Re: json_strip_nulls()

Erwin Brandstetter <brsaweda(at)gmail(dot)com> writes:
> On Sat, 22 Jan 2022 at 20:31, David G. Johnston <david(dot)g(dot)johnston(at)gmail(dot)com>
> wrote:
>> json_strip_nulls doesn't make any promise regarding its output json other
>> than that it is valid. Since we are munging the json we are arguably
>> within our rights to output whatever transformed version we want. The
>> format should not be documented.

> Within our rights, maybe. The manual makes related promises[1]:
>> Because the json type stores an exact copy of the input text, it will
>> preserve semantically-insignificant white space between tokens
> And[2]:
>> As previously stated, when a JSON value is input and then printed without
>> any additional processing, json outputs the same text that was input,

"Without any additional processing" is the key restriction there.

> Not strictly contradicting, but the current behavior of json_strip_nulls()
> is still surprising. Either the input should be preserved as far as
> possible or, failing that, the actual behavior documented.

It is documented --- you just quoted the text that does so.

I don't have a lot of sympathy for "JSON-reading" code that fails to
conform to the JSON RFC, so I'm disinclined to work harder than that.

regards, tom lane