fix(i): Default field value validation (#3137)

## Relevant issue(s)

Resolves #3133

## Description

This PR fixes a bug where default field value types were not properly
validated and would cause a panic when creating a new document.

## Tasks

- [x] I made sure the code is well commented, particularly
hard-to-understand areas.
- [x] I made sure the repository-held documentation is changed
accordingly.
- [x] I made sure the pull request title adheres to the conventional
commit style (the subset used in the project can be found in
[tools/configs/chglog/config.yml](tools/configs/chglog/config.yml)).
- [x] I made sure to discuss its limitations such as threats to
validity, vulnerability to mistake and misuse, robustness to
invalidation of assumptions, resource requirements, ...

## How has this been tested?

Added an integration test.

Specify the platform(s) on which this was tested:
- *(modify the list accordingly*)
- Arch Linux
- Debian Linux
- MacOS
- Windows

docs/data_format_changes/i3137-default-value-fix.md

@@ -0,0 +1,3 @@
+# Default Value Fix
+
+Default value parsing has changed slightly and causes the change detector to fail.

internal/db/definition_validation.go

@@ -166,6 +166,7 @@ var globalValidators = []definitionValidator{
 	validateSelfReferences,
 	validateCollectionMaterialized,
 	validateMaterializedHasNoPolicy,
+	validateCollectionFieldDefaultValue,
 }
 
 var createValidators = append(
@@ -1018,3 +1019,20 @@ func validateMaterializedHasNoPolicy(
 
 	return nil
 }
+
+func validateCollectionFieldDefaultValue(
+	ctx context.Context,
+	db *db,
+	newState *definitionState,
+	oldState *definitionState,
+) error {
+	for name, col := range newState.definitionsByName {
+		// default values are set when a doc is first created
+		_, err := client.NewDocFromMap(map[string]any{}, col)
+		if err != nil {
+			return NewErrDefaultFieldValueInvalid(name, err)
+		}
+	}
+
+	return nil
+}

internal/db/errors.go

@@ -105,6 +105,7 @@ const (
 	errSelfReferenceWithoutSelf                 string = "must specify 'Self' kind for self referencing relations"
 	errColNotMaterialized                       string = "non-materialized collections are not supported"
 	errMaterializedViewAndACPNotSupported       string = "materialized views do not support ACP"
+	errInvalidDefaultFieldValue                 string = "default field value is invalid"
 )
 
 var (
@@ -681,3 +682,11 @@ func NewErrMaterializedViewAndACPNotSupported(collection string) error {
 		errors.NewKV("Collection", collection),
 	)
 }
+
+func NewErrDefaultFieldValueInvalid(collection string, inner error) error {
+	return errors.New(
+		errInvalidDefaultFieldValue,
+		errors.NewKV("Collection", collection),
+		errors.NewKV("Inner", inner),
+	)
+}

internal/request/graphql/schema/collection.go

@@ -427,23 +427,35 @@ func defaultFromAST(
 	if !ok {
 		return nil, NewErrDefaultValueNotAllowed(field.Name.Value, astNamed.Name.Value)
 	}
+	if len(directive.Arguments) != 1 {
+		return nil, NewErrDefaultValueOneArg(field.Name.Value)
+	}
+	arg := directive.Arguments[0]
+	if propName != arg.Name.Value {
+		return nil, NewErrDefaultValueType(field.Name.Value, propName, arg.Name.Value)
+	}
 	var value any
-	for _, arg := range directive.Arguments {
-		if propName != arg.Name.Value {
-			return nil, NewErrDefaultValueInvalid(field.Name.Value, propName, arg.Name.Value)
-		}
-		switch t := arg.Value.(type) {
-		case *ast.IntValue:
-			value = gql.Int.ParseLiteral(arg.Value, nil)
-		case *ast.FloatValue:
-			value = gql.Float.ParseLiteral(arg.Value, nil)
-		case *ast.BooleanValue:
-			value = t.Value
-		case *ast.StringValue:
-			value = t.Value
-		default:
-			value = arg.Value.GetValue()
-		}
+	switch propName {
+	case types.DefaultDirectivePropInt:
+		value = gql.Int.ParseLiteral(arg.Value, nil)
+	case types.DefaultDirectivePropFloat:
+		value = gql.Float.ParseLiteral(arg.Value, nil)
+	case types.DefaultDirectivePropBool:
+		value = gql.Boolean.ParseLiteral(arg.Value, nil)
+	case types.DefaultDirectivePropString:
+		value = gql.String.ParseLiteral(arg.Value, nil)
+	case types.DefaultDirectivePropDateTime:
+		value = gql.DateTime.ParseLiteral(arg.Value, nil)
+	case types.DefaultDirectivePropJSON:
+		value = types.JSONScalarType().ParseLiteral(arg.Value, nil)
+	case types.DefaultDirectivePropBlob:
+		value = types.BlobScalarType().ParseLiteral(arg.Value, nil)
+	}
+	// If the value is nil, then parsing has failed, or a nil value was provided.
+	// Since setting a default value to nil is the same as not providing one,
+	// it is safer to return an error to let the user know something is wrong.
+	if value == nil {
+		return nil, NewErrDefaultValueInvalid(field.Name.Value, propName)
 	}
 	return value, nil
 }

internal/request/graphql/schema/errors.go

@@ -30,8 +30,10 @@ const (
 	errPolicyUnknownArgument         string = "policy with unknown argument"
 	errPolicyInvalidIDProp           string = "policy directive with invalid id property"
 	errPolicyInvalidResourceProp     string = "policy directive with invalid resource property"
-	errDefaultValueInvalid           string = "default value type must match field type"
+	errDefaultValueType              string = "default value type must match field type"
 	errDefaultValueNotAllowed        string = "default value is not allowed for this field type"
+	errDefaultValueInvalid           string = "default value is invalid"
+	errDefaultValueOneArg            string = "default value must specify one argument"
 	errFieldTypeNotSpecified         string = "field type not specified"
 )
 
@@ -141,9 +143,24 @@ func NewErrRelationNotFound(relationName string) error {
 	)
 }
 
-func NewErrDefaultValueInvalid(name string, expected string, actual string) error {
+func NewErrDefaultValueOneArg(field string) error {
+	return errors.New(
+		errDefaultValueOneArg,
+		errors.NewKV("Field", field),
+	)
+}
+
+func NewErrDefaultValueInvalid(field string, arg string) error {
 	return errors.New(
 		errDefaultValueInvalid,
+		errors.NewKV("Field", field),
+		errors.NewKV("Arg", arg),
+	)
+}
+
+func NewErrDefaultValueType(name string, expected string, actual string) error {
+	return errors.New(
+		errDefaultValueType,
 		errors.NewKV("Name", name),
 		errors.NewKV("Expected", expected),
 		errors.NewKV("Actual", actual),

tests/integration/collection_description/with_default_fields_test.go

@@ -58,7 +58,7 @@ func TestCollectionDescription_WithDefaultFieldValues(t *testing.T) {
 							{
 								ID:           3,
 								Name:         "created",
-								DefaultValue: "2000-07-23T03:00:00-00:00",
+								DefaultValue: "2000-07-23T03:00:00Z",
 							},
 							{
 								ID:           4,
@@ -90,6 +90,23 @@ func TestCollectionDescription_WithDefaultFieldValues(t *testing.T) {
 	testUtils.ExecuteTestCase(t, test)
 }
 
+func TestCollectionDescription_WithInvalidDefaultFieldValueType_ReturnsError(t *testing.T) {
+	test := testUtils.TestCase{
+		Actions: []any{
+			testUtils.SchemaUpdate{
+				Schema: `
+					type Users {
+						active: Boolean @default(bool: invalid)
+					}
+				`,
+				ExpectedError: "default value is invalid. Field: active, Arg: bool",
+			},
+		},
+	}
+
+	testUtils.ExecuteTestCase(t, test)
+}
+
 func TestCollectionDescription_WithIncorrectDefaultFieldValueType_ReturnsError(t *testing.T) {
 	test := testUtils.TestCase{
 		Actions: []any{
@@ -116,7 +133,7 @@ func TestCollectionDescription_WithMultipleDefaultFieldValueTypes_ReturnsError(t
 						name: String @default(string: "Bob", int: 10, bool: true, float: 10)
 					}
 				`,
-				ExpectedError: "default value type must match field type. Name: name, Expected: string, Actual: int",
+				ExpectedError: "default value must specify one argument. Field: name",
 			},
 		},
 	}