The mandoc(1) manual already mentions that -T man output mode

neither supports tbl(7) nor eqn(7) input.
If an input file contains such code anyway, tell the user
rather than failing an assert(3)ion.

Fixing a crash reported by Bjarni Ingi Gislason <bjarniig at rhi dot hi dot is>
in https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=901636 which the
Debian maintainer of mandoc, Michael at Stapelberg dot ch, forwarded to me.

1 files changed, 21 insertions, 1 deletions

diff --git a/mandoc.1 b/mandoc.1
index 00e7eec3..669cf9fb 100644
--- a/mandoc.1
+++ b/mandoc.1
@@ -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: June 28 2021 $
+.Dd $Mdocdate: July 4 2021 $
 .Dt MANDOC 1
 .Os
 .Sh NAME
@@ -2314,6 +2314,26 @@ or
 macro or of an undefined macro.
 The macro is ignored, and its arguments are handled
 as if they were a text line.
+.It Sy "skipping tbl in -Tman mode"
+.Pq mdoc , tbl
+An input file contains the
+.Ic \&TS
+macro.
+This message is only generated in
+.Fl T Cm man
+output mode, where
+.Xr tbl 7
+input is not supported.
+.It Sy "skipping eqn in -Tman mode"
+.Pq mdoc , eqn
+An input file contains the
+.Ic \&EQ
+macro.
+This message is only generated in
+.Fl T Cm man
+output mode, where
+.Xr eqn 7
+input is not supported.
 .El
 .Ss Bad command line arguments
 .Bl -ohang