Handle invalid amounts in ExprRandomCharacter (#6502)

* protect against bad amounts

* Update ExprCharacters.sk

.%

* switch to Integer instead of Number and let chaos reign

---------

Co-authored-by: Moderocky <admin@moderocky.com>

src/main/java/ch/njol/skript/expressions/ExprRandomCharacter.java

@@ -50,17 +50,17 @@ public class ExprRandomCharacter extends SimpleExpression<String> {
 
 	static {
 		Skript.registerExpression(ExprRandomCharacter.class, String.class, ExpressionType.COMBINED,
-				"[a|%-number%] random [:alphanumeric] character[s] (from|between) %string% (to|and) %string%");
+				"[a|%-integer%] random [:alphanumeric] character[s] (from|between) %string% (to|and) %string%");
 	}
 
 	@Nullable
-	private Expression<Number> amount;
+	private Expression<Integer> amount;
 	private Expression<String> from, to;
 	private boolean isAlphanumeric;
 
 	@Override
 	public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelayed, ParseResult parseResult) {
-		amount = (Expression<Number>) exprs[0];
+		amount = (Expression<Integer>) exprs[0];
 		from = (Expression<String>) exprs[1];
 		to = (Expression<String>) exprs[2];
 		isAlphanumeric = parseResult.hasTag("alphanumeric");
@@ -70,7 +70,10 @@ public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelaye
 	@Override
 	@Nullable
 	protected String[] get(Event event) {
-		int amount = this.amount == null ? 1 : this.amount.getOptionalSingle(event).orElse(1).intValue();
+		Integer amount = this.amount == null ? Integer.valueOf(1) : this.amount.getSingle(event);
+		if (amount == null || amount <= 0)
+			return new String[0];
+
 		String from = this.from.getSingle(event);
 		String to = this.to.getSingle(event);
 		if (from == null || to == null)
@@ -117,7 +120,7 @@ protected String[] get(Event event) {
 	@Override
 	public boolean isSingle() {
 		if (amount instanceof Literal)
-			return ((Literal<Number>) amount).getSingle().intValue() == 1;
+			return ((Literal<Integer>) amount).getSingle() == 1;
 		return amount == null;
 	}
 

src/test/skript/tests/syntaxes/expressions/ExprCharacters.sk

@@ -1,5 +1,13 @@
 test "characters between":
 	set {_a} to 1 random character between "a" and "z"
+	assert {_a} is set with "failed to generate random character"
+
+	set {_a::*} to -10 random character between "a" and "z"
+	assert {_a::*} is not set with "-10 random characters returned non-null value: %{_a::*}%"
+
+	set {_a::*} to {_null} random character between "a" and "z"
+	assert {_a::*} is not set with "null random characters returned non-null value: %{_a::*}%"
+
 	assert join characters between "a" and "d" is "abcd" with "Invalid characters between a and d"
 	assert join characters between "d" and "a" is "dcba" with "Invalid characters between d and a"
 	assert join characters between "Z" and "a" is "Z[\]^_`a" with "Invalid characters between Z and a"