standardize some error messages

* maint.mk: (sc_error_message_warn_fatal, sc_error_message_uppercase):
(sc_error_message_period): Add automatic checks for non-standard error
messages.
* .x-sc_error_message_uppercase: explicit exclusion for this check
* src/cp.c: Standardize some error messages.
* src/date.c: Likewise.
* src/dircolors.c: Likewise.
* src/du.c: Likewise.
* src/expr.c: Likewise.
* src/install.c: Likewise.
* src/join.c: Likewise.
* src/ln.c: Likewise.
* src/mv.c: Likewise.
* src/od.c: Likewise.
* src/pr.c: Likewise.
* src/split.c: Likewise.
* src/truncate.c: Likewise.
* src/wc.c: Likewise.
* tests/du/files0-from: Expect new error message.
* tests/misc/join: Likewise.
* tests/misc/split-a: Likewise.
* tests/misc/wc-files0-from: Likewise.
* tests/misc/xstrtol: Likewise.
* lib/xmemxfrm.c: Likewise.

22 files changed, 56 insertions, 33 deletions

diff --git a/.x-sc_error_message_uppercase b/.x-sc_error_message_uppercase
new file mode 100644
index 000000000..245223016
--- /dev/null
+++ b/.x-sc_error_message_uppercase
@@ -0,0 +1 @@
+build-aux/cvsu
diff --git a/lib/xmemxfrm.c b/lib/xmemxfrm.c
index 039f97818..84f51583b 100644
--- a/lib/xmemxfrm.c
+++ b/lib/xmemxfrm.c
@@ -52,9 +52,9 @@ xmemxfrm (char *restrict dest, size_t destsize,
   if (errno)
     {
       error (0, errno, _("string transformation failed"));
-      error (0, 0, _("Set LC_ALL='C' to work around the problem."));
+      error (0, 0, _("set LC_ALL='C' to work around the problem"));
       error (exit_failure, 0,
-	     _("The untransformed string was %s."),
+	     _("the untransformed string was %s"),
 	     quotearg_n_style_mem (0, locale_quoting_style, src, srcsize));
     }
 
diff --git a/maint.mk b/maint.mk
index 5f9f1f006..88448293c 100644
--- a/maint.mk
+++ b/maint.mk
@@ -144,6 +144,29 @@ sc_error_exit_success:
 	  { echo '$(ME): found error (EXIT_SUCCESS' 1>&2;		\
 	    exit 1; } || :
 
+# `FATAL:' should be fully upper-cased in error messages
+# `WARNING:' should be fully upper-cased, or fully lower-cased
+sc_error_message_warn_fatal:
+	@grep -nEA2 '[^rp]error \(' $$($(VC_LIST_EXCEPT))		\
+	    | grep -E '"Warning|"Fatal|"fatal' &&			\
+	  { echo '$(ME): use FATAL, WARNING or warning'	1>&2;		\
+	    exit 1; } || :
+
+# Error messages should not start with a capital letter
+sc_error_message_uppercase:
+	@grep -nEA2 '[^rp]error \(' $$($(VC_LIST_EXCEPT))		\
+	    | grep -E '"[A-Z]'						\
+	    | grep -vE '"FATAL|"WARNING|"Java|"C#|PRIuMAX' &&		\
+	  { echo '$(ME): found capitalized error message' 1>&2;		\
+	    exit 1; } || :
+
+# Error messages should not end with a period
+sc_error_message_period:
+	@grep -nEA2 '[^rp]error \(' $$($(VC_LIST_EXCEPT))		\
+	    | grep -E '[^."]\."' &&					\
+	  { echo '$(ME): found error message ending in period' 1>&2;	\
+	    exit 1; } || :
+
 sc_file_system:
 	@grep -ni 'file''system' $$($(VC_LIST_EXCEPT)) &&		\
 	  { echo '$(ME): found use of "file''system";'			\
diff --git a/src/cp.c b/src/cp.c
index 01b9c18d3..c768d1bc9 100644
--- a/src/cp.c
+++ b/src/cp.c
@@ -592,7 +592,7 @@ do_copy (int n_files, char **file, const char *target_directory,
     {
       if (target_directory)
 	error (EXIT_FAILURE, 0,
-	       _("Cannot combine --target-directory (-t) "
+	       _("cannot combine --target-directory (-t) "
 		 "and --no-target-directory (-T)"));
       if (2 < n_files)
 	{
diff --git a/src/date.c b/src/date.c
index aa4d69dcb..24390529c 100644
--- a/src/date.c
+++ b/src/date.c
@@ -441,8 +441,8 @@ main (int argc, char **argv)
 	{
 	  error (0, 0,
 		 _("the argument %s lacks a leading `+';\n"
-		   "When using an option to specify date(s), any non-option\n"
-		   "argument must be a format string beginning with `+'."),
+		   "when using an option to specify date(s), any non-option\n"
+		   "argument must be a format string beginning with `+'"),
 		 quote (argv[optind]));
 	  usage (EXIT_FAILURE);
 	}
diff --git a/src/dircolors.c b/src/dircolors.c
index 44ec537fd..56194f793 100644
--- a/src/dircolors.c
+++ b/src/dircolors.c
@@ -448,8 +448,8 @@ to select a shell syntax are mutually exclusive"));
       error (0, 0, _("extra operand %s"), quote (argv[!print_database]));
       if (print_database)
 	fprintf (stderr, "%s\n",
-		 _("File operands cannot be combined with "
-		   "--print-database (-p)."));
+		 _("file operands cannot be combined with "
+		   "--print-database (-p)"));
       usage (EXIT_FAILURE);
     }
 
diff --git a/src/du.c b/src/du.c
index 32cb3631d..d9749919e 100644
--- a/src/du.c
+++ b/src/du.c
@@ -937,7 +937,7 @@ main (int argc, char **argv)
 	{
 	  error (0, 0, _("extra operand %s"), quote (argv[optind]));
 	  fprintf (stderr, "%s\n",
-		   _("File operands cannot be combined with --files0-from."));
+		   _("file operands cannot be combined with --files0-from"));
 	  usage (EXIT_FAILURE);
 	}
 
diff --git a/src/expr.c b/src/expr.c
index d6b19855b..bbcb5a922 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -777,9 +777,9 @@ eval2 (bool evaluate)
 	      if (errno)
 		{
 		  error (0, errno, _("string comparison failed"));
-		  error (0, 0, _("Set LC_ALL='C' to work around the problem."));
+		  error (0, 0, _("set LC_ALL='C' to work around the problem"));
 		  error (EXPR_INVALID, 0,
-			 _("The strings compared were %s and %s."),
+			 _("the strings compared were %s and %s"),
 			 quotearg_n_style (0, locale_quoting_style, l->u.s),
 			 quotearg_n_style (1, locale_quoting_style, r->u.s));
 		}
diff --git a/src/install.c b/src/install.c
index aa14b948d..0d3927df4 100644
--- a/src/install.c
+++ b/src/install.c
@@ -420,8 +420,8 @@ main (int argc, char **argv)
 	case PRESERVE_CONTEXT_OPTION:
 	  if ( ! selinux_enabled)
 	    {
-	      error (0, 0, _("Warning: ignoring --preserve-context; "
-			     "this kernel is not SELinux-enabled."));
+	      error (0, 0, _("WARNING: ignoring --preserve-context; "
+			     "this kernel is not SELinux-enabled"));
 	      break;
 	    }
 	  x.preserve_security_context = true;
@@ -430,8 +430,8 @@ main (int argc, char **argv)
 	case 'Z':
 	  if ( ! selinux_enabled)
 	    {
-	      error (0, 0, _("Warning: ignoring --context (-Z); "
-			     "this kernel is not SELinux-enabled."));
+	      error (0, 0, _("WARNING: ignoring --context (-Z); "
+			     "this kernel is not SELinux-enabled"));
 	      break;
 	    }
 	  scontext = optarg;
@@ -487,7 +487,7 @@ main (int argc, char **argv)
     {
       if (target_directory)
 	error (EXIT_FAILURE, 0,
-	       _("Cannot combine --target-directory (-t) "
+	       _("cannot combine --target-directory (-t) "
 		 "and --no-target-directory (-T)"));
       if (2 < n_files)
 	{
diff --git a/src/join.c b/src/join.c
index 32872681c..4c506d1ac 100644
--- a/src/join.c
+++ b/src/join.c
@@ -380,7 +380,7 @@ check_order (const struct line *prev,
 	    {
 	      error ((check_input_order == CHECK_ORDER_ENABLED
 		      ? EXIT_FAILURE : 0),
-		     0, _("File %d is not in sorted order"), whatfile);
+		     0, _("file %d is not in sorted order"), whatfile);
 
 	      /* If we get to here, the message was just a warning, but we
 		 want only to issue it once. */
diff --git a/src/ln.c b/src/ln.c
index 137224073..2dc5628e8 100644
--- a/src/ln.c
+++ b/src/ln.c
@@ -507,7 +507,7 @@ main (int argc, char **argv)
     {
       if (target_directory)
 	error (EXIT_FAILURE, 0,
-	       _("Cannot combine --target-directory "
+	       _("cannot combine --target-directory "
 		 "and --no-target-directory"));
       if (n_files != 2)
 	{
diff --git a/src/mv.c b/src/mv.c
index bab26ba46..fc255f368 100644
--- a/src/mv.c
+++ b/src/mv.c
@@ -450,7 +450,7 @@ main (int argc, char **argv)
     {
       if (target_directory)
 	error (EXIT_FAILURE, 0,
-	       _("Cannot combine --target-directory (-t) "
+	       _("cannot combine --target-directory (-t) "
 		 "and --no-target-directory (-T)"));
       if (2 < n_files)
 	{
diff --git a/src/od.c b/src/od.c
index 3273ec2ee..4df8e7dae 100644
--- a/src/od.c
+++ b/src/od.c
@@ -1838,7 +1838,7 @@ it must be one character from [doxn]"),
 	{
 	  error (0, 0, _("extra operand %s"), quote (argv[optind + 1]));
 	  error (0, 0, "%s\n",
-		 _("Compatibility mode supports at most one file."));
+		 _("compatibility mode supports at most one file"));
 	  usage (EXIT_FAILURE);
 	}
     }
diff --git a/src/pr.c b/src/pr.c
index 27ff8593f..6ffe8f154 100644
--- a/src/pr.c
+++ b/src/pr.c
@@ -913,7 +913,7 @@ main (int argc, char **argv)
 	      error (EXIT_FAILURE, 0,
 		     _("`--pages=FIRST_PAGE[:LAST_PAGE]' missing argument"));
 	    else if (! first_last_page (oi, 0, optarg))
-	      error (EXIT_FAILURE, 0, _("Invalid page range %s"),
+	      error (EXIT_FAILURE, 0, _("invalid page range %s"),
 		     quote (optarg));
 	    break;
 	  }
@@ -1099,11 +1099,11 @@ main (int argc, char **argv)
 
   if (parallel_files & explicit_columns)
     error (EXIT_FAILURE, 0,
-	 _("Cannot specify number of columns when printing in parallel."));
+	 _("cannot specify number of columns when printing in parallel"));
 
   if (parallel_files & print_across_flag)
     error (EXIT_FAILURE, 0,
-       _("Cannot specify both printing across and printing in parallel."));
+       _("cannot specify both printing across and printing in parallel"));
 
 /* Translate some old short options to new/long options.
    To meet downward compatibility with other UNIX pr utilities
@@ -2394,7 +2394,7 @@ print_header (void)
   print_white_space ();
 
   if (page_number == 0)
-    error (EXIT_FAILURE, 0, _("Page number overflow"));
+    error (EXIT_FAILURE, 0, _("page number overflow"));
 
   /* The translator must ensure that formatting the translation of
      "Page %"PRIuMAX does not generate more than (sizeof page_text - 1)
diff --git a/src/split.c b/src/split.c
index 71200fb32..181d83783 100644
--- a/src/split.c
+++ b/src/split.c
@@ -189,7 +189,7 @@ next_file_name (void)
 	  sufindex[i] = 0;
 	  outfile_mid[i] = suffix_alphabet[sufindex[i]];
 	}
-      error (EXIT_FAILURE, 0, _("Output file suffixes exhausted"));
+      error (EXIT_FAILURE, 0, _("output file suffixes exhausted"));
     }
 }
 
diff --git a/src/truncate.c b/src/truncate.c
index f3530675e..f26fd45a8 100644
--- a/src/truncate.c
+++ b/src/truncate.c
@@ -326,7 +326,7 @@ main (int argc, char **argv)
   /* must specify either size or reference file */
   if ((ref_file && got_size) || (!ref_file && !got_size))
     {
-      error (0, 0, _("You must specify one of %s or %s"),
+      error (0, 0, _("you must specify one of %s or %s"),
              quote_n (0, "--size"), quote_n (1, "--reference"));
       usage (EXIT_FAILURE);
     }
diff --git a/src/wc.c b/src/wc.c
index 8073bb0f9..e6b9a1ebb 100644
--- a/src/wc.c
+++ b/src/wc.c
@@ -646,7 +646,7 @@ main (int argc, char **argv)
 	{
 	  error (0, 0, _("extra operand %s"), quote (argv[optind]));
 	  fprintf (stderr, "%s\n",
-		   _("File operands cannot be combined with --files0-from."));
+		   _("file operands cannot be combined with --files0-from"));
 	  usage (EXIT_FAILURE);
 	}
 
diff --git a/tests/du/files0-from b/tests/du/files0-from
index 3e299f34e..5cdbd8960 100755
--- a/tests/du/files0-from
+++ b/tests/du/files0-from
@@ -31,7 +31,7 @@ my @Tests =
    # invalid extra command line argument
    ['f-extra-arg', '--files0-from=- no-such', {IN=>"a"}, {EXIT=>1},
     {ERR => "$prog: extra operand `no-such'\n"
-        . "File operands cannot be combined with --files0-from.\n"
+	. "file operands cannot be combined with --files0-from\n"
         . "Try `$prog --help' for more information.\n"}
     ],
 
diff --git a/tests/misc/join b/tests/misc/join
index 772c2c4ad..4c36c32a5 100755
--- a/tests/misc/join
+++ b/tests/misc/join
@@ -166,7 +166,7 @@ my @tv = (
 # With check, both inputs out of order (in fact, in reverse order)
 ['chkodr-5', '--check-order',
  [" b 1\n a 2\n", " b Y\n a Z\n"], "", 1,
- "$prog: File 1 is not in sorted order\n"],
+ "$prog: file 1 is not in sorted order\n"],
 
 # Without order check, both inputs out of order and some lines
 # unpairable.  This is NOT supported by the GNU extension.  All that
diff --git a/tests/misc/split-a b/tests/misc/split-a
index b39009942..19f3f0aed 100755
--- a/tests/misc/split-a
+++ b/tests/misc/split-a
@@ -38,7 +38,7 @@ for f in $files; do
   printf 'creating file `%s'\''\n' $f
 done > exp || framework_failure
 
-echo split: Output file suffixes exhausted \
+echo split: output file suffixes exhausted \
   > exp-too-short || framework_failure
 
 fail=0
diff --git a/tests/misc/wc-files0-from b/tests/misc/wc-files0-from
index 505014301..c8ce7d6e5 100755
--- a/tests/misc/wc-files0-from
+++ b/tests/misc/wc-files0-from
@@ -31,8 +31,8 @@ my @Tests =
    # invalid extra command line argument
    ['f-extra-arg', '--files0-from=- no-such', {IN=>"a"}, {EXIT=>1},
     {ERR => "$prog: extra operand `no-such'\n"
-        . "File operands cannot be combined with --files0-from.\n"
-        . "Try `$prog --help' for more information.\n"}
+	. "file operands cannot be combined with --files0-from\n"
+	. "Try `$prog --help' for more information.\n"}
     ],
 
    # missing input file
diff --git a/tests/misc/xstrtol b/tests/misc/xstrtol
index 0ebd32bdc..08f9d1d86 100755
--- a/tests/misc/xstrtol
+++ b/tests/misc/xstrtol
@@ -38,9 +38,8 @@ my @Tests =
    ['simply-inval', "--pages=x", {EXIT => 1},
     {ERR=>"$prog: invalid --pages argument `x'\n"}],
 
-   # FIXME: should be lower case "invalid".
    ['inv-pg-range', "--pages=9x", {EXIT => 1},
-    {ERR=>"$prog: Invalid page range `9x'\n"}],
+    {ERR=>"$prog: invalid page range `9x'\n"}],
   );
 
 my $save_temps = $ENV{DEBUG};