Unsatisfied %expectations

[Akim Demaille]

I was just horrified to discover that unmet %expect are not errors.  I
had an ambiguity that sneaked in and remain hidden in the lengthy
compilation.  I propose the following patch, which is admittedly not
backward compatible, but otherwise the feature is quite meaningless...

An alternative would be introducing -Werror, but (i) that's more work
:( and (ii) it still should be an error, not a warning!

Index: ChangeLog
from  Akim Demaille  <address@hidden>

        * src/conflicts.c (conflicts_print): Unsatisfied %expectation are
        errors.

Index: NEWS
===================================================================
RCS file: /cvsroot/bison/bison/NEWS,v
retrieving revision 1.130
diff -u -u -r1.130 NEWS
--- NEWS 21 Oct 2005 11:36:22 -0000 1.130
+++ NEWS 18 Nov 2005 11:43:16 -0000
@@ -3,6 +3,10 @@
 
 Changes in version 2.1a:
 
+* %expect, %expect-rr
+  Incorrect numbers of expected conflicts are now actual errors,
+  instead of warnings.
+
 * GLR, YACC parsers.
   The %parse-params are available in the %destructor's (and the
   experimental %printer's) as per the documentation.
Index: doc/bison.texinfo
===================================================================
RCS file: /cvsroot/bison/bison/doc/bison.texinfo,v
retrieving revision 1.166
diff -u -u -r1.166 bison.texinfo
--- doc/bison.texinfo 12 Nov 2005 14:13:03 -0000 1.166
+++ doc/bison.texinfo 18 Nov 2005 11:43:17 -0000
@@ -3915,17 +3915,16 @@
 
 Here @var{n} is a decimal integer.  The declaration says there should be
 no warning if there are @var{n} shift/reduce conflicts and no
-reduce/reduce conflicts.  The usual warning is
-given if there are either more or fewer conflicts, or if there are any
-reduce/reduce conflicts.
-
-For normal @acronym{LALR}(1) parsers, reduce/reduce conflicts are more serious,
-and should be eliminated entirely.  Bison will always report
-reduce/reduce conflicts for these parsers.  With @acronym{GLR} parsers, 
however,
-both shift/reduce and reduce/reduce are routine (otherwise, there
-would be no need to use @acronym{GLR} parsing).  Therefore, it is also possible
-to specify an expected number of reduce/reduce conflicts in @acronym{GLR}
-parsers, using the declaration:
+reduce/reduce conflicts.  An error is issued if there are either more or
+fewer conflicts, or if there are any reduce/reduce conflicts.
+
+For normal @acronym{LALR}(1) parsers, reduce/reduce conflicts are more
+serious, and should be eliminated entirely.  Bison will always report
+reduce/reduce conflicts for these parsers.  With @acronym{GLR} parsers,
+however, both shift/reduce and reduce/reduce are routine (otherwise,
+there would be no need to use @acronym{GLR} parsing).  Therefore, it is
+also possible to specify an expected number of reduce/reduce conflicts
+in @acronym{GLR} parsers, using the declaration:
 
 @example
 %expect-rr @var{n}
@@ -3950,8 +3949,8 @@
 @end itemize
 
 Now Bison will stop annoying you if you do not change the number of
-conflicts, but it will warn you again if changes in the grammar result
-in more or fewer conflicts.
+conflicts, unless changes in the grammar result in more or fewer
+conflicts.
 
 @node Start Decl
 @subsection The Start-Symbol
Index: src/conflicts.c
===================================================================
RCS file: /cvsroot/bison/bison/src/conflicts.c,v
retrieving revision 1.111
diff -u -u -r1.111 conflicts.c
--- src/conflicts.c 14 May 2005 06:49:47 -0000 1.111
+++ src/conflicts.c 18 Nov 2005 11:43:17 -0000
@@ -1,6 +1,6 @@
 /* Find and resolve or report look-ahead conflicts for bison,
 
-   Copyright (C) 1984, 1989, 1992, 2000, 2001, 2002, 2003, 2004
+   Copyright (C) 1984, 1989, 1992, 2000, 2001, 2002, 2003, 2004, 2005
    Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
@@ -508,13 +508,13 @@
       int sr = expected_sr_conflicts == -1 ? 0 : expected_sr_conflicts;
       int rr = expected_rr_conflicts == -1 ? 0 : expected_rr_conflicts;
       if (! src_ok)
-       warn (ngettext ("expected %d shift/reduce conflict",
-                       "expected %d shift/reduce conflicts",
-                       sr), sr);
+       complain (ngettext ("expected %d shift/reduce conflict",
+                           "expected %d shift/reduce conflicts",
+                           sr), sr);
       if (! rrc_ok)
-       warn (ngettext ("expected %d reduce/reduce conflict",
-                       "expected %d reduce/reduce conflicts",
-                       rr), rr);
+       complain (ngettext ("expected %d reduce/reduce conflict",
+                           "expected %d reduce/reduce conflicts",
+                           rr), rr);
     }
 }