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Add warning for ambiguous arg subtraction #7808

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Add warning for ambiguous arg subtraction #7808

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5682bff
Add warning for ambiguous arg subtraction
sovdeeth Apr 18, 2025
402dc39
optimize condition and check if the second literal is specifically 1.
sovdeeth Apr 18, 2025
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32 changes: 21 additions & 11 deletions src/main/java/ch/njol/skript/expressions/ExprArgument.java
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Original file line number Diff line number Diff line change
@@ -1,15 +1,5 @@
package ch.njol.skript.expressions;

import java.util.List;
import java.util.regex.MatchResult;

import ch.njol.skript.lang.EventRestrictedSyntax;
import ch.njol.util.coll.CollectionUtils;
import org.bukkit.event.Event;
import org.bukkit.event.player.PlayerCommandPreprocessEvent;
import org.bukkit.event.server.ServerCommandEvent;
import org.jetbrains.annotations.Nullable;

import ch.njol.skript.Skript;
import ch.njol.skript.classes.ClassInfo;
import ch.njol.skript.command.Argument;
Expand All @@ -19,6 +9,7 @@
import ch.njol.skript.doc.Examples;
import ch.njol.skript.doc.Name;
import ch.njol.skript.doc.Since;
import ch.njol.skript.lang.EventRestrictedSyntax;
import ch.njol.skript.lang.Expression;
import ch.njol.skript.lang.ExpressionType;
import ch.njol.skript.lang.Literal;
Expand All @@ -29,6 +20,14 @@
import ch.njol.skript.util.Utils;
import ch.njol.util.Kleenean;
import ch.njol.util.StringUtils;
import ch.njol.util.coll.CollectionUtils;
import org.bukkit.event.Event;
import org.bukkit.event.player.PlayerCommandPreprocessEvent;
import org.bukkit.event.server.ServerCommandEvent;
import org.jetbrains.annotations.Nullable;

import java.util.List;
import java.util.regex.MatchResult;

@Name("Argument")
@Description({
Expand Down Expand Up @@ -65,7 +64,9 @@ public class ExprArgument extends SimpleExpression<Object> implements EventRestr
private Argument<?> argument;

private int ordinal = -1; // Available in ORDINAL and sometimes CLASSINFO


private boolean couldCauseArithmeticConfusion = false;

@Override
@SuppressWarnings("unchecked")
public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelayed, ParseResult parseResult) {
Expand All @@ -81,6 +82,8 @@ public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelaye
break;
case 3:
what = parseResult.mark == 1 ? ALL : SINGLE;
if (what == SINGLE && parseResult.expr.matches("(the )?arg(ument)?"))
couldCauseArithmeticConfusion = true; // 'arg-1' could be parsed as 'argument - 1'
break;
case 4:
case 5:
Expand Down Expand Up @@ -246,6 +249,13 @@ protected Object[] get(final Event e) {
public boolean isSingle() {
return argument != null ? argument.isSingle() : what != ALL;
}

/**
* @return whether the expression is 'arg', a single argument that could cause confusion with 'arg-1' being parsed as 'argument - 1'.
*/
public boolean couldCauseArithmeticConfusion() {
return couldCauseArithmeticConfusion;
}

@Override
public Class<?> getReturnType() {
Expand Down
22 changes: 21 additions & 1 deletion src/main/java/ch/njol/skript/expressions/arithmetic/ExprArithmetic.java
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Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@
import ch.njol.skript.doc.Examples;
import ch.njol.skript.doc.Name;
import ch.njol.skript.doc.Since;
import ch.njol.skript.expressions.ExprArgument;
import ch.njol.skript.lang.Expression;
import ch.njol.skript.lang.ExpressionType;
import ch.njol.skript.lang.Literal;
Expand All @@ -26,8 +27,8 @@

import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.List;
import java.util.Collection;
import java.util.List;

@Name("Arithmetic")
@Description("Arithmetic expressions, e.g. 1 + 2, (health of player - 2) / 3, etc.")
Expand Down Expand Up @@ -113,6 +114,9 @@ public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelaye
rightGrouped = patternInfo.rightGrouped;
operator = patternInfo.operator;

// print warning for arg-1 confusion scenario
printArgWarning(first, second, operator);

/*
* Step 1: UnparsedLiteral Resolving
*
Expand Down Expand Up @@ -294,6 +298,22 @@ public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelaye
return arithmeticGettable != null || error(firstClass, secondClass);
}

private void printArgWarning(Expression<L> first, Expression<R> second, Operator operator) {
if (operator == Operator.SUBTRACTION && !rightGrouped && !leftGrouped // if the operator is '-' and the user didn't use ()
&& first instanceof ExprArgument argument && argument.couldCauseArithmeticConfusion() // if the first expression is 'arg'
&& second instanceof ExprArithmetic<?, ?, ?> secondArith && secondArith.first instanceof Literal<?> literal // this ambiguity only occurs when the code is parsed as `arg - (1 * 2)` or a similar PEMDAS priority.
&& literal.canReturn(Number.class)) {
// ensure that the second literal is a 1
Literal<?> secondLiteral = (Literal<?>) LiteralUtils.defendExpression(literal);
if (LiteralUtils.canInitSafely(secondLiteral)) {
double number = ((Number) secondLiteral.getSingle()).doubleValue();
if (number == 1)
Skript.warning("This subtraction is ambiguous and could be interpreted either as 'arg-1' or as '(arg) - 1'. " +
"If you meant to use 'arg-1', use 'arg 1' instead or use parentheses to clarify your intent.");
}
}
}

@Override
@SuppressWarnings("unchecked")
protected T[] get(Event event) {
Expand Down