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Improve outer block reference mechanism
Just passing along blocks to the embedded templates will quickly end up in recursive loops, not using the correct blocks etc. Blocks are still passed along but their name is being randomized. A BlockStack object is introduced which keeps track of the location of a block definition and the relation to each embedded component, and that randomized name, so that when the component instance is rendered the correct block definition can be accessed via the special outerBlocks variable (which refers to the BlockStack).
1 parent c086fff commit bead9df

34 files changed

+583
-72
lines changed

‎src/TwigComponent/src/BlockStack.php

Lines changed: 146 additions & 0 deletions
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@@ -0,0 +1,146 @@
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<?php
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declare(strict_types=1);
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namespace Symfony\UX\TwigComponent;
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use Twig\Template;
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/**
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* @author Bart Vanderstukken <bart.vanderstukken@gmail.com>
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*
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* @internal
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*/
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final class BlockStack
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{
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private const OUTER_BLOCK_PREFIX = 'outer__';
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public const OUTER_BLOCK_FALLBACK_NAME = self::OUTER_BLOCK_PREFIX.'block_fallback';
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/**
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* @var array<string, array<int, array<int, string>>>
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*/
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private array $stack;
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public function convert(array $blocks, int $targetEmbeddedTemplateIndex): array
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{
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$newBlocks = [];
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foreach ($blocks as $blockName => $block) {
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// Keep already converted outer blocks untouched
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if (str_starts_with($blockName, self::OUTER_BLOCK_PREFIX)) {
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$newBlocks[$blockName] = $block;
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continue;
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}
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// Determine the location of the block where it is defined in the host Template
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// Each component has its own embedded template. That template's index uniquely
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// identifies the block definition.
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$hostEmbeddedTemplateIndex = $this->findHostEmbeddedTemplateIndex();
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if (0 === $hostEmbeddedTemplateIndex) {
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// If there is no embedded template index, that means we're in a normal level template.
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// It wouldn't make sense to make these available as outer blocks,
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// since the block already printed in place.
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continue;
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}
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// Change name of outer blocks to something unique so blocks of nested components aren't overridden,
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// which otherwise might cause a recursion loop when nesting components.
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$newName = self::OUTER_BLOCK_PREFIX.$blockName.'_'.mt_rand();
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$newBlocks[$newName] = $block;
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// That index combined with the index of the embedded template where the block can be used
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// allows us to remember the link between the original name and the new randomized name.
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// That way we can map a call like `block(outerBlocks.block_name)` to the randomized name.
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$this->stack[$blockName][$targetEmbeddedTemplateIndex][$hostEmbeddedTemplateIndex] = $newName;
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}
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return $newBlocks;
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}
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public function __call(string $name, array $arguments)
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{
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$callingEmbeddedTemplateIndex = $this->findCallingEmbeddedTemplateIndex();
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$hostEmbeddedTemplateIndex = $this->findHostEmbeddedTemplateIndexFromCaller();
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return $this->stack[$name][$callingEmbeddedTemplateIndex][$hostEmbeddedTemplateIndex] ?? self::OUTER_BLOCK_FALLBACK_NAME;
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}
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private function findHostEmbeddedTemplateIndex(): int
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{
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$backtrace = debug_backtrace(\DEBUG_BACKTRACE_IGNORE_ARGS | \DEBUG_BACKTRACE_PROVIDE_OBJECT);
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$componentTemplateClassName = null;
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foreach ($backtrace as $trace) {
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if (isset($trace['object']) && $trace['object'] instanceof Template) {
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$classname = $trace['object']::class;
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$templateIndex = $this->getTemplateIndexFromTemplateClassname($classname);
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if ($templateIndex) {
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// If there's no template index, then we're in a component template
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// and we need to go up until we find the embedded template
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// (which will have the block definitions).
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return $templateIndex;
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}
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}
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}
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return 0;
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}
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private function findCallingEmbeddedTemplateIndex(): int
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{
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$backtrace = debug_backtrace(\DEBUG_BACKTRACE_IGNORE_ARGS | \DEBUG_BACKTRACE_PROVIDE_OBJECT);
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foreach ($backtrace as $trace) {
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if (isset($trace['object']) && $trace['object'] instanceof Template) {
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return $this->getTemplateIndexFromTemplateClassname($trace['object']::class);
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}
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}
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}
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private function findHostEmbeddedTemplateIndexFromCaller(): int
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{
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$backtrace = debug_backtrace(\DEBUG_BACKTRACE_IGNORE_ARGS | \DEBUG_BACKTRACE_PROVIDE_OBJECT);
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$blockCallerStack = [];
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$renderer = null;
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foreach ($backtrace as $trace) {
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if (isset($trace['object']) && $trace['object'] instanceof Template) {
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$classname = $trace['object']::class;
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$templateIndex = $this->getTemplateIndexFromTemplateClassname($classname);
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if (null === $renderer) {
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if ($templateIndex) {
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// This class is an embedded template
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// Next class is either the renderer or a previous template that's passing blocks through.
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$blockCallerStack[$classname] = $classname;
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continue;
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}
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// If it's not an embedded template anymore, we've reached the renderer
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// From now on we'll travel back up the hierachy
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$renderer = $classname;
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continue;
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}
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if ($classname === $renderer || isset($blockCallerStack[$classname])) {
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continue;
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}
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if (!$templateIndex) {
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continue;
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}
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// This is the first template that's not part of the callstack,
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// so it's the template that has the outer block definition
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return $templateIndex;
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}
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}
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// If the component is not an embedded one, just return 0, so the fallback content (aka nothing) is used
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return 0;
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}
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private function getTemplateIndexFromTemplateClassname(string $classname): int
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{
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return (int) substr($classname, strrpos($classname, '___') + 3);
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}
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}

‎src/TwigComponent/src/ComponentRenderer.php

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@@ -71,7 +71,13 @@ public function embeddedContext(string $name, array $props, array $context): arr
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{
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$context[PreRenderEvent::EMBEDDED] = true;
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return $this->preRender($this->factory->create($name, $props), $context)->getVariables();
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$embeddedContext = $this->preRender($this->factory->create($name, $props), $context)->getVariables();
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if (!isset($embeddedContext['outerBlocks'])) {
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$embeddedContext['outerBlocks'] = new BlockStack();
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}
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return $embeddedContext;
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}
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private function preRender(MountedComponent $mounted, array $context = []): PreRenderEvent

‎src/TwigComponent/src/Twig/ComponentNode.php

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@@ -35,7 +35,7 @@ public function compile(Compiler $compiler): void
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$compiler->addDebugInfo($this);
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$compiler
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->raw('$props = $this->extensions[')
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->write('$embeddedContext = $this->extensions[')
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->string(ComponentExtension::class)
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->raw(']->embeddedContext(')
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->string($this->getAttribute('component'))
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->raw(");\n")
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;
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$compiler->write('$embeddedBlocks = $embeddedContext[')
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->string('outerBlocks')
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->raw(']->convert($blocks, ')
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->string($this->getAttribute('index'))
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->raw(");\n")
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;
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$this->addGetTemplate($compiler);
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$compiler->raw('->display($props, $blocks);');
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$compiler->raw('->display($embeddedContext, $embeddedBlocks);');
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$compiler->raw("\n");
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}
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}

‎src/TwigComponent/src/Twig/ComponentTokenParser.php

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@@ -11,6 +11,7 @@
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namespace Symfony\UX\TwigComponent\Twig;
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use Symfony\UX\TwigComponent\BlockStack;
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use Symfony\UX\TwigComponent\ComponentFactory;
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use Twig\Node\Expression\AbstractExpression;
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use Twig\Node\Expression\ArrayExpression;
@@ -61,6 +62,17 @@ public function parse(Token $token): Node
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new Token(Token::NAME_TYPE, 'extends', $token->getLine()),
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$parentToken,
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new Token(Token::BLOCK_END_TYPE, '', $token->getLine()),
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// Add an empty block which can act as a fallback for when an outer
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// block is referenced that is not passed in from the embedded component
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// See BlockStack::__call()
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new Token(Token::BLOCK_START_TYPE, '', $token->getLine()),
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new Token(Token::NAME_TYPE, 'block', $token->getLine()),
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new Token(Token::NAME_TYPE, BlockStack::OUTER_BLOCK_FALLBACK_NAME, $token->getLine()),
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new Token(Token::BLOCK_END_TYPE, '', $token->getLine()),
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new Token(Token::BLOCK_START_TYPE, '', $token->getLine()),
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new Token(Token::NAME_TYPE, 'endblock', $token->getLine()),
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new Token(Token::BLOCK_END_TYPE, '', $token->getLine()),
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]);
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$module = $this->parser->parse($stream, fn (Token $token) => $token->test("end{$this->getTag()}"), true);

‎src/TwigComponent/tests/Fixtures/Component/DivComponent.php

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#[AsTwigComponent]
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final class DivComponent
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{
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public string $divComponentName = 'foo';
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public function someFunction(): string
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{
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return 'calling DivComponent';
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}
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}

‎src/TwigComponent/tests/Fixtures/Component/DivComponent1.php

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<?php
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/*
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* This file is part of the Symfony package.
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*
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* (c) Fabien Potencier <fabien@symfony.com>
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
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*/
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namespace Symfony\UX\TwigComponent\Tests\Fixtures\Component;
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use Symfony\UX\TwigComponent\Attribute\AsTwigComponent;
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/**
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* @author Bart Vanderstukken <bart.vanderstukken@gmail.com>
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*/
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#[AsTwigComponent]
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final class DivComponent1
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{
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}

‎src/TwigComponent/tests/Fixtures/Component/DivComponent2.php

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<?php
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/*
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* This file is part of the Symfony package.
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*
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* (c) Fabien Potencier <fabien@symfony.com>
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
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*/
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namespace Symfony\UX\TwigComponent\Tests\Fixtures\Component;
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use Symfony\UX\TwigComponent\Attribute\AsTwigComponent;
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/**
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* @author Bart Vanderstukken <bart.vanderstukken@gmail.com>
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*/
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#[AsTwigComponent]
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final class DivComponent2
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{
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}

‎src/TwigComponent/tests/Fixtures/Component/DivComponent3.php

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<?php
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/*
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* This file is part of the Symfony package.
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*
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* (c) Fabien Potencier <fabien@symfony.com>
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
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*/
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namespace Symfony\UX\TwigComponent\Tests\Fixtures\Component;
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use Symfony\UX\TwigComponent\Attribute\AsTwigComponent;
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/**
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* @author Bart Vanderstukken <bart.vanderstukken@gmail.com>
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*/
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#[AsTwigComponent]
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final class DivComponent3
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{
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}

‎src/TwigComponent/tests/Fixtures/Component/DivComponent4.php

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<?php
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/*
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* This file is part of the Symfony package.
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*
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* (c) Fabien Potencier <fabien@symfony.com>
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
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*/
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namespace Symfony\UX\TwigComponent\Tests\Fixtures\Component;
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use Symfony\UX\TwigComponent\Attribute\AsTwigComponent;
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/**
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* @author Bart Vanderstukken <bart.vanderstukken@gmail.com>
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*/
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#[AsTwigComponent]
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final class DivComponent4
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{
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}

‎src/TwigComponent/tests/Fixtures/Component/DivComponent5.php

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<?php
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/*
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* This file is part of the Symfony package.
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*
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* (c) Fabien Potencier <fabien@symfony.com>
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
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*/
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namespace Symfony\UX\TwigComponent\Tests\Fixtures\Component;
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use Symfony\UX\TwigComponent\Attribute\AsTwigComponent;
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/**
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* @author Bart Vanderstukken <bart.vanderstukken@gmail.com>
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*/
19+
#[AsTwigComponent]
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final class DivComponent5
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{
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public string $divComponentName = 'foo';
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public function someFunction(): string
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{
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return 'calling DivComponent';
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}
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}

‎src/TwigComponent/tests/Fixtures/Component/DivComponentNoPass.php

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<?php
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/*
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* This file is part of the Symfony package.
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*
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* (c) Fabien Potencier <fabien@symfony.com>
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
10+
*/
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namespace Symfony\UX\TwigComponent\Tests\Fixtures\Component;
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use Symfony\UX\TwigComponent\Attribute\AsTwigComponent;
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/**
17+
* @author Bart Vanderstukken <bart.vanderstukken@gmail.com>
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*/
19+
#[AsTwigComponent]
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final class DivComponentNoPass
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{
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}

‎src/TwigComponent/tests/Fixtures/Component/DivComponentWrapper2.php

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<?php
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/*
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* This file is part of the Symfony package.
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*
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* (c) Fabien Potencier <fabien@symfony.com>
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
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*/
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namespace Symfony\UX\TwigComponent\Tests\Fixtures\Component;
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use Symfony\UX\TwigComponent\Attribute\AsTwigComponent;
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/**
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* @author Bart Vanderstukken <bart.vanderstukken@gmail.com>
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*/
19+
#[AsTwigComponent]
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final class DivComponentWrapper2
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{
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}

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