David Wilson <d...@botanicus.net> added the comment:
Interesting, this immediately turns into a little rabbit hole :) The reason read() is failing in this case, is because argument clinic defaults the size parameter to -1, which redirects the call to readall(). So this issue is actually about readall(). Calling read(8) in the previous reproduction returns the buffer up to the point of EIO as expected. readall() is somewhat awkward. It is not really expected that a user would call it twice, and so the old semantic of the second read() returning EIO doesn't seem to apply cleanly. So >=2 issues: - readall() is discarding the partial buffer, that seems unavoidably like a bug - readall() does not intuitively feel like a function you might want to call twice - nothing in fileio.c or fileutils.c make any attempt to understand errno except for handling EINTR. I'm guessing the 2.x behaviour in this case was that no parsing of errno was done either, just silently discard any error when a partial buffer exists. But that leaves the awkward possibility that some real scary error occurred, for example EBADF or EFAULT, and the single call by the user to readall() never flagged it. Opinions? ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue37696> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
