warning on undefined macros

I cleaned up one regression of traced-but-undefined macros on 2008-08-21, but 
missed the fact that I introduced another one when adding the ability to warn 
on popping undefined macros.  Only branch-1.6 has the bug, but I'm also porting 
the testsuite improvement to master.


From: Eric Blake <[email protected]>
Date: Wed, 11 Feb 2009 08:49:43 -0700
Subject: [PATCH] Warn when popping traced but undefined macro.

* src/symtab.c (lookup_symbol): Recognize traced placeholder when
delete is requested.  Bug introduced 2008-07-18.
* doc/m4.texinfo (Trace): Test it.

Signed-off-by: Eric Blake <[email protected]>
---
 ChangeLog      |    7 +++++++
 doc/m4.texinfo |   12 +++++++++++-
 src/symtab.c   |    8 +++++---
 3 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index b96dccc..2aa09b4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2009-02-11  Eric Blake  <[email protected]>
+
+	Warn when popping traced but undefined macro.
+	* src/symtab.c (lookup_symbol): Recognize traced placeholder when
+	delete is requested.  Bug introduced 2008-07-18.
+	* doc/m4.texinfo (Trace): Test it.
+
 2009-02-09  Eric Blake  <[email protected]>

 	Enhance index to support starting offset.
diff --git a/doc/m4.texinfo b/doc/m4.texinfo
index 8341cc9..b337e5e 100644
--- a/doc/m4.texinfo
+++ b/doc/m4.texinfo
@@ -4134,6 +4134,16 @@ Trace
 defn(`foo')
 @error{}m4:stdin:4: Warning: defn: undefined macro `foo'
 @result{}
+undefine(`foo')
+@error{}m4:stdin:5: Warning: undefine: undefined macro `foo'
+@result{}
+pushdef(`foo')
+@result{}
+popdef(`foo')
+@result{}
+popdef(`foo')
+@error{}m4:stdin:8: Warning: popdef: undefined macro `foo'
+@result{}
 define(`foo', `bar')
 @result{}
 foo
@@ -4144,7 +4154,7 @@ Trace
 ifdef(`foo', `yes', `no')
 @result{}no
 indir(`foo')
-@error{}m4:stdin:9: Warning: indir: undefined macro `foo'
+@error{}m4:stdin:13: Warning: indir: undefined macro `foo'
 @result{}
 define(`foo', `blah')
 @result{}
diff --git a/src/symtab.c b/src/symtab.c
index a9160c8..6631e9c 100644
--- a/src/symtab.c
+++ b/src/symtab.c
@@ -1,7 +1,7 @@
 /* GNU m4 -- A simple macro processor

-   Copyright (C) 1989, 1990, 1991, 1992, 1993, 1994, 2003, 2006, 2007, 2008
-   Free Software Foundation, Inc.
+   Copyright (C) 1989, 1990, 1991, 1992, 1993, 1994, 2003, 2006, 2007,
+   2008, 2009 Free Software Foundation, Inc.

    This file is part of GNU M4.

@@ -333,7 +333,9 @@ lookup_symbol (const char *name, size_t len, symbol_lookup 
mode)
 	 definition is still in use, let the caller free the memory
 	 after it is done with the symbol.  */

-      if (!entry)
+      if (!entry
+	  || (SYMBOL_TYPE (entry) == TOKEN_VOID && entry->stack == entry
+	      && SYMBOL_TRACED (entry)))
 	return NULL;
       {
 	bool traced = false;
-- 
1.6.1.2