Fix error when unloading a script with multiple variables sections

src/main/java/ch/njol/skript/structures/StructVariables.java

@@ -18,14 +18,7 @@
  */
 package ch.njol.skript.structures;
 
-import java.util.ArrayDeque;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Deque;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Locale;
-import java.util.Map;
+import java.util.*;
 
 import org.bukkit.event.Event;
 import org.jetbrains.annotations.Nullable;
@@ -87,14 +80,14 @@ public static class DefaultVariables implements ScriptData {
 
 		private final Deque<Map<String, Class<?>[]>> hints = new ArrayDeque<>();
 		private final List<NonNullPair<String, Object>> variables;
+		private boolean loaded;
 
 		public DefaultVariables(Collection<NonNullPair<String, Object>> variables) {
 			this.variables = ImmutableList.copyOf(variables);
 		}
 
-		@SuppressWarnings("unchecked")
 		public void add(String variable, Class<?>... hints) {
-			if (hints == null || hints.length <= 0)
+			if (hints == null || hints.length == 0)
 				return;
 			if (CollectionUtils.containsAll(hints, Object.class)) // Ignore useless type hint.
 				return;
@@ -115,7 +108,7 @@ public void exitScope() {
 		/**
 		 * Returns the type hints of a variable.
 		 * Can be null if no type hint was saved.
-		 * 
+		 *
 		 * @param variable The variable string of a variable.
 		 * @return type hints of a variable if found otherwise null.
 		 */
@@ -140,14 +133,24 @@ public boolean hasDefaultVariables() {
 		public List<NonNullPair<String, Object>> getVariables() {
 			return variables;
 		}
+
+		private boolean isLoaded() {
+			return loaded;
+		}
 	}
 
 	@Override
 	public boolean init(Literal<?>[] args, int matchedPattern, ParseResult parseResult, EntryContainer entryContainer) {
 		SectionNode node = entryContainer.getSource();
 		node.convertToEntries(0, "=");
-
-		List<NonNullPair<String, Object>> variables = new ArrayList<>();
+		List<NonNullPair<String, Object>> variables;
+		Script script = getParser().getCurrentScript();
+		DefaultVariables existing = script.getData(DefaultVariables.class); // if the user has TWO variables: sections
+		if (existing != null && existing.hasDefaultVariables()) {
+			variables = new ArrayList<>(existing.variables);
+		} else {
+			variables = new ArrayList<>();
+		}
 		for (Node n : node) {
 			if (!(n instanceof EntryNode)) {
 				Skript.error("Invalid line in variables structure");
@@ -227,29 +230,40 @@ public boolean init(Literal<?>[] args, int matchedPattern, ParseResult parseResu
 			}
 			variables.add(new NonNullPair<>(name, o));
 		}
-		getParser().getCurrentScript().addData(new DefaultVariables(variables));
+		script.addData(new DefaultVariables(variables)); // we replace the previous entry
 		return true;
 	}
 
 	@Override
 	public boolean load() {
 		DefaultVariables data = getParser().getCurrentScript().getData(DefaultVariables.class);
+		if (data == null) { // this shouldn't happen
+			Skript.error("Default variables data missing");
+			return false;
+		} else if (data.isLoaded()) {
+			return true;
+		}
 		for (NonNullPair<String, Object> pair : data.getVariables()) {
 			String name = pair.getKey();
 			if (Variables.getVariable(name, null, false) != null)
 				continue;
-
 			Variables.setVariable(name, pair.getValue(), null, false);
 		}
+		data.loaded = true;
 		return true;
 	}
 
 	@Override
 	public void postUnload() {
 		Script script = getParser().getCurrentScript();
 		DefaultVariables data = script.getData(DefaultVariables.class);
-		for (NonNullPair<String, Object> pair : data.getVariables())
-			Variables.setVariable(pair.getKey(), null, null, false);
+		if (data == null) // band-aid fix for this section's behaviour being handled by a previous section
+			return; // see https://github.com/SkriptLang/Skript/issues/6013
+		for (NonNullPair<String, Object> pair : data.getVariables()) {
+			String name = pair.getKey();
+			if (name.contains("<") && name.contains(">")) // probably a template made by us
+				Variables.setVariable(pair.getKey(), null, null, false);
+		}
 		script.removeData(DefaultVariables.class);
 	}