PSR12.Files.ImportStatement.LeadingSlash sometimes have to insert a space to avoid broken code

[umherirrender]

If you have the following code:

use\Import\SomeClass;
use const\Import\SomeConst;
use function\Import\SomeFunction;

PSR12.Files.ImportStatement.LeadingSlash would remove the slash and the new code is broken. In this case the sniff have to insert a space instead to keep the php file valid.

The class import may not broken when also have PSR2.Namespaces.UseDeclaration.SpaceAfterUse in use, but the const and function gets broken (see #2960 for an improvment of that sniff)

[jrfnl]

Just a heads-up: as an alternative you can use the PHPCSExtra Universal.UseStatements.NoLeadingBackslash sniff which doesn't have this issue.

[rodrigoprimo]

In PHPCS 3.x, the code sample above triggered the PSR12.Files.ImportStatement.LeadingSlash error and PHPCBF would incorrectly remove the slash, producing broken code. Since PHPCS 4.0, the code sample no longer triggers any errors/warnings. As far as I can see, this is the correct behavior, and it is due to changes in how PHPCS tokenizes namespace names.

In the code sample, const and function are not recognized by PHP (and PHPCS) as keywords. Instead, they are treated as namespace segments (see https://3v4l.org/3oAhJ). Therefore, the names after use are qualified names starting with const or function, not fully qualified names starting with a backslash, and should not trigger the PSR12.Files.ImportStatement.LeadingSlash sniff.

I suggest closing this issue.

[jrfnl]

As far as I can see, it is due to changes in how PHPCS tokenizes namespace names.

@rodrigoprimo Not really. The code is interpreted differently by PHP itself due to changes made in PHP 8.0 and would already be broken when running on PHP >= 8.0.

PHPCS 4.0 just means this now becomes visible in the sniff results too.

Either way, I agree with your conclusion that there is nothing actionable here.

It is impossible for PHPCS to distinguish between an intentional (PHP 8.0+) use const\Import\SomeConst; and an accidental use const\Import\SomeConst;, which should have been use const Import\SomeConst;. With that in mind, I agree that this issue should be closed.