Issue2325

In Jython 2.7rc2, if the stdin is a pipe, the printing of the interactive prompts is not suppressed. This worked in 2.5:

 $ echo 'print 1' | python2.7
 1
 $ echo 'print 1' | pypy
 1
 $ echo 'print 1' | jython2.5.4/bin/jython
 1
 
 $ echo 'print 1' | jython2.7rc2/bin/jython
 >>> 1
 >>>
 $

(Both versions print an extra newline, but that's probably ok.)

Unfortunately, this breaks `tox`:

 $ tox --version
 1.9.2 imported from ...
 $ tox -e jython
 GLOB sdist-make: transaction/setup.py
 jython create: transaction/.tox/jython
 ERROR: InvocationError: Failed to get version_info for jython: could not decode ">>> ... ... ... >>> {'version_info': (2, 7, 0, 'candidate', 2)}\n>>> "

The launcher, being written in CPython, can truly figure out if interactive or not, which we can see like so:

$ echo 'print 1' | ~/jython2.7rc2/bin/jython --print
java -Xmx512m -Xss1024k -classpath /Users/jbaker/jython2.7rc2/jython.jar -Dpython.home=/Users/jbaker/jython2.7rc2 -Dpython.executable=/Users/jbaker/jython2.7rc2/bin/jython -Dpython.launcher.uname=darwin -Dpython.launcher.tty=false -Dfile.encoding=UTF-8 org.python.util.jython

So -Dpython.launcher.tty=false should be authoritative, but it does not appear to be the case.

The attached patch seems to do it for me. There were two issues; the first is that InteractiveConsole.interact() always resets the prompts, even if it they had previously been set to empty, so we need to call `_interact` if we're not interactive instead. Second, like you said 'python.launcher.tty' wasn't always being respected as authoritative. 

  $ dist/bin/jython
  Jython 2.7rc2+ (default:5064a5c5b1a3+, Apr 14 2015, 09:32:56)
  [Java HotSpot(TM) 64-Bit Server VM (Oracle Corporation)] on java1.8.0_40
  Type "help", "copyright", "credits" or "license" for more information.
  >>> ^D
  $ dist/bin/jython.py
  Jython 2.7rc2+ (default:5064a5c5b1a3+, Apr 14 2015, 09:32:56)
  [Java HotSpot(TM) 64-Bit Server VM (Oracle Corporation)] on java1.8.0_40
  Type "help", "copyright", "credits" or "license" for more information.
  >>> ^D
  $ echo 'print 1' | dist/bin/jython.py
  1

  $ echo 'print 1' | dist/bin/jython
  1
 
  $

(This is my first time trying to suggest a patch here, and I haven't spent any time trying to look back at previous bug reports to see how patches are usually attached so I probably did it wrong. I just wanted to get this up there quickly. I'll take a look to see if I can find better conventions.)

Patch looks good, I will add a test based on your initial bug report, and we should be good.

Thank you! I'm just learning my way around the codebase so I wasn't sure where a test case would go. I will look forward to seeing it in the commit.

Fixed as of https://hg.python.org/jython/rev/cc3e787c0a7c

I also removed the extra \n (or \r\n on Windows)

Good idea, makes sense, sorry I missed that. With that change, I see no difference in the 'echo' examples anymore, which is a big part of the Tox battle :) Thank you!