Extract LinkGenerator interface for replaceable/decoratable link generation

[jelen07]

Problem

Since v3.2.3, the link generation logic was moved from Presenter to the LinkGenerator class (which is a great improvement). However, the class is final and Presenter::getLinkGenerator() is also final, which means there is no way to customize link generation behavior.

Real-world use case

In our application, we use referenceable modals that can overlap each other. When a user arrives at a page with open modals (via direct link or after a page refresh), links generated in components below the modal incorrectly include persistent parameters of all opened modals.

To solve this, we needed to intercept link generation and nullify persistent parameters based on context. Since LinkGenerator is final and getLinkGenerator() is also final, we were forced to create a workaround that overrides four methods (link(), isLinkCurrent(), redirect(), redirectPermanent()) on every component via a trait, all full of @phpstan-ignore-line comments because we access @internal methods. This works but is fragile and not a clean solution.

We believe this is a valid use case that the framework should support natively.

Solution

This PR extracts a LinkGenerator interface from the existing class (renamed to DefaultLinkGenerator), following Nette's established naming convention (plain noun for interfaces, e.g. TemplateFactory, Response, Renderable).

Changes

New files:

• src/Application/LinkGenerator.php — interface with link(), createRequest(), requestToUrl(), withReferenceUrl(), getLastRequest()
• src/Application/DefaultLinkGenerator.php — the original class, renamed, implements the interface

Modified files:

• Presenter — property typed as LinkGenerator (interface), getLinkGenerator() is no longer final and returns the interface, injectPrimary() accepts optional ?LinkGenerator for custom injection
• ApplicationExtension — registers the service with type LinkGenerator (interface) and factory DefaultLinkGenerator
• LinkBaseNode — static calls updated to DefaultLinkGenerator::applyBase()

How it enables decoration

Users can now create a custom LinkGenerator implementation (decorator) and inject it via DI:

services:
    application.linkGenerator:
        type: Nette\Application\LinkGenerator
        factory: App\MyCustomLinkGenerator(
            inner: Nette\Application\DefaultLinkGenerator(...)
        )

Or override getLinkGenerator() in a Presenter subclass for more specific control.

BC impact

Usage	Impact
LinkGenerator $x type hints	No break — interface satisfies existing hints
DI autowiring	No break — extension registers the interface type
new LinkGenerator(...)	Breaks — use new DefaultLinkGenerator(...) (rare in userland, DI handles this)
LinkGenerator::parseDestination()	Breaks — use DefaultLinkGenerator::parseDestination() (@internal)
LinkGenerator::applyBase()	Breaks — use DefaultLinkGenerator::applyBase() (@internal)

The breaking changes only affect direct instantiation and @internal static method calls, which are not part of the public API and are extremely rare in userland code.

Tests

• All existing tests updated and passing (9 pre-existing failures unrelated to this PR)
• New test: LinkGenerator.interface.phpt — interface contract verification
• New test: LinkGenerator.decorator.phpt — decorator injection and URL modification patterns

Resolves #333

Thank you for your time and for the framework!