CreatesPotentiallyTranslatedStrings Trait

Purpose and Scope

The CreatesPotentiallyTranslatedStrings trait provides functionality for creating deferred translations with automatic message collection, primarily used in validation contexts. This trait enables the creation of special PotentiallyTranslatedString instances that automatically register their translated content into a messages array upon destruction.

For information about the base PotentiallyTranslatedString class and its translation capabilities, see 8.1. For broader context on advanced translation features, see 8.

Sources: src/CreatesPotentiallyTranslatedStrings.php1-47

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Overview

The trait consists of a single protected method that returns an anonymous class extending PotentiallyTranslatedString. This anonymous class adds destructor behavior that automatically collects the translated message when the object goes out of scope. This pattern is particularly useful in validation scenarios where error messages need to be accumulated and potentially translated lazily.

The trait expects to be used within a class that has:

• A $messages property (array for storing validation messages)
• A $validator property that provides access to a Translator instance via getTranslator()

Sources: src/CreatesPotentiallyTranslatedStrings.php10-46

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Class Relationships

Sources: src/CreatesPotentiallyTranslatedStrings.php10-46 src/PotentiallyTranslatedString.php11-73

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The pendingPotentiallyTranslatedString Method

Method Signature

Parameters

Parameter	Type	Description
$attribute	string	The attribute name associated with the message (used as fallback if $message is null)
$message	?string	The message key or actual message to translate (optional)

Return Value

Returns an anonymous class instance that extends PotentiallyTranslatedString with custom destructor behavior.

Sources: src/CreatesPotentiallyTranslatedStrings.php15-19

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Destructor Factory Pattern

The method creates one of two destructor closures based on whether $message is provided:

When $message is null

src/CreatesPotentiallyTranslatedStrings.php18

The destructor appends the translated message to the $messages array without an associative key. This is used for general error messages not tied to specific attributes.

When $message is provided

src/CreatesPotentiallyTranslatedStrings.php19

The destructor stores the translated message in the $messages array with $attribute as the key. This is used for attribute-specific validation error messages.

Condition	Destructor Behavior	Result
$message === null	$messages[] = $translated	Numeric-indexed array entry
$message !== null	$messages[$attribute] = $translated	Attribute-keyed array entry

Sources: src/CreatesPotentiallyTranslatedStrings.php17-19

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Anonymous Class Extension

The method returns an anonymous class defined inline at src/CreatesPotentiallyTranslatedStrings.php21-44 This class:

Extends PotentiallyTranslatedString

Inherits all translation capabilities from the base class, including:

• translate() method for standard translation
• translateChoice() method for pluralization
• original() method to get the untranslated string
• __toString() magic method for string conversion

Adds Destructor Property

src/CreatesPotentiallyTranslatedStrings.php25

Stores the closure that will be invoked when the object destructs.

Overrides Constructor

src/CreatesPotentiallyTranslatedStrings.php30-35

The constructor:

1. Calls parent constructor with $message and $translator
2. Stores the provided $destructor closure
3. Enables the automatic message collection behavior

Implements __destruct Magic Method

src/CreatesPotentiallyTranslatedStrings.php40-43

When the object is destroyed (garbage collected), this method:

1. Converts the object to a string via toString() (which triggers translation if not already performed)
2. Passes the translated string to the stored destructor closure
3. The closure adds the translated message to the $messages array

Sources: src/CreatesPotentiallyTranslatedStrings.php21-44

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Lifecycle and Execution Flow

Sources: src/CreatesPotentiallyTranslatedStrings.php15-44 src/PotentiallyTranslatedString.php61-72

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Message Collection Behavior

The trait implements a deferred message collection pattern:

Array Structure Based on Usage

Key Determination Logic

1. Null Message: When $message is null, the $attribute parameter serves as both the translation key and the fallback value. The result is appended to the array without a key.

2. Provided Message: When $message is provided, it serves as the translation key, and the result is stored with $attribute as the array key.

Sources: src/CreatesPotentiallyTranslatedStrings.php17-19

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Integration with Validation System

Expected Context Properties

The trait expects the consuming class to provide:

Property	Type	Purpose
$this->messages	array	Array to store validation messages
$this->validator	Object with getTranslator()	Provides access to the Translator instance

Validator Integration Pattern

src/CreatesPotentiallyTranslatedStrings.php19-21

The trait accesses $this->validator->getTranslator() to obtain the translator instance, indicating it is designed to be used within validation classes that:

1. Maintain a collection of validation error messages
2. Have access to a translator for message localization
3. Need to defer translation until messages are actually needed

Typical Usage Pattern

1. Validation rule evaluates → fails
2. Create pending translated string via trait method
3. Optionally perform explicit translation
4. Object goes out of scope
5. Destructor automatically adds message to $messages array

Sources: src/CreatesPotentiallyTranslatedStrings.php15-44

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Comparison with Standard PotentiallyTranslatedString

Feature	Standard PotentiallyTranslatedString	Trait's Anonymous Extension
Base class	PotentiallyTranslatedString	Extends PotentiallyTranslatedString
Destructor	None	Custom destructor that registers message
Message collection	Manual	Automatic on destruction
Use case	General deferred translation	Validation message collection
Closure injection	N/A	Injected via constructor
Array registration	N/A	Automatic based on attribute/message params

Sources: src/CreatesPotentiallyTranslatedStrings.php21-44 src/PotentiallyTranslatedString.php11-73

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Design Rationale

Automatic Registration

The destructor pattern ensures that validation messages are registered even if the developer forgets to manually add them to the messages array. This makes the validation system more robust and less error-prone.

Lazy Translation

By extending PotentiallyTranslatedString, the trait enables lazy translation—messages are only translated when actually needed (typically when converted to string or explicitly translated).

Flexible Array Keys

The dual-mode destructor (numeric vs. associative keys) provides flexibility for different validation scenarios:

• Attribute-specific errors: Use associative keys for field-level validation messages
• General errors: Use numeric indices for general validation failures

Anonymous Class Pattern

Using an anonymous class allows the trait to:

1. Extend the base PotentiallyTranslatedString class
2. Add custom behavior without creating a separate named class
3. Encapsulate the destructor logic within the trait
4. Maintain backward compatibility with code expecting PotentiallyTranslatedString instances

Sources: src/CreatesPotentiallyTranslatedStrings.php10-46

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Memory and Performance Considerations

Object Lifecycle

The anonymous class instances are typically short-lived:

• Created during validation rule evaluation
• Translation may occur immediately or be deferred
• Destroyed when validation context completes
• Destructor triggers automatic message registration

Translation Timing

Translation can occur at two points:

1. Explicit: Via translate() or translateChoice() calls before destruction
2. Implicit: During toString() call in destructor if not previously translated

If translation is never explicitly performed, the original string (translation key or attribute) is registered in the messages array.

Sources: src/CreatesPotentiallyTranslatedStrings.php40-43 src/PotentiallyTranslatedString.php61-72