Regression: Docblock-defined type 0|int<1, 16> for $length is never int(1)

[kamil-tekiela]

In the following example Docblock-defined type 0|int<1, 16> for $length is never int(1) the length can be between 0 and 15 which makes 1 a valid possibility. Psalm started to complain about it in the recent version.

Docblock-defined type 0|int<1, 16> for $length is never int(1)

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/b9df4ac358

<?php

/** @var string $secret */
$length = strlen($secret);
if ($length > 16) {
    return substr($secret, 0, 16);
}

$length == 1 ? $secret : substr($secret, 0, -1);

Psalm output (using commit aa7e400):

ERROR: DocblockTypeContradiction - 9:1 - Docblock-defined type 0|int<1, 16> for $length is never int(1)

ERROR: RedundantConditionGivenDocblockType - 9:26 - Docblock-defined type 0|int<1, 16> for $length is never int(1)

ERROR: UnusedFunctionCall - 9:26 - The call to substr is not used

[orklah]

I fixed only one side of the issue in #7224. The other side is technically a duplicate of #6871 but this is very not obvious so I'll keep that one open too.

As I said there: the other side, while easily fixed causes other false positives that I just don't know how to fix yet.

[orklah]

This has been fixed in master branch and will be released in Psalm 5