ltsmin: make it easier to find the README

Fixes #550, reported by Daniel Stan.

* tests/ltsmin/README: Move...
* README.ltsmin: ... here.
* Makefile.am (EXTRA_DIST): Add README.ltsmin.
* README: Mention README.ltsmin.
* spot/ltsmin/spins_interface.cc: Mention README.ltsmin in the error
message.
* tests/ltsmin/check.test, tests/ltsmin/check3.test: Adjust reference
to README.
* NEWS: Mention this fix.
* THANKS: Add Danial.

Makefile.am

@@ -1,6 +1,6 @@
 ## -*- coding: utf-8 -*-
-## Copyright (C) 2011-2017, 2020, 2022 Laboratoire de Recherche et Développement
-## de l'Epita (LRDE).
+## Copyright (C) 2011-2017, 2020, 2022-2023 Laboratoire de Recherche
+## et Développement de l'Epita (LRDE).
 ## Copyright (C) 2003, 2005  Laboratoire d'Informatique de Paris 6 (LIP6),
 ## département Systèmes Répartis Coopératifs (SRC), Université Pierre
 ## et Marie Curie.
@@ -69,7 +69,7 @@ EXTRA_DIST = HACKING ChangeLog.1 tools/gitlog-to-changelog	\
 	     tools/help2man tools/man2html.pl			\
 	     tools/test-driver-teamcity $(UTF8) $(DEBIAN)	\
 	     m4/gnulib-cache.m4 .dir-locals.el			\
-	     spot.spec spot.spec.in
+	     spot.spec spot.spec.in README.ltsmin
 
 dist-hook: gen-ChangeLog
 

NEWS

@@ -108,6 +108,9 @@ New in spot 2.11.6.dev  (not yet released)
     removal of superfluous APs that is now performed by ltlsynt
     (search for --polarity and --global-equivalence above).
 
+  - ltsmin's interface will now point to README.ltsmin in case an
+    error is found while running divine or spins.
+
   Python:
 
   - The spot.automata() and spot.automaton() functions now accept a

README

@@ -93,6 +93,10 @@ automata.
 If the SAT-solver glucose is found on your system, it will be used by
 our test suite to test our SAT-based minimization algorithm.
 
+If you want to use Spot with DiVinE2 (for model checking DVE models)
+or with SpinS (for model checking Promela models), please read the
+file named "README.ltsmin" for installation instructions.
+
 Spot used to distribute a modified version of LBTT (an LTL to Büchi
 test bench), mostly fixing errors reported by recent compilers.
 However Spot now distributes its own reimplementation of LBTT, called

THANKS

@@ -10,6 +10,7 @@ Caroline Lemieux
 Christian Dax
 Christopher Ziegler
 Clément Tamines
+Daniel Stan
 David Dokoupil
 David Müller
 Dávid Smolka

spot/ltsmin/spins_interface.cc

@@ -1,5 +1,5 @@
 // -*- coding: utf-8 -*-
-// Copyright (C) 2019, 2020 Laboratoire de Recherche et Développement
+// Copyright (C) 2019, 2020, 2023 Laboratoire de Recherche et Développement
 // de l'Epita (LRDE)
 //
 // This file is part of Spot, a model checking library.
@@ -45,22 +45,26 @@ namespace spot
     static void
     compile_model(std::string& filename, const std::string& ext)
     {
+      const char* cmd;
       std::string command;
       std::string compiled_ext;
 
       if (ext == ".gal")
         {
-          command = "gal2c " + filename;
+          cmd = "gal2c ";
+          command = cmd + filename;
           compiled_ext = "2C";
         }
       else if (ext == ".prom" || ext == ".pm" || ext == ".pml")
         {
-          command = "spins " + filename;
+          cmd = "spins ";
+          command = cmd + filename;
           compiled_ext = ".spins";
         }
       else if (ext == ".dve")
         {
-          command = "divine compile --ltsmin " + filename;
+          cmd = "divine ";
+          command = cmd + "compile --ltsmin "s + filename;
           command += " 2> /dev/null"; // FIXME needed for Clang on MacOSX
           compiled_ext = "2C";
         }
@@ -92,9 +96,17 @@ namespace spot
 
       int res = system(command.c_str());
       if (res)
-        throw std::runtime_error("Execution of '"s
-                                 + command.c_str() + "' returned exit code "
-                                 + std::to_string(WEXITSTATUS(res)));
+        {
+          std::ostringstream os;
+          int status = WEXITSTATUS(res);
+          os << "Execution of '" << command << "' returned exit code "
+             << status << '.';
+          if (status == 127)
+            os << "\nIs " << cmd << "installed and on your $PATH?\n"
+              "Read README.ltsmin in Spot's sources for "
+              "installation instructions.";
+          throw std::runtime_error(os.str());
+        }
     }
   }
 

tests/ltsmin/check.test

@@ -1,7 +1,7 @@
 #!/bin/sh
 # -*- coding: utf-8 -*-
-# Copyright (C) 2011, 2012, 2014, 2015, 2016, 2017, 2019, 2020 Laboratoire
-# de Recherche et Développement de l'Epita (LRDE).
+# Copyright (C) 2011-2012, 2014-2017, 2019-2020, 2023 Laboratoire de
+# Recherche et Développement de l'Epita (LRDE).
 #
 # This file is part of Spot, a model checking library.
 #
@@ -48,7 +48,7 @@ fi
 
 # dve2
 for opt in '' '--compress 1'; do
-  # The three examples from the README.
+  # The three examples from README.ltsmin.
   # (Don't run the first one using "run 0" because it would take too much
   # time with valgrind.).
 

tests/ltsmin/check3.test

@@ -1,6 +1,6 @@
 #!/bin/sh
 # -*- coding: utf-8 -*-
-# Copyright (C) 2016, 2017 Laboratoire de Recherche
+# Copyright (C) 2016-2017, 2023 Laboratoire de Recherche
 # et Développement de l'Epita (LRDE).
 #
 # This file is part of Spot, a model checking library.
@@ -28,10 +28,6 @@ fi
 set -e
 
 for opt in '' '--compress 1'; do
-  # The three examples from the README.
-  # (Don't run the first one using "run 0" because it would take too much
-  # time with valgrind.).
-
   run 1 ../modelcheck $opt --is-empty --model  $srcdir/beem-peterson.4.gal \
     --formula '!G("P_0.state==2" -> F "P_0.state==1")'
   run 1 ../modelcheck $opt --is-empty --model $srcdir/beem-peterson.4.gal \