vet: hide skipped file messages behind verbose flag (#9823)

cmd/tools/vvet/vvet.v

@@ -27,16 +27,17 @@ struct Options {
 	use_color     bool
 }
 
-const vet_options = cmdline.options_after(os.args, ['vet'])
+const term_colors = term.can_show_color_on_stderr()
 
 fn main() {
+	vet_options := cmdline.options_after(os.args, ['vet'])
 	mut vt := Vet{
 		opt: Options{
 			is_force: '-force' in vet_options
 			is_werror: '-W' in vet_options
 			is_verbose: '-verbose' in vet_options || '-v' in vet_options
-			show_warnings: '-hide-warnings' !in vet_options
-			use_color: should_use_color()
+			show_warnings: '-hide-warnings' !in vet_options && '-w' !in vet_options
+			use_color: '-color' in vet_options || (term_colors && '-nocolor' !in vet_options)
 		}
 	}
 	mut paths := cmdline.only_non_options(vet_options)
@@ -88,7 +89,7 @@ fn (mut vt Vet) vet_file(path string) {
 		// skip all /tests/ files, since usually their content is not
 		// important enough to be documented/vetted, and they may even
 		// contain intentionally invalid code.
-		eprintln("skipping test file: '$path' ...")
+		vt.vprintln("skipping test file: '$path' ...")
 		return
 	}
 	vt.file = path
@@ -252,14 +253,3 @@ fn (mut vt Vet) warn(msg string, line int, fix vet.FixKind) {
 		vt.warns << w
 	}
 }
-
-fn should_use_color() bool {
-	mut color := term.can_show_color_on_stderr()
-	if '-nocolor' in vet_options {
-		color = false
-	}
-	if '-color' in vet_options {
-		color = true
-	}
-	return color
-}

cmd/v/help/vet.txt

@@ -5,7 +5,14 @@ Usage:
 Reports suspicious code constructs.
 
 Options:
-  -W               Exit with code 1, even if vet only reported warnings. Useful for checks in CI.
-  -hide-warnings   Do not print warnings to stderr.
-  -v, -verbose     Enable verbose logging.
-  -force           (NB: vet development only!) Do not skip the vet regression tests.
+  -W
+     Exit with code 1, even if vet only reported warnings. Useful for checks in CI.
+
+  -w, -hide-warnings
+     Do not print warnings to stderr.
+
+  -v, -verbose
+     Enable verbose logging.
+
+  -force
+     (NB: vet development only!) Do not skip the vet regression tests.