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fix: Fix ExecutionResult Decoder to Conform to GraphQL Spec (#144)
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4 files changed

+209
-3
lines changed

4 files changed

+209
-3
lines changed

‎Sources/GraphQL/Execution.swift‎

Lines changed: 16 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -43,6 +43,8 @@ extension ExecutionArgs: Hashable {
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public struct ExecutionResult: Equatable, Encodable, Decodable {
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/// Result of a successfull execution of a query.
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/// - NOTE: AnyCodable is represented as a non-nullable value because it's easier to handle results if we represent `nil` value as `AnyCodable(nil)` value.
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/// Because GraphQL Specification allows the possibility of missing `data` field, we manually decode execution result.
4648
public var data: AnyCodable
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4850
/// Any errors that occurred during the GraphQL execution of the server.
@@ -65,6 +67,20 @@ public struct ExecutionResult: Equatable, Encodable, Decodable {
6567
self.hasNext = hasNext
6668
self.extensions = extensions
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}
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public init(from decoder: Decoder) throws {
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let container = try decoder.container(keyedBy: CodingKeys.self)
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// NOTE: GraphQL Specification allows the possibility of missing `data` field, but the
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// code in the library assumes that AnyCodable value is always present.
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// As a workaround, we manually construct a nil literal using AnyCodable to simplify further processing.
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let data = try container.decodeIfPresent(AnyCodable.self, forKey: .data)
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self.data = data ?? AnyCodable.init(nilLiteral: ())
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self.errors = try container.decodeIfPresent([GraphQLError].self, forKey: .errors)
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self.hasNext = try container.decodeIfPresent(Bool.self, forKey: .hasNext)
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self.extensions = try container.decodeIfPresent([String : AnyCodable].self, forKey: .extensions)
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}
6884
}
6985

7086
// MARK: - Extra

‎Sources/SwiftGraphQL/Selection/Selection+Transform.swift‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -55,7 +55,7 @@ public extension Selection {
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switch fields.__state {
5656
case let .decoding(data):
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switch data.value {
58-
case is Void:
58+
case is Void, is NSNull:
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throw ObjectDecodingError.unexpectedNilValue
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default:
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return try self.__decode(data: data)

‎Tests/GraphQLTests/ExecutionTests.swift‎

Lines changed: 145 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,145 @@
1+
import GraphQL
2+
import XCTest
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/// A suite of tests that check all edge cases of the response format as described in [GraphQL Spec Response Format](http://spec.graphql.org/October2021/#sec-Response-Format) section.
5+
final class ExecutionTests: XCTestCase {
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func testExecutionWithDataAndErrors() throws {
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let result: ExecutionResult = """
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{
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"data": "Hello World!",
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"errors": [
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{
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"message": "Message.",
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"locations": [ { "line": 6, "column": 7 } ],
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"path": [ "hero", "heroFriends", 1, "name" ]
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}
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]
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}
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""".decode()
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XCTAssertEqual(
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result,
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ExecutionResult(
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data: AnyCodable("Hello World!"),
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errors: [
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GraphQL.GraphQLError(
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message: "Message.",
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locations: [
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GraphQL.GraphQLError.Location(line: 6, column: 7)
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],
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path: [
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GraphQL.GraphQLError.PathLink.path("hero"),
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GraphQL.GraphQLError.PathLink.path("heroFriends"),
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GraphQL.GraphQLError.PathLink.index(1),
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GraphQL.GraphQLError.PathLink.path("name")
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],
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extensions: nil
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)
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],
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hasNext: nil,
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extensions: nil
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)
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)
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}
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func testExecutionWithErrorsField() throws {
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let result: ExecutionResult = """
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{
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"errors": [
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{
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"message": "Message.",
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"locations": [ { "line": 6, "column": 7 } ],
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"path": [ "hero", "heroFriends", 1, "name" ]
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}
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]
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}
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""".decode()
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XCTAssertEqual(
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result,
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GraphQL.ExecutionResult(
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data: nil,
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errors: [
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GraphQL.GraphQLError(
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message: "Message.",
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locations: [
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GraphQL.GraphQLError.Location(line: 6, column: 7)
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],
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path: [
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GraphQL.GraphQLError.PathLink.path("hero"),
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GraphQL.GraphQLError.PathLink.path("heroFriends"),
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GraphQL.GraphQLError.PathLink.index(1),
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GraphQL.GraphQLError.PathLink.path("name")
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],
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extensions: nil
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)
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],
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hasNext: nil,
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extensions: nil
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)
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)
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}
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func testExecutionWithoutErrorsField() throws {
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let result: ExecutionResult = """
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{
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"data": "Hello World!"
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}
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""".decode()
90+
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XCTAssertEqual(
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result,
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GraphQL.ExecutionResult(
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data: AnyCodable("Hello World!"),
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errors: nil,
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hasNext: nil,
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extensions: nil
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)
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)
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}
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func testExecutionWithErrorsWithExtensions() throws {
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let result: ExecutionResult = """
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{
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"errors": [
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{
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"message": "Bad Request Exception",
108+
"extensions": {
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"code": "BAD_USER_INPUT",
110+
}
111+
}
112+
],
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"data": null
114+
}
115+
""".decode()
116+
117+
XCTAssertEqual(
118+
result,
119+
GraphQL.ExecutionResult(
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data: nil,
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errors: [
122+
GraphQL.GraphQLError(
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message: "Bad Request Exception",
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locations: nil,
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path: nil,
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extensions: [
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"code": AnyCodable("BAD_USER_INPUT")
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]
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)
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],
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hasNext: nil,
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extensions: nil
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)
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)
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}
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}
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extension String {
140+
/// Converts a string representation of a GraphQL result into the execution result if possible.
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fileprivate func decode() -> ExecutionResult {
142+
let decoder = JSONDecoder()
143+
return try! decoder.decode(ExecutionResult.self, from: self.data(using: .utf8)!)
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}
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}

‎Tests/SwiftGraphQLTests/Selection/SelectionDecodingTests.swift‎

Lines changed: 47 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -46,6 +46,25 @@ final class SelectionDecodingTests: XCTestCase {
4646
XCTAssertEqual(decoded, nil)
4747
XCTAssertEqual(result.errors, nil)
4848
}
49+
50+
func testMissingDataField() throws {
51+
let result: ExecutionResult = """
52+
{}
53+
""".execution()
54+
55+
let selection = Selection<String?, String?> {
56+
switch $0.__state {
57+
case let .decoding(data):
58+
return try String?(from: data)
59+
case .selecting:
60+
return "wrong"
61+
}
62+
}
63+
64+
let decoded = try selection.decode(raw: result.data)
65+
XCTAssertEqual(decoded, nil)
66+
XCTAssertEqual(result.errors, nil)
67+
}
4968

5069
func testNullableNSNull() throws {
5170
let result: ExecutionResult = """
@@ -194,13 +213,39 @@ final class SelectionDecodingTests: XCTestCase {
194213

195214
XCTAssertThrowsError(try selection.nonNullOrFail.decode(raw: result.data)) { (error) -> Void in
196215
switch error {
197-
case let ScalarDecodingError.unexpectedScalarType(expected: expected, received: _):
198-
XCTAssertEqual(expected, "String")
216+
case ObjectDecodingError.unexpectedNilValue:
217+
()
199218
default:
200219
XCTFail()
201220
}
202221
}
203222
}
223+
224+
func testInvalidScalarError() throws {
225+
let result: ExecutionResult = """
226+
{
227+
"data": 1
228+
}
229+
""".execution()
230+
231+
let selection = Selection<String, String> {
232+
switch $0.__state {
233+
case let .decoding(data):
234+
return try String(from: data)
235+
case .selecting:
236+
return "wrong"
237+
}
238+
}
239+
240+
XCTAssertThrowsError(try selection.nonNullOrFail.decode(raw: result.data)) { (error) -> Void in
241+
switch error {
242+
case let ScalarDecodingError.unexpectedScalarType(expected: expected, received: _):
243+
XCTAssertEqual(expected, "String")
244+
default:
245+
XCTFail()
246+
}
247+
}
248+
}
204249

205250
func testCustomError() throws {
206251
let result: ExecutionResult = """

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