Fix JavaFunctions not returning keys in getReturnedKeys

Author: Efnilite

src/main/java/ch/njol/skript/lang/function/Function.java

@@ -190,8 +190,12 @@ public Class<T> type() {
 	}
 
 	@Override
-	public @NotNull SequencedCollection<String> getReturnedKeys() {
-		return Collections.emptyList();
+	public final @NotNull SequencedCollection<String> getReturnedKeys() {
+		String[] returnedKeys = returnedKeys();
+		if (returnedKeys == null || returnedKeys.length == 0) {
+			return Collections.emptyList();
+		}
+		return Arrays.asList(returnedKeys);
 	}
 
 	/**

src/main/java/org/skriptlang/skript/common/function/DefaultFunction.java

@@ -140,12 +140,12 @@ interface Builder<T> {
 		 * Completes this builder with the code to execute on call of this function.
 		 * Adds a function for setting the returned keys by this function.
 		 *
-		 * @param keys The function which sets the return keys.
+		 * @param keys    The function which sets the return keys.
 		 * @param execute The code to execute and the key consumer.
 		 * @return The final function.
 		 */
 		DefaultFunction<T> buildKeyed(@NotNull java.util.function.Function<FunctionArguments, SequencedCollection<String>> keys,
-									  @NotNull java.util.function.Function<FunctionArguments, T> execute);
+		                              @NotNull java.util.function.Function<FunctionArguments, T> execute);
 
 	}
 

src/main/java/org/skriptlang/skript/common/function/DefaultFunctionImpl.java

@@ -153,11 +153,6 @@ public boolean resetReturnValue() {
 		return returnedKeys.toArray(new String[0]);
 	}
 
-	@Override
-	public @NotNull SequencedCollection<String> getReturnedKeys() {
-		return returnedKeys;
-	}
-
 	@Override
 	public @NotNull String name() {
 		return getName();
@@ -290,7 +285,7 @@ public DefaultFunction<T> build(@NotNull Function<FunctionArguments, T> execute)
 			Preconditions.checkNotNull(execute, "execute cannot be null");
 
 			return new DefaultFunctionImpl<>(source, name, parameters,
-					returnType, !returnType.isArray(), contract, execute, (_) -> Collections.emptyList(),
+					returnType, !returnType.isArray(), contract, execute, (args) -> Collections.emptyList(),
 					description, since, examples, keywords, requires);
 		}
 

src/main/java/org/skriptlang/skript/common/function/Function.java

@@ -5,7 +5,6 @@
 import org.jetbrains.annotations.ApiStatus.Internal;
 import org.jetbrains.annotations.ApiStatus.NonExtendable;
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
 
 import java.util.SequencedCollection;
 
@@ -23,7 +22,7 @@ public interface Function<T> {
 	/**
 	 * Executes this function with the given parameters.
 	 *
-	 * @param event The event that is associated with this function execution.
+	 * @param event     The event that is associated with this function execution.
 	 * @param arguments The arguments to execute the function with.
 	 * @return The return value.
 	 */
@@ -43,6 +42,7 @@ public interface Function<T> {
 	/**
 	 * @return The returned keys.
 	 */
+	@Experimental
 	@NotNull SequencedCollection<String> getReturnedKeys();
 
 }