[groff] 18/18: [troff]: Fix Savannah #64592 (default color name).

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit 6ed670b656cbdb57c494bc8cd559f9bfcd26ad9e
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Fri Jan 5 19:59:13 2024 -0600

    [troff]: Fix Savannah #64592 (default color name).
    
    * src/libs/libgroff/color.cpp: Explicitly name the default color
      "default", instead of permitting it to have a null name.
    
    * doc/groff.texi (Colors):
    * man/groff.7.man (Read-only regsiters):
    * NEWS: Document it.
    
    Fixes <https://savannah.gnu.org/bugs/?64592>.  Thanks to Deri James,
    Dave Kemper, and Peter Schaffter for the discussion.
---
 ChangeLog                   | 14 ++++++++++++++
 NEWS                        |  4 ++++
 doc/groff.texi              |  9 ++++-----
 man/groff.7.man             |  6 ++++--
 src/libs/libgroff/color.cpp |  2 +-
 5 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 48184e93d..7c6c9ecc6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+2024-01-05  G. Branden Robinson <g.branden.robinson@gmail.com>
+
+       [troff]: Fix Savannah #64592 (default color name).
+
+       * src/libs/libgroff/color.cpp: Explicitly name the default color
+       "default", instead of permitting it to have a null name.
+
+       * doc/groff.texi (Colors):
+       * man/groff.7.man (Read-only regsiters):
+       * NEWS: Document it.
+
+       Fixes <https://savannah.gnu.org/bugs/?64592>.  Thanks to Deri
+       James, Dave Kemper, and Peter Schaffter for the discussion.
+
 2024-01-05  G. Branden Robinson <g.branden.robinson@gmail.com>
 
        [troff]: Implement new `pcolor` request.
diff --git a/NEWS b/NEWS
index 2f219aa7f..82a0433fa 100644
--- a/NEWS
+++ b/NEWS
@@ -37,6 +37,10 @@ o A new request, `phw`, reports to the standard error stream 
the current
 o The `hla` request, when invoked with no arguments, now clears the
   hyphenation language, disabling automatic hyphenation.
 
+o The read-only registers `.m` and `.M` now interpolate "default" when
+  the default color is selected as the stroke or fill color,
+  respectively, rather than interpolating nothing.
+
 eqn
 ---
 
diff --git a/doc/groff.texi b/doc/groff.texi
index a956f1a6b..f479f47c7 100644
--- a/doc/groff.texi
+++ b/doc/groff.texi
@@ -12377,8 +12377,8 @@ does a @code{gcolor} request without an argument.
 @cindex color name, stroke, register (@code{.m})
 The name of the current stroke color is available in the read-only
 string-valued register @samp{.m}; it is associated with the environment
-(@pxref{Environments}).  It interpolates nothing when the stroke color
-is the default.
+(@pxref{Environments}).  The default stroke color is named
+@samp{default}.
 
 @code{\m} doesn't produce an input token in GNU @code{troff}
 (@pxref{Gtroff Internals}).  It therefore can be used in requests like
@@ -12407,9 +12407,8 @@ color, as does an @code{fcolor} request without an 
argument.
 @cindex color name, fill, register (@code{.M})
 The name of the current fill color is available in the read-only
 string-valued register @samp{.M}; it is associated with the environment
-(@pxref{Environments}).  It interpolates nothing when the fill color
-is the default.  @code{\M} doesn't produce an input token in GNU
-@code{troff}.
+(@pxref{Environments}).  The default fill color is named @samp{default}.
+@code{\M} doesn't produce an input token in GNU @code{troff}.
 
 Create an ellipse with a red interior as follows.
 
diff --git a/man/groff.7.man b/man/groff.7.man
index 79d10884e..6357f38ad 100644
--- a/man/groff.7.man
+++ b/man/groff.7.man
@@ -6179,7 +6179,8 @@ see
 and
 .esc m .
 .
-Empty if the stroke color is the default.
+The default stroke color is named
+.RB \[lq] default \[rq].
 .
 .TP
 .REG .M
@@ -6189,7 +6190,8 @@ see
 and
 .esc M .
 .
-Empty if the fill color is the default.
+The default fill color is named
+.RB \[lq] default \[rq].
 .
 .TP
 .REG .n
diff --git a/src/libs/libgroff/color.cpp b/src/libs/libgroff/color.cpp
index cc4498f44..426b2bca9 100644
--- a/src/libs/libgroff/color.cpp
+++ b/src/libs/libgroff/color.cpp
@@ -399,7 +399,7 @@ char *color::print_color()
   return s;
 }
 
-color default_color("");
+color default_color("default");
 
 // Local Variables:
 // fill-column: 72