[groff] 05/05: [man]: Fix Savannah #61408.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit 34c5fed1be8e4590b67ea9d243ad16ec73ab61b2
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Tue Nov 2 21:35:40 2021 +1100

    [man]: Fix Savannah #61408.
    
    * tmac/an.tmac (an-prepare-inner-footer): Don't try to get a substring
      of an empty string; the man page author might not have specified a
      third argument to `TH` (or supplied an empty one).
    
    Fixes <https://savannah.gnu.org/bugs/?61408>.  Thanks to Bjarni Ingi
    Gislason for the report.
---
 ChangeLog    | 11 +++++++++++
 tmac/an.tmac |  6 ++++--
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 51fb254..f4053a8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,16 @@
 2021-11-02  G. Branden Robinson <g.branden.robinson@gmail.com>
 
+       [man]: Fix Savannah #61408.
+
+       * tmac/an.tmac (an-prepare-inner-footer): Don't try to get a
+       substring of an empty string; the man page author might not have
+       specified a third argument to `TH` (or supplied an empty one).
+
+       Fixes <https://savannah.gnu.org/bugs/?61408>.  Thanks to Bjarni
+       Ingi Gislason for the report.
+
+2021-11-02  G. Branden Robinson <g.branden.robinson@gmail.com>
+
        [man]: Add regression test for Savannah #61408.
 
        * tmac/tests/an_inner-footer-abbreviation-works.sh: Do it.
diff --git a/tmac/an.tmac b/tmac/an.tmac
index b842385..4952efb 100644
--- a/tmac/an.tmac
+++ b/tmac/an.tmac
@@ -399,8 +399,10 @@
 .de an-prepare-inner-footer
 .  ds an-half-cfoot \\*[an-extra1]\"
 .  length an-half-cfoot-length \\*[an-half-cfoot]
-.  nr an-half-cfoot-length (\\n[an-half-cfoot-length] / 2u)
-.  substring an-half-cfoot 0 \\n[an-half-cfoot-length]
+.  if \\n[an-half-cfoot-length] \{\
+.    nr an-half-cfoot-length (\\n[an-half-cfoot-length] / 2u)
+.    substring an-half-cfoot 0 \\n[an-half-cfoot-length]
+.  \}
 .  rr an-half-cfoot-length
 .  ds an-ifoot \\*[an-extra2]\"
 .  nr an-half-title-width (\\n[.lt] / 2u)