[groff] 08/08: src/roff/troff/div.cpp: Error on meaningless .ch.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit e3b909eda11419daaf9e1ff028defc0e972ac827
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Tue Nov 17 21:23:37 2020 +1100

    src/roff/troff/div.cpp: Error on meaningless .ch.
    
    * src/roff/troff/div.cpp (top_level_diversion::change_trap): Emit error
      diagnostic if an attempt is made to move an unplanted macro.  This
      could have been a warning, as it's pretty harmless (though possibly a
      big surprise to anyone who was wondering why their .ch was a no-op),
      but there's no good warning category for this kind of problem and I am
      not about to start a bike shed discussion about it right now.
---
 ChangeLog              | 10 ++++++++++
 src/roff/troff/div.cpp |  3 ++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/ChangeLog b/ChangeLog
index 4fa7960..3fd83cd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2020-11-17  G. Branden Robinson <g.branden.robinson@gmail.com>
+
+       * src/roff/troff/div.cpp (top_level_diversion::change_trap):
+       Emit error diagnostic if an attempt is made to move an unplanted
+       macro.  This could have been a warning, as it's pretty harmless
+       {though possibly a big surprise to anyone who was wondering why
+       their .ch was a no-op}, but there's no good warning category for
+       this kind of problem and I am not about to start a bike shed
+       discussion about it right now.
+
 2020-11-15  G. Branden Robinson <g.branden.robinson@gmail.com>
 
        * doc/groff.texi: Update.  Add introductory material.  Rewrite
diff --git a/src/roff/troff/div.cpp b/src/roff/troff/div.cpp
index 808ccbe..014d865 100644
--- a/src/roff/troff/div.cpp
+++ b/src/roff/troff/div.cpp
@@ -523,7 +523,7 @@ void top_level_diversion::remove_trap_at(vunits pos)
       return;
     }
 }
-      
+
 void top_level_diversion::change_trap(symbol nam, vunits pos)
 {
   for (trap *p = page_trap_list; p; p = p->next)
@@ -531,6 +531,7 @@ void top_level_diversion::change_trap(symbol nam, vunits 
pos)
       p->position = pos;
       return;
     }
+  error("cannot move unplanted trap macro '%1'", nam.contents());
 }
 
 void top_level_diversion::print_traps()