Re: Java parser throws ArrayIndexOutOfBoundsException if first token leads to syntax error

[Tim Landscheidt]

I wrote:

> [...]
>   There is a test for syntax errors on the first token in
> tests/java.at, but apparently only in combination with an
> "error" token.  I hope fixing it is easier than isolating
> it was :-).

Nope.  Anyway, attached is the fix.  The test case is a bit
non-hackily lengthy, but I did not want to interlace it in
the existing suite and subtly break half of them in the
process.

Tim

>From 415333112ba8224264d75164628ca1a173ffb514 Mon Sep 17 00:00:00 2001
From: Tim Landscheidt <address@hidden>
Date: Sun, 12 Feb 2012 01:29:41 +0000
Subject: [PATCH] Java: Fix syntax error handling without error token.

* data/lalr1.java (YYParser::parse): Here.
* tests/java.at: Add test case.
---
 data/lalr1.java |    2 +-
 tests/java.at   |   67 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 68 insertions(+), 1 deletions(-)

diff --git a/data/lalr1.java b/data/lalr1.java
index 57ff993..a40d6c2 100644
--- a/data/lalr1.java
+++ b/data/lalr1.java
@@ -686,7 +686,7 @@ m4_popdef([b4_at_dollar])])dnl
               }
 
             /* Pop the current state because it cannot handle the error token. 
 */
-            if (yystack.height == 1)
+            if (yystack.height == 0)
               return false;
 
             ]b4_locations_if([yyerrloc = yystack.locationAt (0);])[
diff --git a/tests/java.at b/tests/java.at
index b3e79e9..b8279d1 100644
--- a/tests/java.at
+++ b/tests/java.at
@@ -781,3 +781,70 @@ AT_CHECK([[$EGREP -v ' */?\*' YYParser.java | grep 
'Position']], [1], [ignore])
 AT_CHECK([[$EGREP -v ' */?\*' YYParser.java | grep 'Location']], [1], [ignore])
 
 AT_CLEANUP
+
+
+# ----------------------------------------------- #
+# Java syntax error handling without error token. #
+# ----------------------------------------------- #
+
+AT_SETUP([Java syntax error handling without error token])
+
+AT_DATA([[YYParser.y]], [[%language "Java"
+
+%code imports
+  {
+    import java.io.IOException;
+  }
+
+%code
+  {
+    public static void main (String args []) throws IOException
+      {
+        YYParser p = new YYParser (new YYLexer (args [0]));
+        p.parse ();
+      }
+  }
+
+%%
+input:
+  '-' '-'
+;
+%%
+class YYLexer implements YYParser.Lexer
+  {
+    int pos = 0;
+    String s;
+
+    public YYLexer (String ps)
+      {
+        s = ps;
+      }
+
+    public void yyerror (String s)
+      {
+        System.err.println (s);
+      }
+
+    public Object getLVal ()
+      {
+        return null;
+      }
+
+    public int yylex ()
+      {
+        if (pos >= s.length ())
+          return YYParser.Lexer.EOF;
+        else
+          return s.charAt (pos++);
+      }
+  }
+]])
+AT_BISON_CHECK([[YYParser.y]])
+AT_JAVA_COMPILE([[YYParser.java]])
+AT_JAVA_PARSER_CHECK([[YYParser --]], [[0]], [[]], [[]])
+AT_JAVA_PARSER_CHECK([[YYParser -+]], [[0]], [[]], [[syntax error
+]])
+AT_JAVA_PARSER_CHECK([[YYParser +-]], [[0]], [[]], [[syntax error
+]])
+
+AT_CLEANUP
-- 
1.6.2.5