[tinkerpop] 01/03: Fixed bug in grammar for handling empty queries.

[sp...@apache.org]

This is an automated email from the ASF dual-hosted git repository.

spmallette pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/tinkerpop.git

commit 7b02a28d10ce8568b3d5a5dae05e6679b612ae63
Author: Stephen Mallette <st...@amazon.com>
AuthorDate: Wed Aug 17 08:23:21 2022 -0400

    Fixed bug in grammar for handling empty queries.
    
    This worked in 3.5.x, but broke after some refactoring for 3.6.0 CTR
---
 CHANGELOG.asciidoc                                 |  2 +-
 .../language/grammar/GremlinQueryParserTest.java   | 32 ++++++++++++++++++++++
 gremlin-language/src/main/antlr4/Gremlin.g4        | 13 ++++-----
 3 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/CHANGELOG.asciidoc b/CHANGELOG.asciidoc
index 5cc05c61c0..88565a0925 100644
--- a/CHANGELOG.asciidoc
+++ b/CHANGELOG.asciidoc
@@ -25,7 +25,7 @@ image::https://raw.githubusercontent.com/apache/tinkerpop/master/docs/static/ima
 
 This release also includes changes from <<release-3-5-5, 3.5.5>>.
 
-
+* Fixed bug in the Gremlin grammar for parsing of empty queries.
 
 [[release-3-6-1]]
 === TinkerPop 3.6.1 (Release Date: July 18, 2022)
diff --git a/gremlin-core/src/test/java/org/apache/tinkerpop/gremlin/language/grammar/GremlinQueryParserTest.java b/gremlin-core/src/test/java/org/apache/tinkerpop/gremlin/language/grammar/GremlinQueryParserTest.java
new file mode 100644
index 0000000000..b9d600dda8
--- /dev/null
+++ b/gremlin-core/src/test/java/org/apache/tinkerpop/gremlin/language/grammar/GremlinQueryParserTest.java
@@ -0,0 +1,32 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.tinkerpop.gremlin.language.grammar;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class GremlinQueryParserTest {
+
+    @Test
+    public void shouldParseEmpty() {
+        assertEquals("", GremlinQueryParser.parse("\"\""));
+        assertEquals("", GremlinQueryParser.parse("''"));
+    }
+}
diff --git a/gremlin-language/src/main/antlr4/Gremlin.g4 b/gremlin-language/src/main/antlr4/Gremlin.g4
index 495e318e53..33a94d4248 100644
--- a/gremlin-language/src/main/antlr4/Gremlin.g4
+++ b/gremlin-language/src/main/antlr4/Gremlin.g4
@@ -1348,7 +1348,7 @@ genericLiteralExpr
 
 genericLiteralRange
     : integerLiteral DOT DOT integerLiteral
-    | StringLiteral DOT DOT StringLiteral
+    | stringLiteral DOT DOT stringLiteral
     ;
 
 genericLiteralCollection
@@ -1400,7 +1400,8 @@ mapEntry
     ;
 
 stringLiteral
-    : StringLiteral
+    : EmptyStringLiteral
+    | NonEmptyStringLiteral
     ;
 
 integerLiteral
@@ -1421,7 +1422,8 @@ booleanLiteral
     ;
 
 stringBasedLiteral
-    : StringLiteral
+    : EmptyStringLiteral
+    | NonEmptyStringLiteral
     | NullLiteral
     | gremlinStringConstants
     ;
@@ -1641,11 +1643,6 @@ InfLiteral
 
 // String Literals
 
-StringLiteral
-    : NonEmptyStringLiteral
-    | EmptyStringLiteral
-    ;
-
 // String literal is customized since Java only allows double quoted strings where Groovy supports single quoted
 // literals also. A side effect of this is ANTLR will not be able to parse single character string literals with
 // single quoted so we instead remove char literal altogether and only have string literal in lexer tokens.