JSONDecoder throws a broken error when parsing decimal value as Int #1604
Description
Describe the bug
JSONDecoder throws an error when the value is decimal but the expected type is Int. In the final release of Swift 5, the error represents the situation correctly, but not in Swift 6.
The behavior is slightly different between macOS and Linux.
To Reproduce
Minimal code:
import Foundation
struct Object: Decodable {
var foo: Int
}
let json = """
{
"foo": 123.45
}
""".data(using: .utf8)!
do {
_ = try JSONDecoder().decode(Object.self, from: json)
} catch let error {
print(error)
}Result:
| Target | Swift | Result | codingPath |
debugDescription |
|---|---|---|---|---|
| Linux | 6.2.1 | dataCorrupted(Swift.DecodingError.Context(codingPath: [], debugDescription: "The given data was not valid JSON.", underlyingError: nil)) |
❌ | ❌ |
| Linux | 6.0 | dataCorrupted(Swift.DecodingError.Context(codingPath: [], debugDescription: "The given data was not valid JSON.", underlyingError: nil)) |
❌ | ❌ |
| Linux | 5.10.1 | dataCorrupted(Swift.DecodingError.Context(codingPath: [CodingKeys(stringValue: "foo", intValue: nil)], debugDescription: "Parsed JSON number <123.45> does not fit in Int.", underlyingError: nil)) |
✅ | ✅ |
| macOS | 6.2 | dataCorrupted(Swift.DecodingError.Context(codingPath: [], debugDescription: "The given data was not valid JSON.", underlyingError: Optional(Error Domain=NSCocoaErrorDomain Code=3840 "Number 123.45 is not representable in Swift." UserInfo={NSDebugDescription=Number 123.45 is not representable in Swift.}))) |
❌ | ❓ available in underlyingError |
Expected behavior
codingPathshould be correctly provided.debugDescriptionshould tell us what is actually happening.- ❓ On macOS,
underlyingErrorprovides more detailed information, butdebugDescriptiondoes not, although I believe it should.
Configuration (please complete the following information):
See the table above.
Regression information:
- On Linux:
- Swift 5.10.1 works fine.
- Swift 6.0 is the first broken version.
- Swift 6.2.1 is the latest release and still broken.
- On macOS:
- Swift 6.2 is broken.
Additional context
Similar report about iOS/macOS: #274