Fix panic related to env values from files and sprig dict funcs (#625)

* fix: 0.68.0: go panic w/ multiple bases/layers

Fixes #623

* fix: 0.64.1+: getOrNil/hasKey fails on Environment.Values with nested maps

Fixes #624

state/environment_values_loader.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"github.com/imdario/mergo"
 	"github.com/roboll/helmfile/environment"
+	"github.com/roboll/helmfile/pkg/maputil"
 	"github.com/roboll/helmfile/tmpl"
 	"gopkg.in/yaml.v2"
 	"path/filepath"
@@ -53,21 +54,16 @@ func (ld *EnvironmentValuesLoader) LoadEnvironmentValues(missingFileHandler *str
 				}
 			}
 		case map[interface{}]interface{}:
-			m := map[string]interface{}{}
-			for k, v := range typedValue {
-				switch typedKey := k.(type) {
-				case string:
-					m[typedKey] = v
-				default:
-					return nil, fmt.Errorf("unexpected type of key in inline environment values %v: expected string, got %T", typedValue, typedKey)
-				}
+			m, err := maputil.CastKeysToStrings(typedValue)
+			if err != nil {
+				return nil, err
 			}
 			if err := mergo.Merge(&envVals, &m, mergo.WithOverride); err != nil {
 				return nil, fmt.Errorf("failed to merge %v: %v", typedValue, err)
 			}
 			continue
 		default:
-			return nil, fmt.Errorf("unexpected type of values entry: %T", typedValue)
+			return nil, fmt.Errorf("unexpected type of value: value=%v, type=%T", typedValue, typedValue)
 		}
 	}
 

state/state.go

@@ -1319,7 +1319,7 @@ func (st *HelmState) generateTemporaryValuesFiles(values []interface{}, missingF
 			}
 			generatedFiles = append(generatedFiles, valfile.Name())
 		default:
-			return nil, fmt.Errorf("unexpected type of values entry: %T", typedValue)
+			return nil, fmt.Errorf("unexpected type of value: value=%v, type=%T", typedValue, typedValue)
 		}
 	}
 	return generatedFiles, nil