[RFC] str_icontains

On Tue, Jun 24, 2025 at 1:56 AM youkidearitai youkidearitai@gmail.com
wrote:

2025年6月24日(火) 9:00 Larry Garfield larry@garfieldtech.com:

Hello internals,

I'd like to present my first RFC - str_icontains, a case-insensitive
friend of str_contains

RFC: https://wiki.php.net/rfc/str_icontains
PR (including tests): https://github.com/php/php-src/pull/18705

Previous discussion: https://externals.io/message/127504

Thanks,
Adam

When str_contains() was added, a case-insensitive version was
deliberately omitted in favor of "just use strtolower() yourself." Have
you gone back to see the arguments for that to determine if they're still
relevant?

(I don't recall the details; I think one of them was function count
explosion, but I think there were more.)

--Larry Garfield

Hi
I have concerns from multibyte(Unicode) user.

As someone who relies on Unicode, I feel that it is not worth using
that function.
str_contains can matches binary, so this is benefit of many reason,
but str_icontains is only support ASCII.
This only benefits some regions.

Regards
Yuya

--

Yuya Hamada (tekimen)

• https://tekitoh-memdhoi.info
• https://github.com/youkidearitai

---

Hi Yuya,

Thanks for your message.
I totally appreciate the multibyte issue here. I've detailed about it in
the RFC.
This function is there just to help those that expect it to be available as
parity to strpos, strstr that have ASCII case-folding case-insensitive
versions available.

Thanks,
Adam

Hello internals,

I'd like to present my first RFC - str_icontains, a case-insensitive
friend of str_contains

RFC: https://wiki.php.net/rfc/str_icontains
PR (including tests): https://github.com/php/php-src/pull/18705

Previous discussion: https://externals.io/message/127504

Thanks,
Adam

When str_contains() was added, a case-insensitive version was deliberately omitted in favor of "just use strtolower() yourself." Have you gone back to see the arguments for that to determine if they're still relevant?

(I don't recall the details; I think one of them was function count explosion, but I think there were more.)

--Larry Garfield

Thanks Larry.

Yes, I did spend time reading through the past discussions on both
str_contains and the str_starts/end_with functions.
I think initial RFCs failed because (a) people felt that the functions
didn't necessarily bring a whole heap of functionality above userland
code and (b) the debate about whether case-insensitive versions should
be included.

Now that these functions exist, it seems weird as a PHP user that
case-insensitive versions aren't available to easily switch between.
Obviously we have the UTF-8 question that I've detailed, but I'm hoping
adding this will solve a tiny issue where people expect this function
to exist, but it doesn't.

Adam

A discussion of that, and why you think the new position outweighs the original decision, should be included in the RFC.

(At the moment I'm undecided; yeah it's an easy enough utility to add, but the UTF-8 issue is real, and one could easily argue that it's stripos() that's wrong, because it's misleading as it only works on ASCII.)

The ideal answer would be Derick's built-in String object RFC, which I don't think has been touched in a while, sadly...

--Larry Garfield