Issue with PHP substr() and empty strings

Question

Issue with PHP substr() and empty strings

djmattyg007 opened this issue 5 years ago · comments

Description

PHP's implementation of substr() returns an empty string under the following conditions, not false:

substr("", 0);
substr("", 0, 0);

Locutus's implementation of substr() returns false for these arguments.

Matthew Gamble · Answer 1 · Sat Jan 18 2020 14:53:08 GMT+0800 (China Standard Time)

Actually it looks like PHP's implementation of substr() returns an empty string if the first two arguments are "", and 0, regardless of what the third argument is.

Matthew Gamble · Answer 2 · Sat Jan 18 2020 18:15:34 GMT+0800 (China Standard Time)

Further investigation: it will return false if the third argument is less than zero. It will only return an empty string if the third argument is greater than or equal to zero.

Rafał Kukawski · Answer 3 · Sun Jan 19 2020 06:31:15 GMT+0800 (China Standard Time)

I'll work on this, unless you (@djmattyg007) are interested in preparing a pull request?
I will check the PHP function's source code.

Matthew Gamble · Answer 4 · Sun Jan 19 2020 16:29:36 GMT+0800 (China Standard Time)

I don't have time sorry. Feel free to go ahead yourself.

Rafał Kukawski · Answer 5 · Thu Mar 19 2020 23:22:55 GMT+0800 (China Standard Time)

I've pushed a tiny patch that fixes just the reported scenario, but there are more nuances in PHP that potentially need to be covered, which I'll do in separate patches.