Add the ability to ignore missing pages on ItemLink attributes

docs/docs/30-authoring/index.md

@@ -151,6 +151,10 @@ same as the [Minecraft give command](https://minecraft.wiki/w/Commands/give). Th
 shown item name are retrieved from. `<ItemLink id="minecraft:stick" components="rarity=epic" />` will show the tooltip
 using the epic rarity color, for example.
 
+If the link targets an item from the same namespace as the page, an error will be shown if there's no page for that item.
+You can opt out of this behavior by adding `optional={true}` or just `optional` to the link, or opt in for items of other mods by 
+adding `optional={false}`.
+
 ### Command Links
 
 You can make links that run a command when clicked using `<CommandLink command="/command">text text</CommandLink>`.

src/main/java/guideme/compiler/tags/ItemLinkCompiler.java

@@ -25,9 +25,13 @@ public void compile(PageCompiler compiler, LytFlowParent parent, MdxJsxElementFi
         var stack = itemAndId.getRight();
 
         var linksTo = compiler.getIndex(ItemIndex.class).get(id);
+
         // We'll error out for item-links to our own mod because we expect them to have a page
         // while we don't have pages for Vanilla items or items from other mods.
-        if (linksTo == null && id.getNamespace().equals(compiler.getPageId().getNamespace())) {
+        // But authors can opt-in or out of this behavior.
+        boolean defaultOptional = !id.getNamespace().equals(compiler.getPageId().getNamespace());
+        var optional = MdxAttrs.getBoolean(compiler, parent, el, "optional", defaultOptional);
+        if (linksTo == null && !optional) {
             parent.append(compiler.createErrorFlowContent("No page found for item " + id, el));
             return;
         }

src/main/java/guideme/compiler/tags/MdxAttrs.java

@@ -465,6 +465,10 @@ public static boolean getBoolean(MdxJsxElementFields el, String name, boolean de
             } else if (expressionValue.equals("false")) {
                 return false;
             }
+        } else if (attribute.getStringValue() == null) {
+            // This allows for standalone attributes ("<Tag attr />") to be recognized as true
+            // but differentiates them from <Tag attr={null} />
+            return true;
         }
 
         throw new AttributeException(name, name + " should be {true} or {false}");

src/test/java/guideme/compiler/tags/ItemLinkCompilerTest.java

@@ -0,0 +1,74 @@
+package guideme.compiler.tags;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import guideme.Guide;
+import guideme.GuidePage;
+import guideme.compiler.PageCompiler;
+import guideme.compiler.TagCompiler;
+import guideme.extensions.ExtensionCollection;
+import guideme.internal.GuideME;
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import net.minecraft.resources.Identifier;
+import net.minecraft.server.MinecraftServer;
+import net.neoforged.testframework.junit.EphemeralTestServerProvider;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+
+@ExtendWith(EphemeralTestServerProvider.class)
+class ItemLinkCompilerTest {
+
+    public ItemLinkCompilerTest(MinecraftServer server) {
+    }
+
+    @Test
+    void testMissingTargetPageFromSameNamespace() throws IOException {
+        var page = compilePage("minecraft:test_page", """
+                <ItemLink id="minecraft:stick" />
+                """);
+
+        assertThat(page.document().getTextContent()).contains("No page found for item minecraft:stick");
+    }
+
+    @Test
+    void testMissingTargetPageFromSameNamespaceButOptional() throws IOException {
+        var page = compilePage("minecraft:test_page", """
+                <ItemLink id="minecraft:stick" optional />
+                """);
+
+        assertThat(page.document().getTextContent()).isEqualTo("Stick");
+    }
+
+    @Test
+    void testMissingTargetPageFromOtherNamespace() throws IOException {
+        var page = compilePage("giudeme:test_page", """
+                <ItemLink id="minecraft:stick" />
+                """);
+
+        assertThat(page.document().getTextContent()).isEqualTo("Stick");
+    }
+
+    @Test
+    void testMissingTargetPageFromOtherNamespaceButExplicitlyNonOptional() throws IOException {
+        var page = compilePage("giudeme:test_page", """
+                <ItemLink id="minecraft:stick" optional={false} />
+                """);
+
+        assertThat(page.document().getTextContent()).contains("No page found for item minecraft:stick");
+    }
+
+    private static GuidePage compilePage(String pageId, String content) throws IOException {
+        try (var in = new ByteArrayInputStream(content.getBytes())) {
+            var parsed = PageCompiler.parse(GuideME.MOD_ID, "en_us", Identifier.parse(pageId), in);
+            var testPages = Guide.builder(Identifier.fromNamespaceAndPath(GuideME.MOD_ID, "test"))
+                    .watchDevelopmentSources(false)
+                    .register(false)
+                    .disableOpenHotkey()
+                    .build();
+            return PageCompiler.compile(testPages, ExtensionCollection.builder()
+                    .add(TagCompiler.EXTENSION_POINT, new ItemLinkCompiler())
+                    .build(), parsed);
+        }
+    }
+}

src/test/java/guideme/compiler/tags/MdxAttrsTest.java

@@ -1,11 +1,17 @@
 package guideme.compiler.tags;
 
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
 import guideme.compiler.PageCompiler;
 import guideme.document.LytErrorSink;
+import guideme.internal.GuideME;
 import guideme.libs.mdast.mdx.model.MdxJsxAttribute;
 import guideme.libs.mdast.mdx.model.MdxJsxAttributeNode;
 import guideme.libs.mdast.mdx.model.MdxJsxElementFields;
 import guideme.libs.mdast.mdx.model.MdxJsxTextElement;
+import java.io.ByteArrayInputStream;
 import java.util.HashMap;
 import org.junit.jupiter.api.Test;
 import org.mockito.Mock;
@@ -45,4 +51,29 @@ void testVector3() {
                 "");
         MdxAttrs.getVector3(compiler, errorSink, el, "from", null);
     }
+
+    @Test
+    void testBooleanAttrsWithExpression() throws Exception {
+        var parsedPage = PageCompiler.parse("ignored", "en_us", GuideME.makeId("test"),
+                new ByteArrayInputStream("<Tag attr={true} />".getBytes()));
+        var firstTag = parsedPage.getAstRoot().children().getFirst();
+        assertTrue(MdxAttrs.getBoolean((MdxJsxElementFields) firstTag, "attr", false));
+    }
+
+    @Test
+    void testBooleanAttrsWithoutValue() throws Exception {
+        var parsedPage = PageCompiler.parse("ignored", "en_us", GuideME.makeId("test"),
+                new ByteArrayInputStream("<Tag attr />".getBytes()));
+        var firstTag = parsedPage.getAstRoot().children().getFirst();
+        assertTrue(MdxAttrs.getBoolean((MdxJsxElementFields) firstTag, "attr", false));
+    }
+
+    @Test
+    void testBooleanAttrsWithNullExpressionValue() throws Exception {
+        var parsedPage = PageCompiler.parse("ignored", "en_us", GuideME.makeId("test"),
+                new ByteArrayInputStream("<Tag attr={null} />".getBytes()));
+        var firstTag = parsedPage.getAstRoot().children().getFirst();
+        var e = assertThrows(Exception.class, () -> MdxAttrs.getBoolean((MdxJsxElementFields) firstTag, "attr", false));
+        assertThat(e).hasMessage("attr should be {true} or {false}");
+    }
 }