Fix SectionNode claiming edge cases (#8232)

Author: APickledWalrus

src/main/java/ch/njol/skript/lang/EffectSection.java

@@ -23,6 +23,10 @@
  */
 public abstract class EffectSection extends Section {
 
+	static {
+		ParserInstance.registerData(EffectSectionContext.class, EffectSectionContext::new);
+	}
+
 	private boolean hasSection;
 
 	public boolean hasSection() {
@@ -34,10 +38,23 @@ public boolean hasSection() {
 	 */
 	@Override
 	public boolean init(Expression<?>[] expressions, int matchedPattern, Kleenean isDelayed, ParseResult parseResult) {
-		SectionContext sectionContext = getParser().getData(SectionContext.class);
+		ParserInstance parser = getParser();
+		SectionContext sectionContext = parser.getData(SectionContext.class);
+		EffectSectionContext effectSectionContext = parser.getData(EffectSectionContext.class);
+		SectionNode sectionNode = sectionContext.sectionNode;
+		if (!effectSectionContext.isNodeForEffectSection) {
+			sectionContext.sectionNode = null;
+		}
+
 		//noinspection ConstantConditions - For an EffectSection, it may be null
 		hasSection = sectionContext.sectionNode != null;
-		return super.init(expressions, matchedPattern, isDelayed, parseResult);
+		boolean result = super.init(expressions, matchedPattern, isDelayed, parseResult);
+
+		if (!effectSectionContext.isNodeForEffectSection) {
+			sectionContext.sectionNode = sectionNode;
+		}
+
+		return result;
 	}
 
 	@Override
@@ -52,15 +69,48 @@ public abstract boolean init(Expression<?>[] expressions,
 	 * Similar to {@link Section#parse(String, String, SectionNode, List)}, but will only attempt to parse from other {@link EffectSection}s.
 	 */
 	public static @Nullable EffectSection parse(String input, @Nullable String defaultError, @Nullable SectionNode sectionNode, @Nullable List<TriggerItem> triggerItems) {
-		SectionContext sectionContext = ParserInstance.get().getData(SectionContext.class);
+		return parse(input, defaultError, sectionNode, true,  triggerItems);
+	}
+
+	/**
+	 * Similar to {@link Section#parse(String, String, SectionNode, List)}, but will only attempt to parse from other {@link EffectSection}s.
+	 * @param isNodeForEffectSection Whether {@code sectionNode} can be {@link SectionContext#claim(SyntaxElement)}-ed by the parsed EffectSection.
+	 */
+	public static @Nullable EffectSection parse(String input, @Nullable String defaultError, SectionNode sectionNode, boolean isNodeForEffectSection, List<TriggerItem> triggerItems) {
+		ParserInstance parser = ParserInstance.get();
+		SectionContext sectionContext = parser.getData(SectionContext.class);
+		EffectSectionContext effectSectionContext = parser.getData(EffectSectionContext.class);
+		boolean wasNodeForEffectSection = effectSectionContext.isNodeForEffectSection;
+		effectSectionContext.isNodeForEffectSection = isNodeForEffectSection;
 
-		return sectionContext.modify(sectionNode, triggerItems, () -> {
+		EffectSection effectSection = sectionContext.modify(sectionNode, triggerItems, () -> {
 			var iterator = Skript.instance().syntaxRegistry().syntaxes(org.skriptlang.skript.registration.SyntaxRegistry.SECTION).stream()
-					.filter(info -> EffectSection.class.isAssignableFrom(info.type()))
-					.iterator();
+				.filter(info -> EffectSection.class.isAssignableFrom(info.type()))
+				.iterator();
 			//noinspection unchecked,rawtypes
-			return (EffectSection) SkriptParser.parse(input, (Iterator) iterator, defaultError);
+			EffectSection parsed = (EffectSection) SkriptParser.parse(input, (Iterator) iterator, defaultError);
+			if (parsed != null && sectionNode != null && !sectionContext.claimed()) {
+				Skript.error("The line '" + input + "' is a valid statement but cannot function as a section (:) because there is no syntax in the line to manage it.");
+				return null;
+			}
+			return parsed;
 		});
+
+		effectSectionContext.isNodeForEffectSection = wasNodeForEffectSection;
+		return effectSection;
+	}
+
+	private static class EffectSectionContext extends ParserInstance.Data {
+
+		/**
+		 * Whether the {@link SectionContext#sectionNode} can be used by the initializing {@link EffectSection}.
+		 */
+		public boolean isNodeForEffectSection = true;
+
+		public EffectSectionContext(ParserInstance parserInstance) {
+			super(parserInstance);
+		}
+
 	}
 
 }

src/main/java/ch/njol/skript/lang/Statement.java

@@ -33,7 +33,14 @@ public abstract class Statement extends TriggerItem implements SyntaxElement {
 			Section.SectionContext sectionContext = ParserInstance.get().getData(Section.SectionContext.class);
 			EffFunctionCall functionCall;
 			if (node != null) {
-				functionCall = sectionContext.modify(node, items, () -> EffFunctionCall.parse(input));
+				functionCall = sectionContext.modify(node, items, () -> {
+					EffFunctionCall parsed = EffFunctionCall.parse(input);
+					if (parsed != null && !sectionContext.claimed()) {
+						Skript.error("The line '" + input + "' is a valid function call but cannot function as a section (:) because there is no parameter to manage it.");
+						return null;
+					}
+					return parsed;
+				});
 			} else {
 				functionCall = EffFunctionCall.parse(input);
 			}
@@ -46,7 +53,7 @@ public abstract class Statement extends TriggerItem implements SyntaxElement {
 			}
 			log.clear();
 
-			EffectSection section = EffectSection.parse(input, null, null, items);
+			EffectSection section = EffectSection.parse(input, null, node, false, items);
 			if (section != null) {
 				log.printLog();
 				return new EffectSectionEffect(section);

src/test/skript/tests/regressions/8199-parse exprsecs in function args.sk

@@ -4,3 +4,9 @@ local function f(x: worldborder):
 test "load expr secs in functions":
     f(a worldborder):
         set worldborder warning time to 20 ticks
+
+    # ensure it fails for unclaimed sections
+    parse:
+        f({_null}):
+            stop
+    assert first element of last parse logs contains "is a valid function call but cannot function as a section" with "failed to correctly error for unclaimed section"