fix: retract v11.0.1, gate init nil pointers (#318)

* fix: retract v11.0.1, gate init nil pointers

as it would automatically initialize nil pointers.

this retracts that version, and gate this new feature behind an `init`
tag option.

closes #317
refs  #306

* test: make sure #310 is covered too

closes #310

* test: add test for multiple tag options

Signed-off-by: Carlos Alexandro Becker <caarlos0@users.noreply.github.com>

* fix: typo

* perf: cheap first

Signed-off-by: Carlos Alexandro Becker <caarlos0@users.noreply.github.com>

---------

Signed-off-by: Carlos Alexandro Becker <caarlos0@users.noreply.github.com>

Author: caarlos0

README.md

@@ -227,6 +227,20 @@ $ PORT=8080 go run main.go
 {Host:localhost Port:8080 Address:localhost:8080}
 ```
 
+## Init `nil` pointers
+
+You can automatically initialize `nil` pointers regardless of if a variable is
+set for them or not.
+This behavior can be enabled by using the `init` tag option.
+
+Example:
+
+```go
+type config struct {
+	URL *url.URL `env:"URL,init"`
+}
+```
+
 ## Not Empty fields
 
 While `required` demands the environment variable to be set, it doesn't check

env.go

@@ -300,13 +300,13 @@ func doParseField(refField reflect.Value, refTypeField reflect.StructField, proc
 		return err
 	}
 
-	if isStructPtr(refField) && refField.IsNil() {
+	if params.Init && isStructPtr(refField) && refField.IsNil() {
 		refField.Set(reflect.New(refField.Type().Elem()))
 		refField = refField.Elem()
-	}
 
-	if _, ok := opts.FuncMap[refField.Type()]; ok {
-		return nil
+		if _, ok := opts.FuncMap[refField.Type()]; ok {
+			return nil
+		}
 	}
 
 	if reflect.Struct == refField.Kind() {
@@ -361,6 +361,7 @@ type FieldParams struct {
 	Unset           bool
 	NotEmpty        bool
 	Expand          bool
+	Init            bool
 }
 
 func parseFieldParams(field reflect.StructField, opts Options) (FieldParams, error) {
@@ -393,6 +394,8 @@ func parseFieldParams(field reflect.StructField, opts Options) (FieldParams, err
 			result.NotEmpty = true
 		case "expand":
 			result.Expand = true
+		case "init":
+			result.Init = true
 		default:
 			return FieldParams{}, newNoSupportedTagOptionError(tag)
 		}

env_test.go

@@ -137,9 +137,10 @@ type Config struct {
 }
 
 type ParentStruct struct {
-	InnerStruct *InnerStruct
-	unexported  *InnerStruct
-	Ignored     *http.Client
+	InnerStruct    *InnerStruct `env:",init"`
+	NilInnerStruct *InnerStruct
+	unexported     *InnerStruct
+	Ignored        *http.Client
 }
 
 type InnerStruct struct {
@@ -2041,7 +2042,7 @@ func TestIssue234(t *testing.T) {
 		Str string `env:"TEST"`
 	}
 	type ComplexConfig struct {
-		Foo   *Test `envPrefix:"FOO_"`
+		Foo   *Test `envPrefix:"FOO_" env:",init"`
 		Bar   Test  `envPrefix:"BAR_"`
 		Clean *Test
 	}
@@ -2077,3 +2078,76 @@ func TestIssue308(t *testing.T) {
 	isNoErr(t, Parse(&cfg))
 	isEqual(t, Issue308Map{"FOO": []string{"BAR", "ZAZ"}}, cfg.Inner)
 }
+
+func TestIssue317(t *testing.T) {
+	type TestConfig struct {
+		U1 *url.URL `env:"U1"`
+		U2 *url.URL `env:"U2,init"`
+	}
+	cases := []struct {
+		desc                   string
+		environment            map[string]string
+		expectedU1, expectedU2 *url.URL
+	}{
+		{
+			desc:        "unset",
+			environment: map[string]string{},
+			expectedU1:  nil,
+			expectedU2:  &url.URL{},
+		},
+		{
+			desc:        "empty",
+			environment: map[string]string{"U1": "", "U2": ""},
+			expectedU1:  nil,
+			expectedU2:  &url.URL{},
+		},
+		{
+			desc:        "set",
+			environment: map[string]string{"U1": "https://example.com/"},
+			expectedU1:  &url.URL{Scheme: "https", Host: "example.com", Path: "/"},
+			expectedU2:  &url.URL{},
+		},
+	}
+	for _, tc := range cases {
+		t.Run(tc.desc, func(t *testing.T) {
+			cfg := TestConfig{}
+			err := ParseWithOptions(&cfg, Options{Environment: tc.environment})
+			isNoErr(t, err)
+			isEqual(t, tc.expectedU1, cfg.U1)
+			isEqual(t, tc.expectedU2, cfg.U2)
+		})
+	}
+}
+
+func TestIssue310(t *testing.T) {
+	type TestConfig struct {
+		URL *url.URL
+	}
+	cfg, err := ParseAs[TestConfig]()
+	isNoErr(t, err)
+	isEqual(t, nil, cfg.URL)
+}
+
+func TestMultipleTagOptions(t *testing.T) {
+	type TestConfig struct {
+		URL *url.URL `env:"URL,init,unset"`
+	}
+	t.Run("unset", func(t *testing.T) {
+		cfg, err := ParseAs[TestConfig]()
+		isNoErr(t, err)
+		isEqual(t, &url.URL{}, cfg.URL)
+	})
+	t.Run("empty", func(t *testing.T) {
+		t.Setenv("URL", "")
+		cfg, err := ParseAs[TestConfig]()
+		isNoErr(t, err)
+		isEqual(t, &url.URL{}, cfg.URL)
+	})
+	t.Run("set", func(t *testing.T) {
+		t.Setenv("URL", "https://github.com/caarlos0")
+		cfg, err := ParseAs[TestConfig]()
+		isNoErr(t, err)
+		isEqual(t, &url.URL{Scheme: "https", Host: "github.com", Path: "/caarlos0"}, cfg.URL)
+		isEqual(t, "", os.Getenv("URL"))
+	})
+}

go.mod

@@ -1,3 +1,5 @@
 module github.com/caarlos0/env/v11
 
+retract v11.0.1 // v11.0.1 accidentally introduced a breaking change regarding the behavior of nil pointers. You can now chose to auto-initialize them by setting the `init` tag option.
+
 go 1.18