[build] Fix buildtags parsing if only one tag is specified (#1858)

* [build] Fix buildtags parsing if only one tag is specified
Co-authored-by: Lea Anthony <lea.anthony@gmail.com>

v2/pkg/commands/buildtags/buildtags.go

@@ -2,20 +2,19 @@ package buildtags
 
 import (
 	"errors"
-	"github.com/samber/lo"
 	"strings"
+
+	"github.com/samber/lo"
 )
 
 // Parse parses the given tags string and returns
 // a cleaned slice of strings. Both comma and space delimeted
 // tags are supported but not mixed. If mixed, an error is returned.
 func Parse(tags string) ([]string, error) {
-
 	if tags == "" {
 		return nil, nil
 	}
 
-	var userTags []string
 	separator := ""
 	if strings.Contains(tags, ",") {
 		separator = ","
@@ -26,6 +25,14 @@ func Parse(tags string) ([]string, error) {
 		}
 		separator = " "
 	}
+	if separator == "" {
+		// We couldn't find any separator, so the whole string is used as user tag
+		// Otherwise we would end up with a list of every single character of the tags string,
+		// e.g.: `t,e,s,t`
+		return []string{tags}, nil
+	}
+
+	var userTags []string
 	for _, tag := range strings.Split(tags, separator) {
 		thisTag := strings.TrimSpace(tag)
 		if thisTag != "" {

v2/pkg/commands/buildtags/buildtags_test.go

@@ -0,0 +1,78 @@
+package buildtags
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestParse(t *testing.T) {
+	tests := []struct {
+		name    string
+		tags    string
+		want    []string
+		wantErr bool
+	}{
+		{
+			name:    "should support single tags",
+			tags:    "test",
+			want:    []string{"test"},
+			wantErr: false,
+		},
+		{
+			name:    "should support space delimited tags",
+			tags:    "test test2",
+			want:    []string{"test", "test2"},
+			wantErr: false,
+		},
+		{
+			name:    "should support comma delimited tags",
+			tags:    "test,test2",
+			want:    []string{"test", "test2"},
+			wantErr: false,
+		},
+		{
+			name:    "should error if mixed tags",
+			tags:    "test,test2 test3",
+			want:    nil,
+			wantErr: true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := Parse(tt.tags)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("Parse() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("Parse() got = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestStringify(t *testing.T) {
+	tests := []struct {
+		name string
+		tags []string
+		want string
+	}{
+		{
+			name: "should support single tags",
+			tags: []string{"test"},
+			want: "test",
+		},
+		{
+			name: "should support multiple tags",
+			tags: []string{"test", "test2"},
+			want: "test,test2",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := Stringify(tt.tags); got != tt.want {
+				t.Errorf("Stringify() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}