ltldo: improve error messages

Use ltldo:... instead of error:... and warning:... and also improve
the diagnostic displayed after a translation failure to mention the
tool and formula.

Incidentally, this fixes a spurious test case failure observed by
Philipp Schlehuber on CentOS7.7 where glibc 2.17 is installed.  With
this system, when posix_spawn() starts a binary that does not exist,
it returns success and let the child die with exit code 127.  On more
recent glibc, posix_spawn() manages to return execve()'s errno, as if
the child had not been created.  We handle those two different ways to
fail, but before this patch one used to print "error:..." and the
other "ltldo:...".

* bin/ltldo.cc: Display the program_name in error message.  Display
the command name and formula on translation failure.
* tests/core/ltldo.test: Adjust test case.
* NEWS: Mention the fix.

NEWS

@@ -58,6 +58,9 @@ New in spot 2.9.0.dev (not yet released)
     every place where 0 occur, and then the acceptance would be
     renumbered to Fin(0)|Fin(1)|Fin(2).  This is now fixed.
 
+  - Improve ltldo diagnostics to fix spurious test-suite failure on
+    systems with antique GNU libc.
+
 New in spot 2.9 (2020-04-30)
 
   Command-line tools:

bin/ltldo.cc

@@ -1,5 +1,5 @@
 // -*- coding: utf-8 -*-
-// Copyright (C) 2015-2019 Laboratoire de Recherche et Développement
+// Copyright (C) 2015-2020 Laboratoire de Recherche et Développement
 // de l'Epita (LRDE).
 //
 // This file is part of Spot, a model checking library.
@@ -39,6 +39,7 @@
 #include "common_hoaread.hh"
 
 #include <spot/tl/relabel.hh>
+#include <spot/tl/print.hh>
 #include <spot/misc/bareword.hh>
 #include <spot/misc/timer.hh>
 #include <spot/twaalgos/lbtt.hh>
@@ -233,18 +234,13 @@ namespace
       problem = false;
       if (timed_out)
         {
-          // A timeout is considered benign
+          // A timeout is considered benign, unless --fail-on-timeout.
           if (fail_on_timeout)
-            {
+            problem = true;
-              std::cerr << "error:";
-              problem = true;
-            }
           else
-            {
+            ++timeout_count;
-              std::cerr << "warning:";
+          std::cerr << program_name
-              ++timeout_count;
+                    << ": timeout during execution of command \""
-            }
-          std::cerr << " timeout during execution of command \""
                     << cmd << "\"\n";
         }
       else if (WIFSIGNALED(es))
@@ -253,7 +249,7 @@ namespace
             {
               problem = true;
               es = WTERMSIG(es);
-              std::cerr << "error: execution of command \"" << cmd
+              std::cerr << program_name << ": execution of command \"" << cmd
                         << "\" terminated by signal " << es << ".\n";
             }
         }
@@ -263,7 +259,7 @@ namespace
             {
               problem = true;
               es = WEXITSTATUS(es);
-              std::cerr << "error: execution of command \"" << cmd
+              std::cerr << program_name << ": execution of command \"" << cmd
                         << "\" returned exit code " << es << ".\n";
             }
         }
@@ -275,14 +271,14 @@ namespace
           if (!aut->errors.empty() && errors_opt != errors_ignore)
             {
               problem = true;
-              std::cerr << "error: failed to parse the automaton "
+              std::cerr << program_name << ": failed to parse the automaton "
                 "produced by \"" << cmd << "\".\n";
               aut->format_errors(std::cerr);
             }
           else if (aut->aborted && errors_opt != errors_ignore)
             {
               problem = true;
-              std::cerr << "error: command \"" << cmd
+              std::cerr << program_name << ": command \"" << cmd
                         << "\" aborted its output.\n";
             }
           else
@@ -410,11 +406,14 @@ namespace
           auto aut = runner.translate(t, problem, timer);
           if (problem)
             {
-              if (errors_opt == errors_abort)
+              // An error message already occurred about the problem,
-                error_at_line(2, 0, filename, linenum, "aborting here");
+              // but this additional one will print filename &
-              else
+              // linenum, and possibly exit.
-                error_at_line(0, 0, filename, linenum,
+              std::string sf = spot::str_psl(f);
-                              "failed to translate this input");
+              error_at_line(errors_opt == errors_abort ? 2 : 0, 0,
+                            filename, linenum,
+                            "failed to run `%s' on `%s'",
+                            tools[t].name, sf.c_str());
             }
           if (aut)
             {

tests/core/ltldo.test

@@ -1,6 +1,6 @@
 #!/bin/sh
 # -*- coding: utf-8 -*-
-# Copyright (C) 2015-2019 Laboratoire de Recherche et Développement de
+# Copyright (C) 2015-2020 Laboratoire de Recherche et Développement de
 # l'Epita (LRDE).
 #
 # This file is part of Spot, a model checking library.
@@ -43,21 +43,23 @@ genltl --or-g=1..2 |
 run 0 ltldo -t 'sleep 10; echo %f' -T1 -t 'sleep 10; echo %f' \
 	     >output 2>stderr
 test -z "`cat output`"
-test 4 = `grep -c warning: stderr`
+test 4 = `grep -c ltldo: stderr`
+grep -q 'failed to' stderr && exit 1
 
 genltl --or-g=1..2 |
 run 0 ltldo -t 'sleep 10; echo %f' -T1 -t 'sleep 10; echo %f' \
 	     --fail-on-timeout --error=warn >output 2>stderr
 test -z "`cat output`"
-test 4 = `grep -c error: stderr`
+test 8 = `grep -c ltldo: stderr`
-grep -q 'aborting here' stderr && exit 1
+test 4 = `grep -c ltldo:-: stderr`
+grep -q 'failed to' stderr
 
 genltl --or-g=1..2 |
 run 2 ltldo -t 'sleep 10; echo %f' -T1 -t 'sleep 10; echo %f' \
 	     --fail-on-timeout >output 2>stderr
 test -z "`cat output`"
-test 1 = `grep -c error: stderr`
+test 2 = `grep -c ltldo: stderr`
-grep -q 'aborting here' stderr
+grep -q 'failed to' stderr
 
 test "`echo 1,a,3,4 | ltldo -F-/2 ltl2tgba --stats='%<,%s,%>'`" = '1,2,3,4'
 
@@ -143,7 +145,7 @@ diff output expected
 ltldo ': %s; true>%O' -f GFa 2>stderr && exit 1
 test $? = 2
 grep ':.*empty input' stderr
-grep 'ltldo: aborting' stderr
+grep 'ltldo: failed to run' stderr
 
 ltldo ': %s; true>%O' --errors=ignore -f GFa 2>stderr
 test $? = 0