`str_split()` / `mb_str_split()` length must be `positive-int`

str_split() / mb_str_split() length must be positive-int

Group: Native types · Category: language · File: native_types_str_split_length.php

The interesting call is str_split($s, -1): tools that model the stub reject a non-positive length. Return non-emptiness is not probed here — a array receiver would accept empty and non-empty alike. Source: vimeo/psalm#6324 (4.10.0). References: - psalm#6324

Analyzer results

Analyzer	Version	Result	Diagnostics
phan	6.0.11Phan 6.0.11 php-ast version 1.1.3 PHP version used to run Phan: 8.5.11	Pass	native_types_str_split_length.php:27: Argument #2 of this call to \str_split is typically a literal or constant but isn't, but argument #1 (which is typically a variable) is a literal or constant. The arguments may be in the wrong order. [PhanParamSuspiciousOrder]
phpstan	2.3.5PHPStan - PHP Static Analysis Tool 2.3.5	Pass reported Lv.4+	native_types_str_split_length.php:27: Parameter #2 $length of function str_split expects int<1, max>, -1 given. [reported-from-level=5] native_types_str_split_length.php:28: Parameter #2 $length of function str_split expects int<1, max>, 0 given. [reported-from-level=5] native_types_str_split_length.php:32: Call to function mb_str_split() on a separate line has no effect. [reported-from-level=4] native_types_str_split_length.php:32: Parameter #2 $length of function mb_str_split expects int<1, max>, -1 given. [reported-from-level=5] With strict-rules native_types_str_split_length.php:27: Parameter #2 $length of function str_split expects int<1, max>, -1 given. native_types_str_split_length.php:28: Parameter #2 $length of function str_split expects int<1, max>, 0 given. native_types_str_split_length.php:32: Call to function mb_str_split() on a separate line has no effect. native_types_str_split_length.php:32: Parameter #2 $length of function mb_str_split expects int<1, max>, -1 given.
psalm	6.20.9Psalm 6.20.9@f67170ac3c3b931f5088681e21d6c8babc601c08 next: 7.0.4	Pass	native_types_str_split_length.php:27: Argument 2 of str_split expects int<1, max>, but -1 provided [InvalidArgument] native_types_str_split_length.php:28: Argument 2 of str_split expects int<1, max>, but 0 provided [InvalidArgument] native_types_str_split_length.php:32: Argument 2 of mb_str_split expects int<1, max>, but -1 provided [InvalidArgument]
mago	1.59.0mago 1.59.0	Pass	native_types_str_split_length.php:27: Invalid argument type for argument #2 of `str_split`: expected `positive-int`, but found `int(-1)`. [invalid-argument] native_types_str_split_length.php:27: Expression has no effect as a statement [unused-statement] native_types_str_split_length.php:28: Invalid argument type for argument #2 of `str_split`: expected `positive-int`, but found `int(0)`. [invalid-argument] native_types_str_split_length.php:28: Expression has no effect as a statement [unused-statement] native_types_str_split_length.php:32: Expression has no effect as a statement [unused-statement]
mir	0.91.0mir 0.91.0	Fail	native_types_str_split_length.php:31: MixedArgument: Argument $value of takesString() is mixed [MIR1200] Expectation diff Line 31: Expected valid value to be accepted, got ["MixedArgument: Argument $value of takesString() is mixed [MIR1200]"]
phpantom	0.11.1phpantom_lsp 0.11.1	Pass	No diagnostics reported.
intelephense	1.18.5intelephense 1.18.5	Pass	No diagnostics reported.
phpactor	2026.10.07.0Phpactor 2026.10.07.0	Pass	No diagnostics reported.
phpy	1.0.19490phpy 1.0.19490	Pass	No diagnostics reported.
qodana	262.11879.104PhpStorm 262.11879.104	Pass	No diagnostics reported.
noverify	0.5.5NoVerify, version 0.5.5: built on: 2025.04.22 14:36:46 OS: r-kuchinskas arm64 Commit: 4774b82f8adc53fbef38f95e97af4b953b4d1529	Fail	native_types_str_split_length.php:25: potentially not safe array access in parameter value of function Conformance\Tests\NativeTypesStrSplitLength\takesString [notSafeCall] native_types_str_split_length.php:31: potentially not safe array access in parameter value of function Conformance\Tests\NativeTypesStrSplitLength\takesString [notSafeCall] Expectation diff Line 25: Expected valid value to be accepted, got ["potentially not safe array access in parameter value of function Conformance\\Tests\\NativeTypesStrSplitLength\\takesString [notSafeCall]"] Line 31: Expected valid value to be accepted, got ["potentially not safe array access in parameter value of function Conformance\\Tests\\NativeTypesStrSplitLength\\takesString [notSafeCall]"]
steins	0.1.8steins 0.1.8 (2026-09-21 revision 76306a9)	Pass	No diagnostics reported.
phpstan-strict	2.3.5PHPStan - PHP Static Analysis Tool 2.3.5	Pass	native_types_str_split_length.php:27: Parameter #2 $length of function str_split expects int<1, max>, -1 given. native_types_str_split_length.php:28: Parameter #2 $length of function str_split expects int<1, max>, 0 given. native_types_str_split_length.php:32: Call to function mb_str_split() on a separate line has no effect. native_types_str_split_length.php:32: Parameter #2 $length of function mb_str_split expects int<1, max>, -1 given.
psalm-next	7.0.4Psalm 7.0.4@fa5b1f6e665cb743838ffd865b8fc96207f9409f	Pass	native_types_str_split_length.php:27: Argument 2 of str_split expects int<1, max>, but -1 provided [InvalidArgument] native_types_str_split_length.php:28: Argument 2 of str_split expects int<1, max>, but 0 provided [InvalidArgument] native_types_str_split_length.php:32: Argument 2 of mb_str_split expects int<1, max>, but -1 provided [InvalidArgument]

Analyzer

Version

Result

Diagnostics

phan

Pass

native_types_str_split_length.php:27: Argument #2 of this call to \str_split is typically a literal or constant but isn't, but argument #1 (which is typically a variable) is a literal or constant. The arguments may be in the wrong order. [PhanParamSuspiciousOrder]

phpstan

Pass reported Lv.4+

native_types_str_split_length.php:27: Parameter #2 $length of function str_split expects int<1, max>, -1 given. [reported-from-level=5]
native_types_str_split_length.php:28: Parameter #2 $length of function str_split expects int<1, max>, 0 given. [reported-from-level=5]
native_types_str_split_length.php:32: Call to function mb_str_split() on a separate line has no effect. [reported-from-level=4]
native_types_str_split_length.php:32: Parameter #2 $length of function mb_str_split expects int<1, max>, -1 given. [reported-from-level=5]

With strict-rules

native_types_str_split_length.php:27: Parameter #2 $length of function str_split expects int<1, max>, -1 given.
native_types_str_split_length.php:28: Parameter #2 $length of function str_split expects int<1, max>, 0 given.
native_types_str_split_length.php:32: Call to function mb_str_split() on a separate line has no effect.
native_types_str_split_length.php:32: Parameter #2 $length of function mb_str_split expects int<1, max>, -1 given.

psalm

next: 7.0.4

Pass

native_types_str_split_length.php:27: Argument 2 of str_split expects int<1, max>, but -1 provided [InvalidArgument]
native_types_str_split_length.php:28: Argument 2 of str_split expects int<1, max>, but 0 provided [InvalidArgument]
native_types_str_split_length.php:32: Argument 2 of mb_str_split expects int<1, max>, but -1 provided [InvalidArgument]

mago

Pass

native_types_str_split_length.php:27: Invalid argument type for argument #2 of `str_split`: expected `positive-int`, but found `int(-1)`. [invalid-argument]
native_types_str_split_length.php:27: Expression has no effect as a statement [unused-statement]
native_types_str_split_length.php:28: Invalid argument type for argument #2 of `str_split`: expected `positive-int`, but found `int(0)`. [invalid-argument]
native_types_str_split_length.php:28: Expression has no effect as a statement [unused-statement]
native_types_str_split_length.php:32: Expression has no effect as a statement [unused-statement]

mir

Fail

native_types_str_split_length.php:31: MixedArgument: Argument $value of takesString() is mixed [MIR1200]

Expectation diff

Line 31: Expected valid value to be accepted, got ["MixedArgument: Argument $value of takesString() is mixed [MIR1200]"]

phpantom

Pass

No diagnostics reported.

intelephense

Pass

No diagnostics reported.

phpactor

Pass

No diagnostics reported.

phpy

Pass

No diagnostics reported.

qodana

Pass

No diagnostics reported.

noverify

Fail

native_types_str_split_length.php:25: potentially not safe array access in parameter value of function Conformance\Tests\NativeTypesStrSplitLength\takesString [notSafeCall]
native_types_str_split_length.php:31: potentially not safe array access in parameter value of function Conformance\Tests\NativeTypesStrSplitLength\takesString [notSafeCall]

Expectation diff

Line 25: Expected valid value to be accepted, got ["potentially not safe array access in parameter value of function Conformance\\Tests\\NativeTypesStrSplitLength\\takesString [notSafeCall]"]
Line 31: Expected valid value to be accepted, got ["potentially not safe array access in parameter value of function Conformance\\Tests\\NativeTypesStrSplitLength\\takesString [notSafeCall]"]

steins

Pass

No diagnostics reported.

phpstan-strict

Pass

native_types_str_split_length.php:27: Parameter #2 $length of function str_split expects int<1, max>, -1 given.
native_types_str_split_length.php:28: Parameter #2 $length of function str_split expects int<1, max>, 0 given.
native_types_str_split_length.php:32: Call to function mb_str_split() on a separate line has no effect.
native_types_str_split_length.php:32: Parameter #2 $length of function mb_str_split expects int<1, max>, -1 given.

psalm-next

Pass

native_types_str_split_length.php:27: Argument 2 of str_split expects int<1, max>, but -1 provided [InvalidArgument]
native_types_str_split_length.php:28: Argument 2 of str_split expects int<1, max>, but 0 provided [InvalidArgument]
native_types_str_split_length.php:32: Argument 2 of mb_str_split expects int<1, max>, but -1 provided [InvalidArgument]

Source

<?php declare(strict_types=1); namespace Conformance\Tests\NativeTypesStrSplitLength; /** * `str_split()` / `mb_str_split()` length must be `positive-int`. * * The interesting call is `str_split($s, -1)`: tools that model the stub * reject a non-positive length. Return non-emptiness is not probed here — * a `array` receiver would accept empty and non-empty alike. * * Source: vimeo/psalm#6324 (4.10.0). * * References: * - https://github.com/vimeo/psalm/pull/6324 */ function takesString(string $value): void { } $parts = str_split('hello', 2); takesString($parts[0]); // V str_split('hello', -1); // E?: length must be positive-int str_split('hello', 0); // E?: 0 is not a positive-int $mb = mb_str_split('hello', 2); takesString($mb[0]); // V mb_str_split('hello', -1); // E?: length must be positive-int

str_split() / mb_str_split() length must be positive-int

Analyzer results

Source

`str_split()` / `mb_str_split()` length must be `positive-int`