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To: Nikita Popov <nikita.ppv@gmail.com>, PHP internals
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Thread-Topic: [PHP-DEV] Make sorting stable
Thread-Index: AQHV8kPunyeuXKV5iEqDcKcWxF+rfqg4riJC
Date: Wed, 4 Mar 2020 17:30:01 +0000
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Subject: Re: [PHP-DEV] Make sorting stable
From: tysonandre775@hotmail.com (tyson andre)

> What do people think about this? Is there interest in making sorting=0A=
> stable? Is it okay to break code using illegal comparison callbacks?=0A=
=0A=
I'd be interested in having a stable sort.=0A=
When migrating from php 5.6 to 7 a long time ago,=0A=
the fact that sorting was no longer stable was an inconvenience for reasoni=
ng about code=0A=
(such as sorting a list of elements to render),=0A=
and making it stable again would be a benefit for people reading php code=
=0A=
(e.g. JS implementations now guarantee it - https://v8.dev/features/stable-=
sort).=0A=
I used the same type of userland fallback you discussed.=0A=
=0A=
For illegal comparison callbacks, it would be useful to emit a notice such =
as the following:=0A=
(Not sure if the following would be accurate for all edge cases)=0A=
=0A=
"E_DEPRECATED: The callback for sort() should return an integer, but return=
ed a boolean.=0A=
To guarantee a correct sort, implementations should return negative numbers=
=0A=
if an element is less than another element.=0A=
To preserve the incorrect sorting behavior, cast the returned result to an =
integer."=0A=
=0A=
(and check if the error handler threw a Throwable)=0A=
=0A=
- Tyson=