utils/cobrautil(bind): implementation based on Replace(val []string) …

…with tests

utils/cobrautil/bind.go

@@ -10,6 +10,7 @@ import (
 	"fmt"
 	"strings"
 
+	"github.com/spf13/cast"
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 	"github.com/spf13/viper"
@@ -55,8 +56,8 @@ func BindAll(cmd *cobra.Command, envPrefix, configFileFlagName string) error {
 		ok = true
 		fs.VisitAll(func(f *pflag.Flag) {
 			if !f.Changed && v.IsSet(f.Name) {
-				if err := setFlagFromViper(f, fs, v.Get(f.Name)); err != nil {
-					fmt.Fprintln(cmd.ErrOrStderr(), err.Error())
+				if err := setFlagFromViper(f, v.Get(f.Name)); err != nil {
+					fmt.Fprintf(cmd.ErrOrStderr(), "%s: %s\n", f.Name, err)
 					ok = false
 				}
 			}
@@ -75,11 +76,22 @@ func BindAll(cmd *cobra.Command, envPrefix, configFileFlagName string) error {
 	return nil
 }
 
-func setFlagFromViper(f *pflag.Flag, fs *pflag.FlagSet, v any) error {
-	s := fmt.Sprintf("%v", v)
-	s = strings.TrimPrefix(s, "[")
-	s = strings.TrimSuffix(s, "]")
-	s = strings.NewReplacer(", ", ",", " ", ",").Replace(s)
+func setFlagFromViper(f *pflag.Flag, v any) error {
+	if vs, ok := v.([]interface{}); ok {
+		sr, ok := f.Value.(sliceReplacer)
+		if !ok {
+			return fmt.Errorf("trying to set list to %s", f.Value.Type())
+		}
+		ss, err := cast.ToStringSliceE(vs)
+		if err != nil {
+			return err
+		}
+		return sr.Replace(ss)
+	}
+
+	return f.Value.Set(fmt.Sprintf("%v", v))
+}
 
-	return fs.Set(f.Name, s)
+type sliceReplacer interface {
+	Replace(val []string) error
 }

utils/cobrautil/bind_test.go

@@ -0,0 +1,66 @@
+// Copyright 2023 Sauce Labs Inc. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package cobrautil
+
+import (
+	"net/netip"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	"github.com/mmatczuk/anyflag"
+	"github.com/spf13/cobra"
+)
+
+type testSliceStruct struct {
+	Strings []string
+	Ints    []int
+	Bools   []bool
+	IPs     []netip.Addr
+}
+
+func TestBindSlice(t *testing.T) {
+	formats := []string{
+		"yaml",
+		"json",
+		"toml",
+	}
+
+	for _, ext := range formats {
+		t.Run(ext, func(t *testing.T) {
+			cmd := &cobra.Command{}
+			fs := cmd.Flags()
+
+			var v testSliceStruct
+			fs.String("config-file", "testdata/bind-slice."+ext, "")
+			fs.StringSliceVar(&v.Strings, "strings", nil, "")
+			fs.IntSliceVar(&v.Ints, "ints", nil, "")
+			fs.BoolSliceVar(&v.Bools, "bools", nil, "")
+			fs.Var(anyflag.NewSliceValue[netip.Addr](nil, &v.IPs, netip.ParseAddr), "ips", "")
+
+			if err := BindAll(cmd, "TEST", "config-file"); err != nil {
+				t.Fatal(err)
+			}
+
+			expected := testSliceStruct{
+				Strings: []string{"a", "b", "c"},
+				Ints:    []int{1, 2, 3},
+				Bools:   []bool{true, false},
+				IPs: []netip.Addr{
+					netip.MustParseAddr("127.0.0.1"),
+					netip.MustParseAddr("127.0.0.2"),
+				},
+			}
+
+			ipcmp := cmp.Comparer(func(a, b netip.Addr) bool {
+				return a.String() == b.String()
+			})
+			if diff := cmp.Diff(expected, v, ipcmp); diff != "" {
+				t.Fatalf("unexpected result (-want +got):\n%s", diff)
+			}
+		})
+	}
+}

utils/cobrautil/testdata/bind-slice.json

@@ -0,0 +1,6 @@
+{
+  "strings": ["a", "b", "c"],
+  "ints": [1, 2, 3],
+  "bools": [true, false],
+  "ips": ["127.0.0.1", "127.0.0.2"]
+}

utils/cobrautil/testdata/bind-slice.toml

@@ -0,0 +1,4 @@
+strings = ["a", "b", "c"]
+ints = [1, 2, 3]
+bools = [true, false]
+ips = ["127.0.0.1", "127.0.0.2"]

utils/cobrautil/testdata/bind-slice.yaml

@@ -0,0 +1,17 @@
+strings:
+  - a
+  - b
+  - c
+
+ints:
+  - 1
+  - 2
+  - 3
+
+bools:
+  - true
+  - false
+
+ips:
+  - 127.0.0.1
+  - 127.0.0.2