Fix constructor inheritance

enigma/src/main/java/org/quiltmc/enigma/api/translation/mapping/IndexEntryResolver.java

@@ -64,7 +64,7 @@ public <E extends Entry<?>> Collection<E> resolveEntry(E entry, ResolutionStrate
 		}
 
 		Entry<ClassEntry> entryAsClassChild = this.getClassChild(entry);
-		if (entryAsClassChild != null && !(entryAsClassChild instanceof ClassEntry)) {
+		if (entryAsClassChild != null) {
 			AccessFlags access = this.entryIndex.getEntryAccess(entryAsClassChild);
 
 			// If we're looking for the closest and this entry exists, we're done looking
@@ -73,8 +73,12 @@ public <E extends Entry<?>> Collection<E> resolveEntry(E entry, ResolutionStrate
 			}
 
 			// Don't search existing private and/or static entries up the hierarchy
-			// Fields and classes can't be redefined, don't search them up the hierarchy
-			if (access != null && (access.isPrivate() || access.isStatic() || entry instanceof FieldEntry || entry instanceof ClassEntry)) {
+			// Fields can't be redefined, don't search them up the hierarchy
+			// Constructors can't be redefined, don't search them up the hierarchy
+			if (
+					(access != null && (access.isPrivate() || access.isStatic() || entry instanceof FieldEntry))
+						|| (entry instanceof MethodEntry method && method.isConstructor())
+			) {
 				return Collections.singleton(entry);
 			} else {
 				// Search the entry up the hierarchy; if the entry exists we can skip static entries, since this one isn't static
@@ -97,7 +101,10 @@ public <E extends Entry<?>> Collection<E> resolveEntry(E entry, ResolutionStrate
 	 * Get a direct child of any class that is an ancestor of the given entry.
 	 *
 	 * @param entry the descendant of a class
-	 * @return the direct child of a class, which is an ancestor of the given entry or the entry itself
+	 *
+	 * @return the direct child of a class, which is an ancestor of the given entry or the entry itself;
+	 * returns {@code null} if the passed {@code entry} is a {@link ClassEntry} or if all of its ancestors are
+	 * {@link ClassEntry}s; never returns a {@link ClassEntry}
 	 */
 	@Nullable
 	private Entry<ClassEntry> getClassChild(Entry<?> entry) {

enigma/src/test/java/org/quiltmc/enigma/TestJarIndexInheritanceTree.java

@@ -15,6 +15,7 @@
 import org.quiltmc.enigma.api.class_provider.ProjectClassProvider;
 import org.quiltmc.enigma.api.translation.mapping.EntryResolver;
 import org.quiltmc.enigma.api.translation.mapping.IndexEntryResolver;
+import org.quiltmc.enigma.api.translation.mapping.ResolutionStrategy;
 import org.quiltmc.enigma.api.translation.representation.AccessFlags;
 import org.quiltmc.enigma.api.translation.representation.entry.ClassEntry;
 import org.quiltmc.enigma.api.translation.representation.entry.FieldEntry;
@@ -34,13 +35,21 @@ public class TestJarIndexInheritanceTree {
 	public static final Path JAR = TestUtil.obfJar("inheritance_tree");
 
 	private static final ClassEntry OBJECT_CLASS = TestEntryFactory.newClass("java/lang/Object");
+
 	private static final ClassEntry BASE_CLASS = TestEntryFactory.newClass("a");
-	private static final ClassEntry SUB_CLASS_A = TestEntryFactory.newClass("b");
-	private static final ClassEntry SUB_CLASS_AA = TestEntryFactory.newClass("d");
-	private static final ClassEntry SUB_CLASS_B = TestEntryFactory.newClass("c");
+	private static final ClassEntry SUB_CLASS_A = TestEntryFactory.newClass("d");
+	private static final ClassEntry SUB_CLASS_AA = TestEntryFactory.newClass("f");
+	private static final ClassEntry SUB_CLASS_B = TestEntryFactory.newClass("e");
 	private static final FieldEntry NAME_FIELD = TestEntryFactory.newField(BASE_CLASS, "a", "Ljava/lang/String;");
 	private static final FieldEntry NUM_THINGS_FIELD = TestEntryFactory.newField(SUB_CLASS_B, "a", "I");
 
+	private static final ClassEntry CONSTRUCTOR_PARENT = TestEntryFactory.newClass("b");
+	private static final ClassEntry CONSTRUCTOR_SUB_CLASS = TestEntryFactory.newClass("c");
+	private static final MethodEntry PARENT_NO_ARGS_CONSTRUCTOR = TestEntryFactory.newMethod(CONSTRUCTOR_PARENT.getFullName(), "<init>", "()V");
+	private static final MethodEntry PARENT_INT_CONSTRUCTOR = TestEntryFactory.newMethod(CONSTRUCTOR_PARENT.getFullName(), "<init>", "(I)V");
+	private static final MethodEntry SUB_CLASS_NO_ARGS_CONSTRUCTOR = TestEntryFactory.newMethod(CONSTRUCTOR_SUB_CLASS.getFullName(), "<init>", "()V");
+	private static final MethodEntry SUB_CLASS_INT_CONSTRUCTOR = TestEntryFactory.newMethod(CONSTRUCTOR_SUB_CLASS.getFullName(), "<init>", "(I)V");
+
 	private final JarIndex index;
 
 	public TestJarIndexInheritanceTree() throws Exception {
@@ -52,7 +61,9 @@ public TestJarIndexInheritanceTree() throws Exception {
 	@Test
 	public void obfEntries() {
 		assertThat(this.index.getIndex(EntryIndex.class).getClasses(), Matchers.containsInAnyOrder(
-				TestEntryFactory.newClass("org/quiltmc/enigma/input/Keep"), BASE_CLASS, SUB_CLASS_A, SUB_CLASS_AA, SUB_CLASS_B
+				TestEntryFactory.newClass("org/quiltmc/enigma/input/Keep"),
+				BASE_CLASS, SUB_CLASS_A, SUB_CLASS_AA, SUB_CLASS_B,
+				CONSTRUCTOR_PARENT, CONSTRUCTOR_SUB_CLASS
 		));
 	}
 
@@ -216,4 +227,19 @@ public void containsEntries() {
 		assertThat(entryIndex.hasMethod(TestEntryFactory.newMethod(SUB_CLASS_AA, "b", "()V")), is(false));
 		assertThat(entryIndex.hasMethod(TestEntryFactory.newMethod(SUB_CLASS_B, "b", "()V")), is(true));
 	}
+
+	@Test
+	public void noConstructorInheritance() {
+		assertThat(
+				this.index.getEntryResolver()
+					.resolveEntry(SUB_CLASS_NO_ARGS_CONSTRUCTOR, ResolutionStrategy.RESOLVE_ROOT),
+				contains(SUB_CLASS_NO_ARGS_CONSTRUCTOR)
+		);
+
+		assertThat(
+				this.index.getEntryResolver()
+					.resolveEntry(SUB_CLASS_INT_CONSTRUCTOR, ResolutionStrategy.RESOLVE_ROOT),
+				contains(SUB_CLASS_INT_CONSTRUCTOR)
+		);
+	}
 }

enigma/src/test/java/org/quiltmc/enigma/input/inheritance_tree/ConstructorParent.java

@@ -0,0 +1,7 @@
+package org.quiltmc.enigma.input.inheritance_tree;
+
+public class ConstructorParent {
+	ConstructorParent() { }
+
+	ConstructorParent(int i) { }
+}

enigma/src/test/java/org/quiltmc/enigma/input/inheritance_tree/ConstructorSubClass.java

@@ -0,0 +1,7 @@
+package org.quiltmc.enigma.input.inheritance_tree;
+
+class ConstructorSubClass extends ConstructorParent {
+	ConstructorSubClass() { }
+
+	ConstructorSubClass(int i) { }
+}