Issue1723

From interactive mode:
>>> import sys
>>> sys.stdout.write("Hello.")
>>> sys.stderr.write("Hello.")
Hello.>>>

The first write should print 'Hello.' to console, but prints nothing.

I also noticed it looks like the print command is printing to stderr, not to stdout (at least it looks like this from another program I have with colored output).

This bug should be against 2.5.2 final.  I don't see it in the list.  On Ubuntu 10.10.

The behavior is as expected when using the -u flag.

It works if you follow the command by sys.stdout.flush().  The difference between Python and Jython behavior appears to be autoflush.

IIRC our problem is our JLine console reader doesn't actually output everything (like the >>> prompt) via sys.stdout. If you disable it and use the bare minimum console I believe we'd match CPython's behavior

So on CPython you're seeing autoflush like behavior because the prompt is immediately printed afterwards and a flush is done to ensure the prompt shows up

Otherwise you'd see similar behavior in cpython if you did:

>>> sys.stdout.write('hello'); time.sleep(2)

Anyway I see this as a very minor implementation detail, but it would be nice to fix this at some point. Though it may be problematic to fix (see #695383 for a somewhat related problem)

So we are writing this output out immediately, per msg6451, however, it does interact poorly with the console prompt being redisplayed by JLine2:

>>> sys.stdout.write("Hello.")
Hello.>>> sys.stderr.write("Hello.")
>>> o.>>>

where as CPython 2.7 does the following:

>>> import sys
>>> sys.stdout.write("Hello.")
Hello.>>> sys.stderr.write("Hello.")
Hello.>>>