Error Identifier: empty.variable
Every error reported by PHPStan has an error identifier. Here’s a list of all error identifiers. In PHPStan Pro you can see the error identifier next to each error and filter errors by their identifiers.
Code example #
<?php declare(strict_types = 1);
function doFoo(): void
{
empty($undefined);
}
Why is it reported? #
The variable used inside empty() is never defined in the current scope. The empty() language construct is intended to check whether a variable exists and has a non-empty value. When used on a variable that is never defined, the result is always true (because undefined variables are treated as empty). This usually indicates a logic error, such as a typo in the variable name or a missing assignment.
How to fix it #
Define the variable before using it with empty(), or fix the variable name if it is a typo:
<?php declare(strict_types = 1);
function doFoo(): void
{
- empty($undefined);
+ $value = getValue();
+ if (empty($value)) {
+ // handle empty case
+ }
}
If the intent is to check whether an optional variable has been set, use isset() instead with proper variable initialization:
<?php declare(strict_types = 1);
-function doFoo(): void
+function doFoo(?string $value = null): void
{
- empty($undefined);
+ if ($value === null || $value === '') {
+ // handle missing/empty case
+ }
}
How to ignore this error #
You can use the identifier empty.variable to ignore this error using a comment:
// @phpstan-ignore empty.variable
codeThatProducesTheError();You can also use only the identifier key to ignore all errors of the same type in your configuration file in the ignoreErrors parameter:
parameters:
ignoreErrors:
-
identifier: empty.variable