all: quote string arguments in error messages

These strings are often file names or other user specified
parameters, which can give confusing errors in
the presence of unexpected characters for example.

* cfg.mk (sc_error_quotes): A new syntax check rule.
* src/*.c: Wrap error() string arguments with quote().
* tests/: Adjust accordingly.
* NEWS: Mention the improvement.

1 files changed, 4 insertions, 4 deletions

diff --git a/src/nl.c b/src/nl.c
index 1132af398..f431d9839 100644
--- a/src/nl.c
+++ b/src/nl.c
@@ -255,7 +255,7 @@ build_type_arg (char const **typep,
         RE_SYNTAX_POSIX_BASIC & ~RE_CONTEXT_INVALID_DUP & ~RE_NO_EMPTY_RANGES;
       errmsg = re_compile_pattern (optarg, strlen (optarg), regexp);
       if (errmsg)
-        error (EXIT_FAILURE, 0, "%s", errmsg);
+        error (EXIT_FAILURE, 0, "%s", (errmsg));
       break;
     default:
       rval = false;
@@ -426,7 +426,7 @@ nl_file (char const *file)
       stream = fopen (file, "r");
       if (stream == NULL)
         {
-          error (0, errno, "%s", file);
+          error (0, errno, "%s", quote (file));
           return false;
         }
     }
@@ -437,14 +437,14 @@ nl_file (char const *file)
 
   if (ferror (stream))
     {
-      error (0, errno, "%s", file);
+      error (0, errno, "%s", quote (file));
       return false;
     }
   if (STREQ (file, "-"))
     clearerr (stream);		/* Also clear EOF. */
   else if (fclose (stream) == EOF)
     {
-      error (0, errno, "%s", file);
+      error (0, errno, "%s", quote (file));
       return false;
     }
   return true;