Do not crash on stray .Ta macros found outside column lists.

Problem reported by jmc@, thanks.

4 files changed, 15 insertions, 10 deletions

diff --git a/TODO b/TODO
index 66418fd7..8f5b6a5d 100644
--- a/TODO
+++ b/TODO
@@ -7,11 +7,7 @@
 * crashes
 ************************************************************************
 
-- $ echo ".Ta" >> ls.1
-  $ mandoc ls.1
-  assertion "MDOC_BLOCK == p->parent->type" failed:
-  file "/usr/src/usr.bin/mandoc/mdoc.c", line 399, function "node_append"
-  from jmc@  Thu, 20 Sep 2012 21:35:58 +0059
+None known right now.
 
 ************************************************************************
 * missing features
diff --git a/mandoc.h b/mandoc.h
index 1a53ea11..774f2481 100644
--- a/mandoc.h
+++ b/mandoc.h
@@ -1,6 +1,7 @@
 /*	$Id$ */
 /*
  * Copyright (c) 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
+ * Copyright (c) 2012 Ingo Schwarze <schwarze@openbsd.org>
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -135,6 +136,7 @@ enum	mandocerr {
 	MANDOCERR_MACRO, /* skipping unknown macro */
 	MANDOCERR_REQUEST, /* NOT IMPLEMENTED: skipping request */
 	MANDOCERR_ARGCOUNT, /* argument count wrong */
+	MANDOCERR_STRAYTA, /* skipping column outside column list */
 	MANDOCERR_NOSCOPE, /* skipping end of block that is not open */
 	MANDOCERR_SCOPEBROKEN, /* missing end of block */
 	MANDOCERR_SCOPEEXIT, /* scope open on exit */
diff --git a/mdoc_macro.c b/mdoc_macro.c
index e946d7ab..e7ccd62f 100644
--- a/mdoc_macro.c
+++ b/mdoc_macro.c
@@ -1759,16 +1759,22 @@ phrase(struct mdoc *mdoc, int line, int ppos, char *buf)
 static int
 phrase_ta(MACRO_PROT_ARGS)
 {
+	struct mdoc_node *n;
 	int		  la;
 	enum mdoct	  ntok;
 	enum margserr	  ac;
 	char		 *p;
 
-	/*
-	 * FIXME: this is overly restrictive: if the `Ta' is unexpected,
-	 * it should simply error out with ARGSLOST.
-	 */
+	/* Make sure we are in a column list or ignore this macro. */
+	n = mdoc->last;
+	while (NULL != n && MDOC_Bl != n->tok)
+		n = n->parent;
+	if (NULL == n || LIST_column != n->norm->Bl.type) {
+		mdoc_pmsg(mdoc, line, ppos, MANDOCERR_STRAYTA);
+		return(1);
+	}
 
+	/* Advance to the next column. */
 	if ( ! rew_sub(MDOC_BODY, mdoc, MDOC_It, line, ppos))
 		return(0);
 	if ( ! mdoc_body_alloc(mdoc, line, ppos, MDOC_It))
diff --git a/read.c b/read.c
index a553e6f4..a7986ec7 100644
--- a/read.c
+++ b/read.c
@@ -1,7 +1,7 @@
 /*	$Id$ */
 /*
  * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
- * Copyright (c) 2010, 2011 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2010, 2011, 2012 Ingo Schwarze <schwarze@openbsd.org>
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -180,6 +180,7 @@ static	const char * const	mandocerrs[MANDOCERR_MAX] = {
 	"skipping unknown macro",
 	"NOT IMPLEMENTED, please use groff: skipping request",
 	"argument count wrong",
+	"skipping column outside column list",
 	"skipping end of block that is not open",
 	"missing end of block",
 	"scope open on exit",