Add an --errors-only command line option

When set, only errors (and not warnings) will be reported.

README.md

@@ -15,6 +15,8 @@ usage: thriftcheck [options] [file ...]
     	include path (can be specified multiple times)
   -c, --config string
     	configuration file path (default "thriftcheck.toml")
+  --errors-only
+    	only report errors (not warnings)
   -h, --help
     	show command help
   -l, --list

cmd/main.go

@@ -70,6 +70,7 @@ var (
 	revision      = "dev"
 	includes      Includes
 	configFile    = flag.String("c", "thriftcheck.toml", "configuration file path")
+	errorsOnly    = flag.Bool("errors-only", false, "only report errors (not warnings)")
 	helpFlag      = flag.Bool("h", false, "show command help")
 	listFlag      = flag.Bool("l", false, "list all available checks and exit")
 	stdinFilename = flag.String("stdin-filename", "stdin", "filename used when piping from stdin")
@@ -185,6 +186,9 @@ func main() {
 	// Print any messages reported by the linter
 	status := 0
 	for _, m := range messages {
+		if *errorsOnly && m.Severity != thriftcheck.Error {
+			continue
+		}
 		fmt.Println(m)
 		status |= 1 << uint(m.Severity)
 	}