From d8dc27c896429a7cddb9c2789e26aacc6cbb5bba Mon Sep 17 00:00:00 2001
From: Carlos Alexandro Becker <caarlos0@users.noreply.github.com>
Date: Tue, 30 Nov 2021 10:20:29 -0300
Subject: [PATCH] fix: prefixes on pointers (#203)

closes #202

Signed-off-by: Carlos A Becker <caarlos0@gmail.com>
---
 env.go      | 28 ++++++++++++++++++----------
 env_test.go | 30 +++++++++++++++++++++++++-----
 2 files changed, 43 insertions(+), 15 deletions(-)

diff --git a/env.go b/env.go
index 53e36c4..6279555 100644
--- a/env.go
+++ b/env.go
@@ -204,15 +204,19 @@ func doParse(ref reflect.Value, funcMap map[reflect.Type]ParserFunc, opts []Opti
 			continue
 		}
 		if reflect.Ptr == refField.Kind() && !refField.IsNil() {
-			err := ParseWithFuncs(refField.Interface(), funcMap, opts...)
-			if err != nil {
+			if refField.Elem().Kind() == reflect.Struct {
+				if err := ParseWithFuncs(refField.Interface(), funcMap, optsWithPrefix(refType.Field(i), opts)...); err != nil {
+					return err
+				}
+				continue
+			}
+			if err := ParseWithFuncs(refField.Interface(), funcMap, opts...); err != nil {
 				return err
 			}
 			continue
 		}
 		if reflect.Struct == refField.Kind() && refField.CanAddr() && refField.Type().Name() == "" {
-			err := Parse(refField.Addr().Interface(), opts...)
-			if err != nil {
+			if err := Parse(refField.Addr().Interface(), opts...); err != nil {
 				return err
 			}
 			continue
@@ -224,12 +228,7 @@ func doParse(ref reflect.Value, funcMap map[reflect.Type]ParserFunc, opts []Opti
 		}
 		if value == "" {
 			if reflect.Struct == refField.Kind() {
-				subOpts := make([]Options, len(opts))
-				copy(subOpts, opts)
-				if prefix := refType.Field(i).Tag.Get("envPrefix"); prefix != "" {
-					subOpts[0].Prefix += prefix
-				}
-				if err := doParse(refField, funcMap, subOpts); err != nil {
+				if err := doParse(refField, funcMap, optsWithPrefix(refType.Field(i), opts)); err != nil {
 					return err
 				}
 			}
@@ -475,3 +474,12 @@ func (e parseError) Error() string {
 func newNoParserError(sf reflect.StructField) error {
 	return fmt.Errorf(`env: no parser found for field "%s" of type "%s"`, sf.Name, sf.Type)
 }
+
+func optsWithPrefix(field reflect.StructField, opts []Options) []Options {
+	subOpts := make([]Options, len(opts))
+	copy(subOpts, opts)
+	if prefix := field.Tag.Get("envPrefix"); prefix != "" {
+		subOpts[0].Prefix += prefix
+	}
+	return subOpts
+}
diff --git a/env_test.go b/env_test.go
index 3e04dd3..8f9036c 100644
--- a/env_test.go
+++ b/env_test.go
@@ -1433,13 +1433,34 @@ func TestPrefix(t *testing.T) {
 		Clean Config
 	}
 	cfg := ComplexConfig{}
-	err := Parse(&cfg, Options{Environment: map[string]string{"FOO_HOME": "/foo", "BAR_HOME": "/bar", "HOME": "/clean"}})
-	is.NoErr(err)
+	is.NoErr(Parse(&cfg, Options{Environment: map[string]string{"FOO_HOME": "/foo", "BAR_HOME": "/bar", "HOME": "/clean"}}))
 	is.Equal("/foo", cfg.Foo.Home)
 	is.Equal("/bar", cfg.Bar.Home)
 	is.Equal("/clean", cfg.Clean.Home)
 }
 
+func TestPrefixPointers(t *testing.T) {
+	is := is.New(t)
+	type Test struct {
+		Str string `env:"TEST"`
+	}
+	type ComplexConfig struct {
+		Foo   *Test `envPrefix:"FOO_"`
+		Bar   *Test `envPrefix:"BAR_"`
+		Clean *Test
+	}
+
+	cfg := ComplexConfig{
+		Foo:   &Test{},
+		Bar:   &Test{},
+		Clean: &Test{},
+	}
+	is.NoErr(Parse(&cfg, Options{Environment: map[string]string{"FOO_TEST": "kek", "BAR_TEST": "lel", "TEST": "clean"}}))
+	is.Equal("kek", cfg.Foo.Str)
+	is.Equal("lel", cfg.Bar.Str)
+	is.Equal("clean", cfg.Clean.Str)
+}
+
 func TestComplePrefix(t *testing.T) {
 	is := is.New(t)
 	type Config struct {
@@ -1452,7 +1473,7 @@ func TestComplePrefix(t *testing.T) {
 		Blah  string `env:"BLAH"`
 	}
 	cfg := ComplexConfig{}
-	err := Parse(&cfg, Options{
+	is.NoErr(Parse(&cfg, Options{
 		Prefix: "T_",
 		Environment: map[string]string{
 			"T_FOO_HOME": "/foo",
@@ -1460,8 +1481,7 @@ func TestComplePrefix(t *testing.T) {
 			"T_BLAH":     "blahhh",
 			"T_HOME":     "/clean",
 		},
-	})
-	is.NoErr(err)
+	}))
 	is.Equal("/foo", cfg.Foo.Home)
 	is.Equal("/bar", cfg.Bar.Home)
 	is.Equal("/clean", cfg.Clean.Home)