Fix error message on incorrect regexp

cmd/porto/main.go

@@ -6,8 +6,6 @@ import (
 	"log"
 	"os"
 	"path/filepath"
-	"regexp"
-	"strings"
 
 	"github.com/jcchavezs/porto"
 )
@@ -48,15 +46,9 @@ Add import path to a folder
 		log.Fatalf("failed to resolve base absolute path for current working dir: %v", err)
 	}
 
-	var skipFilesRegex []*regexp.Regexp
-	if len(*flagSkipFiles) > 0 {
-		for _, sfrp := range strings.Split(*flagSkipFiles, ",") {
-			sfr, err := regexp.Compile(sfrp)
-			if err != nil {
-				log.Fatalf("failed to resolve base absolute path for %q: %v", baseDir, err)
-			}
-			skipFilesRegex = append(skipFilesRegex, sfr)
-		}
+	skipFilesRegex, err := porto.GetRegexpList(*flagSkipFiles)
+	if err != nil {
+		log.Fatalf("failed to build files regexes: %v", err)
 	}
 
 	diffCount, err := porto.FindAndAddVanityImportForDir(workingDir, baseAbsDir, porto.Options{

regexes.go

@@ -0,0 +1,22 @@
+package porto
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+)
+
+func GetRegexpList(regexps string) ([]*regexp.Regexp, error) {
+	var regexes []*regexp.Regexp
+	if len(regexps) > 0 {
+		for _, sfrp := range strings.Split(regexps, ",") {
+			sfr, err := regexp.Compile(sfrp)
+			if err != nil {
+				return nil, fmt.Errorf("failed to compile regex %q: %w", sfrp, err)
+			}
+			regexes = append(regexes, sfr)
+		}
+	}
+
+	return regexes, nil
+}

regexes_test.go

@@ -0,0 +1,44 @@
+package porto
+
+import (
+	"regexp"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetRegexpList(t *testing.T) {
+	tests := []struct {
+		name     string
+		regexps  string
+		expected []*regexp.Regexp
+		err      string
+	}{
+		{
+			name:     "single regex",
+			regexps:  "^.*pb.go$",
+			expected: []*regexp.Regexp{regexp.MustCompile("^.*pb.go$")},
+		},
+		{
+			name:    "failing regex",
+			regexps: "^.*pb.go$,*$$",
+			err:     "failed to compile regex \"*$$\": error parsing regexp: missing argument to repetition operator: `*`",
+		},
+		{
+			name:     "multiple regexes",
+			regexps:  "^.*pb.go$,^tools.go$",
+			expected: []*regexp.Regexp{regexp.MustCompile("^.*pb.go$"), regexp.MustCompile("^tools.go$")},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			actual, err := GetRegexpList(tt.regexps)
+			if err != nil || tt.err != "" {
+				assert.EqualError(t, err, tt.err)
+			} else {
+				assert.Equal(t, tt.expected, actual)
+			}
+		})
+	}
+}