From 36ec5596bdd9341a9aea84040d3e495409828d4a Mon Sep 17 00:00:00 2001
From: schwarze <schwarze@openbsd.org>
Date: Mon, 15 Aug 2022 18:44:24 +0000
Subject: [PATCH] Simplify handling of no-fill mode in man(7) by inspecting
 NODE_NOFILL at the beginning of the node handler, in the same way as it is
 done in the mdoc(7) node handler.

As a side effect, this also fixes a bug: if an input line contained
nothing but an escape sequence producing no output whatsoever (for
example, \fR), the old code incorrectly emitted a blank line anyway,
whereas the new code only emits such a blank link if the input line
actually produces output (even invisible zero-width output). To make
the distinction, the ASCII_NBRZW -> lastcol -> term_newln() mechanism
established in term.c rev. 1.149 is used.
---
 usr.bin/mandoc/man_term.c | 46 ++++++++++++++++++---------------------
 1 file changed, 21 insertions(+), 25 deletions(-)

diff --git a/usr.bin/mandoc/man_term.c b/usr.bin/mandoc/man_term.c
index 2433abcdbae..2ca2533dfa6 100644
--- a/usr.bin/mandoc/man_term.c
+++ b/usr.bin/mandoc/man_term.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: man_term.c,v 1.191 2022/08/15 13:01:40 schwarze Exp $ */
+/* $OpenBSD: man_term.c,v 1.192 2022/08/15 18:44:24 schwarze Exp $ */
 /*
  * Copyright (c) 2010-2015,2017-2020,2022 Ingo Schwarze <schwarze@openbsd.org>
  * Copyright (c) 2008-2012 Kristaps Dzonsons <kristaps@bsd.lv>
@@ -515,7 +515,7 @@ pre_IP(DECL_ARGS)
 		p->trailspace = 1;
 		break;
 	case ROFFT_BODY:
-		p->flags |= TERMP_NOSPACE;
+		p->flags |= TERMP_NOSPACE | TERMP_NONEWLINE;
 		break;
 	default:
 		abort();
@@ -589,7 +589,7 @@ pre_TP(DECL_ARGS)
 		p->trailspace = 1;
 		break;
 	case ROFFT_BODY:
-		p->flags |= TERMP_NOSPACE;
+		p->flags |= TERMP_NOSPACE | TERMP_NONEWLINE;
 		break;
 	default:
 		abort();
@@ -898,6 +898,19 @@ print_man_node(DECL_ARGS)
 	const struct man_term_act *act;
 	int c;
 
+	/*
+	 * In no-fill mode, break the output line at the beginning
+	 * of new input lines except after \c, and nowhere else.
+	 */
+
+	if (n->flags & NODE_NOFILL) {
+		if (n->flags & NODE_LINE &&
+		    (p->flags & TERMP_NONEWLINE) == 0)
+			term_newln(p);
+		p->flags |= TERMP_BRNEVER;
+	} else
+		p->flags &= ~TERMP_BRNEVER;
+
 	if (n->flags & NODE_ID)
 		term_tag_write(n, p->line);
 
@@ -962,28 +975,11 @@ print_man_node(DECL_ARGS)
 		term_fontrepl(p, TERMFONT_NONE);
 
 out:
-	/*
-	 * If we're in a literal context, make sure that words
-	 * together on the same line stay together.  This is a
-	 * POST-printing call, so we check the NEXT word.  Since
-	 * -man doesn't have nested macros, we don't need to be
-	 * more specific than this.
-	 */
-	if (n->flags & NODE_NOFILL &&
-	    ! (p->flags & (TERMP_NOBREAK | TERMP_NONEWLINE)) &&
-	    (n->next == NULL || n->next->flags & NODE_LINE)) {
-		p->flags |= TERMP_BRNEVER | TERMP_NOSPACE;
-		p->tcol->taboff = 0;
-		if (n->string != NULL && *n->string != '\0')
-			term_flushln(p);
-		else
-			term_newln(p);
-		p->flags &= ~TERMP_BRNEVER;
-		if (p->tcol->rmargin < p->maxrmargin &&
-		    n->parent->tok == MAN_HP) {
-			p->tcol->offset = p->tcol->rmargin;
-			p->tcol->rmargin = p->maxrmargin;
-		}
+	if (n->parent->tok == MAN_HP && n->parent->type == ROFFT_BODY &&
+	    n->prev == NULL && n->flags & NODE_NOFILL) {
+		term_newln(p);
+		p->tcol->offset = p->tcol->rmargin;
+		p->tcol->rmargin = p->maxrmargin;
 	}
 	if (n->flags & NODE_EOS)
 		p->flags |= TERMP_SENTENCE;
-- 
2.20.1