Python3 byte conversion and flushing

[vsajip]

Original report by Henry Perschk (Bitbucket: [Henry Perschk](https://bitbucket.org/Henry Perschk), ).

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Python 3.7.0, Sarge 0.1.5.post0 (through pip).

I followed the tutorial part "Interacting with child processes".

With Python 3, I had to execute the example slightly differently to get it to work. Please consider changing the docs, or telling me if I did something wrong :)

1. >>> p.stdin.write('Fred\n') has to be passed a bytes object (p.stdin.write(b'Fred\n')) (otherwise: TypeError: a bytes-like object is required, not 'str').

2. >>> p.stdin.write('Fred\n')
>>> p.stdout.readline()

requires p.stdin.flush() to be called after writing to stdin, otherwise stdout will be empty.

There seems to be some kind of bug in Popen (see: https://stackoverflow.com/questions/27571305/subprocess-stdin-buffer-not-flushing-on-newline-with-bufsize-1), but even adding the suggested universal_newlines=True to the Command object didn't work for me (stdout empty, only works when flushing stdin).

[vsajip]

Original changes by Henry Perschk (Bitbucket: [Henry Perschk](https://bitbucket.org/Henry Perschk), ).

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changed content from "Python 3.7.0, Sarge 0.1.5.post0 (through pip).

I followed the tutorial part "Interacting with child processes".

With Python 3, I had to execute the example slightly differently to get it to work. Please consider changing the docs, or telling me if I did something wrong :)

1. >>> p.stdin.write('Fred\n') has to be passed a bytes object (p.stdin.write(b'Fred\n')) (otherwise: TypeError: a bytes-like object is required, not 'str').

2. `>>> p.stdin.write('Fred\n')

p.stdout.readline()`

requires p.stdin.flush() to be called after writing to stdin, otherwise stdout will be empty.

There seems to be some kind of bug in Popen (see: https://stackoverflow.com/questions/27571305/subprocess-stdin-buffer-not-flushing-on-newline-with-bufsize-1), but even adding the suggested universal_newlines=True to the Command object didn't work for me (stdout empty, only works when flushing stdin)." to "Python 3.7.0, Sarge 0.1.5.post0 (through pip).

I followed the tutorial part "Interacting with child processes".

With Python 3, I had to execute the example slightly differently to get it to work. Please consider changing the docs, or telling me if I did something wrong :)

1. >>> p.stdin.write('Fred\n') has to be passed a bytes object (p.stdin.write(b'Fred\n')) (otherwise: TypeError: a bytes-like object is required, not 'str').

2. >>> p.stdin.write('Fred\n')
>>> p.stdout.readline()

requires p.stdin.flush() to be called after writing to stdin, otherwise stdout will be empty.

There seems to be some kind of bug in Popen (see: https://stackoverflow.com/questions/27571305/subprocess-stdin-buffer-not-flushing-on-newline-with-bufsize-1), but even adding the suggested universal_newlines=True to the Command object didn't work for me (stdout empty, only works when flushing stdin)."

[vsajip]

Thanks for the report. I've updated the documentation, see

https://sarge.readthedocs.io/en/latest/tutorial.html#interacting-with-child-processes

(you may need to clear your browser cache to get the latest version of the documentation page).

[vsajip]

Original changes by Vinay Sajip (Bitbucket: vinay.sajip, GitHub: vsajip).

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changed state from "new" to "resolved"

[vsajip]

Original comment by Henry Perschk (Bitbucket: [Henry Perschk](https://bitbucket.org/Henry Perschk), ).

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Thanks!