v2-0001-fix-transformJsonFuncExpr-pathspec-cache-lookup-failure.patch

From b1fe8643aa1ab8a351ab0269d5b7037a071bd669 Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Tue, 18 Nov 2025 16:13:50 +0800
Subject: [PATCH v2 1/1] fix transformJsonFuncExpr pathspec cache lookup
 failure

discussion: https://postgr.es/m/CACJufxHunVg81JMuNo8Yvv_hJD0DicgaVN2Wteu8aJbVJPBjZA@mail.gmail.com
---
 src/backend/parser/parse_expr.c               | 22 ++++++++++++-------
 .../regress/expected/sqljson_queryfuncs.out   |  8 +++++++
 src/test/regress/sql/sqljson_queryfuncs.sql   |  2 ++
 3 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c
index 32d6ae918ca..67fb2fb485d 100644
--- a/src/backend/parser/parse_expr.c
+++ b/src/backend/parser/parse_expr.c
@@ -4285,8 +4285,11 @@ transformJsonFuncExpr(ParseState *pstate, JsonFuncExpr *func)
 {
 	JsonExpr   *jsexpr;
 	Node	   *path_spec;
+	Node	   *coerced_expr;
 	const char *func_name = NULL;
 	JsonFormatType default_format;
+	Oid			pathspec_type;
+	ParseLoc	pathspec_loc;
 
 	switch (func->op)
 	{
@@ -4500,17 +4503,20 @@ transformJsonFuncExpr(ParseState *pstate, JsonFuncExpr *func)
 	jsexpr->format = func->context_item->format;
 
 	path_spec = transformExprRecurse(pstate, func->pathspec);
-	path_spec = coerce_to_target_type(pstate, path_spec, exprType(path_spec),
-									  JSONPATHOID, -1,
-									  COERCION_EXPLICIT, COERCE_IMPLICIT_CAST,
-									  exprLocation(path_spec));
-	if (path_spec == NULL)
+	pathspec_type = exprType(path_spec);
+	pathspec_loc = exprLocation(path_spec);
+
+	coerced_expr = coerce_to_target_type(pstate, path_spec, pathspec_type,
+										 JSONPATHOID, -1,
+										 COERCION_EXPLICIT, COERCE_IMPLICIT_CAST,
+										 pathspec_loc);
+	if (coerced_expr == NULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_DATATYPE_MISMATCH),
 				 errmsg("JSON path expression must be of type %s, not of type %s",
-						"jsonpath", format_type_be(exprType(path_spec))),
-				 parser_errposition(pstate, exprLocation(path_spec))));
-	jsexpr->path_spec = path_spec;
+						"jsonpath", format_type_be(pathspec_type)),
+				 parser_errposition(pstate, pathspec_loc)));
+	jsexpr->path_spec = coerced_expr;
 
 	/* Transform and coerce the PASSING arguments to jsonb. */
 	transformJsonPassingArgs(pstate, func_name,
diff --git a/src/test/regress/expected/sqljson_queryfuncs.out b/src/test/regress/expected/sqljson_queryfuncs.out
index 5a35aeb7bba..53145f50f18 100644
--- a/src/test/regress/expected/sqljson_queryfuncs.out
+++ b/src/test/regress/expected/sqljson_queryfuncs.out
@@ -1331,6 +1331,10 @@ SELECT JSON_QUERY(jsonb '{"a": 123}', '$' || '.' || 'a' WITH WRAPPER);
  [123]
 (1 row)
 
+SELECT JSON_QUERY(jsonb '{"a": 123}', ('$' || '.' || 'a' || NULL)::date WITH WRAPPER);
+ERROR:  JSON path expression must be of type jsonpath, not of type date
+LINE 1: SELECT JSON_QUERY(jsonb '{"a": 123}', ('$' || '.' || 'a' || ...
+                                               ^
 -- Should fail (invalid path)
 SELECT JSON_QUERY(jsonb '{"a": 123}', 'error' || ' ' || 'error');
 ERROR:  syntax error at or near " " of jsonpath input
@@ -1355,6 +1359,10 @@ SELECT json_value('"aaa"', path RETURNING json) FROM jsonpaths;
  "aaa"
 (1 row)
 
+SELECT json_value('"aaa"', jsonpaths RETURNING json) FROM jsonpaths;
+ERROR:  JSON path expression must be of type jsonpath, not of type jsonpaths
+LINE 1: SELECT json_value('"aaa"', jsonpaths RETURNING json) FROM js...
+                                   ^
 -- Test PASSING argument parsing
 SELECT JSON_QUERY(jsonb 'null', '$xyz' PASSING 1 AS xy);
 ERROR:  could not find jsonpath variable "xyz"
diff --git a/src/test/regress/sql/sqljson_queryfuncs.sql b/src/test/regress/sql/sqljson_queryfuncs.sql
index 8d7b225b612..a5d5e256d7f 100644
--- a/src/test/regress/sql/sqljson_queryfuncs.sql
+++ b/src/test/regress/sql/sqljson_queryfuncs.sql
@@ -450,6 +450,7 @@ SELECT JSON_VALUE(jsonb '{"a": 123}', '$' || '.' || 'a');
 SELECT JSON_VALUE(jsonb '{"a": 123}', '$' || '.' || 'b' DEFAULT 'foo' ON EMPTY);
 SELECT JSON_QUERY(jsonb '{"a": 123}', '$' || '.' || 'a');
 SELECT JSON_QUERY(jsonb '{"a": 123}', '$' || '.' || 'a' WITH WRAPPER);
+SELECT JSON_QUERY(jsonb '{"a": 123}', ('$' || '.' || 'a' || NULL)::date WITH WRAPPER);
 -- Should fail (invalid path)
 SELECT JSON_QUERY(jsonb '{"a": 123}', 'error' || ' ' || 'error');
 
@@ -460,6 +461,7 @@ SELECT JSON_QUERY(NULL FORMAT JSON, '$');
 -- Test non-const jsonpath
 CREATE TEMP TABLE jsonpaths (path) AS SELECT '$';
 SELECT json_value('"aaa"', path RETURNING json) FROM jsonpaths;
+SELECT json_value('"aaa"', jsonpaths RETURNING json) FROM jsonpaths;
 
 -- Test PASSING argument parsing
 SELECT JSON_QUERY(jsonb 'null', '$xyz' PASSING 1 AS xy);
-- 
2.34.1