From b4413e865642fc32145986721902c6f4d4954804 Mon Sep 17 00:00:00 2001
From: Sam Harwell <sam@tunnelvisionlabs.com>
Date: Tue, 26 Mar 2013 23:29:03 -0500
Subject: [PATCH] Fix handling of empty options{} block in grammar (fixes #194)

---
 tool/src/org/antlr/v4/tool/Grammar.java       |  2 +-
 .../v4/tool/GrammarTransformPipeline.java     |  2 +-
 .../antlr/v4/test/TestCompositeGrammars.java  | 17 +++++++
 .../antlr/v4/test/TestToolSyntaxErrors.java   | 45 +++++++++++++++++++
 4 files changed, 64 insertions(+), 2 deletions(-)

diff --git a/tool/src/org/antlr/v4/tool/Grammar.java b/tool/src/org/antlr/v4/tool/Grammar.java
index 679609ad0..2b1ef17df 100644
--- a/tool/src/org/antlr/v4/tool/Grammar.java
+++ b/tool/src/org/antlr/v4/tool/Grammar.java
@@ -756,7 +756,7 @@ public class Grammar implements AttributeResolver {
 	 */
 	public static void setNodeOptions(GrammarAST node, GrammarAST options) {
 		GrammarASTWithOptions t = (GrammarASTWithOptions)node;
-		if ( t.getChildCount()==0 ) return;
+		if ( t.getChildCount()==0 || options.getChildCount()==0 ) return;
 		for (Object o : options.getChildren()) {
 			GrammarAST c = (GrammarAST)o;
 			if ( c.getType()==ANTLRParser.ASSIGN ) {
diff --git a/tool/src/org/antlr/v4/tool/GrammarTransformPipeline.java b/tool/src/org/antlr/v4/tool/GrammarTransformPipeline.java
index 5fd0b248d..6f9bf037d 100644
--- a/tool/src/org/antlr/v4/tool/GrammarTransformPipeline.java
+++ b/tool/src/org/antlr/v4/tool/GrammarTransformPipeline.java
@@ -293,7 +293,7 @@ public class GrammarTransformPipeline {
 		// COPY OPTIONS
 		GrammarAST optionsRoot =
 			(GrammarAST)combinedAST.getFirstChildWithType(ANTLRParser.OPTIONS);
-		if ( optionsRoot!=null ) {
+		if ( optionsRoot!=null && optionsRoot.getChildCount()!=0 ) {
 			GrammarAST lexerOptionsRoot = (GrammarAST)adaptor.dupNode(optionsRoot);
 			lexerAST.addChild(lexerOptionsRoot);
 			GrammarAST[] options = optionsRoot.getChildren().toArray(new GrammarAST[0]);
diff --git a/tool/test/org/antlr/v4/test/TestCompositeGrammars.java b/tool/test/org/antlr/v4/test/TestCompositeGrammars.java
index 112cac938..e91440cfc 100644
--- a/tool/test/org/antlr/v4/test/TestCompositeGrammars.java
+++ b/tool/test/org/antlr/v4/test/TestCompositeGrammars.java
@@ -664,4 +664,21 @@ public class TestCompositeGrammars extends BaseTest {
 		assertEquals("", found);
 	}
 
+	@Test public void testImportedGrammarWithEmptyOptions() throws Exception {
+		String slave =
+			"parser grammar S;\n" +
+			"options {}\n" +
+			"a : B ;\n";
+		mkdir(tmpdir);
+		writeFile(tmpdir, "S.g4", slave);
+		String master =
+			"grammar M;\n" +
+			"import S;\n" +
+			"s : a ;\n" +
+			"B : 'b' ;" +
+			"WS : (' '|'\\n') -> skip ;\n" ;
+		String found = execParser("M.g4", master, "MParser", "MLexer",
+								  "s", "b", debug);
+		assertEquals("", found);
+	}
 }
diff --git a/tool/test/org/antlr/v4/test/TestToolSyntaxErrors.java b/tool/test/org/antlr/v4/test/TestToolSyntaxErrors.java
index 143b5f37c..f8864e20a 100644
--- a/tool/test/org/antlr/v4/test/TestToolSyntaxErrors.java
+++ b/tool/test/org/antlr/v4/test/TestToolSyntaxErrors.java
@@ -172,4 +172,49 @@ public class TestToolSyntaxErrors extends BaseTest {
 		super.testErrors(pair, true);
 	}
 
+	/**
+	 * This is a regression test for antlr/antlr4#194
+	 * "NullPointerException on 'options{}' in grammar file"
+	 * https://github.com/antlr/antlr4/issues/194
+	 */
+	@Test public void testEmptyGrammarOptions() {
+		String[] pair = new String[] {
+			"grammar A;\n" +
+			"options {}\n" +
+			"a : 'x' ;\n",
+
+			""
+		};
+		super.testErrors(pair, true);
+	}
+
+	/**
+	 * This is a "related" regression test for antlr/antlr4#194
+	 * "NullPointerException on 'options{}' in grammar file"
+	 * https://github.com/antlr/antlr4/issues/194
+	 */
+	@Test public void testEmptyRuleOptions() {
+		String[] pair = new String[] {
+			"grammar A;\n" +
+			"a options{} : 'x' ;\n",
+
+			""
+		};
+		super.testErrors(pair, true);
+	}
+
+	/**
+	 * This is a "related" regression test for antlr/antlr4#194
+	 * "NullPointerException on 'options{}' in grammar file"
+	 * https://github.com/antlr/antlr4/issues/194
+	 */
+	@Test public void testEmptyBlockOptions() {
+		String[] pair = new String[] {
+			"grammar A;\n" +
+			"a : (options{} : 'x') ;\n",
+
+			""
+		};
+		super.testErrors(pair, true);
+	}
 }