autfilt: print match count even on parse errors

* bin/autfilt.cc: If -c is used, print the match_count even
in present of parse errors.
* tests/core/readsave.test: Adjust.
* NEWS: Mention the bug.

NEWS

@@ -23,6 +23,9 @@ New in spot 2.11.2.dev  (not yet released)
     (e.g., when the State: header declare many more states than the body
     of the file).  It now warns about those.
 
+  - 'autfilt -c ...' should display a match count even in present of
+    parse errors.
+
 New in spot 2.11.2  (2022-10-26)
 
   Command-line tools:

bin/autfilt.cc

@@ -1763,15 +1763,17 @@ main(int argc, char** argv)
       post.set_level(level);
 
       autfilt_processor processor(post, o.dict);
-      if (processor.run())
-        return 2;
-
-      // Diagnose unused -x options
-      extra_options.report_unused_options();
+      int err = processor.run();
 
       if (automaton_format == Count)
         std::cout << match_count << std::endl;
 
+      // Diagnose unused -x options
+      if (!err)
+        extra_options.report_unused_options();
+      else
+        return 2;
+
       check_cout();
       return match_count ? 0 : 1;
     });

tests/core/readsave.test

@@ -963,7 +963,8 @@ EOF
 test `autfilt -c --is-inherently-weak input7` = 1
 test `autfilt -c --is-weak input7` = 0
 test `autfilt -c --is-stutter-invariant input7` = 1
-autfilt --check input7 -H >output7
+autfilt --check input7 -H >output7 && exit 0
+test $? -eq 2
 cat >expected7 <<EOF
 HOA: v1
 States: 3
@@ -1004,11 +1005,11 @@ EOF
 test `autfilt -c --is-inherently-weak input8` = 0
 test `autfilt -c --is-weak input8` = 0
 
-autfilt input8 -Hl >oneline.hoa
-autfilt input8 --stats='%h' >oneline2.hoa
-autfilt input8 --stats='%H' >oneline3.hoa
-autfilt input8 --randomize --stats='%h' >oneline4.hoa
-autfilt input8 --randomize --stats='%H' >oneline5.hoa
+autfilt input8 -Hl >oneline.hoa && exit 1
+autfilt input8 --stats='%h' >oneline2.hoa && exit 1
+autfilt input8 --stats='%H' >oneline3.hoa && exit 1
+autfilt input8 --randomize --stats='%h' >oneline4.hoa && exit 1
+autfilt input8 --randomize --stats='%H' >oneline5.hoa && exit 1
 diff oneline.hoa oneline2.hoa
 diff oneline.hoa oneline3.hoa
 diff oneline.hoa oneline4.hoa && exit 1