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[Capability] Suppress list-changed events during the initial registry load #480

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Merged
chr-hertel merged 3 commits into from
Aug 24, 2026
+66 −8
Merged

[Capability] Suppress list-changed events during the initial registry load #480

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95c37fc
[Capability] Suppress list-changed events during the initial registry…
chr-hertel Aug 22, 2026
59ad41f
Shorten dispatch() comment to a one-liner
chr-hertel Aug 24, 2026
f9a667f
Use multi-line docblock format for dispatch() comment
chr-hertel Aug 24, 2026
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28 changes: 20 additions & 8 deletions src/Capability/Registry.php
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Original file line number Diff line number Diff line change
Expand Up @@ -108,7 +108,7 @@ public function registerTool(Tool $tool, callable|array|string $handler): ToolRe
$reference = new ToolReference($tool, $handler);
$this->tools[$tool->name] = $reference;

$this->eventDispatcher?->dispatch(new ToolListChangedEvent());
$this->dispatch(new ToolListChangedEvent());

return $reference;
}
Expand All @@ -118,7 +118,7 @@ public function registerResource(ResourceDefinition $resource, callable|array|st
$reference = new ResourceReference($resource, $handler);
$this->resources[$resource->uri] = $reference;

$this->eventDispatcher?->dispatch(new ResourceListChangedEvent());
$this->dispatch(new ResourceListChangedEvent());

return $reference;
}
Expand All @@ -131,7 +131,7 @@ public function registerResourceTemplate(
$reference = new ResourceTemplateReference($template, $handler, $completionProviders);
$this->resourceTemplates[$template->uriTemplate] = $reference;

$this->eventDispatcher?->dispatch(new ResourceTemplateListChangedEvent());
$this->dispatch(new ResourceTemplateListChangedEvent());

return $reference;
}
Expand All @@ -144,7 +144,7 @@ public function registerPrompt(
$reference = new PromptReference($prompt, $handler, $completionProviders);
$this->prompts[$prompt->name] = $reference;

$this->eventDispatcher?->dispatch(new PromptListChangedEvent());
$this->dispatch(new PromptListChangedEvent());

return $reference;
}
Expand All @@ -157,7 +157,7 @@ public function unregisterTool(string $name): void

unset($this->tools[$name]);

$this->eventDispatcher?->dispatch(new ToolListChangedEvent());
$this->dispatch(new ToolListChangedEvent());
}

public function unregisterResource(string $uri): void
Expand All @@ -168,7 +168,7 @@ public function unregisterResource(string $uri): void

unset($this->resources[$uri]);

$this->eventDispatcher?->dispatch(new ResourceListChangedEvent());
$this->dispatch(new ResourceListChangedEvent());
}

public function unregisterResourceTemplate(string $uriTemplate): void
Expand All @@ -179,7 +179,7 @@ public function unregisterResourceTemplate(string $uriTemplate): void

unset($this->resourceTemplates[$uriTemplate]);

$this->eventDispatcher?->dispatch(new ResourceTemplateListChangedEvent());
$this->dispatch(new ResourceTemplateListChangedEvent());
}

public function unregisterPrompt(string $name): void
Expand All @@ -190,7 +190,7 @@ public function unregisterPrompt(string $name): void

unset($this->prompts[$name]);

$this->eventDispatcher?->dispatch(new PromptListChangedEvent());
$this->dispatch(new PromptListChangedEvent());
}

public function hasTool(string $name): bool
Expand Down Expand Up @@ -390,6 +390,18 @@ public function getPrompt(string $name): PromptReference
return $this->prompts[$name] ?? throw new PromptNotFoundException($name);
}

/**
* Suppressed while the deferred loader runs, since it only sets up initial state.
*/
private function dispatch(object $event): void
{
if ($this->loading) {
return;
}

$this->eventDispatcher?->dispatch($event);
}

/**
* Calculate next cursor for pagination.
*
Expand Down
46 changes: 46 additions & 0 deletions tests/Unit/Capability/RegistryTest.php
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@
use Mcp\Capability\Registry\ResourceTemplateReference;
use Mcp\Capability\Registry\ToolReference;
use Mcp\Capability\RegistryInterface;
use Mcp\Event\ToolListChangedEvent;
use Mcp\Exception\PromptNotFoundException;
use Mcp\Exception\ResourceNotFoundException;
use Mcp\Exception\ToolNotFoundException;
Expand All @@ -31,6 +32,7 @@
use Mcp\Schema\Tool;
use PHPUnit\Framework\MockObject\MockObject;
use PHPUnit\Framework\TestCase;
use Psr\EventDispatcher\EventDispatcherInterface;
use Psr\Log\LoggerInterface;

class RegistryTest extends TestCase
Expand Down Expand Up @@ -722,6 +724,50 @@ public function load(RegistryInterface $registry): void
$this->assertArrayHasKey('loaded', $registry->getTools()->references);
}

public function testListChangedEventsAreSuppressedDuringTheDeferredLoad(): void
{
$eventDispatcher = $this->createMock(EventDispatcherInterface::class);
$eventDispatcher->expects($this->never())->method('dispatch');

$loader = new class($this->createValidTool('loaded'), $this->createValidResource('file:///loaded'), $this->createValidResourceTemplate('file:///loaded/{id}'), $this->createValidPrompt('loaded_prompt')) implements LoaderInterface {
public function __construct(
private readonly Tool $tool,
private readonly ResourceDefinition $resource,
private readonly ResourceTemplate $template,
private readonly Prompt $prompt,
) {
}

public function load(RegistryInterface $registry): void
{
$registry->registerTool($this->tool, 'handler');
$registry->registerResource($this->resource, 'handler');
$registry->registerResourceTemplate($this->template, 'handler');
$registry->registerPrompt($this->prompt, 'handler');
}
};

$registry = new Registry($eventDispatcher, $this->logger, loader: $loader);

$this->assertTrue($registry->hasTools());
$this->assertTrue($registry->hasPrompts());
}

public function testListChangedEventsAreStillDispatchedForRuntimeRegistrations(): void
{
$eventDispatcher = $this->createMock(EventDispatcherInterface::class);
$eventDispatcher->expects($this->once())
->method('dispatch')
->with($this->isInstanceOf(ToolListChangedEvent::class))
->willReturnArgument(0);

$loader = $this->toolLoader($this->createValidTool('loaded'));
$registry = new Registry($eventDispatcher, $this->logger, loader: $loader);
$registry->load();

$registry->registerTool($this->createValidTool('runtime'), 'handler');
}

public function testLoadRunsTheConfiguredLoaderEagerly(): void
{
$loader = $this->createMock(LoaderInterface::class);
Expand Down