Make the SDK provider's ValidateCredentials validator reject empty …

…strings

mmv1/third_party/terraform/provider/provider_internal_test.go

@@ -42,10 +42,17 @@ func TestProvider_ValidateCredentials(t *testing.T) {
 				return string(contents)
 			},
 		},
+		"configuring credentials as an empty string is not valid": {
+			ConfigValue: func(t *testing.T) interface{} {
+				return ""
+			},
+			ExpectedErrors: []error{
+				errors.New("please provide a value that isn't an empty string to this field"),
+			},
+		},
 		"leaving credentials unconfigured is valid": {
 			ValueNotProvided: true,
 		},
-		// configuring credentials as an empty string is handled by another validator
 	}
 
 	for tn, tc := range cases {

mmv1/third_party/terraform/provider/provider_validators.go.erb

@@ -10,10 +10,18 @@ import (
 )
 
 func ValidateCredentials(v interface{}, k string) (warnings []string, errors []error) {
-	if v == nil || v.(string) == "" {
+	if v == nil {
 		return
 	}
 	creds := v.(string)
+
+	// reject empty strings
+	if v.(string) == "" {
+		errors = append(errors,
+			fmt.Errorf("please provide a value that isn't an empty string to this field"))
+		return
+	}
+
 	// if this is a path and we can stat it, assume it's ok
 	if _, err := os.Stat(creds); err == nil {
 		return