[groff] 09/09: [man]: Fix Savannah #60624.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit 4e1dbb55dc805d8eb5f5bcfa8ab8cbe1059cb7fd
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Tue Jun 15 04:20:30 2021 +1000

    [man]: Fix Savannah #60624.
    
    [man]: Don't spuriously break a page after a paragraph tag when the tag
    is short enough to fit within the paragraph's indentation.
    
    * tmac/an-old.tmac (an-write-paragraph-tag): Reserve ("need") 2 vees
      plus 1 basic unit of vertical space regardless of the width of the
      tag.  In the short tag case, we reverse space by one vee after
      outputting the diversion in which the tag is stored, but it will
      always contain a break, and by the time we reverse, we might have
      already hit a page location trap (an-break-body-text), and by then
      it's too late to back up.
    
    Fixes <https://savannah.gnu.org/bugs/index.php?60624>.
---
 ChangeLog        | 14 ++++++++++++++
 tmac/an-old.tmac |  3 +--
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 861bcaf..fd521cc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,9 +1,23 @@
 2021-06-15  G. Branden Robinson <g.branden.robinson@gmail.com>
 
+       [man]: Don't spuriously break a page after a paragraph tag when
+       the tag is short enough to fit within the paragraph's
+       indentation.
+
+       * tmac/an-old.tmac (an-write-paragraph-tag): Reserve ("need") 2
+       vees plus 1 basic unit of vertical space regardless of the width
+       of the tag.  In the short tag case, we reverse space by one vee
+       after outputting the diversion in which the tag is stored, but
+       it will always contain a break, and by the time we reverse, we
+       might have already hit a page location trap
+       {an-break-body-text}, and by then it's too late to back up.
+
        * tmac/tests/an-old_no-break-after-short-paragraph-tags.sh: Test
        it.
        * tmac/tmac.am (tmac_TESTS): Run test.
 
+       Fixes <https://savannah.gnu.org/bugs/index.php?60624>.
+
 2021-06-15  G. Branden Robinson <g.branden.robinson@gmail.com>
 
        * tmac/an-old.tmac: Rename environments to be more descriptive.
diff --git a/tmac/an-old.tmac b/tmac/an-old.tmac
index 67d7cbd..b26b775 100644
--- a/tmac/an-old.tmac
+++ b/tmac/an-old.tmac
@@ -528,8 +528,8 @@
 .  mc
 .  nf
 .  in \\n[an-margin]u
+.  ne (2v + 1u)
 .  ie (\\n[dl] + \\n[an-tag-separation] > \\n[an-prevailing-indent]) \{\
-.    ne (2v + 1u)
 .    an-div
 .    ev
 .    in (\\n[an-margin]u + \\n[an-prevailing-indent]u)
@@ -538,7 +538,6 @@
 .    \" In nroff mode, the indentation value should be an integer
 .    \" multiple of the character cell, to avoid different results
 .    \" compared to the .ie part above.
-.    ne (1v + 1u)
 .    DEVTAG-COL 1
 .    an-div
 .    sp -1