Fix CLI flags

cmd/spancheck/main.go

@@ -1,11 +1,33 @@
 package main
 
 import (
+	"flag"
+	"fmt"
+	"strings"
+
 	"golang.org/x/tools/go/analysis/singlechecker"
 
 	"github.com/jjti/go-spancheck"
 )
 
 func main() {
-	singlechecker.Main(spancheck.NewAnalyzer())
+	// Set the list of checks to enable.
+	checkOptions := []string{}
+	for check := range spancheck.Checks {
+		checkOptions = append(checkOptions, check)
+	}
+
+	checkStrings := ""
+	flag.StringVar(&checkStrings, "checks", "end", fmt.Sprintf("comma-separated list of checks to enable (options: %v)", strings.Join(checkOptions, ", ")))
+
+	// Set the list of function signatures to ignore checks for.
+	ignoreCheckSignatures := ""
+	flag.StringVar(&ignoreCheckSignatures, "ignore-check-signatures", "", "comma-separated list of regex for function signatures that disable checks on errors")
+	flag.Parse()
+
+	cfg := spancheck.NewDefaultConfig()
+	cfg.EnabledChecks = strings.Split(checkStrings, ",")
+	cfg.IgnoreChecksSignaturesSlice = strings.Split(ignoreCheckSignatures, ",")
+
+	singlechecker.Main(spancheck.NewAnalyzerWithConfig(cfg))
 }

config.go

@@ -64,27 +64,6 @@ type Config struct {
 	ignoreChecksSignatures *regexp.Regexp
 }
 
-// NewConfigFromFlags returns a new Config with default values and flags for CLI usage.
-func NewConfigFromFlags() *Config {
-	cfg := NewDefaultConfig()
-
-	cfg.fs = flag.FlagSet{}
-
-	// Set the list of checks to enable.
-	checkOptions := []string{}
-	for check := range Checks {
-		checkOptions = append(checkOptions, check)
-	}
-	checkStrings := cfg.fs.String("checks", "end", fmt.Sprintf("comma-separated list of checks to enable (options: %v)", strings.Join(checkOptions, ", ")))
-	cfg.EnabledChecks = strings.Split(*checkStrings, ",")
-
-	// Set the list of function signatures to ignore checks for.
-	ignoreCheckSignatures := flag.String("ignore-check-signatures", "", "comma-separated list of regex for function signatures that disable checks on errors")
-	cfg.ignoreChecksSignatures = parseSignatures(*ignoreCheckSignatures)
-
-	return cfg
-}
-
 // NewDefaultConfig returns a new Config with default values.
 func NewDefaultConfig() *Config {
 	return &Config{
@@ -105,6 +84,10 @@ func (c *Config) finalize() {
 // parseSignatures sets the Ignore*CheckSignatures regex from the string slices.
 func (c *Config) parseSignatures() {
 	if c.ignoreChecksSignatures == nil && len(c.IgnoreChecksSignaturesSlice) > 0 {
+		if len(c.IgnoreChecksSignaturesSlice) == 1 && c.IgnoreChecksSignaturesSlice[0] == "" {
+			return
+		}
+
 		c.ignoreChecksSignatures = createRegex(c.IgnoreChecksSignaturesSlice)
 	}
 }
@@ -132,24 +115,6 @@ func parseChecks(checksSlice []string) []Check {
 	return checks
 }
 
-func parseSignatures(sigFlag string) *regexp.Regexp {
-	if sigFlag == "" {
-		return nil
-	}
-
-	sigs := []string{}
-	for _, sig := range strings.Split(sigFlag, ",") {
-		sig = strings.TrimSpace(sig)
-		if sig == "" {
-			continue
-		}
-
-		sigs = append(sigs, sig)
-	}
-
-	return createRegex(sigs)
-}
-
 func createRegex(sigs []string) *regexp.Regexp {
 	if len(sigs) == 0 {
 		return nil

spancheck.go

@@ -28,12 +28,6 @@ var (
 	errorType = types.Universe.Lookup("error").Type().Underlying().(*types.Interface)
 )
 
-// NewAnalyzer returns a new analyzer that checks for mistakes with OTEL trace spans.
-// Its config is sourced from flags.
-func NewAnalyzer() *analysis.Analyzer {
-	return newAnalyzer(NewConfigFromFlags())
-}
-
 // NewAnalyzerWithConfig returns a new analyzer configured with the Config passed in.
 // Its config can be set for testing.
 func NewAnalyzerWithConfig(config *Config) *analysis.Analyzer {

spancheck_test.go

@@ -12,7 +12,7 @@ func Test(t *testing.T) {
 	t.Parallel()
 
 	for dir, config := range map[string]*spancheck.Config{
-		"base": spancheck.NewConfigFromFlags(),
+		"base": spancheck.NewDefaultConfig(),
 		"disableerrorchecks": {
 			EnabledChecks: []string{
 				spancheck.EndCheck.String(),