iOS 17, beta 1: new exceptions in StreamDecoder about j2objc

[cfdrake]

Hello!

I've been probing more into this recently and think I have found the root issue.

Here is a minimal test case that will work on iOS 16 and fail on iOS 17 beta, calling into j2objc's JRE emulation:

func testDecodeStream() {
    let testString = "{testtest}"
    let data = testString.data(using: .utf8)
    let byteArray = IOSByteArray(nsData: data)
    let stream: JavaIoInputStream = JavaIoByteArrayInputStream(byteArray: byteArray)
    let reader: JavaIoReader = JavaIoInputStreamReader(javaIoInputStream: stream, with: "UTF-8")
        
    print("ready? \(reader.ready())")
    while (reader.ready()) {
        let byte = reader.read()
        print(byte)
        print("--")
    }
}

On iOS 16 I see that the reader indicates it is ready, the stream has 10 characters available to read, and the loop executes printing each character out line by line.

With no changes, on iOS 17 beta I see that the reader indicates it is ready, the first byte is read, but the loop only executes once printing 65533.

Based on what I've been reading, GSON is using these functions/classes internally for parsing JSON responses, which is why we're seeing the failures in our app.

[cfdrake]

Just a note I've found that writing to a stream fails on iOS 17 as well. See the test code here:

private func testWriteSteam() {
        let stream = JavaIoByteArrayOutputStream()
        let writer = JavaIoBufferedWriter(javaIoWriter: JavaIoOutputStreamWriter(javaIoOutputStream: stream, with: "UTF-8"))
        
        let testString = "{testtest}"
        let byteArray = IOSCharArray(nsString: testString)!
        
        writer.write(with: byteArray, with: 0, with: byteArray.length())
        writer.flush()
        
        print(stream)
        print("DONE!")
    }

On iOS 16 I see "{testtest}" and on iOS 17 it just prints an empty line.

[litstrong]

Hi Cotlin, I apologize for my late reply. Your finding looks real, and thanks for your report and test cases!

The team is sort of under-staffed at the moment, so the response might be a bit slow. But this one is indeed import to us, and we'll look into it.

Thanks again. :)

[cfdrake]

@litstrong Great, thanks for confirming.

Just a note I've done some further testing on this and interestingly it only appears to be an issue with the simulator, not physical devices running the beta.

[litstrong]

Hi Cotlin,

I tested your code snippet under Xcode 15 beta 8 (simulator), and it seems running well.