early jass error for using uninitialized vars

Frotty · Frotty · commit 67690caef1ed · 2026-03-11T12:40:25.000+01:00
diff --git a/de.peeeq.wurstscript/src/main/java/de/peeeq/wurstscript/jass/AntlrJassParseTreeTransformer.java b/de.peeeq.wurstscript/src/main/java/de/peeeq/wurstscript/jass/AntlrJassParseTreeTransformer.java
@@ -15,9 +15,11 @@
 import org.eclipse.jdt.annotation.Nullable;
 
 import java.util.List;
+import java.util.Set;
 
 
 public class AntlrJassParseTreeTransformer {
+    private static final Set<String> JASS_PRIMITIVE_TYPES = Set.of("integer", "real", "boolean");
     private final String file;
     private final ErrorHandler cuErrorHandler;
     private final LineOffsets lineOffsets;
@@ -123,12 +125,23 @@ private WStatements transformJassLocals(List<JassParser.JassLocalContext> jassLo
             OptTypeExpr optTyp = transformOptionalType(l.jassTypeExpr());
             Identifier name = Ast.Identifier(source(l.name), l.name.getText());
             OptExpr initialExpr = transformOptionalExpr(l.initial);
+            if (l.initial == null && shouldDefaultLocalToNull(optTyp)) {
+                initialExpr = Ast.ExprNull(source(l));
+            }
             result.add(Ast.LocalVarDef(source(l), modifiers, optTyp, name,
                     initialExpr));
         }
         return result;
     }
 
+    private boolean shouldDefaultLocalToNull(OptTypeExpr optTyp) {
+        if (!(optTyp instanceof TypeExprSimple)) {
+            return false;
+        }
+        String typeName = ((TypeExprSimple) optTyp).getTypeName();
+        return !JASS_PRIMITIVE_TYPES.contains(typeName);
+    }
+
     private WStatements transformJassStatements(JassParser.JassStatementsContext stmts) {
         WStatements result = Ast.WStatements();
         for (JassParser.JassStatementContext s : stmts.jassStatement()) {
diff --git a/de.peeeq.wurstscript/src/main/java/de/peeeq/wurstscript/jurst/AntlrJurstParseTreeTransformer.java b/de.peeeq.wurstscript/src/main/java/de/peeeq/wurstscript/jurst/AntlrJurstParseTreeTransformer.java
@@ -17,8 +17,10 @@
 import org.eclipse.jdt.annotation.Nullable;
 
 import java.util.List;
+import java.util.Set;
 
 public class AntlrJurstParseTreeTransformer {
+    private static final Set<String> JASS_PRIMITIVE_TYPES = Set.of("integer", "real", "boolean");
 
     private final String file;
     private final ErrorHandler cuErrorHandler;
@@ -134,12 +136,23 @@ private WStatements transformJassLocals(List<JassLocalContext> jassLocals) {
             OptTypeExpr optTyp = transformOptionalType(l.typeExpr());
             Identifier name = text(l.name);
             OptExpr initialExpr = transformOptionalExpr(l.initial);
+            if (l.initial == null && shouldDefaultJassLocalToNull(optTyp)) {
+                initialExpr = Ast.ExprNull(source(l));
+            }
             result.add(Ast.LocalVarDef(source(l), modifiers, optTyp, name,
                     initialExpr));
         }
         return result;
     }
 
+    private boolean shouldDefaultJassLocalToNull(OptTypeExpr optTyp) {
+        if (!(optTyp instanceof TypeExprSimple)) {
+            return false;
+        }
+        String typeName = ((TypeExprSimple) optTyp).getTypeName();
+        return !JASS_PRIMITIVE_TYPES.contains(typeName);
+    }
+
     private WStatements transformJassStatements(JassStatementsContext stmts) {
         WStatements result = Ast.WStatements();
         for (JassStatementContext s : stmts.jassStatement()) {
diff --git a/de.peeeq.wurstscript/src/main/java/de/peeeq/wurstscript/parser/antlr/AntlrWurstParseTreeTransformer.java b/de.peeeq.wurstscript/src/main/java/de/peeeq/wurstscript/parser/antlr/AntlrWurstParseTreeTransformer.java
@@ -27,10 +27,12 @@
 import java.util.Comparator;
 import java.util.Deque;
 import java.util.List;
+import java.util.Set;
 import java.util.stream.Collectors;
 
 @SuppressWarnings("Duplicates")
 public class AntlrWurstParseTreeTransformer {
+    private static final Set<String> JASS_PRIMITIVE_TYPES = Set.of("integer", "real", "boolean");
 
     private final String file;
     private final ErrorHandler cuErrorHandler;
@@ -225,12 +227,23 @@ private WStatements transformJassLocals(List<JassLocalContext> jassLocals) {
             OptTypeExpr optTyp = transformOptionalType(l.typeExpr());
             Identifier name = text(l.name);
             OptExpr initialExpr = transformOptionalExpr(l.initial);
+            if (l.initial == null && shouldDefaultJassLocalToNull(optTyp)) {
+                initialExpr = Ast.ExprNull(source(l));
+            }
             result.add(Ast.LocalVarDef(source(l), modifiers, optTyp, name,
                     initialExpr));
         }
         return result;
     }
 
+    private boolean shouldDefaultJassLocalToNull(OptTypeExpr optTyp) {
+        if (!(optTyp instanceof TypeExprSimple)) {
+            return false;
+        }
+        String typeName = ((TypeExprSimple) optTyp).getTypeName();
+        return !JASS_PRIMITIVE_TYPES.contains(typeName);
+    }
+
     private WStatements transformJassStatements(JassStatementsContext stmts) {
         WStatements result = Ast.WStatements();
         if (stmts != null && stmts.jassStatement() != null) {
diff --git a/de.peeeq.wurstscript/src/main/java/de/peeeq/wurstscript/validation/WurstValidator.java b/de.peeeq.wurstscript/src/main/java/de/peeeq/wurstscript/validation/WurstValidator.java
@@ -1643,9 +1643,71 @@ private void checkUninitializedVars(FunctionLike f) {
             && !f.getSource().getFile().endsWith("blizzard.j")
             && !f.getSource().getFile().endsWith("war3map.j")) {
             new DataflowAnomalyAnalysis(Utils.isJassCode(f)).execute(f);
+            checkJassImplicitNullLocalsReadWithoutExplicitWrite(f);
         }
     }
 
+    /**
+     * JASS compatibility shim: we currently synthesize "= null" for uninitialized non-primitive
+     * locals to avoid invalid emitted JASS. Still report likely user bugs early when such a local
+     * is read but never explicitly assigned in the input.
+     */
+    private void checkJassImplicitNullLocalsReadWithoutExplicitWrite(FunctionLike f) {
+        if (!Utils.isJassCode(f)) {
+            return;
+        }
+
+        List<LocalVarDef> implicitNullLocals = new ArrayList<>();
+        f.accept(new Element.DefaultVisitor() {
+            @Override
+            public void visit(LocalVarDef localVarDef) {
+                super.visit(localVarDef);
+                if (isImplicitNullInit(localVarDef)) {
+                    implicitNullLocals.add(localVarDef);
+                }
+            }
+        });
+        if (implicitNullLocals.isEmpty()) {
+            return;
+        }
+
+        Set<LocalVarDef> explicitWrites = new HashSet<>();
+        f.accept(new Element.DefaultVisitor() {
+            @Override
+            public void visit(StmtSet stmtSet) {
+                super.visit(stmtSet);
+                NameLink link = stmtSet.getUpdatedExpr().attrNameLink();
+                if (link != null && link.getDef() instanceof LocalVarDef) {
+                    explicitWrites.add((LocalVarDef) link.getDef());
+                }
+            }
+        });
+
+        for (LocalVarDef local : implicitNullLocals) {
+            if (explicitWrites.contains(local)) {
+                continue;
+            }
+            if (f.attrReadVariables().contains(local)) {
+                local.addError("Variable " + local.getName()
+                    + " is read before explicit initialization in input JASS.");
+            }
+        }
+    }
+
+    private boolean isImplicitNullInit(LocalVarDef localVarDef) {
+        if (!(localVarDef.getInitialExpr() instanceof ExprNull)) {
+            return false;
+        }
+        // Synthetic null-inits created by the JASS parser use the exact local declaration source span.
+        return sameSourceSpan(localVarDef.getInitialExpr().attrSource(), localVarDef.attrSource());
+    }
+
+    private boolean sameSourceSpan(de.peeeq.wurstscript.parser.WPos a, de.peeeq.wurstscript.parser.WPos b) {
+        return a.getFile().equals(b.getFile())
+            && a.getLeftPos() == b.getLeftPos()
+            && a.getRightPos() == b.getRightPos();
+    }
+
 
 
 
diff --git a/de.peeeq.wurstscript/src/test/java/tests/wurstscript/tests/CompilationUnitTests.java b/de.peeeq.wurstscript/src/test/java/tests/wurstscript/tests/CompilationUnitTests.java
@@ -38,4 +38,32 @@ public void jass() {
                 ));
     }
 
+    @Test
+    public void jassLocalHandleDefaultsToNull() {
+        testAssertOkLinesWithStdLib(false,
+            "function tiw takes nothing returns nothing",
+            "local location uiw",
+            "set uiw = null",
+            "endfunction",
+            "package B",
+            "    init",
+            "        tiw()",
+            "endpackage"
+        );
+    }
+
+    @Test
+    public void jassLocalHandleReadWithoutExplicitInitReportsEarly() {
+        testAssertErrorsLinesWithStdLib(false, "read before explicit initialization in input JASS",
+            "function tiw takes nothing returns nothing",
+            "local location uiw",
+            "call RemoveLocation(uiw)",
+            "endfunction",
+            "package B",
+            "    init",
+            "        tiw()",
+            "endpackage"
+        );
+    }
+
 }
