Qute: fix rendered=false if a fragment includes nested fragment

- problem occurs if a fragment is rendered separately and that fragment
includes a template that declares another fragment like `{#fragment
rendered=false}` - the `rendered=false` is ignored
- fixes quarkusio#44281

independent-projects/qute/core/src/main/java/io/quarkus/qute/FragmentSectionHelper.java

@@ -19,12 +19,15 @@ public class FragmentSectionHelper implements SectionHelper {
 
     private static final String ID = "id";
 
+    // the generated id of the template that declares this fragment section
+    private final String generatedTemplateId;
     private final String identifier;
     private final Expression rendered;
 
-    FragmentSectionHelper(String identifier, Expression isVisible) {
+    FragmentSectionHelper(String identifier, Expression rendered, String generatedTemplateId) {
         this.identifier = identifier;
-        this.rendered = isVisible;
+        this.rendered = rendered;
+        this.generatedTemplateId = generatedTemplateId;
     }
 
     public String getIdentifier() {
@@ -33,18 +36,25 @@ public String getIdentifier() {
 
     @Override
     public CompletionStage<ResultNode> resolve(SectionResolutionContext context) {
-        if (rendered == null
-                // executed from an include section
-                || context.getParameters().containsKey(Template.Fragment.ATTRIBUTE)
-                // the attribute is set if executed separately via Template.Fragment
-                || context.resolutionContext().getAttribute(Fragment.ATTRIBUTE) != null) {
+        if (isAlwaysExecuted(context)) {
             return context.execute();
         }
         return context.resolutionContext().evaluate(rendered).thenCompose(r -> {
             return Booleans.isFalsy(r) ? ResultNode.NOOP : context.execute();
         });
     }
 
+    private boolean isAlwaysExecuted(SectionResolutionContext context) {
+        if (rendered == null
+                // executed from an include section
+                || context.getParameters().containsKey(Fragment.ATTRIBUTE)) {
+            return true;
+        }
+        Object attribute = context.resolutionContext().getAttribute(Fragment.ATTRIBUTE);
+        // the attribute is set if executed separately via Template.Fragment
+        return attribute != null && attribute.equals(generatedTemplateId + identifier);
+    }
+
     public static class Factory implements SectionHelperFactory<FragmentSectionHelper> {
 
         static final Pattern FRAGMENT_PATTERN = Pattern.compile("[a-zA-Z0-9_]+");
@@ -99,7 +109,7 @@ public FragmentSectionHelper initialize(SectionInitContext context) {
                             .build();
                 }
             }
-            return new FragmentSectionHelper(id, context.getExpression(RENDERED));
+            return new FragmentSectionHelper(id, context.getExpression(RENDERED), generatedId);
         }
 
         @Override

independent-projects/qute/core/src/main/java/io/quarkus/qute/TemplateImpl.java

@@ -391,7 +391,9 @@ public Template getOriginalTemplate() {
         @Override
         public TemplateInstance instance() {
             TemplateInstance instance = super.instance();
-            instance.setAttribute(Fragment.ATTRIBUTE, true);
+            // when a fragment is executed separately we need a way to instruct FragmentSectionHelper to ignore the "renreded" parameter
+            // Fragment.ATTRIBUTE contains the generated id of the template that declares the fragment section and the fragment identifier
+            instance.setAttribute(Fragment.ATTRIBUTE, TemplateImpl.this.getGeneratedId() + FragmentImpl.this.getId());
             return instance;
         }
 

independent-projects/qute/core/src/test/java/io/quarkus/qute/FragmentTest.java

@@ -77,4 +77,41 @@ public void testInvalidId() {
                 expected.getMessage());
     }
 
+    @Test
+    public void testNestedFragmentRendered() {
+        Engine engine = Engine.builder().addDefaults().build();
+        Template alpha = engine.parse("""
+                    OK
+                    {#fragment id=\"nested\" rendered=false}
+                    NOK
+                    {/}
+                    {#fragment id=\"visible\"}
+                    01
+                    {/fragment}
+                """);
+        engine.putTemplate("alpha", alpha);
+        assertEquals("OK01", alpha.render().replaceAll("\\s", ""));
+        assertEquals("NOK", alpha.getFragment("nested").render().trim());
+
+        Template bravo = engine.parse("""
+                {#include $nested}
+                {#fragment id=\"nested\" rendered=false}
+                OK
+                {/}
+                """);
+        assertEquals("OK", bravo.render().trim());
+        assertEquals("OK", bravo.getFragment("nested").render().trim());
+
+        assertEquals("NOK", engine.parse("{#include alpha$nested /}").render().trim());
+        Template charlie = engine.parse("{#include alpha /}");
+        assertEquals("OK01", charlie.render().replaceAll("\\s", ""));
+
+        Template delta = engine.parse("""
+                {#fragment id=\"nested\" rendered=false}
+                    {#include alpha /}
+                {/}
+                """);
+        assertEquals("OK01", delta.getFragment("nested").render().replaceAll("\\s", ""));
+    }
+
 }