mirror of
https://github.com/danog/psalm.git
synced 2024-12-12 09:19:40 +01:00
559 lines
15 KiB
Markdown
559 lines
15 KiB
Markdown
# Supported docblock annotations
|
||
|
||
Psalm supports a wide range of docblock annotations.
|
||
|
||
## PHPDoc tags
|
||
|
||
Psalm uses the following PHPDoc tags to understand your code:
|
||
|
||
- [`@var`](https://docs.phpdoc.org/latest/guide/references/phpdoc/tags/var.html)
|
||
Used for specifying the types of properties and variables@
|
||
- [`@return`](https://docs.phpdoc.org/latest/guide/references/phpdoc/tags/return.html)
|
||
Used for specifying the return types of functions, methods and closures
|
||
- [`@param`](https://docs.phpdoc.org/latest/guide/references/phpdoc/tags/param.html)
|
||
Used for specifying types of parameters passed to functions, methods and closures
|
||
- [`@property`](https://docs.phpdoc.org/latest/guide/references/phpdoc/tags/property.html)
|
||
Used to specify what properties can be accessed on an object that uses `__get` and `__set`
|
||
- [`@property-read`](https://docs.phpdoc.org/latest/guide/references/phpdoc/tags/property-read.html)
|
||
Used to specify what properties can be read on object that uses `__get`
|
||
- [`@property-write`](https://docs.phpdoc.org/latest/guide/references/phpdoc/tags/property-write.html)
|
||
Used to specify what properties can be written on object that uses `__set`
|
||
- [`@method`](https://docs.phpdoc.org/latest/guide/references/phpdoc/tags/method.html)
|
||
Used to specify which magic methods are available on object that uses `__call`.
|
||
- [`@deprecated`](https://docs.phpdoc.org/latest/guide/references/phpdoc/tags/deprecated.html)
|
||
Used to mark functions, methods, classes and interfaces as being deprecated
|
||
- [`@internal`](https://docs.phpdoc.org/latest/guide/references/phpdoc/tags/internal.html)
|
||
used to mark classes, functions and properties that are internal to an application or library.
|
||
|
||
### Off-label usage of the `@var` tag
|
||
|
||
The `@var` tag is supposed to only be used for properties. Psalm, taking a lead from PHPStorm and other static analysis tools, allows its use inline in the form `@var Type [VariableReference]`.
|
||
|
||
If `VariableReference` is provided, it should be of the form `$variable` or `$variable->property`. If used above an assignment, Psalm checks whether the `VariableReference` matches the variable being assigned. If they differ, Psalm will assign the `Type` to `VariableReference` and use it in the expression below.
|
||
|
||
If no `VariableReference` is given, the annotation tells Psalm that the right hand side of the expression, whether an assignment or a return, is of type `Type`.
|
||
|
||
```php
|
||
<?php
|
||
/** @var string */
|
||
$a = $_GET['foo'];
|
||
|
||
/** @var string $b */
|
||
$b = $_GET['bar'];
|
||
|
||
function bat(): string {
|
||
/** @var string */
|
||
return $_GET['bat'];
|
||
}
|
||
```
|
||
|
||
## Psalm-specific tags
|
||
|
||
There are a number of custom tags that determine how Psalm treats your code.
|
||
|
||
### `@psalm-consistent-constructor`
|
||
|
||
See [UnsafeInstantiation](../running_psalm/issues/UnsafeInstantiation.md)
|
||
|
||
### `@psalm-consistent-templates`
|
||
|
||
See [UnsafeGenericInstantiation](../running_psalm/issues/UnsafeGenericInstantiation.md)
|
||
|
||
### `@param-out`, `@psalm-param-out`
|
||
|
||
This is used to specify that a by-ref type is different from the one that entered. In the function below the first param can be null, but once the function has executed the by-ref value is not null.
|
||
|
||
```php
|
||
<?php
|
||
/**
|
||
* @param-out string $s
|
||
*/
|
||
function addFoo(?string &$s) : void {
|
||
if ($s === null) {
|
||
$s = "hello";
|
||
}
|
||
$s .= "foo";
|
||
}
|
||
```
|
||
|
||
### `@psalm-var`, `@psalm-param`, `@psalm-return`, `@psalm-property`, `@psalm-property-read`, `@psalm-property-write`, `@psalm-method`
|
||
|
||
When specifying types in a format not supported by phpDocumentor ([but supported by Psalm](#type-syntax)) you may wish to prepend `@psalm-` to the PHPDoc tag, so as to avoid confusing your IDE. If a `@psalm`-prefixed tag is given, Psalm will use it in place of its non-prefixed counterpart.
|
||
|
||
### `@psalm-ignore-var`
|
||
|
||
This annotation is used to ignore the `@var` annotation written in the same docblock. Some IDEs don't fully understand complex types like generics. To take advantage of such IDE's auto-completion, you may sometimes want to use explicit `@var` annotations even when psalm can infer the type just fine. This weakens the effectiveness of type checking in many cases since the explicit `@var` annotation overrides the types inferred by psalm. As psalm ignores the `@var` annotation which is co-located with `@psalm-ignore-var`, IDEs can use the type specified by the `@var` for auto-completion, while psalm can still use its own inferred type for type checking.
|
||
|
||
```php
|
||
<?php
|
||
/** @return iterable<array-key,\DateTime> $f */
|
||
function getTimes(int $n): iterable {
|
||
while ($n--) {
|
||
yield new \DateTime();
|
||
}
|
||
};
|
||
/**
|
||
* @var \Datetime[] $times
|
||
* @psalm-ignore-var
|
||
*/
|
||
$times = getTimes(3);
|
||
// this trace shows "iterable<array-key, DateTime>" instead of "array<array-key, Datetime>"
|
||
/** @psalm-trace $times */
|
||
foreach ($times as $time) {
|
||
echo $time->format('Y-m-d H:i:s.u') . PHP_EOL;
|
||
}
|
||
```
|
||
|
||
### `@psalm-suppress SomeIssueName`
|
||
|
||
This annotation is used to suppress issues. It can be used in function docblocks, class docblocks and also inline, applying to the following statement.
|
||
|
||
Function docblock example:
|
||
|
||
```php
|
||
<?php
|
||
/**
|
||
* @psalm-suppress PossiblyNullOperand
|
||
*/
|
||
function addString(?string $s) {
|
||
echo "hello " . $s;
|
||
}
|
||
```
|
||
|
||
Inline example:
|
||
|
||
```php
|
||
<?php
|
||
function addString(?string $s) {
|
||
/** @psalm-suppress PossiblyNullOperand */
|
||
echo "hello " . $s;
|
||
}
|
||
```
|
||
|
||
`@psalm-suppress all` can be used to suppress all issues instead of listing them individually.
|
||
|
||
### `@psalm-assert`, `@psalm-assert-if-true` and `@psalm-assert-if-false`
|
||
|
||
See [Adding assertions](adding_assertions.md).
|
||
|
||
### `@psalm-ignore-nullable-return`
|
||
|
||
This can be used to tell Psalm not to worry if a function/method returns null. It’s a bit of a hack, but occasionally useful for scenarios where you either have a very high confidence of a non-null value, or some other function guarantees a non-null value for that particular code path.
|
||
|
||
```php
|
||
<?php
|
||
class Foo {}
|
||
function takesFoo(Foo $f): void {}
|
||
|
||
/** @psalm-ignore-nullable-return */
|
||
function getFoo(): ?Foo {
|
||
return rand(0, 10000) > 1 ? new Foo() : null;
|
||
}
|
||
|
||
takesFoo(getFoo());
|
||
```
|
||
|
||
### `@psalm-ignore-falsable-return`
|
||
|
||
This provides the same, but for `false`. Psalm uses this internally for functions like `preg_replace`, which can return false if the given input has encoding errors, but where 99.9% of the time the function operates as expected.
|
||
|
||
### `@psalm-seal-properties`
|
||
|
||
If you have a magic property getter/setter, you can use `@psalm-seal-properties` to instruct Psalm to disallow getting and setting any properties not contained in a list of `@property` (or `@property-read`/`@property-write`) annotations.
|
||
|
||
```php
|
||
<?php
|
||
/**
|
||
* @property string $foo
|
||
* @psalm-seal-properties
|
||
*/
|
||
class A {
|
||
public function __get(string $name): ?string {
|
||
if ($name === "foo") {
|
||
return "hello";
|
||
}
|
||
}
|
||
|
||
public function __set(string $name, $value): void {}
|
||
}
|
||
|
||
$a = new A();
|
||
$a->bar = 5; // this call fails
|
||
```
|
||
|
||
### `@psalm-internal`
|
||
|
||
Used to mark a class, property or function as internal to a given namespace. Psalm treats this slightly differently to
|
||
the PHPDoc `@internal` tag. For `@internal`, an issue is raised if the calling code is in a namespace completely
|
||
unrelated to the namespace of the calling code, i.e. not sharing the first element of the namespace.
|
||
|
||
In contrast for `@psalm-internal`, the docbloc line must specify a namespace. An issue is raised if the calling code
|
||
is not within the given namespace.
|
||
|
||
```php
|
||
<?php
|
||
namespace A\B {
|
||
/**
|
||
* @internal
|
||
* @psalm-internal A\B
|
||
*/
|
||
class Foo { }
|
||
}
|
||
|
||
namespace A\B\C {
|
||
class Bat {
|
||
public function batBat(): void {
|
||
$a = new \A\B\Foo(); // this is fine
|
||
}
|
||
}
|
||
}
|
||
|
||
namespace A\C {
|
||
class Bat {
|
||
public function batBat(): void {
|
||
$a = new \A\B\Foo(); // error
|
||
}
|
||
}
|
||
}
|
||
```
|
||
|
||
### `@psalm-readonly` and `@readonly`
|
||
|
||
Used to annotate a property that can only be written to in its defining class's constructor.
|
||
|
||
```php
|
||
<?php
|
||
class B {
|
||
/** @readonly */
|
||
public string $s;
|
||
|
||
public function __construct(string $s) {
|
||
$this->s = $s;
|
||
}
|
||
}
|
||
|
||
$b = new B("hello");
|
||
echo $b->s;
|
||
$b->s = "boo"; // disallowed
|
||
```
|
||
|
||
### `@psalm-mutation-free`
|
||
|
||
Used to annotate a class method that does not mutate state, either internally or externally of the class's scope.
|
||
|
||
```php
|
||
<?php
|
||
class D {
|
||
private string $s;
|
||
|
||
public function __construct(string $s) {
|
||
$this->s = $s;
|
||
}
|
||
|
||
/**
|
||
* @psalm-mutation-free
|
||
*/
|
||
public function getShort() : string {
|
||
return substr($this->s, 0, 5);
|
||
}
|
||
|
||
/**
|
||
* @psalm-mutation-free
|
||
*/
|
||
public function getShortMutating() : string {
|
||
$this->s .= "hello"; // this is a bug
|
||
return substr($this->s, 0, 5);
|
||
}
|
||
}
|
||
```
|
||
|
||
### `@psalm-external-mutation-free`
|
||
|
||
Used to annotate a class method that does not mutate state externally of the class's scope.
|
||
|
||
```php
|
||
<?php
|
||
class E {
|
||
private string $s;
|
||
|
||
public function __construct(string $s) {
|
||
$this->s = $s;
|
||
}
|
||
|
||
/**
|
||
* @psalm-external-mutation-free
|
||
*/
|
||
public function getShortMutating() : string {
|
||
$this->s .= "hello"; // this is fine
|
||
return substr($this->s, 0, 5);
|
||
}
|
||
|
||
/**
|
||
* @psalm-external-mutation-free
|
||
*/
|
||
public function save() : void {
|
||
file_put_contents("foo.txt", $this->s); // this is a bug
|
||
}
|
||
}
|
||
```
|
||
|
||
### `@psalm-immutable`
|
||
|
||
Used to annotate a class where every property is treated by consumers as `@psalm-readonly` and every instance method is treated as `@psalm-mutation-free`.
|
||
|
||
```php
|
||
<?php
|
||
/**
|
||
* @psalm-immutable
|
||
*/
|
||
abstract class Foo
|
||
{
|
||
public string $baz;
|
||
|
||
abstract public function bar(): int;
|
||
}
|
||
|
||
/**
|
||
* @psalm-immutable
|
||
*/
|
||
final class ChildClass extends Foo
|
||
{
|
||
public function __construct(string $baz)
|
||
{
|
||
$this->baz = $baz;
|
||
}
|
||
|
||
public function bar(): int
|
||
{
|
||
return 0;
|
||
}
|
||
}
|
||
|
||
$anonymous = new /** @psalm-immutable */ class extends Foo
|
||
{
|
||
public string $baz = "B";
|
||
|
||
public function bar(): int
|
||
{
|
||
return 1;
|
||
}
|
||
};
|
||
```
|
||
|
||
### `@psalm-pure`
|
||
|
||
Used to annotate a [pure function](https://en.wikipedia.org/wiki/Pure_function) - one whose output is just a function of its input.
|
||
|
||
```php
|
||
<?php
|
||
class Arithmetic {
|
||
/** @psalm-pure */
|
||
public static function add(int $left, int $right) : int {
|
||
return $left + $right;
|
||
}
|
||
|
||
/** @psalm-pure - this is wrong */
|
||
public static function addCumulative(int $left) : int {
|
||
/** @var int */
|
||
static $i = 0; // this is a side effect, and thus a bug
|
||
$i += $left;
|
||
return $i;
|
||
}
|
||
}
|
||
|
||
echo Arithmetic::add(40, 2);
|
||
echo Arithmetic::add(40, 2); // same value is emitted
|
||
|
||
echo Arithmetic::addCumulative(3); // outputs 3
|
||
echo Arithmetic::addCumulative(3); // outputs 6
|
||
```
|
||
|
||
On the other hand, `pure-callable` can be used to denote a callable which needs to be pure.
|
||
|
||
```php
|
||
/**
|
||
* @param pure-callable(mixed): int $callback
|
||
*/
|
||
function foo(callable $callback) {...}
|
||
|
||
// this fails since random_int is not pure
|
||
foo(
|
||
/** @param mixed $p */
|
||
fn($p) => random_int(1, 2)
|
||
);
|
||
```
|
||
|
||
### `@psalm-allow-private-mutation`
|
||
|
||
Used to annotate readonly properties that can be mutated in a private context. With this, public properties can be read from another class but only be mutated within a method of its own class.
|
||
|
||
```php
|
||
<?php
|
||
class Counter {
|
||
/**
|
||
* @readonly
|
||
* @psalm-allow-private-mutation
|
||
*/
|
||
public int $count = 0;
|
||
|
||
public function increment() : void {
|
||
$this->count++;
|
||
}
|
||
}
|
||
|
||
$counter = new Counter();
|
||
echo $counter->count; // outputs 0
|
||
$counter->increment(); // Method can mutate property
|
||
echo $counter->count; // outputs 1
|
||
$counter->count = 5; // This will fail, as it's mutating a property directly
|
||
```
|
||
|
||
### `@psalm-readonly-allow-private-mutation`
|
||
|
||
This is a shorthand for the property annotations `@readonly` and `@psalm-allow-private-mutation`.
|
||
|
||
```php
|
||
<?php
|
||
class Counter {
|
||
/**
|
||
* @psalm-readonly-allow-private-mutation
|
||
*/
|
||
public int $count = 0;
|
||
|
||
public function increment() : void {
|
||
$this->count++;
|
||
}
|
||
}
|
||
|
||
$counter = new Counter();
|
||
echo $counter->count; // outputs 0
|
||
$counter->increment(); // Method can mutate property
|
||
echo $counter->count; // outputs 1
|
||
$counter->count = 5; // This will fail, as it's mutating a property directly
|
||
```
|
||
|
||
### `@psalm-trace`
|
||
|
||
You can use this annotation to trace inferred type (applied to the *next* statement).
|
||
|
||
```php
|
||
<?php
|
||
|
||
/** @psalm-trace $username */
|
||
$username = $_GET['username']; // prints something like "test.php:4 $username: mixed"
|
||
|
||
```
|
||
|
||
*Note*: it throws [special low-level issue](../running_psalm/issues/Trace.md), so you have to set errorLevel to 1, override it in config or invoke Psalm with `--show-info=true`.
|
||
|
||
### `@psalm-taint-*`
|
||
|
||
See [Security Analysis annotations](../security_analysis/annotations.md).
|
||
|
||
### `@psalm-type`
|
||
|
||
This allows you to define an alias for another type.
|
||
|
||
```php
|
||
<?php
|
||
/**
|
||
* @psalm-type PhoneType = array{phone: string}
|
||
*/
|
||
class Phone {
|
||
/**
|
||
* @psalm-return PhoneType
|
||
*/
|
||
public function toArray(): array {
|
||
return ["phone" => "Nokia"];
|
||
}
|
||
}
|
||
```
|
||
|
||
### `@psalm-import-type`
|
||
|
||
You can use this annotation to import a type defined with [`@psalm-type`](#psalm-type) if it was defined somewhere else.
|
||
|
||
```php
|
||
<?php
|
||
/**
|
||
* @psalm-import-type PhoneType from Phone
|
||
*/
|
||
class User {
|
||
/**
|
||
* @psalm-return PhoneType
|
||
*/
|
||
public function toArray(): array {
|
||
return array_merge([], (new Phone())->toArray());
|
||
}
|
||
}
|
||
```
|
||
|
||
You can also alias a type when you import it:
|
||
|
||
```php
|
||
<?php
|
||
/**
|
||
* @psalm-import-type PhoneType from Phone as MyPhoneTypeAlias
|
||
*/
|
||
class User {
|
||
/**
|
||
* @psalm-return MyPhoneTypeAlias
|
||
*/
|
||
public function toArray(): array {
|
||
return array_merge([], (new Phone())->toArray());
|
||
}
|
||
}
|
||
```
|
||
|
||
### `@psalm-require-extends`
|
||
|
||
The `@psalm-require-extends` annotation allows you to define a requirements that a trait imposes on the using class.
|
||
|
||
```php
|
||
<?php
|
||
abstract class DatabaseModel {
|
||
// methods, properties, etc.
|
||
}
|
||
|
||
/**
|
||
* @psalm-require-extends DatabaseModel
|
||
*/
|
||
trait SoftDeletingTrait {
|
||
// useful but scoped functionality, that depends on methods/properties from DatabaseModel
|
||
}
|
||
|
||
|
||
class MyModel extends DatabaseModel {
|
||
// valid
|
||
use SoftDeletingTrait;
|
||
}
|
||
|
||
class NormalClass {
|
||
// triggers an error
|
||
use SoftDeletingTrait;
|
||
}
|
||
```
|
||
|
||
### `@psalm-require-implements`
|
||
|
||
Behaves the same way as `@psalm-require-extends`, but for interfaces.
|
||
|
||
### `@no-named-arguments`
|
||
|
||
This will prevent access to the function or method tagged with named parameters (by emitting a `NamedArgumentNotAllowed` issue).
|
||
|
||
Incidentally, it will change the inferred type for the following code:
|
||
```php
|
||
<?php
|
||
function a(int ...$a){
|
||
var_dump($a);
|
||
}
|
||
```
|
||
The type of `$a` is `array<array-key, int>` without `@no-named-arguments` but becomes `list<int>` with it, because it exclude the case where the offset would be a string with the name of the parameter
|
||
|
||
## Type Syntax
|
||
|
||
Psalm supports PHPDoc’s [type syntax](https://docs.phpdoc.org/latest/guide/guides/types.html), and also the [proposed PHPDoc PSR type syntax](https://github.com/php-fig/fig-standards/blob/master/proposed/phpdoc.md#appendix-a-types).
|
||
|
||
A detailed write-up is found in [Typing in Psalm](typing_in_psalm.md)
|