--- ../File-Slurp-9999.19.orig/lib/File/Slurp.pm	2011-05-30 15:58:53.000000000 -0400
+++ lib/File/Slurp.pm	2015-09-18 11:20:12.294297000 -0400
@@ -446,6 +446,7 @@
 
 # in atomic mode, we spew to a temp file so make one and save the original
 # file name.
+			_check_file($file_name);
 			$orig_file_name = $file_name ;
 			$file_name .= ".$$" ;
 		}
@@ -614,6 +615,7 @@
 #print "EXIST [$$existing_data]\n" ;
 
 	$opts->{atomic} = 1 ;
+	_check_file($file_name);
 	my $write_result =
 		eval { write_file( $file_name, $opts,
 		       $prepend_data, $$existing_data ) ;
@@ -671,6 +673,7 @@
 	my( $edited_data ) = map { $edit_code->(); $_ } $$existing_data ;
 
 	$opts->{atomic} = 1 ;
+	_check_file($file_name);
 	my $write_result =
 		eval { write_file( $file_name, $opts, $edited_data ) } ;
 
@@ -724,6 +727,7 @@
 	my @edited_data = map { $edit_code->(); $_ } @$existing_data ;
 
 	$opts->{atomic} = 1 ;
+	_check_file($file_name);
 	my $write_result =
 		eval { write_file( $file_name, $opts, @edited_data ) } ;
 
@@ -807,6 +811,15 @@
 	return undef ;
 }
 
+sub _check_file {
+    my $file = shift;
+    my $file_temp .= "$file.$$";
+    if (-e $file_temp) {
+        # We should unconditionally die
+        croak("Error: atomic temporary file ($file_temp) already exists");
+    }
+}
+
 1;
 __END__
 
@@ -1066,7 +1079,8 @@
 file is closed it is renamed to the original file name (and rename is
 an atomic operation on most OS's). If the program using this were to
 crash in the middle of this, then the file with the pid suffix could
-be left behind.
+be left behind.  If the temporary file already exists, the code will
+C<croak>, regardless of the C<err_mode> setting.
 
 =head3 append