# Configuration
Psalm uses an XML config file (by default, `psalm.xml`). A barebones example looks like this:
```xml
```
Configuration file may be split into several files using [XInclude](https://www.w3.org/TR/xinclude/) tags (c.f. previous example):
#### psalm.xml
```xml
```
#### files.xml
```xml
```
## Optional <psalm /> attributes
### Coding style
#### errorLevel
```xml
```
This corresponds to Psalm‘s [error-detection level](error_levels.md).
#### reportMixedIssues
```xml
```
Setting this to `"false"` hides all issues with `Mixed` types in Psalm’s output. If not given, this defaults to `"false"` when `errorLevel` is 3 or higher, and `"true"` when the error level is 1 or 2.
#### totallyTyped
```xml
```
\(Deprecated\) Setting `totallyTyped` to `"true"` is equivalent to setting `errorLevel` to `"1"`. Setting `totallyTyped` to `"false"` is equivalent to setting `errorLevel` to `"2"` and `reportMixedIssues` to `"false"`
#### resolveFromConfigFile
```xml
```
If this is enabled, relative directories mentioned in the config file will be resolved relative to the location
of the config file. If it is disabled, or absent they will be resolved relative to the working directory of the Psalm process.
New versions of Psalm enable this option when generating config files. Older versions did not include it.
#### useDocblockTypes
```xml
```
Whether or not to use types as defined in docblocks. Defaults to `true`.
#### useDocblockPropertyTypes
```xml
```
If not using all docblock types, you can still use docblock property types. Defaults to `false` (though only relevant if `useDocblockTypes` is `false`).
#### usePhpDocMethodsWithoutMagicCall
```xml
```
The PHPDoc `@method` annotation normally only applies to classes with a `__call` method. Setting this to `true` allows you to use the `@method` annotation to override inherited method return types. Defaults to `false`.
#### usePhpDocPropertiesWithoutMagicCall
```xml
```
The PHPDoc `@property`, `@property-read` and `@property-write` annotations normally only apply to classes with `__get`/`__set` methods. Setting this to `true` allows you to use the `@property`, `@property-read` and `@property-write` annotations to override property existence checks and resulting property types. Defaults to `false`.
#### strictBinaryOperands
```xml
```
If true we force strict typing on numerical and string operations (see https://github.com/vimeo/psalm/issues/24). Defaults to `false`.
#### rememberPropertyAssignmentsAfterCall
```xml
```
Setting this to `false` means that any function calls will cause Psalm to forget anything it knew about object properties within the scope of the function it's currently analysing. This duplicates functionality that Hack has. Defaults to `true`.
#### allowStringToStandInForClass
```xml
```
When `true`, strings can be used as classes, meaning `$some_string::someMethod()` is allowed. If `false`, only class constant strings (of the form `Foo\Bar::class`) can stand in for classes, otherwise an `InvalidStringClass` issue is emitted. Defaults to `false`.
#### memoizeMethodCallResults
```xml
```
When `true`, the results of method calls without arguments passed are remembered between repeated calls of that method on a given object. Defaults to `false`.
#### hoistConstants
```xml
```
When `true`, constants defined in a function in a file are assumed to be available when requiring that file, and not just when calling that function. Defaults to `false` (i.e. constants defined in functions will *only* be available for use when that function is called)
#### addParamDefaultToDocblockType
```xml
```
Occasionally a param default will not match up with the docblock type. By default, Psalm emits an issue. Setting this flag to `true` causes it to expand the param type to include the param default. Defaults to `false`.
#### checkForThrowsDocblock
```xml
```
When `true`, Psalm will check that the developer has supplied `@throws` docblocks for every exception thrown in a given function or method. Defaults to `false`.
#### checkForThrowsInGlobalScope
```xml
```
When `true`, Psalm will check that the developer has caught every exception in global scope. Defaults to `false`.
#### ignoreInternalFunctionFalseReturn
```xml
```
When `true`, Psalm ignores possibly-false issues stemming from return values of internal functions (like `preg_split`) that may return false, but do so rarely. Defaults to `true`.
#### ignoreInternalFunctionNullReturn
```xml
```
When `true`, Psalm ignores possibly-null issues stemming from return values of internal array functions (like `current`) that may return null, but do so rarely. Defaults to `true`.
#### inferPropertyTypesFromConstructor
```xml
```
When `true`, Psalm infers property types from assignments seen in straightforward constructors. Defaults to `true`.
#### findUnusedVariablesAndParams
```xml
```
When `true`, Psalm will attempt to find all unused variables, the equivalent of running with `--find-unused-variables`. Defaults to `false`.
#### findUnusedCode
```xml
```
When `true`, Psalm will attempt to find all unused code (including unused variables), the equivalent of running with `--find-unused-code`. Defaults to `false`.
#### findUnusedPsalmSuppress
```xml
```
When `true`, Psalm will report all `@psalm-suppress` annotations that aren't used, the equivalent of running with `--find-unused-psalm-suppress`. Defaults to `false`.
#### loadXdebugStub
```xml
```
If not present, Psalm will only load the Xdebug stub if Psalm has unloaded the extension.
When `true`, Psalm will load the Xdebug extension stub (as the extension is unloaded when Psalm runs).
Setting to `false` prevents the stub from loading.
#### ensureArrayStringOffsetsExist
```xml
```
When `true`, Psalm will complain when referencing an explicit string offset on an array e.g. `$arr['foo']` without a user first asserting that it exists (either via an `isset` check or via an object-like array). Defaults to `false`.
#### ensureArrayIntOffsetsExist
```xml
```
When `true`, Psalm will complain when referencing an explicit integer offset on an array e.g. `$arr[7]` without a user first asserting that it exists (either via an `isset` check or via an object-like array). Defaults to `false`.
#### phpVersion
```xml
```
Set the php version Psalm should assume when checking and/or fixing the project. If this attribute is not set, Psalm uses the declaration in `composer.json` if one is present. It will check against the earliest version of PHP that satisfies the declared `php` dependency
This can be overridden on the command-line using the `--php-version=` flag which takes the highest precedence over both the `phpVersion` setting and the version derived from `composer.json`.
#### skipChecksOnUnresolvableIncludes
```xml
```
When `true`, Psalm will skip checking classes, variables and functions after it comes across an `include` or `require` it cannot resolve. This allows code to reference functions and classes unknown to Psalm.
This defaults to `false`.
#### sealAllMethods
```xml
```
When `true`, Psalm will treat all classes as if they had sealed methods, meaning that if you implement the magic method `__call`, you also have to add `@method` for each magic method. Defaults to false.
#### sealAllProperties
```xml
```
When `true`, Psalm will treat all classes as if they had sealed properties, meaning that Psalm will disallow getting and setting any properties not contained in a list of `@property` (or `@property-read`/`@property-write`) annotations and not explicitly defined as a `property`. Defaults to false.
#### runTaintAnalysis
```xml
```
When `true`, Psalm will run [Taint Analysis](../security_analysis/index.md) on your codebase. This config is the same as if you were running Psalm with `--taint-analysis`.
#### reportInfo
```xml
```
When `false`, Psalm will not consider issue at lower level than `errorLevel` as `info` (they will be suppressed instead). This can be a big improvement in analysis time for big projects. However, this config will prevent Psalm to count or suggest fixes for suppressed issue
#### allowNamedArgumentCalls
```xml
```
When `false`, Psalm will not report `ParamNameMismatch` issues in your code anymore. This does not replace the use of individual `@no-named-arguments` to prevent external access to a library's method or to reduce the type to a `list` when using variadics
#### triggerErrorExits
```xml
```
Describe the behavior of trigger_error. `always` means it always exits, `never` means it never exits, `default` means it exits only for `E_USER_ERROR`. Default is `default`
### Running Psalm
#### autoloader
```xml
```
If your application registers one or more custom autoloaders, and/or declares universal constants/functions, this autoloader script will be executed by Psalm before scanning starts. Psalm always registers composer's autoloader by default.
#### throwExceptionOnError
```xml
```
Useful in testing, this makes Psalm throw a regular-old exception when it encounters an error. Defaults to `false`.
#### hideExternalErrors
```xml
```
Whether or not to show issues in files that are used by your project files, but which are not included in ``. Defaults to `false`.
#### cacheDirectory
```xml
```
The directory used to store Psalm's cache data - if you specify one (and it does not already exist), its parent directory must already exist, otherwise Psalm will throw an error.
Defaults to `$XDG_CACHE_HOME/psalm`. If `$XDG_CACHE_HOME` is either not set or empty, a default equal to `$HOME/.cache/psalm` is used or `sys_get_temp_dir() . '/psalm'` when not defined.
#### allowFileIncludes
```xml
```
Whether or not to allow `require`/`include` calls in your PHP. Defaults to `true`.
#### serializer
```xml
```
Allows you to hard-code a serializer for Psalm to use when caching data. By default, Psalm uses `ext-igbinary` *if* the version is greater than or equal to 2.0.5, otherwise it defaults to PHP's built-in serializer.
#### threads
```xml
```
Allows you to hard-code a serializer for Psalm to use when caching data. By default, Psalm uses `ext-igbinary` *if* the version is greater than or equal to 2.0.5, otherwise it defaults to PHP's built-in serializer.
## Project settings
#### <projectFiles>
Contains a list of all the directories that Psalm should inspect. You can also specify a set of files and folders to ignore with the `` directive, e.g.
```xml
```
#### <extraFiles>
Optional. Same format as ``. Directories Psalm should load but not inspect.
#### <fileExtensions>
Optional. A list of extensions to search over. See [Checking non-PHP files](checking_non_php_files.md) to understand how to extend this.
#### <plugins>
Optional. A list of `` entries. See the [Plugins](plugins/using_plugins.md) section for more information.
#### <issueHandlers>
Optional. If you don't want Psalm to complain about every single issue it finds, the issueHandler tag allows you to configure that. [Dealing with code issues](dealing_with_code_issues.md) tells you more.
#### <mockClasses>
Optional. Do you use mock classes in your tests? If you want Psalm to ignore them when checking files, include a fully-qualified path to the class with ``
#### <universalObjectCrates>
Optional. Do you have objects with properties that cannot be determined statically? If you want Psalm to treat all properties on a given classlike as mixed, include a fully-qualified path to the class with ``. By default, `stdClass` and `SimpleXMLElement` are configured to be universal object crates.
#### <stubs>
Optional. If your codebase uses classes and functions that are not visible to Psalm via reflection
(e.g. if there are internal packages that your codebase relies on that are not available on the machine running Psalm),
you can use stub files. Used by PhpStorm (a popular IDE) and others, stubs provide a description of classes and
functions without the implementations.
You can find a list of stubs for common classes [here](https://github.com/JetBrains/phpstorm-stubs).
List out each file with ``. In case classes to be tested use parent classes
or interfaces defined in a stub file, this stub should be configured with attribute `preloadClasses="true"`.
```xml
```
#### <ignoreExceptions>
Optional. A list of exceptions to not report for `checkForThrowsDocblock` or `checkForThrowsInGlobalScope`. If an exception has `onlyGlobalScope` set to `true`, only `checkForThrowsInGlobalScope` is ignored for that exception, e.g.
```xml
```
#### <globals>
Optional. If your codebase uses global variables that are accessed with the `global` keyword, you can declare their type. e.g.
```xml
```
Some frameworks and libraries expose functionalities through e.g. `$GLOBALS[DB]->query($query)`.
The following configuration declares custom types for super-globals (`$GLOBALS`, `$_GET`, ...).
```xml
```
The example above declares global variables as shown below
* `$GLOBALS`
+ `DB` of type `MyVendor\DatabaseConnection`
+ `VIEW` of type `MyVendor\TemplateView`
* `$_GET`
+ `data` e.g. like `["id" => "123", "title" => "Nice"]`
## Accessing Psalm configuration in plugins
Plugins can access or modify the global configuration in plugins using
[singleton Psalm\Config](https://github.com/vimeo/psalm/blob/master/src/Psalm/Config.php).
```php
$config = \Psalm\Config::getInstance();
if (!isset($config->globals['$GLOBALS'])) {
$config->globals['$GLOBALS'] = 'array{data: array}';
}
```