From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Manuel Reyes Bravo Date: Tue, 3 Nov 2026 12:44:24 -0300 Subject: [PATCH v5 2/2] Treat arrays of user-defined base types as mutable in JSON check Since ecd9288624a, json_check_mutability() recurses into the element type of an array. When the element is a user-defined base type, or a domain over one, it is converted through a cast to json if one exists, looked up at run time, so a cast created or dropped after CREATE INDEX changes the indexed value. 18 treats every array as mutable. Treat such arrays as mutable, as user-defined ranges already are. Arrays of built-in types, and of domains over them, are not affected. The same type used directly, or through a domain, has had this problem since before 19 and is left alone here. --- src/backend/utils/adt/jsonfuncs.c | 13 +++++++++-- src/test/regress/expected/sqljson.out | 32 +++++++++++++++++++++++++++ src/test/regress/sql/sqljson.sql | 17 ++++++++++++++ 3 files changed, 60 insertions(+), 2 deletions(-) diff --git a/src/backend/utils/adt/jsonfuncs.c b/src/backend/utils/adt/jsonfuncs.c index 3bee50f948b..d8e5712f90c 100644 --- a/src/backend/utils/adt/jsonfuncs.c +++ b/src/backend/utils/adt/jsonfuncs.c @@ -6155,8 +6155,17 @@ json_check_mutability(Oid typoid, bool *has_mutable) if (OidIsValid(att_typelem)) { - /* recurse into array element type */ - json_check_mutability(att_typelem, has_mutable); + /* + * Elements of a user-defined base type are printed through a cast + * to json if one exists, looked up at run time, so creating or + * dropping that cast later changes the output. Treat such arrays + * as mutable, like user-defined ranges; otherwise recurse into the + * element type. + */ + if (getBaseType(att_typelem) >= FirstNormalObjectId) + *has_mutable = true; + else + json_check_mutability(att_typelem, has_mutable); return; } } diff --git a/src/test/regress/expected/sqljson.out b/src/test/regress/expected/sqljson.out index 10116dc0785..f5f1056de74 100644 --- a/src/test/regress/expected/sqljson.out +++ b/src/test/regress/expected/sqljson.out @@ -1487,6 +1487,38 @@ LINE 1: create index on test_range_immutable(json_object('key' value... ^ drop table test_range_immutable; drop type range_int; +-- Arrays of a user-defined base type, or of a domain over one, are mutable: +-- their elements are converted through a cast to json, looked up at run time +create type mytext_t; +create function mytext_t_in(cstring) returns mytext_t + language internal immutable strict as 'textin'; +NOTICE: return type mytext_t is only a shell +create function mytext_t_out(mytext_t) returns cstring + language internal immutable strict as 'textout'; +NOTICE: argument type mytext_t is only a shell +LINE 1: create function mytext_t_out(mytext_t) returns cstring + ^ +create type mytext_t (input = mytext_t_in, output = mytext_t_out, like = text); +create domain d_mytext_t as mytext_t; +create table test_base_array(a mytext_t[], b d_mytext_t[]); +create index on test_base_array(json_array(a returning jsonb)); -- error +ERROR: functions in index expression must be marked IMMUTABLE +LINE 1: create index on test_base_array(json_array(a returning jsonb... + ^ +create index on test_base_array(json_array(b returning jsonb)); -- error +ERROR: functions in index expression must be marked IMMUTABLE +LINE 1: create index on test_base_array(json_array(b returning jsonb... + ^ +create index on test_base_array(json_object('key' value a returning jsonb)); -- error +ERROR: functions in index expression must be marked IMMUTABLE +LINE 1: create index on test_base_array(json_object('key' value a re... + ^ +drop table test_base_array; +drop domain d_mytext_t; +drop type mytext_t cascade; +NOTICE: drop cascades to 2 other objects +DETAIL: drop cascades to function mytext_t_in(cstring) +drop cascades to function mytext_t_out(mytext_t) -- IS JSON predicate SELECT NULL IS JSON; ?column? diff --git a/src/test/regress/sql/sqljson.sql b/src/test/regress/sql/sqljson.sql index 504d00b5b2b..f32b5def1ed 100644 --- a/src/test/regress/sql/sqljson.sql +++ b/src/test/regress/sql/sqljson.sql @@ -573,6 +573,23 @@ create index on test_range_immutable(json_object('key' value m returning jsonb)) drop table test_range_immutable; drop type range_int; +-- Arrays of a user-defined base type, or of a domain over one, are mutable: +-- their elements are converted through a cast to json, looked up at run time +create type mytext_t; +create function mytext_t_in(cstring) returns mytext_t + language internal immutable strict as 'textin'; +create function mytext_t_out(mytext_t) returns cstring + language internal immutable strict as 'textout'; +create type mytext_t (input = mytext_t_in, output = mytext_t_out, like = text); +create domain d_mytext_t as mytext_t; +create table test_base_array(a mytext_t[], b d_mytext_t[]); +create index on test_base_array(json_array(a returning jsonb)); -- error +create index on test_base_array(json_array(b returning jsonb)); -- error +create index on test_base_array(json_object('key' value a returning jsonb)); -- error +drop table test_base_array; +drop domain d_mytext_t; +drop type mytext_t cascade; + -- IS JSON predicate SELECT NULL IS JSON; SELECT NULL IS NOT JSON; -- 2.56.0