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[5.7] Fix JSONDecoder superDecoder darwin/linux discrepancy #4631

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Merged
merged 1 commit into from
Oct 5, 2022
Merged

[5.7] Fix JSONDecoder superDecoder darwin/linux discrepancy #4631

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65 changes: 48 additions & 17 deletions Sources/Foundation/JSONDecoder.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -227,34 +227,46 @@ extension JSONDecoderImpl: Decoder {
@usableFromInline func container<Key>(keyedBy _: Key.Type) throws ->
KeyedDecodingContainer<Key> where Key: CodingKey
{
guard case .object(let dictionary) = self.json else {
switch self.json {
case .object(let dictionary):
let container = KeyedContainer<Key>(
impl: self,
codingPath: codingPath,
dictionary: dictionary
)
return KeyedDecodingContainer(container)
case .null:
throw DecodingError.valueNotFound([String: JSONValue].self, DecodingError.Context(
codingPath: self.codingPath,
debugDescription: "Cannot get keyed decoding container -- found null value instead"
))
default:
throw DecodingError.typeMismatch([String: JSONValue].self, DecodingError.Context(
codingPath: self.codingPath,
debugDescription: "Expected to decode \([String: JSONValue].self) but found \(self.json.debugDataTypeDescription) instead."
))
}

let container = KeyedContainer<Key>(
impl: self,
codingPath: codingPath,
dictionary: dictionary
)
return KeyedDecodingContainer(container)
}

@usableFromInline func unkeyedContainer() throws -> UnkeyedDecodingContainer {
guard case .array(let array) = self.json else {
switch self.json {
case .array(let array):
return UnkeyedContainer(
impl: self,
codingPath: self.codingPath,
array: array
)
case .null:
throw DecodingError.valueNotFound([String: JSONValue].self, DecodingError.Context(
codingPath: self.codingPath,
debugDescription: "Cannot get unkeyed decoding container -- found null value instead"
))
default:
throw DecodingError.typeMismatch([JSONValue].self, DecodingError.Context(
codingPath: self.codingPath,
debugDescription: "Expected to decode \([JSONValue].self) but found \(self.json.debugDataTypeDescription) instead."
))
}

return UnkeyedContainer(
impl: self,
codingPath: self.codingPath,
array: array
)
}

@usableFromInline func singleValueContainer() throws -> SingleValueDecodingContainer {
Expand Down Expand Up @@ -750,11 +762,11 @@ extension JSONDecoderImpl {
}

func superDecoder() throws -> Decoder {
try decoderForKey(_JSONKey.super)
return decoderForKeyNoThrow(_JSONKey.super)
}

func superDecoder(forKey key: K) throws -> Decoder {
try decoderForKey(key)
return decoderForKeyNoThrow(key)
}

private func decoderForKey<LocalKey: CodingKey>(_ key: LocalKey) throws -> JSONDecoderImpl {
Expand All @@ -770,6 +782,25 @@ extension JSONDecoderImpl {
)
}

private func decoderForKeyNoThrow<LocalKey: CodingKey>(_ key: LocalKey) -> JSONDecoderImpl {
let value: JSONValue
do {
value = try getValue(forKey: key)
} catch {
// if there no value for this key then return a null value
value = .null
}
var newPath = self.codingPath
newPath.append(key)

return JSONDecoderImpl(
userInfo: self.impl.userInfo,
from: value,
codingPath: newPath,
options: self.impl.options
)
}

@inline(__always) private func getValue<LocalKey: CodingKey>(forKey key: LocalKey) throws -> JSONValue {
guard let value = dictionary[key.stringValue] else {
throw DecodingError.keyNotFound(key, .init(
Expand Down
20 changes: 20 additions & 0 deletions Tests/Foundation/Tests/TestJSONEncoder.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -456,6 +456,25 @@ class TestJSONEncoder : XCTestCase {
}
}

func test_notFoundSuperDecoder() {
struct NotFoundSuperDecoderTestType: Decodable {
init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
_ = try container.superDecoder(forKey: .superDecoder)
}

private enum CodingKeys: String, CodingKey {
case superDecoder = "super"
}
}
let decoder = JSONDecoder()
do {
let _ = try decoder.decode(NotFoundSuperDecoderTestType.self, from: Data(#"{}"#.utf8))
} catch {
XCTFail("Caught error during decoding empty super decoder: \(error)")
}
}

// MARK: - Test encoding and decoding of built-in Codable types
func test_codingOfBool() {
test_codingOf(value: Bool(true), toAndFrom: "true")
Expand Down Expand Up @@ -1542,6 +1561,7 @@ extension TestJSONEncoder {
("test_encodeDecodeNumericTypesBaseline", test_encodeDecodeNumericTypesBaseline),
("test_nestedContainerCodingPaths", test_nestedContainerCodingPaths),
("test_superEncoderCodingPaths", test_superEncoderCodingPaths),
("test_notFoundSuperDecoder", test_notFoundSuperDecoder),
("test_codingOfBool", test_codingOfBool),
("test_codingOfNil", test_codingOfNil),
("test_codingOfInt8", test_codingOfInt8),
Expand Down