config: Fix merge of config with map[string]string values.

Fixes #8679

common/maps/maps.go

@@ -49,6 +49,15 @@ func ToParamsAndPrepare(in interface{}) (Params, bool) {
 	return m, true
 }
 
+// MustToParamsAndPrepare calls ToParamsAndPrepare and panics if it fails.
+func MustToParamsAndPrepare(in interface{}) Params {
+	if p, ok := ToParamsAndPrepare(in); ok {
+		return p
+	} else {
+		panic(fmt.Sprintf("cannot convert %T to maps.Params", in))
+	}
+}
+
 // ToStringMap converts in to map[string]interface{}.
 func ToStringMap(in interface{}) map[string]interface{} {
 	m, _ := ToStringMapE(in)

common/maps/maps_test.go

@@ -21,10 +21,10 @@ import (
 	qt "github.com/frankban/quicktest"
 )
 
-func TestToLower(t *testing.T) {
+func TestPrepareParams(t *testing.T) {
 	tests := []struct {
-		input    map[string]interface{}
-		expected map[string]interface{}
+		input    Params
+		expected Params
 	}{
 		{
 			map[string]interface{}{
@@ -47,6 +47,9 @@ func TestToLower(t *testing.T) {
 				"gHi": map[string]interface{}{
 					"J": 25,
 				},
+				"jKl": map[string]string{
+					"M": "26",
+				},
 			},
 			Params{
 				"abc": 32,
@@ -60,13 +63,16 @@ func TestToLower(t *testing.T) {
 				"ghi": Params{
 					"j": 25,
 				},
+				"jkl": Params{
+					"m": "26",
+				},
 			},
 		},
 	}
 
 	for i, test := range tests {
 		t.Run(fmt.Sprint(i), func(t *testing.T) {
-			// ToLower modifies input.
+			// PrepareParams modifies input.
 			PrepareParams(test.input)
 			if !reflect.DeepEqual(test.expected, test.input) {
 				t.Errorf("[%d] Expected\n%#v, got\n%#v\n", i, test.expected, test.input)

common/maps/params.go

@@ -226,7 +226,7 @@ func toMergeStrategy(v interface{}) ParamsMergeStrategy {
 // PrepareParams
 // * makes all the keys in the given map lower cased and will do so
 // * This will modify the map given.
-// * Any nested map[interface{}]interface{} will be converted to Params.
+// * Any nested map[interface{}]interface{}, map[string]interface{},map[string]string  will be converted to Params.
 // * Any _merge value will be converted to proper type and value.
 func PrepareParams(m Params) {
 	for k, v := range m {
@@ -236,7 +236,7 @@ func PrepareParams(m Params) {
 			v = toMergeStrategy(v)
 			retyped = true
 		} else {
-			switch v.(type) {
+			switch vv := v.(type) {
 			case map[interface{}]interface{}:
 				var p Params = cast.ToStringMap(v)
 				v = p
@@ -247,6 +247,14 @@ func PrepareParams(m Params) {
 				v = p
 				PrepareParams(p)
 				retyped = true
+			case map[string]string:
+				p := make(Params)
+				for k, v := range vv {
+					p[k] = v
+				}
+				v = p
+				PrepareParams(p)
+				retyped = true
 			}
 		}