Re: [PATCH v5 1/7] string: Add strprefix(), and deprecate str_has_prefix()

[Andy Shevchenko <andriy.shevchenko@intel.com>]

On Fri, Nov 13, 2026 at 04:33:37PM +0200, Andy Shevchenko wrote:
> On Fri, Nov 13, 2026 at 02:10:29PM +0100, Alejandro Colomar wrote:
> > As Bartosz reported, str_has_prefix() has a bug: it can't differentiate
> > between an empty prefix matching an empty string from a non-matching
> > prefix.  This is a fundamental design flaw in this API, and not
> > something that can be fixed.
> > 
> > As always, this is a consequence of choosing sizes instead of pointers.
> > Sizes are often the wrong choice.  In this specific case, pointers are
> > more capable of differentiating these cases, as NULL is a special
> > sentinel value that doesn't need to overload a valid value.
> > 
> > Let's implement strprefix(), a function that returns a pointer
> > right after the prefix if found, and a null pointer if not found.
> > 
> > We'll slowly migrate existing code from str_has_prefix() to strprefix().
> > 
> > Move the description from str_has_prefix(), and describe
> > str_has_prefix() by comparing it to strprefix().
> > 
> > Reported-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
> > Link: https://lore.kernel.org/linux-hardening/20261104-fwnode-for-each-prop-v1-1-6e28fe1c72c4@oss.qualcomm.com/

> It's unreferred Link tag, spurious? Please, refer to it in the commit message
> to understand why it's here. Use Link: $URL [1] and use [1] in the text.

Ah, perhaps you wanted Closes tag instead?

-- 
With Best Regards,
Andy Shevchenko