Throw EOF_CLOSURE error, fixes #3359

Remove EOFInClosure test since now it's not actual on runtime
antlr · Nov 20, 2021 · dedcb3a · dedcb3a
1 parent 957d1b2
commit dedcb3a
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Showing 4 changed files with 44 additions and 22 deletions.
diff --git a/runtime-testsuite/test/org/antlr/v4/test/runtime/descriptors/ParserExecDescriptors.java b/runtime-testsuite/test/org/antlr/v4/test/runtime/descriptors/ParserExecDescriptors.java
@@ -262,28 +262,6 @@ public static class Wildcard extends BaseParserTestDescriptor {
 		public String grammar;
 	}
 
-	/**
-	 * This test ensures that {@link org.antlr.v4.runtime.atn.ParserATNSimulator} does not produce a
-	 * {@link StackOverflowError} when it encounters an {@code EOF} transition
-	 * inside a closure.
-	 */
-	public static class EOFInClosure extends BaseParserTestDescriptor {
-		public String input = "x";
-		public String output = null;
-		public String errors = null;
-		public String startRule = "prog";
-		public String grammarName = "T";
-
-		/**
-		 grammar T;
-		 prog : stat EOF;
-		 stat : 'x' ('y' | EOF)*?;
-		 */
-		@CommentHasStringValue
-		public String grammar;
-
-	}
-
 	public static class IfIfElseGreedyBinding1 extends BaseParserTestDescriptor {
 		public String input = "if y if y x else x";
 		/**

diff --git a/tool-testsuite/test/org/antlr/v4/test/tool/TestToolSyntaxErrors.java b/tool-testsuite/test/org/antlr/v4/test/tool/TestToolSyntaxErrors.java
@@ -363,6 +363,23 @@ public void AllErrorCodesDistinct() {
 		super.testErrors(pair, true);
 	}
 
+	// Test for https://github.com/antlr/antlr4/issues/3359
+	@Test public void testEofClosure() {
+		String grammar =
+				"lexer grammar EofClosure;\n" +
+				"EofClosure: 'x' EOF*;";
+
+		String expected =
+			"error(" + ErrorType.EOF_CLOSURE.code + "): EofClosure.g4:2:0: rule EofClosure contains a closure with at least one alternative that can match EOF\n";
+
+		String[] pair = new String[] {
+				grammar,
+				expected
+		};
+
+		super.testErrors(pair, true);
+	}
+
 	// Test for https://github.com/antlr/antlr4/issues/1203
 	@Test public void testEpsilonOptionalAndClosureAnalysis() {
 		String grammar =

diff --git a/tool/src/org/antlr/v4/automata/ParserATNFactory.java b/tool/src/org/antlr/v4/automata/ParserATNFactory.java
@@ -147,6 +147,9 @@ protected void checkEpsilonClosure() {
 				ErrorType errorType = pair.a instanceof LeftRecursiveRule ? ErrorType.EPSILON_LR_FOLLOW : ErrorType.EPSILON_CLOSURE;
 				g.tool.errMgr.grammarError(errorType, g.fileName, ((GrammarAST)pair.a.ast.getChild(0)).getToken(), pair.a.name);
 			}
+			if ( lookahead.contains(org.antlr.v4.runtime.Token.EOF)) {
+				g.tool.errMgr.grammarError(ErrorType.EOF_CLOSURE, g.fileName, ((GrammarAST)pair.a.ast.getChild(0)).getToken(), pair.a.name);
+			}
 		}
 	}
 

diff --git a/tool/src/org/antlr/v4/tool/ErrorType.java b/tool/src/org/antlr/v4/tool/ErrorType.java
@@ -1089,6 +1089,30 @@ public enum ErrorType {
 			"One of the token <arg> values unreachable. <arg2> is always overlapped by token <arg3>",
 			ErrorSeverity.WARNING),
 
+	/**
+	 * Compiler Error 185.
+	 *
+	 * <p>
+	 * rule <em>rule</em> contains a closure with at least one alternative
+	 * that can match EOF</p>
+	 *
+	 * <p>A rule contains a closure ({@code (...)*}) or positive closure
+	 * ({@code (...)+}) around EOF.</p>
+	 *
+	 * <p>The following rule produces this error.</p>
+	 *
+	 * <pre>
+	 * x : EOF*;         // error
+	 * y : EOF+;         // error
+	 * z : EOF;         // ok
+	 * </pre>
+	 */
+	EOF_CLOSURE(
+			185,
+			"rule <arg> contains a closure with at least one alternative that can match EOF",
+			ErrorSeverity.ERROR
+	),
+
 	/*
 	 * Backward incompatibility errors
 	 */