PHP ReflectionExtension::getVersion() Method: Usage and Examples

When building tools that inspect PHP code, ReflectionExtension::getVersion() helps answer a focused question: returns the extension version string when available.

Reflection is useful in framework tooling, dependency injection, testing, code inspection and debugging.

What Is ReflectionExtension::getVersion()?

Returns the extension version string when available.

Its method signature is:

public function getVersion(): ?string

This method has no required arguments.

Return value: ?string

Example 1: Inspect a loaded extension

Start with a self-contained PHP declaration and inspect the method result.

<?php

declare(strict_types=1);

$extensionReflection = new ReflectionExtension("json");

$result = $extensionReflection->getVersion();
var_dump($result);

Output:

string(6) "8.4.24"

Explanation: Returns the extension version string when available.

Example 2: Compare extension metadata

Next, change the reflected declaration or parameter to observe a related situation.

<?php

declare(strict_types=1);

$extensionReflection = new ReflectionExtension("date");

$result = $extensionReflection->getVersion();
var_dump($result);

// Check the returned value type before using the result.
echo "\nResult type: " . get_debug_type($result);

Output:

string(6) "8.4.24"

Result type: string

Explanation: Some built-in extensions have no separate version and may return null.

Practical Example: Use extension information for diagnostics

This final case shows how the same API can be used when inspecting application definitions.

<?php

declare(strict_types=1);

$extensionReflection = new ReflectionExtension("standard");

$result = $extensionReflection->getVersion();
var_dump($result);

// Use the reflection result in a simple decision.
if (is_bool($result)) {
    echo "\nStatus: " . ($result ? "yes" : "no");
} elseif (is_array($result)) {
    echo "\nEntries: " . count($result);
} elseif ($result === null) {
    echo "\nNo value returned";
} else {
    echo "\nReflection result available";
}

Output:

string(6) "8.4.24"

Reflection result available

Explanation: phpversion with an extension name is another way to query it.

Important Behavior and Edge Cases

• Some built-in extensions have no separate version and may return null.
• phpversion with an extension name is another way to query it.
• Reflection describes declarations and runtime state; requesting metadata does not automatically validate or sanitize application input.

Comparison With Related Approaches

Common Beginner Mistakes

Key Takeaways

• Returns the extension version string when available.
• Some built-in extensions have no separate version and may return null.
• phpversion with an extension name is another way to query it.

Use ReflectionExtension::getVersion() when you need the precise metadata or behavior demonstrated above. Keep the target declaration and relevant PHP version in mind when adapting the examples.