-		if (coercion_expr == (Node *) placeholder)
-			coercion_expr = NULL;
-	}
-
-	jsexpr->coercion_expr = coercion_expr;
-
-	if (coercion_expr == NULL)
-	{
-		/*
-		 * Either no cast was found or coercion is unnecessary but still must
-		 * convert the string value to the output type.
-		 */
-		if (omit_quotes || jsexpr->op == JSON_VALUE_OP)
-			jsexpr->use_io_coercion = true;
-		else
-			jsexpr->use_json_coercion = true;
-	}
-
-	Assert(jsexpr->coercion_expr != NULL ||
-		   (jsexpr->use_io_coercion != jsexpr->use_json_coercion));
-}
-
 /*
  * Recursively checks if the given expression, or its sub-node in some cases,
  * is valid for using as an ON ERROR / ON EMPTY DEFAULT expression.
@@ -4848,11 +4717,24 @@ transformJsonBehavior(ParseState *pstate, JsonBehavior *behavior,
 			 btype == default_behavior))
 			coerce_at_runtime = true;
 		else
+		{
+			int32		baseTypmod = returning->typmod;
+
+			if (get_typtype(returning->typid) == TYPTYPE_DOMAIN)
+				(void) getBaseTypeAndTypmod(returning->typid, &baseTypmod);
+
+			if (baseTypmod > 0)
+				expr = coerce_to_specific_type(pstate, expr, TEXTOID,
+											   "JSON_FUNCTION()");
 			coerced_expr =
 				coerce_to_target_type(pstate, expr, exprType(expr),
-									  returning->typid, returning->typmod,
-									  COERCION_EXPLICIT, COERCE_EXPLICIT_CAST,
+									  returning->typid, baseTypmod,
+									  baseTypmod > 0 ? COERCION_IMPLICIT :
+									  COERCION_EXPLICIT,
+									  baseTypmod > 0 ? COERCE_IMPLICIT_CAST :
+									  COERCE_EXPLICIT_CAST,
 									  exprLocation((Node *) behavior));
+		}
 
 		if (coerced_expr == NULL)
 			ereport(ERROR,

src/backend/utils/adt/jsonfuncs.c

@@ -447,12 +447,13 @@ static Datum populate_composite(CompositeIOData *io, Oid typid,
 								HeapTupleHeader defaultval, JsValue *jsv, bool *isnull,
 								Node *escontext);
 static Datum populate_scalar(ScalarIOData *io, Oid typid, int32 typmod, JsValue *jsv,
-							 bool *isnull, Node *escontext);
+							 bool *isnull, Node *escontext, bool omit_quotes);
 static void prepare_column_cache(ColumnIOData *column, Oid typid, int32 typmod,
 								 MemoryContext mcxt, bool need_scalar);
 static Datum populate_record_field(ColumnIOData *col, Oid typid, int32 typmod,
 								   const char *colname, MemoryContext mcxt, Datum defaultval,
-								   JsValue *jsv, bool *isnull, Node *escontext);
+								   JsValue *jsv, bool *isnull, Node *escontext,
+								   bool omit_quotes);
 static RecordIOData *allocate_record_info(MemoryContext mcxt, int ncolumns);
 static bool JsObjectGetField(JsObject *obj, char *field, JsValue *jsv);
 static void populate_recordset_record(PopulateRecordsetState *state, JsObject *obj);
@@ -2622,7 +2623,8 @@ populate_array_element(PopulateArrayContext *ctx, int ndim, JsValue *jsv)
 									ctx->aio->element_type,
 									ctx->aio->element_typmod,
 									NULL, ctx->mcxt, PointerGetDatum(NULL),
-									jsv, &element_isnull, ctx->escontext);
+									jsv, &element_isnull, ctx->escontext,
+									false);
 	/* Nothing to do on an error. */
 	if (SOFT_ERROR_OCCURRED(ctx->escontext))
 		return false;
@@ -3119,7 +3121,7 @@ populate_composite(CompositeIOData *io,
  */
 static Datum
 populate_scalar(ScalarIOData *io, Oid typid, int32 typmod, JsValue *jsv,
-				bool *isnull, Node *escontext)
+				bool *isnull, Node *escontext, bool omit_quotes)
 {
 	Datum		res;
 	char	   *str = NULL;
@@ -3162,7 +3164,9 @@ populate_scalar(ScalarIOData *io, Oid typid, int32 typmod, JsValue *jsv,
 	{
 		JsonbValue *jbv = jsv->val.jsonb;
 
-		if (typid == JSONBOID)
+		if (jbv->type == jbvString && omit_quotes)
+			str = pnstrdup(jbv->val.string.val, jbv->val.string.len);
+		else if (typid == JSONBOID)
 		{
 			Jsonb	   *jsonb = JsonbValueToJsonb(jbv); /* directly use jsonb */
 
@@ -3225,7 +3229,7 @@ populate_domain(DomainIOData *io,
 		res = populate_record_field(io->base_io,
 									io->base_typid, io->base_typmod,
 									colname, mcxt, PointerGetDatum(NULL),
-									jsv, isnull, escontext);
+									jsv, isnull, escontext, false);
 		Assert(!*isnull || SOFT_ERROR_OCCURRED(escontext));
 	}
 
@@ -3338,7 +3342,7 @@ Datum
 json_populate_type(Datum json_val, Oid json_type,
 				   Oid typid, int32 typmod,
 				   void **cache, MemoryContext mcxt,
-				   bool *isnull,
+				   bool *isnull, bool omit_quotes,
 				   Node *escontext)
 {
 	JsValue		jsv = {0};
@@ -3368,10 +3372,22 @@ json_populate_type(Datum json_val, Oid json_type,
 
 		jsv.val.jsonb = &jbv;
 
-		/* fill binary jsonb value pointing to jb */
-		jbv.type = jbvBinary;
-		jbv.val.binary.data = &jsonb->root;
-		jbv.val.binary.len = VARSIZE(jsonb) - VARHDRSZ;
+		if (omit_quotes)
+		{
+			char	   *str = JsonbUnquote(DatumGetJsonbP(json_val));
+
+			/* fill the quote-stripped string */
+			jbv.type = jbvString;
+			jbv.val.string.len = strlen(str);
+			jbv.val.string.val = str;
+		}
+		else
+		{
+			/* fill binary jsonb value pointing to jb */
+			jbv.type = jbvBinary;
+			jbv.val.binary.data = &jsonb->root;
+			jbv.val.binary.len = VARSIZE(jsonb) - VARHDRSZ;
+		}
 	}
 
 	if (*cache == NULL)
@@ -3379,7 +3395,7 @@ json_populate_type(Datum json_val, Oid json_type,
 
 	return populate_record_field(*cache, typid, typmod, NULL, mcxt,
 								 PointerGetDatum(NULL), &jsv, isnull,
-								 escontext);
+								 escontext, omit_quotes);
 }
 
 /* recursively populate a record field or an array element from a json/jsonb value */
@@ -3392,7 +3408,8 @@ populate_record_field(ColumnIOData *col,
 					  Datum defaultval,
 					  JsValue *jsv,
 					  bool *isnull,
-					  Node *escontext)
+					  Node *escontext,
+					  bool omit_scalar_quotes)
 {
 	TypeCat		typcat;
 
@@ -3426,7 +3443,7 @@ populate_record_field(ColumnIOData *col,
 	{
 		case TYPECAT_SCALAR:
 			return populate_scalar(&col->scalar_io, typid, typmod, jsv,
-								   isnull, escontext);
+								   isnull, escontext, omit_scalar_quotes);
 
 		case TYPECAT_ARRAY:
 			return populate_array(&col->io.array, colname, mcxt, jsv,
@@ -3595,7 +3612,8 @@ populate_record(TupleDesc tupdesc,
 										  nulls[i] ? (Datum) 0 : values[i],
 										  &field,
 										  &nulls[i],
-										  escontext);
+										  escontext,
+										  false);
 	}
 
 	res = heap_form_tuple(tupdesc, values, nulls);

src/include/catalog/catversion.h

@@ -57,6 +57,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	202406171
+#define CATALOG_VERSION_NO	202406281
 
 #endif

src/include/executor/execExpr.h

@@ -707,6 +707,7 @@ typedef struct ExprEvalStep
 		{
 			Oid			targettype;
 			int32		targettypmod;
+			bool		omit_quotes;
 			void	   *json_populate_type_cache;
 			ErrorSaveContext *escontext;
 		}			jsonexpr_coercion;

src/include/nodes/execnodes.h

@@ -1052,9 +1052,8 @@ typedef struct JsonExprState
 
 	/*
 	 * Address of the step to coerce the result value of jsonpath evaluation
-	 * to the RETURNING type using JsonExpr.coercion_expr.  -1 if no coercion
-	 * is necessary or if either JsonExpr.use_io_coercion or
-	 * JsonExpr.use_json_coercion is true.
+	 * to the RETURNING type.  -1 if no coercion if JsonExpr.use_io_coercion
+	 * is true.
 	 */
 	int			jump_eval_coercion;
 

src/include/nodes/primnodes.h

@@ -1838,13 +1838,7 @@ typedef struct JsonExpr
 	/*
 	 * Information about converting the result of jsonpath functions
 	 * JsonPathQuery() and JsonPathValue() to the RETURNING type.
-	 *
-	 * coercion_expr is a cast expression if the parser can find it for the
-	 * source and the target type.  If not, either use_io_coercion or
-	 * use_json_coercion is set to determine the coercion method to use at
-	 * runtime; see coerceJsonExprOutput() and ExecInitJsonExpr().
 	 */
-	Node	   *coercion_expr;
 	bool		use_io_coercion;
 	bool		use_json_coercion;
 
@@ -1854,7 +1848,7 @@ typedef struct JsonExpr
 	/* KEEP or OMIT QUOTES for singleton scalars returned by JSON_QUERY() */
 	bool		omit_quotes;
 
-	/* JsonExpr's collation, if coercion_expr is NULL. */
+	/* JsonExpr's collation. */
 	Oid			collation;
 
 	/* Original JsonFuncExpr's location */

src/include/utils/jsonfuncs.h

@@ -93,6 +93,7 @@ extern Datum json_populate_type(Datum json_val, Oid json_type,
 								Oid typid, int32 typmod,
 								void **cache, MemoryContext mcxt,
 								bool *isnull,
+								bool omit_quotes,
 								Node *escontext);
 
 #endif

src/test/regress/expected/sqljson_jsontable.out

@@ -103,14 +103,14 @@ FROM json_table_test vals
  [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  1 |   1 | 1       | 1       | t    |       1 | 1       | 1            | 1
  [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  2 |     | 1.23    | 1.23    |      |    1.23 | 1.23    | 1.23         | 1.23
  [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  3 |   2 | 2       | 2       |      |       2 | 2       | "2"          | "2"
- [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  4 |     | aaaaaaa | aaaa    |      |         | aaaaaaa | "aaaaaaa"    | "aaaaaaa"
+ [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  4 |     | aaaaaaa |         |      |         | aaaaaaa | "aaaaaaa"    | "aaaaaaa"
  [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  5 |     | foo     | foo     |      |         |         | "foo"        | "foo"
  [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  6 |     |         |         |      |         |         | null         | null
- [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  7 |     | f       | f       | f    |         | f       | false        | false
- [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  8 |     | t       | t       | t    |         | t       | true         | true
+ [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  7 |     | f       | f       | f    |         | false   | false        | false
+ [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  8 |     | t       | t       | t    |         | true    | true         | true
  [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  9 |     |         |         |      |         |         | {"aaa": 123} | {"aaa": 123}
- [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] | 10 |     | [1,2]   | [1,2    |      |         | [1,2]   | "[1,2]"      | "[1,2]"
- [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] | 11 |     | "str"   | "str    |      |         | "str"   | "\"str\""    | "\"str\""
+ [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] | 10 |     | [1,2]   |         |      |         | [1,2]   | "[1,2]"      | "[1,2]"
+ [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] | 11 |     | "str"   |         |      |         | "str"   | "\"str\""    | "\"str\""
 (14 rows)
 
 -- "formatted" columns
@@ -137,14 +137,14 @@ FROM json_table_test vals
  [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  1 | 1            | 1    | 1    | 1            | 1
  [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  2 | 1.23         | 1.23 | 1.23 | 1.23         | 1.23
  [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  3 | "2"          | "2"  | "2"  | "2"          | 2
- [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  4 | "aaaaaaa"    | "aaa | "aaa | "aaaaaaa"    | 
- [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  5 | "foo"        | "foo | "foo | "foo"        | 
+ [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  4 | "aaaaaaa"    |      |      | "aaaaaaa"    | 
+ [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  5 | "foo"        |      |      | "foo"        | 
  [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  6 | null         | null | null | null         | null
- [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  7 | false        | fals | fals | false        | false
+ [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  7 | false        |      |      | false        | false
  [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  8 | true         | true | true | true         | true
- [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  9 | {"aaa": 123} | {"aa | {"aa | {"aaa": 123} | {"aaa": 123}
- [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] | 10 | "[1,2]"      | "[1, | "[1, | "[1,2]"      | [1, 2]
- [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] | 11 | "\"str\""    | "\"s | "\"s | "\"str\""    | "str"
+ [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  9 | {"aaa": 123} |      |      | {"aaa": 123} | {"aaa": 123}
+ [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] | 10 | "[1,2]"      |      |      | "[1,2]"      | [1, 2]
+ [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] | 11 | "\"str\""    |      |      | "\"str\""    | "str"
 (14 rows)
 
 -- EXISTS columns
@@ -175,7 +175,7 @@ FROM json_table_test vals
  [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  6 | f       |       0 |         | false
  [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  7 | f       |       0 |         | false
  [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  8 | f       |       0 |         | false
- [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  9 | t       |       1 |       1 | true
+ [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] |  9 | t       |       0 |         | true
  [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] | 10 | f       |       0 |         | false
  [1, 1.23, "2", "aaaaaaa", "foo", null, false, true, {"aaa": 123}, "[1,2]", "\"str\""] | 11 | f       |       0 |         | false
 (14 rows)
@@ -555,31 +555,21 @@ SELECT * FROM JSON_TABLE(jsonb '"a"', '$' COLUMNS (a int4 EXISTS PATH '$.a'));
 (1 row)
 
 SELECT * FROM JSON_TABLE(jsonb '"a"', '$' COLUMNS (a int2 EXISTS PATH '$.a'));
-ERROR:  cannot cast type boolean to smallint
-LINE 1: ...ELECT * FROM JSON_TABLE(jsonb '"a"', '$' COLUMNS (a int2 EXI...
-                                                             ^
+ERROR:  cannot cast behavior expression of type boolean to smallint
 SELECT * FROM JSON_TABLE(jsonb '"a"', '$' COLUMNS (a int8 EXISTS PATH '$.a'));
-ERROR:  cannot cast type boolean to bigint
-LINE 1: ...ELECT * FROM JSON_TABLE(jsonb '"a"', '$' COLUMNS (a int8 EXI...
-                                                             ^
+ERROR:  cannot cast behavior expression of type boolean to bigint
 SELECT * FROM JSON_TABLE(jsonb '"a"', '$' COLUMNS (a float4 EXISTS PATH '$.a'));
-ERROR:  cannot cast type boolean to real
-LINE 1: ...ELECT * FROM JSON_TABLE(jsonb '"a"', '$' COLUMNS (a float4 E...
-                                                             ^
-SELECT * FROM JSON_TABLE(jsonb '"a"', '$' COLUMNS (a char(3) EXISTS PATH '$.a'));
-  a  
------
- fal
+ERROR:  cannot cast behavior expression of type boolean to real
+SELECT * FROM JSON_TABLE(jsonb '"a"', '$' COLUMNS (a char(5) EXISTS PATH '$.a'));
+   a   
+-------
+ false
 (1 row)
 
 SELECT * FROM JSON_TABLE(jsonb '"a"', '$' COLUMNS (a json EXISTS PATH '$.a'));
-ERROR:  cannot cast type boolean to json
-LINE 1: ...ELECT * FROM JSON_TABLE(jsonb '"a"', '$' COLUMNS (a json EXI...
-                                                             ^
+ERROR:  cannot cast behavior expression of type boolean to json
 SELECT * FROM JSON_TABLE(jsonb '"a"', '$' COLUMNS (a jsonb EXISTS PATH '$.a'));
-ERROR:  cannot cast type boolean to jsonb
-LINE 1: ...ELECT * FROM JSON_TABLE(jsonb '"a"', '$' COLUMNS (a jsonb EX...
-                                                             ^
+ERROR:  cannot cast behavior expression of type boolean to jsonb
 -- JSON_TABLE: WRAPPER/QUOTES clauses on scalar columns
 SELECT * FROM JSON_TABLE(jsonb '"world"', '$' COLUMNS (item text PATH '$' KEEP QUOTES ON SCALAR STRING));
   item   

src/test/regress/expected/sqljson_queryfuncs.out

@@ -234,10 +234,18 @@ SELECT JSON_VALUE(jsonb '"aaa"', '$' RETURNING char(5));
  aaa  
 (1 row)
 
+SELECT JSON_VALUE(jsonb '"aaa"', '$' RETURNING char(2) ERROR ON ERROR);
+ERROR:  value too long for type character(2)
 SELECT JSON_VALUE(jsonb '"aaa"', '$' RETURNING char(2));
  json_value 
 ------------
- aa
+ 
+(1 row)
+
+SELECT JSON_VALUE(jsonb '"aaa"', '$' RETURNING char(3) ERROR ON ERROR);
+ json_value 
+------------
+ aaa
 (1 row)
 
 SELECT JSON_VALUE(jsonb '"aaa"', '$' RETURNING json);
@@ -636,30 +644,28 @@ SELECT JSON_QUERY(jsonb '"aaa"', '$' RETURNING bytea FORMAT JSON OMIT QUOTES ERR
 (1 row)
 
 -- Behavior when a RETURNING type has typmod != -1
-SELECT JSON_QUERY(jsonb '"aaa"', '$' RETURNING char(2));
+SELECT JSON_QUERY(jsonb '"aaa"', '$' RETURNING char(3) ERROR ON ERROR);
+ERROR:  value too long for type character(3)
+SELECT JSON_QUERY(jsonb '"aaa"', '$' RETURNING char(3));
  json_query 
 ------------
- "a
+ 
 (1 row)
 
-SELECT JSON_QUERY(jsonb '"aaa"', '$' RETURNING char(2) OMIT QUOTES);
+SELECT JSON_QUERY(jsonb '"aaa"', '$' RETURNING char(3) OMIT QUOTES ERROR ON ERROR);
  json_query 
 ------------
- aa
+ aaa
 (1 row)
 
-SELECT JSON_QUERY(jsonb '"aaa"', '$.a' RETURNING char(2) OMIT QUOTES DEFAULT 'bbb' ON EMPTY);
+SELECT JSON_QUERY(jsonb '"aaa"', '$.a' RETURNING char(2) OMIT QUOTES DEFAULT 'bb' ON EMPTY);
  json_query 
 ------------
  bb
 (1 row)
 
-SELECT JSON_QUERY(jsonb '"aaa"', '$.a' RETURNING char(2) OMIT QUOTES DEFAULT '"bbb"'::jsonb ON EMPTY);
- json_query 
-------------
- "b
-(1 row)
-
+SELECT JSON_QUERY(jsonb '"aaa"', '$.a' RETURNING char(2) OMIT QUOTES DEFAULT '"bb"'::jsonb ON EMPTY);
+ERROR:  value too long for type character(2)
 -- OMIT QUOTES behavior should not be specified when WITH WRAPPER used:
 -- Should fail
 SELECT JSON_QUERY(jsonb '[1]', '$' WITH WRAPPER OMIT QUOTES);
@@ -828,12 +834,6 @@ SELECT JSON_QUERY(jsonb '[1,2]', '$' RETURNING char(10));
  [1, 2]    
 (1 row)
 
-SELECT JSON_QUERY(jsonb '[1,2]', '$' RETURNING char(3));
- json_query 
-------------
- [1,
-(1 row)
-
 SELECT JSON_QUERY(jsonb '[1,2]', '$' RETURNING text FORMAT JSON);
  json_query 
 ------------
@@ -1369,3 +1369,39 @@ ERROR:  invalid ON ERROR behavior
 LINE 1: SELECT JSON_QUERY(jsonb '1', '$' TRUE ON ERROR);
                                          ^
 DETAIL:  Only ERROR, NULL, EMPTY [ ARRAY ], EMPTY OBJECT, or DEFAULT expression is allowed in ON ERROR for JSON_QUERY().
+-- Test implicit coercion domain over fixed-legth type specified in RETURNING
+CREATE DOMAIN queryfuncs_char2 AS char(2);
+CREATE DOMAIN queryfuncs_char2_chk AS char(2) CHECK (VALUE NOT IN ('12'));
+SELECT JSON_QUERY(jsonb '123', '$' RETURNING queryfuncs_char2 ERROR ON ERROR);
+ERROR:  value too long for type character(2)
+SELECT JSON_QUERY(jsonb '123', '$' RETURNING queryfuncs_char2 DEFAULT '1' ON ERROR);
+ json_query 
+------------
+ 1 
+(1 row)
+
+SELECT JSON_QUERY(jsonb '123', '$' RETURNING queryfuncs_char2_chk ERROR ON ERROR);
+ERROR:  value too long for type character(2)
+SELECT JSON_QUERY(jsonb '123', '$' RETURNING queryfuncs_char2_chk DEFAULT '1' ON ERROR);
+ json_query 
+------------
+ 1 
+(1 row)
+
+SELECT JSON_VALUE(jsonb '123', '$' RETURNING queryfuncs_char2 ERROR ON ERROR);
+ERROR:  value too long for type character(2)
+SELECT JSON_VALUE(jsonb '123', '$' RETURNING queryfuncs_char2 DEFAULT 1 ON ERROR);
+ json_value 
+------------
+ 1 
+(1 row)
+
+SELECT JSON_VALUE(jsonb '123', '$' RETURNING queryfuncs_char2_chk ERROR ON ERROR);
+ERROR:  value too long for type character(2)
+SELECT JSON_VALUE(jsonb '123', '$' RETURNING queryfuncs_char2_chk DEFAULT 1 ON ERROR);
+ json_value 
+------------
+ 1 
+(1 row)
+
+DROP DOMAIN queryfuncs_char2, queryfuncs_char2_chk;

src/test/regress/sql/sqljson_jsontable.sql

@@ -266,7 +266,7 @@ SELECT * FROM JSON_TABLE(jsonb '"a"', '$' COLUMNS (a int4 EXISTS PATH '$.a'));
 SELECT * FROM JSON_TABLE(jsonb '"a"', '$' COLUMNS (a int2 EXISTS PATH '$.a'));
 SELECT * FROM JSON_TABLE(jsonb '"a"', '$' COLUMNS (a int8 EXISTS PATH '$.a'));
 SELECT * FROM JSON_TABLE(jsonb '"a"', '$' COLUMNS (a float4 EXISTS PATH '$.a'));
-SELECT * FROM JSON_TABLE(jsonb '"a"', '$' COLUMNS (a char(3) EXISTS PATH '$.a'));
+SELECT * FROM JSON_TABLE(jsonb '"a"', '$' COLUMNS (a char(5) EXISTS PATH '$.a'));
 SELECT * FROM JSON_TABLE(jsonb '"a"', '$' COLUMNS (a json EXISTS PATH '$.a'));
 SELECT * FROM JSON_TABLE(jsonb '"a"', '$' COLUMNS (a jsonb EXISTS PATH '$.a'));
 

src/test/regress/sql/sqljson_queryfuncs.sql

@@ -53,7 +53,9 @@ SELECT JSON_VALUE(jsonb '"1.23"', '$' RETURNING int ERROR ON ERROR);
 SELECT JSON_VALUE(jsonb '"aaa"', '$');
 SELECT JSON_VALUE(jsonb '"aaa"', '$' RETURNING text);
 SELECT JSON_VALUE(jsonb '"aaa"', '$' RETURNING char(5));
+SELECT JSON_VALUE(jsonb '"aaa"', '$' RETURNING char(2) ERROR ON ERROR);
 SELECT JSON_VALUE(jsonb '"aaa"', '$' RETURNING char(2));
+SELECT JSON_VALUE(jsonb '"aaa"', '$' RETURNING char(3) ERROR ON ERROR);
 SELECT JSON_VALUE(jsonb '"aaa"', '$' RETURNING json);
 SELECT JSON_VALUE(jsonb '"aaa"', '$' RETURNING jsonb);
 SELECT JSON_VALUE(jsonb '"aaa"', '$' RETURNING json ERROR ON ERROR);
@@ -188,10 +190,11 @@ SELECT JSON_QUERY(jsonb '"aaa"', '$' RETURNING json OMIT QUOTES ERROR ON ERROR);
 SELECT JSON_QUERY(jsonb '"aaa"', '$' RETURNING bytea FORMAT JSON OMIT QUOTES ERROR ON ERROR);
 
 -- Behavior when a RETURNING type has typmod != -1
-SELECT JSON_QUERY(jsonb '"aaa"', '$' RETURNING char(2));
-SELECT JSON_QUERY(jsonb '"aaa"', '$' RETURNING char(2) OMIT QUOTES);
-SELECT JSON_QUERY(jsonb '"aaa"', '$.a' RETURNING char(2) OMIT QUOTES DEFAULT 'bbb' ON EMPTY);
-SELECT JSON_QUERY(jsonb '"aaa"', '$.a' RETURNING char(2) OMIT QUOTES DEFAULT '"bbb"'::jsonb ON EMPTY);
+SELECT JSON_QUERY(jsonb '"aaa"', '$' RETURNING char(3) ERROR ON ERROR);
+SELECT JSON_QUERY(jsonb '"aaa"', '$' RETURNING char(3));
+SELECT JSON_QUERY(jsonb '"aaa"', '$' RETURNING char(3) OMIT QUOTES ERROR ON ERROR);
+SELECT JSON_QUERY(jsonb '"aaa"', '$.a' RETURNING char(2) OMIT QUOTES DEFAULT 'bb' ON EMPTY);
+SELECT JSON_QUERY(jsonb '"aaa"', '$.a' RETURNING char(2) OMIT QUOTES DEFAULT '"bb"'::jsonb ON EMPTY);
 
 -- OMIT QUOTES behavior should not be specified when WITH WRAPPER used:
 -- Should fail
@@ -235,7 +238,6 @@ SELECT JSON_QUERY(jsonb '[1,2]', '$' RETURNING jsonb);
 SELECT JSON_QUERY(jsonb '[1,2]', '$' RETURNING jsonb FORMAT JSON);
 SELECT JSON_QUERY(jsonb '[1,2]', '$' RETURNING text);
 SELECT JSON_QUERY(jsonb '[1,2]', '$' RETURNING char(10));
-SELECT JSON_QUERY(jsonb '[1,2]', '$' RETURNING char(3));
 SELECT JSON_QUERY(jsonb '[1,2]', '$' RETURNING text FORMAT JSON);
 SELECT JSON_QUERY(jsonb '[1,2]', '$' RETURNING bytea);
 SELECT JSON_QUERY(jsonb '[1,2]', '$' RETURNING bytea FORMAT JSON);
@@ -464,3 +466,16 @@ SELECT JSON_QUERY(jsonb 'null', '$xyz' PASSING 1 AS xyz);
 SELECT JSON_EXISTS(jsonb '1', '$' DEFAULT 1 ON ERROR);
 SELECT JSON_VALUE(jsonb '1', '$' EMPTY ON ERROR);
 SELECT JSON_QUERY(jsonb '1', '$' TRUE ON ERROR);
+
+-- Test implicit coercion domain over fixed-legth type specified in RETURNING
+CREATE DOMAIN queryfuncs_char2 AS char(2);
+CREATE DOMAIN queryfuncs_char2_chk AS char(2) CHECK (VALUE NOT IN ('12'));
+SELECT JSON_QUERY(jsonb '123', '$' RETURNING queryfuncs_char2 ERROR ON ERROR);
+SELECT JSON_QUERY(jsonb '123', '$' RETURNING queryfuncs_char2 DEFAULT '1' ON ERROR);
+SELECT JSON_QUERY(jsonb '123', '$' RETURNING queryfuncs_char2_chk ERROR ON ERROR);
+SELECT JSON_QUERY(jsonb '123', '$' RETURNING queryfuncs_char2_chk DEFAULT '1' ON ERROR);
+SELECT JSON_VALUE(jsonb '123', '$' RETURNING queryfuncs_char2 ERROR ON ERROR);
+SELECT JSON_VALUE(jsonb '123', '$' RETURNING queryfuncs_char2 DEFAULT 1 ON ERROR);
+SELECT JSON_VALUE(jsonb '123', '$' RETURNING queryfuncs_char2_chk ERROR ON ERROR);
+SELECT JSON_VALUE(jsonb '123', '$' RETURNING queryfuncs_char2_chk DEFAULT 1 ON ERROR);
+DROP DOMAIN queryfuncs_char2, queryfuncs_char2_chk;