Addresses #24291

[einar-hjortdal]

Seems to solve the issue, can't find negatives.
I am not the author of BufferedReader, I do not know what the purpose of the check was.
Adding a test to prevent a regression would be nice, but I do not know what causes the issue in the first place.

[huly-for-github]

Connected to Huly®: V_0.6-22822

[spytheman]

Adding a test to prevent a regression would be nice, but I do not know what causes the issue in the first place.

If you do not know what the cause of the issue is, and can not make a test, how are you sure, that you have fixed it, and that your changes would not regress or cause problems for others?

[einar-hjortdal]

I have investigated this issue. The way I discovered it is by talking to a server that disconnects unexpectedly. When the server disconnects, you would expect Eof to be returned when attempting to read, instead I got Unexpected.
This is because instead of reaching Eof, the algorithm was just wrongly handling read attempts from the underlying TCPConn reader, returning Unexpected immediately when getting no data, instead of trying to get data a second time and reaching Eof.
Now I know that when I am getting Unexpected, the error is actually a Eof. I have reported the error and provided a fix, which admittedly looks rough, but seems to work correctly. Other than testing changes with a real service, I don't know how to write a test for it.
I will also be testing a little more, up until tuesday.

[spytheman]

I do not want to merge it without a test, since this part of the code is brittle and already had a period of instability, where different people wanted different behaviors.

See the existing vlib/io/reader_test.v as an example on how to create a struct instance of the interface, that you can later control in whatever ways you need to simulate the situation you were in, without having to re-create a real service.

[einar-hjortdal]

I do not want to merge it without a test, since this part of the code is brittle and already had a period of instability, where different people wanted different behaviors.

I agree, however, I do not know when I'll have time to write a test.
For now, a user can assume that Unexpected is actually Eof.