Blunt but effective

phpunit/directives/attributes/wp-show.php

@@ -52,6 +52,23 @@ public function test_directive_wraps_content_in_template_if_when_is_false() {
 		$this->assertSame( $context_before->get_context(), $context->get_context(), 'data-wp-show directive changed context' );
 	}
 
+	public function test_directive_does_not_wrap_template_in_template() {
+		$markup = '<template data-wp-show="context.myblock.open">I should not be shown!</template>';
+
+		$tags = new WP_Directive_Processor( $markup );
+		$tags->next_tag();
+
+		$context_before = new WP_Directive_Context( array( 'myblock' => array( 'open' => false ) ) );
+		$context        = clone $context_before;
+		process_wp_show( $tags, $context );
+
+		$tags->next_tag( array( 'tag_closers' => 'visit' ) );
+		process_wp_show( $tags, $context );
+
+		$this->assertSame( $markup, $tags->get_updated_html() );
+		$this->assertSame( $context_before->get_context(), $context->get_context(), 'data-wp-show directive changed context' );
+	}
+
 	public function test_directive_wraps_content_preceded_by_other_html_in_template_if_when_is_false() {
 		$markup = '<p>Some text</p><div data-wp-show="context.myblock.open">I should not be shown!</div>';
 

src/directives/attributes/wp-show.php

@@ -17,6 +17,10 @@ function process_wp_show( $tags, $context ) {
 		return;
 	}
 
+	if ( 'TEMPLATE' === $tags->get_tag() ) {
+		return; // Don't wrap a `<template>` in a `<template>`.
+	}
+
 	$wrapper_bookmark = $tags->wrap_in_tag( 'TEMPLATE' );
 	$tags->seek( $wrapper_bookmark );
 	$tags->set_attribute( 'data-wp-show', $value );