Merge pull request #22236 from hashicorp/jbardin/nil-in-config

don't reflect nil in schema validation

helper/schema/schema.go

@@ -1440,6 +1440,11 @@ func (m schemaMap) validateList(
 		}
 	}
 
+	// schemaMap can't validate nil
+	if raw == nil {
+		return nil, nil
+	}
+
 	// We use reflection to verify the slice because you can't
 	// case to []interface{} unless the slice is exactly that type.
 	rawV := reflect.ValueOf(raw)
@@ -1527,6 +1532,10 @@ func (m schemaMap) validateMap(
 		}
 	}
 
+	// schemaMap can't validate nil
+	if raw == nil {
+		return nil, nil
+	}
 	// We use reflection to verify the slice because you can't
 	// case to []interface{} unless the slice is exactly that type.
 	rawV := reflect.ValueOf(raw)
@@ -1653,6 +1662,12 @@ func (m schemaMap) validateObject(
 	schema map[string]*Schema,
 	c *terraform.ResourceConfig) ([]string, []error) {
 	raw, _ := c.Get(k)
+
+	// schemaMap can't validate nil
+	if raw == nil {
+		return nil, nil
+	}
+
 	if _, ok := raw.(map[string]interface{}); !ok && !c.IsComputed(k) {
 		return nil, []error{fmt.Errorf(
 			"%s: expected object, got %s",
@@ -1697,6 +1712,14 @@ func (m schemaMap) validatePrimitive(
 	raw interface{},
 	schema *Schema,
 	c *terraform.ResourceConfig) ([]string, []error) {
+
+	// a nil value shouldn't happen in the old protocol, and in the new
+	// protocol the types have already been validated. Either way, we can't
+	// reflect on nil, so don't panic.
+	if raw == nil {
+		return nil, nil
+	}
+
 	// Catch if the user gave a complex type where a primitive was
 	// expected, so we can return a friendly error message that
 	// doesn't contain Go type system terminology.

helper/schema/schema_test.go

@@ -5465,6 +5465,39 @@ func TestSchemaMap_Validate(t *testing.T) {
 			},
 			Err: false,
 		},
+
+		"unexpected nils values": {
+			Schema: map[string]*Schema{
+				"strings": &Schema{
+					Type:     TypeList,
+					Optional: true,
+					Elem: &Schema{
+						Type: TypeString,
+					},
+				},
+				"block": &Schema{
+					Type:     TypeList,
+					Optional: true,
+					Elem: &Resource{
+						Schema: map[string]*Schema{
+							"int": &Schema{
+								Type:     TypeInt,
+								Required: true,
+							},
+						},
+					},
+				},
+			},
+
+			Config: map[string]interface{}{
+				"strings": []interface{}{"1", nil},
+				"block": []interface{}{map[string]interface{}{
+					"int": nil,
+				},
+					nil,
+				},
+			},
+		},
 	}
 
 	for tn, tc := range cases {