Psalter --issues=UnusedVariable tries to fix PossiblyUndefinedVariable

[edsrzf]

If I start with this code: (psalm.dev link)

<?php

function foo(bool $b): void {
    if ($b) {
        $v = 'hi';
    }

    if ($b) {
        echo $v;
    }
}

it correctly flags $v as possibly undefined. If I run psalter --issues=UnusedVariable, it alters the file to:

<?php

function foo(bool $b): void {
    if ($b) {
    }

    if ($b) {
        echo $v;
    }
}

This is pretty unexpected, as:

1. It's altered the code incorrectly. Now the variable is definitely undefined!
2. It's tried to fix a PossiblyUndefinedVariable issue, when I only told it to fix UnusedVariable issues.

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/7dad7e88bc

<?php

function foo(bool $b): void {
    if ($b) {
        $v = 'hi';
    }

    if ($b) {
        echo $v;
    }
}

Psalm output (using commit 28db105):

INFO: PossiblyUndefinedVariable - 9:14 - Possibly undefined variable $v, first seen on line 5

INFO: MixedArgument - 9:14 - Argument 1 of echo cannot be mixed, expecting string

[orklah]

What I can say with certitude is that removing this condition:

psalm/src/Psalm/Internal/Analyzer/StatementsAnalyzer.php

Line 918 in fcf4284

if ($codebase->alter_code

stops Psalter from fixing the issue, so it's made here. However, this block only triggers on UnusedVariable.

I tried to find what's going on exactly but I couldn't.

What I could see is that Psalm will only try to emit the UnusedVariable when in Psalter mode. That means there's something wrongly triggering this issue and then Psalter tries to fix it on the go