# Copyright 2015 - 2019 The Cockroach Authors. All rights reserved.
# Copyright Materialize, Inc. and contributors. All rights reserved.
#
# Use of this software is governed by the Business Source License
# included in the LICENSE file at the root of this repository.
#
# As of the Change Date specified in that file, in accordance with
# the Business Source License, use of this software will be governed
# by the Apache License, Version 2.0.
#
# This file is derived from the logic test suite in CockroachDB. The
# original file was retrieved on June 10, 2019 from:
#
#     https://github.com/cockroachdb/cockroach/blob/d2f7fbf5dd1fc1a099bbad790a2e1f7c60a66cc3/pkg/sql/logictest/testdata/logic_test/json_builtins
#
# The original source code is subject to the terms of the Apache
# 2.0 license, a copy of which can be found in the LICENSE file at the
# root of this repository.

mode cockroach

## json_typeof and jsonb_typeof

query T
SELECT json_typeof('-123.4'::JSON)
----
number

query T
SELECT jsonb_typeof('-123.4'::JSON)
----
number

query T
SELECT json_typeof('"-123.4"'::JSON)
----
string

query T
SELECT jsonb_typeof('"-123.4"'::JSON)
----
string

query T
SELECT json_typeof('{"1":{"2":3}}'::JSON)
----
object

query T
SELECT jsonb_typeof('{"1":{"2":3}}'::JSON)
----
object

query T
SELECT json_typeof('[1, 2, [3]]'::JSON)
----
array

query T
SELECT jsonb_typeof('[1, 2, [3]]'::JSON)
----
array

query T
SELECT json_typeof('true'::JSON)
----
boolean

query T
SELECT jsonb_typeof('true'::JSON)
----
boolean

query T
SELECT json_typeof('false'::JSON)
----
boolean

query T
SELECT jsonb_typeof('false'::JSON)
----
boolean

query T
SELECT json_typeof('null'::JSON)
----
null

query T
SELECT jsonb_typeof('null'::JSON)
----
null

## array_to_json
query T
SELECT array_to_json(ARRAY[[1,2],[3,4]])
----
[[1,2],[3,4]]

query T
SELECT array_to_json('{1,2,3}'::INT[])
----
[1,2,3]

query T
SELECT array_to_json('{"a","b","c"}'::STRING[])
----
["a","b","c"]

query T
SELECT array_to_json('{1.0,2.0,3.0}'::DECIMAL[])
----
[1.0,2.0,3.0]

query T
SELECT array_to_json(NULL)
----
NULL

query T
SELECT array_to_json(ARRAY[1,2,3],NULL)
----
NULL

query T
SELECT array_to_json(ARRAY[1,2,3],false)
----
[1,2,3]

query error pq:array_to_json\(\):pretty printing is not supported
SELECT array_to_json(ARRAY[1,2,3],true)

query error pq:unknown signature:array_to_json\(string\)
SELECT array_to_json('hello world')

## to_json and to_jsonb

query T
SELECT to_json(123::INT)
----
123

query T
SELECT to_json('\a'::TEXT)
----
"\\a"

query T
SELECT to_json('\a'::TEXT COLLATE "fr_FR")
----
"\\a"

query T
SELECT to_json(3::OID::INT::OID)
----
"3"

query T
SELECT to_json('a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11'::UUID);
----
"a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11"

query T
SELECT to_json('\x0001'::BYTEA)
----
"\\x0001"

query T
SELECT to_json(true::BOOL)
----
true

query T
SELECT to_json(false::BOOL)
----
false

query T
SELECT to_json('"a"'::JSON)
----
"a"

query T
SELECT to_json(1.234::FLOAT)
----
1.234

query T
SELECT to_json(1.234::DECIMAL)
----
1.234

query T
SELECT to_json('10.1.0.0/16'::INET)
----
"10.1.0.0/16"

query T
SELECT to_json(ARRAY[[1,2],[3,4]])
----
[[1,2],[3,4]]

query T
SELECT to_json('2014-05-28 12:22:35.614298'::TIMESTAMP)
----
"2014-05-28T12:22:35.614298"

query T
SELECT to_json('2014-05-28 12:22:35.614298-04'::TIMESTAMPTZ)
----
"2014-05-28T12:22:35.614298-04:00"

query T
SELECT to_json('2014-05-28 12:22:35.614298-04'::TIMESTAMP)
----
"2014-05-28T12:22:35.614298"

query T
SELECT to_json('2014-05-28'::DATE)
----
"2014-05-28"

query T
SELECT to_json('00:00:00'::TIME)
----
"00:00:00"

query T
SELECT to_json('2h45m2s234ms'::INTERVAL)
----
"02:45:02.234"

query T
SELECT to_json((1,2,'hello',NULL,NULL))
----
{"f1":1,"f2":2,"f3":"hello","f4":null,"f5":null}

query T
SELECT to_jsonb(123::INT)
----
123

query T
SELECT to_jsonb('\a'::TEXT)
----
"\\a"

query T
SELECT to_jsonb('\a'::TEXT COLLATE "fr_FR")
----
"\\a"

query T
SELECT to_jsonb(3::OID::INT::OID)
----
"3"

query T
SELECT to_jsonb('a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11'::UUID);
----
"a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11"

query T
SELECT to_jsonb('\x0001'::BYTEA)
----
"\\x0001"

query T
SELECT to_jsonb(true::BOOL)
----
true

query T
SELECT to_jsonb(false::BOOL)
----
false

query T
SELECT to_jsonb('"a"'::JSON)
----
"a"

query T
SELECT to_jsonb(1.234::FLOAT)
----
1.234

query T
SELECT to_jsonb(1.234::DECIMAL)
----
1.234

query T
SELECT to_jsonb('10.1.0.0/16'::INET)
----
"10.1.0.0/16"

query T
SELECT to_jsonb(ARRAY[[1,2],[3,4]])
----
[[1,2],[3,4]]

query T
SELECT to_jsonb('2014-05-28 12:22:35.614298'::TIMESTAMP)
----
"2014-05-28T12:22:35.614298"

query T
SELECT to_jsonb('2014-05-28 12:22:35.614298-04'::TIMESTAMPTZ)
----
"2014-05-28T12:22:35.614298-04:00"

query T
SELECT to_jsonb('2014-05-28 12:22:35.614298-04'::TIMESTAMP)
----
"2014-05-28T12:22:35.614298"

query T
SELECT to_jsonb('2014-05-28'::DATE)
----
"2014-05-28"

query T
SELECT to_jsonb('00:00:00'::TIME)
----
"00:00:00"

query T
SELECT to_jsonb('2h45m2s234ms'::INTERVAL)
----
"02:45:02.234"

query T
SELECT to_jsonb((1,2,'hello',NULL,NULL))
----
{"f1":1,"f2":2,"f3":"hello","f4":null,"f5":null}

## json_array_elements and jsonb_array_elements

query T
SELECT json_array_elements('[1,2,3]'::JSON)
----
1
2
3

query T
SELECT jsonb_array_elements('[1,2,3]'::JSON)
----
1
2
3

query T
SELECT json_array_elements('[1,true,null,"text",-1.234,{"2":3,"4":"5"},[1,2,3]]'::JSON)
----
1
true
null
"text"
-1.234
{"2":3,"4":"5"}
[1,2,3]

query T
SELECT json_array_elements('[]'::JSON)
----


query error pq:cannot be called on a non-array
SELECT json_array_elements('{"1":2}'::JSON)

query error pq:cannot be called on a non-array
SELECT jsonb_array_elements('{"1":2}'::JSON)


## json_array_elements_text and jsonb_array_elements_text

query T
SELECT json_array_elements_text('[1,2,3]'::JSON)
----
1
2
3

query T
SELECT json_array_elements_text('[1,2,3]'::JSON)
----
1
2
3

query T
SELECT json_array_elements_text('[1,true,null,"text",-1.234,{"2":3,"4":"5"},[1,2,3]]'::JSON)
----
1
true
NULL
text
-1.234
{"2":3,"4":"5"}
[1,2,3]

query T
SELECT json_array_elements('[]'::JSON)
----

query error pq:cannot be called on a non-array
SELECT json_array_elements_text('{"1":2}'::JSON)

query error pq:cannot be called on a non-array
SELECT jsonb_array_elements_text('{"1":2}'::JSON)


## json_object_keys and jsonb_object_keys

query T
SELECT json_object_keys('{"1":2,"3":4}'::JSON)
----
1
3

query T
SELECT jsonb_object_keys('{"1":2,"3":4}'::JSON)
----
1
3

query T
SELECT json_object_keys('{}'::JSON)
----

query T
SELECT json_object_keys('{"\"1\"":2}'::JSON)
----
"1"

# Keys are sorted.
query T
SELECT json_object_keys('{"a":1,"1":2,"3":{"4":5,"6":7}}'::JSON)
----
1
3
a

query error pq:cannot call json_object_keys on a scalar
SELECT json_object_keys('null'::JSON)

query error pq:cannot call json_object_keys on an array
SELECT json_object_keys('[1,2,3]'::JSON)

## json_build_object

query T
SELECT json_build_object()
----
{}

query T
SELECT json_build_object('a',2,'b',4)
----
{"a":2,"b":4}

query T
SELECT jsonb_build_object(true,'val',1,0,1.3,2,date '2019-02-03' - date '2019-01-01',4)
----
{"1":0,"1.3":2,"33":4,"true":"val"}

query T
SELECT json_build_object('a',1,'b',1.2,'c',true,'d',null,'e','{"x":3,"y":[1,2,3]}'::JSON)
----
{"a":1,"b":1.2,"c":true,"d":null,"e":{"x":3,"y":[1,2,3]}}

query T
SELECT json_build_object(
       'a',json_build_object('b',false,'c',99),
       'd',json_build_object('e',ARRAY[9,8,7]::int[])
)
----
{"a":{"b":false,"c":99},"d":{"e":[9,8,7]}}

query T
SELECT json_build_object(a,3) FROM (SELECT 1 AS a,2 AS b) r
----
{"1":3}

query T
SELECT json_build_object('\a'::TEXT COLLATE "fr_FR",1)
----
{"\\a":1}

query T
SELECT json_build_object('\a',1)
----
{"\\a":1}

query T
SELECT json_build_object(json_object_keys('{"x":3,"y":4}'::JSON),2)
----
{"x":2}
{"y":2}

# Regression for panic when bit array is passed as argument.
query T
SELECT json_build_object('a','0100110'::varbit)
----
{"a":"0100110"}

# even number of arguments
query error pq:json_build_object\(\):argument list must have even number of elements
SELECT json_build_object(1,2,3)

# keys must be scalar and not null
query error pq:json_build_object\(\):argument 1 cannot be null
SELECT json_build_object(null,2)

query error pq:json_build_object\(\):key value must be scalar,not array,tuple,or json
SELECT json_build_object((1,2),3)

query error pq:json_build_object\(\):key value must be scalar,not array,tuple,or json
SELECT json_build_object('{"a":1,"b":2}'::JSON,3)

query error pq:json_build_object\(\):key value must be scalar,not array,tuple,or json
SELECT json_build_object('{1,2,3}'::int[],3)

query T
SELECT json_extract_path('{"a":1}','a')
----
1

query T
SELECT json_extract_path('{"a":1}','a',NULL)
----
NULL

query T
SELECT json_extract_path('{"a":1}')
----
{"a":1}

query T
SELECT json_extract_path('{"a":{"b":2}}','a')
----
{"b":2}

query T
SELECT json_extract_path('{"a":{"b":2}}','a','b')
----
2

query T
SELECT jsonb_extract_path('{"a":{"b":2}}','a','b')
----
2

query T
SELECT json_extract_path('{"a":{"b":2}}','a','b','c')
----
NULL

query T
SELECT jsonb_pretty('{"a":1}')
----
{
    "a":1
}

query T
SELECT '[1,2,3]'::JSON || '[4,5,6]'::JSON
----
[1,2,3,4,5,6]

query T
SELECT '{"a":1,"b":2}'::JSON || '{"b":3,"c":4}'
----
{"a":1,"b":3,"c":4}

query error pgcode 22023 invalid concatenation of jsonb objects
SELECT '{"a":1,"b":2}'::JSON || '"c"'

query T
SELECT json_build_array()
----
[]

query T
SELECT json_build_array('\x0001'::BYTEA)
----
["\\x0001"]

query T
SELECT json_build_array(1,'1'::JSON,1.2,NULL,ARRAY['x','y'])
----
[1,1,1.2,null,["x","y"]]

query T
SELECT jsonb_build_array()
----
[]

query T
SELECT jsonb_build_array('\x0001'::BYTEA)
----
["\\x0001"]

query T
SELECT jsonb_build_array(1,'1'::JSON,1.2,NULL,ARRAY['x','y'])
----
[1,1,1.2,null,["x","y"]]

# Regression for cockroach#37318
query T
SELECT jsonb_build_array('+Inf'::FLOAT8,'NaN'::FLOAT8)::STRING::JSONB
----
["Infinity","NaN"]

query error pq:json_object\(\):array must have even number of elements
SELECT json_object('{a,b,c}'::TEXT[])

query error pq:json_object\(\):null value not allowed for object key
SELECT json_object('{NULL,a}'::TEXT[])

query error pq:json_object\(\):null value not allowed for object key
SELECT json_object('{a,b,NULL,"d e f"}'::TEXT[],'{1,2,3,"a b c"}'::TEXT[])

query error pq:json_object\(\):mismatched array dimensions
SELECT json_object('{a,b,c,"d e f",g}'::TEXT[],'{1,2,3,"a b c"}'::TEXT[])

query error pq:json_object\(\):mismatched array dimensions
SELECT json_object('{a,b,c,"d e f"}'::TEXT[],'{1,2,3,"a b c",g}'::TEXT[])

query error pq:unknown signature:json_object\(collatedstring\{fr_FR\}\[\]\)
SELECT json_object(ARRAY['a'::TEXT COLLATE "fr_FR"])

query T
SELECT json_object('{}'::TEXT[])
----
{}

query T
SELECT json_object('{}'::TEXT[],'{}'::TEXT[])
----
{}

query T
SELECT json_object('{b,3,a,1,b,4,a,2}'::TEXT[])
----
{"a":"2","b":"4"}

query T
SELECT json_object('{b,b,a,a}'::TEXT[],'{1,2,3,4}'::TEXT[])
----
{"a":"4","b":"2"}

query T
SELECT json_object('{a,1,b,2,3,NULL,"d e f","a b c"}'::TEXT[])
----
{"3":null,"a":"1","b":"2","d e f":"a b c"}

query T
SELECT json_object('{a,b,"","d e f"}'::TEXT[],'{1,2,3,"a b c"}'::TEXT[])
----
{"":"3","a":"1","b":"2","d e f":"a b c"}

query T
SELECT json_object('{a,b,c,"d e f"}'::TEXT[],'{1,2,3,"a b c"}'::TEXT[])
----
{"a":"1","b":"2","c":"3","d e f":"a b c"}

query error pq:jsonb_object\(\):array must have even number of elements
SELECT jsonb_object('{a,b,c}'::TEXT[])

query error pq:jsonb_object\(\):null value not allowed for object key
SELECT jsonb_object('{NULL,a}'::TEXT[])

query error pq:jsonb_object\(\):null value not allowed for object key
SELECT jsonb_object('{a,b,NULL,"d e f"}'::TEXT[],'{1,2,3,"a b c"}'::TEXT[])

query error pq:jsonb_object\(\):mismatched array dimensions
SELECT jsonb_object('{a,b,c,"d e f",g}'::TEXT[],'{1,2,3,"a b c"}'::TEXT[])

query error pq:jsonb_object\(\):mismatched array dimensions
SELECT jsonb_object('{a,b,c,"d e f"}'::TEXT[],'{1,2,3,"a b c",g}'::TEXT[])

query error pq:unknown signature:jsonb_object\(collatedstring\{fr_FR\}\[\]\)
SELECT jsonb_object(ARRAY['a'::TEXT COLLATE "fr_FR"])

query T
SELECT jsonb_object('{}'::TEXT[])
----
{}

query T
SELECT jsonb_object('{}'::TEXT[],'{}'::TEXT[])
----
{}

query T
SELECT jsonb_object('{b,3,a,1,b,4,a,2}'::TEXT[])
----
{"a":"2","b":"4"}

query T
SELECT jsonb_object('{b,b,a,a}'::TEXT[],'{1,2,3,4}'::TEXT[])
----
{"a":"4","b":"2"}

query T
SELECT jsonb_object('{a,1,b,2,3,NULL,"d e f","a b c"}'::TEXT[])
----
{"3":null,"a":"1","b":"2","d e f":"a b c"}

query T
SELECT jsonb_object('{a,b,"","d e f"}'::TEXT[],'{1,2,3,"a b c"}'::TEXT[])
----
{"":"3","a":"1","b":"2","d e f":"a b c"}

query T
SELECT jsonb_object('{a,b,c,"d e f"}'::TEXT[],'{1,2,3,"a b c"}'::TEXT[])
----
{"a":"1","b":"2","c":"3","d e f":"a b c"}

query error pq:cannot deconstruct an array as an object
SELECT json_each('[1]'::JSON)

query error pq:cannot deconstruct a scalar
SELECT json_each('null'::JSON)

query TT
SELECT * from json_each('{}') q
----

query TT colnames
SELECT * from json_each('{"f1":[1,2,3],"f2":{"f3":1},"f4":null,"f5":99,"f6":"stringy"}') q
----
key  value
f1   [1,2,3]
f2   {"f3":1}
f4   null
f5   99
f6   "stringy"

query error pq:cannot deconstruct an array as an object
SELECT jsonb_each('[1]'::JSON)

query error pq:cannot deconstruct a scalar
SELECT jsonb_each('null'::JSON)

query TT
SELECT * from jsonb_each('{}') q
----

query TT colnames
SELECT * from jsonb_each('{"f1":[1,2,3],"f2":{"f3":1},"f4":null,"f5":99,"f6":"stringy"}') q
----
key  value
f1   [1,2,3]
f2   {"f3":1}
f4   null
f5   99
f6   "stringy"

query error pq:cannot deconstruct an array as an object
SELECT jsonb_each_text('[1]'::JSON)

query error pq:cannot deconstruct a scalar
SELECT jsonb_each_text('null'::JSON)

query TT
SELECT * from jsonb_each_text('{}') q
----

query TT
SELECT * from jsonb_each_text('{}') q
----

query TT colnames
SELECT * from jsonb_each_text('{"f1":[1,2,3],"f2":{"f3":1},"f4":null,"f5":99,"f6":"stringy"}') q
----
key  value
f1   [1,2,3]
f2   {"f3":1}
f4   NULL
f5   99
f6   stringy

query error pq:cannot deconstruct an array as an object
SELECT json_each_text('[1]'::JSON)

query error pq:cannot deconstruct a scalar
SELECT json_each_text('null'::JSON)

query TT
SELECT * from json_each_text('{}') q
----

query TT
SELECT * from json_each_text('{}') q
----

query TT colnames
SELECT * from json_each_text('{"f1":[1,2,3],"f2":{"f3":1},"f4":null,"f5":99,"f6":"stringy"}') q
----
key  value
f1   [1,2,3]
f2   {"f3":1}
f4   NULL
f5   99
f6   stringy

query T
SELECT json_set('{"a":1}','{a}'::STRING[],'2')
----
{"a":2}

query T
SELECT jsonb_set('{"a":1}','{b}'::STRING[],'2')
----
{"a":1,"b":2}

statement error path element at position 1 is null
SELECT jsonb_set('{"a":1}',ARRAY[null,'foo']::STRING[],'2')

statement error path element at position 1 is null
SELECT jsonb_set('{"a":1}','{null,foo}'::STRING[],'2',true)

statement error path element at position 2 is null
SELECT jsonb_set('{"a":1}','{foo,null}'::STRING[],'2',true)

query T
SELECT jsonb_set('{"a":1}','{b}'::STRING[],'2',true)
----
{"a":1,"b":2}

query T
SELECT jsonb_set('{"a":1}','{b}'::STRING[],'2',false)
----
{"a":1}

query T
SELECT jsonb_set('[{"f1":1,"f2":null},2,null,3]','{0,f1}'::STRING[],'[2,3,4]',false)
----
[{"f1":[2,3,4],"f2":null},2,null,3]

query T
SELECT jsonb_set('[{"f1":1,"f2":null},2]','{0,f3}'::STRING[],'[2,3,4]')
----
[{"f1":1,"f2":null,"f3":[2,3,4]},2]

query T
SELECT jsonb_insert('{"a":[0,1,2]}','{a,1}'::STRING[],'"new_value"');
----
{"a":[0,"new_value",1,2]}

query T
SELECT jsonb_insert('[0,1,2,{"a":["a","b","d"]},4]','{3,a,2}'::STRING[],'"c"')
----
[0,1,2,{"a":["a","b","c","d"]},4]

query T
SELECT jsonb_insert('{"a":"foo"}','{b}'::STRING[],'"bar"')
----
{"a":"foo","b":"bar"}

query T
SELECT jsonb_insert(NULL,'{a}',NULL,false)
----
NULL

query T
SELECT jsonb_insert('{"a":[0,1,2]}','{a,1}'::STRING[],'"new_value"',true)
----
{"a":[0,1,"new_value",2]}

query T
SELECT jsonb_insert('{"a":[0,1,2]}','{a,-1}'::STRING[],'"new_value"',true)
----
{"a":[0,1,2,"new_value"]}

query error pq:jsonb_insert\(\):cannot replace existing key
SELECT jsonb_insert('{"a":"foo"}','{a}'::STRING[],'"new_value"',false)

query T
SELECT jsonb_insert('{"a":"foo"}','{a,0}'::STRING[],'"new_value"',false)
----
{"a":"foo"}

query T
SELECT jsonb_insert('[0,1,2,3]','{3}'::STRING[],'10',true)
----
[0,1,2,3,10]

statement error cannot set path in scalar
SELECT jsonb_insert('1','{a}'::STRING[],'10',true)

query T
SELECT jsonb_insert('1',NULL,'10')
----
NULL

statement error path element at position 1 is null
SELECT jsonb_insert('{"a":[0,1,2],"b":"hello","c":"world"}','{NULL,a,0}'::STRING[],'"new_val"')

statement error path element at position 2 is null
SELECT jsonb_insert('{"a":[0,1,2],"b":"hello","c":"world"}','{a,NULL,0}'::STRING[],'"new_val"')

query T
SELECT jsonb_strip_nulls(NULL)
----
NULL

query T
SELECT json_strip_nulls('1')
----
1

query T
SELECT json_strip_nulls('"a string"')
----
"a string"

query T
SELECT json_strip_nulls('null')
----
null

query T
SELECT json_strip_nulls('[1,2,null,3,4]')
----
[1,2,null,3,4]

query T
SELECT json_strip_nulls('{"a":1,"b":null,"c":[2,null,3],"d":{"e":4,"f":null}}')
----
{"a":1,"c":[2,null,3],"d":{"e":4}}

query T
SELECT json_strip_nulls('[1,{"a":1,"b":null,"c":2},3]')
----
[1,{"a":1,"c":2},3]

query T
SELECT jsonb_strip_nulls('{"a":{"b":null,"c":null},"d":{}}')
----
{"a":{},"d":{}}

query T
SELECT jsonb_strip_nulls(NULL)
----
NULL

query T
SELECT jsonb_strip_nulls('1')
----
1

query T
SELECT jsonb_strip_nulls('"a string"')
----
"a string"

query T
SELECT jsonb_strip_nulls('null')
----
null

query T
SELECT jsonb_strip_nulls('[1,2,null,3,4]')
----
[1,2,null,3,4]

query T
SELECT jsonb_strip_nulls('{"a":1,"b":null,"c":[2,null,3],"d":{"e":4,"f":null}}')
----
{"a":1,"c":[2,null,3],"d":{"e":4}}

query T
SELECT jsonb_strip_nulls('[1,{"a":1,"b":null,"c":2},3]')
----
[1,{"a":1,"c":2},3]

query T
SELECT jsonb_strip_nulls('{"a":{"b":null,"c":null},"d":{}}')
----
{"a":{},"d":{}}

query error pq:json_array_length\(\):cannot get array length of a non-array
SELECT json_array_length('{"f1":1,"f2":[5,6]}')

query error pq:json_array_length\(\):cannot get array length of a scalar
SELECT json_array_length('4')

query I
SELECT json_array_length('[1,2,3,{"f1":1,"f2":[5,6]},4]')
----
5

query I
SELECT json_array_length('[]')
----
0

query error pq:jsonb_array_length\(\):cannot get array length of a non-array
SELECT jsonb_array_length('{"f1":1,"f2":[5,6]}')

query error pq:jsonb_array_length\(\):cannot get array length of a scalar
SELECT jsonb_array_length('4')

query I
SELECT jsonb_array_length('[1,2,3,{"f1":1,"f2":[5,6]},4]')
----
5

query I
SELECT jsonb_array_length('[]')
----
0