Thanks for reviewing. I'm glad you like the new approach of introducing "transform_partial". I've attached v22, which addresses some of your feedback, and I ran pgindent again.
The new approach of introducing “transform_partial” looks like a better solution, which leads to less code change to hstore_subs and arraysubs. However, when I tested the v21, I encountered errors when combine composite type, array and jsonb together.
Prepare test data:
```
drop table if exists people;
drop type if exists person;
CREATE TYPE person AS (
name text,
size int[],
meta jsonb[]
);
CREATE TABLE people (
p person
);
INSERT INTO people VALUES (ROW('Alice', array[10, 20], array['{"a": 30}'::jsonb, '{"a": 40}'::jsonb]));
```
Then run the test:
```
# old jsonb accessor works to extract a jsonb field from an array item of a composite field
evantest=# select (p).meta[1]->'a' from people;
?column?
----------
30
(1 row)
# dot notation also works
evantest=# select (p).meta[1].a from people;
a
----
30
(1 row)
# but index accessor doesn’t work
evantest=# select (p).meta[1]['a'] from people;
ERROR: invalid input syntax for type integer: "a"
LINE 1: select (p).meta[1]['a'] from people;
^
This is the expected behavior for array subscripting, and my patch doesn't change that. I don't think this is a problem. With or without my patch, you can avoid the ERROR by adding parentheses:
test=# select ((p).meta[1])['a'] from people;meta------30(1 row)
+/* This should not happen with well-behaved transform functions */
+elog(ERROR, "subscripting transform function failed to consume any indirection elements”);
```
I don’t see an existing error message uses “indirection” and “transform”. This error message looks more like a log message rather than a message to show to end users.
This is a defensive elog message that should not happen. So it is a log message for developers. That said, I'm open to suggestions for better wording.
The rest of your feedback I've made changes accordingly as you suggested.
