[groff] 18/19: [grn, groff, troff]: Improve fatal diagnostics.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit 6e79a0e06401af9ec18162a65912df06a94c0cda
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Thu Sep 16 04:00:26 2021 +1000

    [grn, groff, troff]: Improve fatal diagnostics.
    
    [grn, groff, troff]: Communicate better when device DESC file can't be
    loaded.
    
    * src/libs/libgroff/font.cpp (font::load_desc): Stop writing diagnostic
      to standard error.
    
    * src/preproc/grn/main.cpp (getres):
    * src/roff/troff/troff.cpp (main): Replace "sorry, I can't continue"
      fatal diagnostic with a more informative message.  Instead say
      which device's DESC file the program was trying to open, which might
      reveal a user's logic error or typo.
    
    * src/roff/groff/groff.cpp (main): Replace "invalid device" text of
      fatal diagnostic similarly.  I think it is more helpful to indicate
      the operation that failed rather than saying the device was invalid,
      particularly since there are other ways for a device to be invalid
      even if a DESC file is found and loaded.
---
 ChangeLog                  | 18 ++++++++++++++++++
 src/libs/libgroff/font.cpp |  4 +---
 src/preproc/grn/main.cpp   |  3 ++-
 src/roff/groff/groff.cpp   |  6 ++++--
 src/roff/troff/input.cpp   |  3 ++-
 5 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index f772d23..9eca83f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,23 @@
 2021-09-16  G. Branden Robinson <g.branden.robinson@gmail.com>
 
+       [grn, groff, troff]: Communicate better when device DESC file
+       can't be loaded.
+
+       * src/libs/libgroff/font.cpp (font::load_desc): Stop writing
+       diagnostic to standard error.
+       * src/preproc/grn/main.cpp (getres):
+       * src/roff/troff/troff.cpp (main): Replace "sorry, I can't
+       continue" fatal diagnostic with a more informative message.
+       Instead say which device's DESC file the program was trying to
+       open, which might reveal a user's logic error or typo.
+       * src/roff/groff/groff.cpp (main): Replace "invalid device" text
+       of fatal diagnostic similarly.  I think it is more helpful to
+       indicate the operation that failed rather than saying the device
+       was invalid, particularly since there are other ways for a
+       device to be invalid even if a DESC file is found and loaded.
+
+2021-09-16  G. Branden Robinson <g.branden.robinson@gmail.com>
+
        [troff]: Throw warning diagnostic if device DESC file attempts
        to load unavailable fonts.
 
diff --git a/src/libs/libgroff/font.cpp b/src/libs/libgroff/font.cpp
index 861b04c..0c49ebb 100644
--- a/src/libs/libgroff/font.cpp
+++ b/src/libs/libgroff/font.cpp
@@ -1035,10 +1035,8 @@ bool font::load_desc()
   int nfonts = 0;
   FILE *fp;
   char *path;
-  if ((fp = open_file("DESC", &path)) == 0) {
-    error("can't find 'DESC' file");
+  if ((fp = open_file("DESC", &path)) == 0)
     return false;
-  }
   text_file t(fp, path);
   t.skip_comments = 1;
   res = 0;
diff --git a/src/preproc/grn/main.cpp b/src/preproc/grn/main.cpp
index 3a2e332..c4a57a4 100644
--- a/src/preproc/grn/main.cpp
+++ b/src/preproc/grn/main.cpp
@@ -429,7 +429,8 @@ getres()
   int linepiece;
 
   if (!font::load_desc())
-    fatal("sorry, I can't continue");
+    fatal("cannot load 'DESC' description file for device '%1'",
+         device);
 
   res = font::res;
 
diff --git a/src/roff/groff/groff.cpp b/src/roff/groff/groff.cpp
index f83ab27..39c21e9 100644
--- a/src/roff/groff/groff.cpp
+++ b/src/roff/groff/groff.cpp
@@ -345,9 +345,11 @@ int main(int argc, char **argv)
   }
   font::set_unknown_desc_command_handler(handle_unknown_desc_command);
   if (!font::load_desc())
-    fatal("invalid device '%1'", device);
+    fatal("cannot load 'DESC' description file for device '%1'",
+         device);
   if (!postdriver)
-    fatal("no 'postpro' command in DESC file for device '%1'", device);
+    fatal("no 'postpro' directive in 'DESC' file for device '%1'",
+          device);
   if (predriver && !zflag) {
     commands[TROFF_INDEX].insert_arg(commands[TROFF_INDEX].get_name());
     commands[TROFF_INDEX].set_name(predriver);
diff --git a/src/roff/troff/input.cpp b/src/roff/troff/input.cpp
index abe9bf0..6019dfe 100644
--- a/src/roff/troff/input.cpp
+++ b/src/roff/troff/input.cpp
@@ -8127,7 +8127,8 @@ int main(int argc, char **argv)
   init_charset_table();
   init_hpf_code_table();
   if (!font::load_desc())
-    fatal("sorry, I can't continue");
+    fatal("cannot load 'DESC' description file for device '%1'",
+         device);
   units_per_inch = font::res;
   hresolution = font::hor;
   vresolution = font::vert;