From 4c24c0f89c91172fbf4becb9a0be89c26fc21135 Mon Sep 17 00:00:00 2001
From: Dmitrii Dolgov <9erthalion6@gmail.com>
Date: Thu, 7 Jan 2021 09:04:39 +0100
Subject: [PATCH v45 3/3] Replace assuming a composite object on a scalar
For jsonb subscripting assignment it could happen that the provided path
assumes an object or an array at some level, but the source jsonb has a
scalar value there. Originally the update operation will be skipped and
no message will be shown that nothing happened. Return an error to
indicate such situations.
---
doc/src/sgml/json.sgml | 22 ++++++++++++++++++++--
src/backend/utils/adt/jsonfuncs.c | 11 +++++++++++
src/test/regress/expected/jsonb.out | 12 ++++++++++++
src/test/regress/sql/jsonb.sql | 8 ++++++++
4 files changed, 51 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/json.sgml b/doc/src/sgml/json.sgml
index 9af015d222..924762e128 100644
--- a/doc/src/sgml/json.sgml
+++ b/doc/src/sgml/json.sgml
@@ -612,8 +612,23 @@ SELECT jdoc->'guid', jdoc->'name' FROM api WHERE jdoc @> '{"tags": ["qu
path argument in jsonb_set function,
e.g. in case of arrays it is a 0-based operation or that negative integers
that appear in path count from the end of JSON arrays.
- The result of subscripting expressions is always jsonb data type. An
- example of subscripting syntax:
+ The result of subscripting expressions is always jsonb data type.
+
+
+ UPDATE statements may use subscripting in the
+ SET clause to modify jsonb values. Every
+ affected value must conform to the path defined by the subscript(s). If the
+ path contradicts structure of modified jsonb for any individual
+ value (e.g. path val['a']['b']['c'] assumes keys
+ 'a' and 'b' have object values
+ assigned to them, but if val['a'] or
+ val['b'] is null, a string, or a number, then the path
+ contradicts with the existing structure), an error is raised even if other
+ values do conform.
+
+
+
+ An example of subscripting syntax:
-- Extract value by key
SELECT ('{"a": 1}'::jsonb)['a'];
@@ -628,6 +643,9 @@ SELECT ('[1, "2", null]'::jsonb)[1];
-- needs to be of jsonb type as well
UPDATE table_name SET jsonb_field['key'] = '1';
+-- This will raise an error if jsonb_field is {"a": 1}
+UPDATE table_name SET jsonb_field['a']['b']['c'] = '1';
+
-- Select records using where clause with subscripting. Since the result of
-- subscripting is jsonb and we basically want to compare two jsonb objects, we
-- need to put the value in double quotes to be able to convert it to jsonb.
diff --git a/src/backend/utils/adt/jsonfuncs.c b/src/backend/utils/adt/jsonfuncs.c
index f14f6c3191..ebc0b06f5b 100644
--- a/src/backend/utils/adt/jsonfuncs.c
+++ b/src/backend/utils/adt/jsonfuncs.c
@@ -4943,6 +4943,17 @@ setPath(JsonbIterator **it, Datum *path_elems,
break;
case WJB_ELEM:
case WJB_VALUE:
+ /*
+ * If instructed complain about attempts to replace whithin a
+ * scalar value.
+ */
+ if ((op_type & JB_PATH_FILL_GAPS) && (level < path_len - 1))
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("cannot replace existing key"),
+ errdetail("The path assumes key is a composite object, "
+ "but it is a scalar value.")));
+
res = pushJsonbValue(st, r, &v);
break;
default:
diff --git a/src/test/regress/expected/jsonb.out b/src/test/regress/expected/jsonb.out
index b7c268b53f..0df808c36d 100644
--- a/src/test/regress/expected/jsonb.out
+++ b/src/test/regress/expected/jsonb.out
@@ -5134,6 +5134,18 @@ select * from test_jsonb_subscript;
1 | {"a": [null, {"c": [null, null, 1]}]}
(1 row)
+-- trying replace assuming a composite object, but it's a scalar
+delete from test_jsonb_subscript;
+insert into test_jsonb_subscript values (1, '{"a": 1}');
+update test_jsonb_subscript set test_json['a']['b']['c'] = '1';
+ERROR: cannot replace existing key
+DETAIL: The path assumes key is a composite object, but it is a scalar value.
+update test_jsonb_subscript set test_json['a'][0]['c'] = '1';
+ERROR: cannot replace existing key
+DETAIL: The path assumes key is a composite object, but it is a scalar value.
+update test_jsonb_subscript set test_json['a'][0][0] = '1';
+ERROR: cannot replace existing key
+DETAIL: The path assumes key is a composite object, but it is a scalar value.
-- jsonb to tsvector
select to_tsvector('{"a": "aaa bbb ddd ccc", "b": ["eee fff ggg"], "c": {"d": "hhh iii"}}'::jsonb);
to_tsvector
diff --git a/src/test/regress/sql/jsonb.sql b/src/test/regress/sql/jsonb.sql
index 0320db0ea4..c62a2f9aec 100644
--- a/src/test/regress/sql/jsonb.sql
+++ b/src/test/regress/sql/jsonb.sql
@@ -1371,6 +1371,14 @@ insert into test_jsonb_subscript values (1, '{"a": []}');
update test_jsonb_subscript set test_json['a'][1]['c'][2] = '1';
select * from test_jsonb_subscript;
+-- trying replace assuming a composite object, but it's a scalar
+
+delete from test_jsonb_subscript;
+insert into test_jsonb_subscript values (1, '{"a": 1}');
+update test_jsonb_subscript set test_json['a']['b']['c'] = '1';
+update test_jsonb_subscript set test_json['a'][0]['c'] = '1';
+update test_jsonb_subscript set test_json['a'][0][0] = '1';
+
-- jsonb to tsvector
select to_tsvector('{"a": "aaa bbb ddd ccc", "b": ["eee fff ggg"], "c": {"d": "hhh iii"}}'::jsonb);
--
2.21.0