From ff839dc6db0f5e9abef848a2ddc3b5ae988c51dc Mon Sep 17 00:00:00 2001
From: Colin <valentini.colin@gmail.com>
Date: Tue, 23 Nov 2021 21:57:08 -0500
Subject: [PATCH] Fix env var interpolation (#236)

---
 kong.go          |  1 +
 resolver_test.go | 17 +++++++++++++----
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/kong.go b/kong.go
index 70107d5..45ef8b8 100644
--- a/kong.go
+++ b/kong.go
@@ -201,6 +201,7 @@ func (k *Kong) interpolateValue(value *Value, vars Vars) (err error) {
 		if value.Flag.Env, err = interpolate(value.Flag.Env, vars, nil); err != nil {
 			return fmt.Errorf("env value for %s: %s", value.Summary(), err)
 		}
+		value.Tag.Env = value.Flag.Env
 		updatedVars["env"] = value.Flag.Env
 	}
 	value.Help, err = interpolate(value.Help, vars, updatedVars)
diff --git a/resolver_test.go b/resolver_test.go
index fa83465..81d64f1 100644
--- a/resolver_test.go
+++ b/resolver_test.go
@@ -37,17 +37,26 @@ func TestEnvarsFlagBasic(t *testing.T) {
 	var cli struct {
 		String string `env:"KONG_STRING"`
 		Slice  []int  `env:"KONG_SLICE"`
+		Interp string `env:"${kongInterp}"`
 	}
-	parser, unsetEnvs := newEnvParser(t, &cli, envMap{
-		"KONG_STRING": "bye",
-		"KONG_SLICE":  "5,2,9",
-	})
+	kongInterpEnv := "KONG_INTERP"
+	parser, unsetEnvs := newEnvParser(t, &cli,
+		envMap{
+			"KONG_STRING": "bye",
+			"KONG_SLICE":  "5,2,9",
+			"KONG_INTERP": "foo",
+		},
+		kong.Vars{
+			"kongInterp": kongInterpEnv,
+		},
+	)
 	defer unsetEnvs()
 
 	_, err := parser.Parse([]string{})
 	require.NoError(t, err)
 	require.Equal(t, "bye", cli.String)
 	require.Equal(t, []int{5, 2, 9}, cli.Slice)
+	require.Equal(t, "foo", cli.Interp)
 }
 
 func TestEnvarsFlagOverride(t *testing.T) {