From a28ef4e886aa07659cbef3b85534540414c09092 Mon Sep 17 00:00:00 2001
From: schwarze <schwarze@openbsd.org>
Date: Sat, 14 Aug 2021 13:51:46 +0000
Subject: [PATCH] print a BAGARG message if -T markdown is requested on man(7)
 input; suggested by Michael Stapelberg at debian dot org

---
 usr.bin/mandoc/main.c       |  5 ++++-
 usr.bin/mandoc/mandoc.1     | 12 ++++++++++--
 usr.bin/mandoc/mandoc.h     |  3 ++-
 usr.bin/mandoc/mandoc_msg.c |  3 ++-
 4 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/usr.bin/mandoc/main.c b/usr.bin/mandoc/main.c
index d309d969a41..f16be3caf6e 100644
--- a/usr.bin/mandoc/main.c
+++ b/usr.bin/mandoc/main.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: main.c,v 1.257 2021/06/02 18:27:36 schwarze Exp $ */
+/* $OpenBSD: main.c,v 1.258 2021/08/14 13:51:46 schwarze Exp $ */
 /*
  * Copyright (c) 2010-2012, 2014-2021 Ingo Schwarze <schwarze@openbsd.org>
  * Copyright (c) 2008-2012 Kristaps Dzonsons <kristaps@bsd.lv>
@@ -944,6 +944,9 @@ parse(struct mparse *mp, int fd, const char *file,
 		case OUTT_PS:
 			terminal_man(outst->outdata, meta);
 			break;
+		case OUTT_MARKDOWN:
+			mandoc_msg(MANDOCERR_MAN_TMARKDOWN, 0, 0, NULL);
+			break;
 		default:
 			break;
 		}
diff --git a/usr.bin/mandoc/mandoc.1 b/usr.bin/mandoc/mandoc.1
index 6df390cce3c..1e8dcc4b251 100644
--- a/usr.bin/mandoc/mandoc.1
+++ b/usr.bin/mandoc/mandoc.1
@@ -1,4 +1,4 @@
-.\" $OpenBSD: mandoc.1,v 1.178 2021/07/04 15:38:08 schwarze Exp $
+.\" $OpenBSD: mandoc.1,v 1.179 2021/08/14 13:51:46 schwarze Exp $
 .\"
 .\" Copyright (c) 2012, 2014-2021 Ingo Schwarze <schwarze@openbsd.org>
 .\" Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
@@ -15,7 +15,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: July 4 2021 $
+.Dd $Mdocdate: August 14 2021 $
 .Dt MANDOC 1
 .Os
 .Sh NAME
@@ -2371,6 +2371,14 @@ The
 .Fl O Cm tag
 option was specified but the tag was not found in any of the displayed
 manual pages.
+.It Sy "\-Tmarkdown unsupported for man(7) input"
+.Pq man
+The
+.Fl T Cm markdown
+option was specified but an input file uses the
+.Xr man 7
+language.
+No output is produced for that input file.
 .El
 .Sh SEE ALSO
 .Xr apropos 1 ,
diff --git a/usr.bin/mandoc/mandoc.h b/usr.bin/mandoc/mandoc.h
index 98cf7867485..c23d2285421 100644
--- a/usr.bin/mandoc/mandoc.h
+++ b/usr.bin/mandoc/mandoc.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: mandoc.h,v 1.215 2021/08/10 12:36:42 schwarze Exp $ */
+/* $OpenBSD: mandoc.h,v 1.216 2021/08/14 13:51:46 schwarze Exp $ */
 /*
  * Copyright (c) 2012-2021 Ingo Schwarze <schwarze@openbsd.org>
  * Copyright (c) 2010, 2011, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
@@ -257,6 +257,7 @@ enum	mandocerr {
 	MANDOCERR_BADVAL_BAD, /* bad argument value */
 	MANDOCERR_BADVAL_DUPE, /* duplicate argument value */
 	MANDOCERR_TAG, /* no such tag */
+	MANDOCERR_MAN_TMARKDOWN, /* -Tmarkdown unsupported for man(7) input */
 
 	MANDOCERR_SYSERR, /* ===== start of system errors ===== */
 
diff --git a/usr.bin/mandoc/mandoc_msg.c b/usr.bin/mandoc/mandoc_msg.c
index 26306dad7e9..a3897c65247 100644
--- a/usr.bin/mandoc/mandoc_msg.c
+++ b/usr.bin/mandoc/mandoc_msg.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: mandoc_msg.c,v 1.13 2021/07/04 15:38:09 schwarze Exp $ */
+/* $OpenBSD: mandoc_msg.c,v 1.14 2021/08/14 13:51:46 schwarze Exp $ */
 /*
  * Copyright (c) 2014-2021 Ingo Schwarze <schwarze@openbsd.org>
  * Copyright (c) 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
@@ -255,6 +255,7 @@ static	const char *const type_message[MANDOCERR_MAX] = {
 	"bad option value",
 	"duplicate option value",
 	"no such tag",
+	"-Tmarkdown unsupported for man(7) input",
 
 	/* system errors */
 	NULL,
-- 
2.20.1