Add `exec` subcommand to use PIPE and REDIRECTION ?

PIPE and REDIRECTION are not working with pipenv run, because this uses pexpect.spawn pexpect.spawn.wait with non-interactive environment.

$ pipenv run python3 -c "print('foo')" | grep foo
# => not found
$ pipenv run python3 -c "print('foo')" > bar.txt
# => bar.txt is empty

If use os.exec instead of spawn, pipe and redirection are available.

diff --git a/pipenv/cli.py b/pipenv/cli.py
index 62a4165..f48b9e7 100644
--- a/pipenv/cli.py
+++ b/pipenv/cli.py
@@ -997,7 +997,8 @@ def run(command, args, no_interactive=False, three=None, python=False):

     # Spawn the new process, and interact with it.
     try:
-        c = pexpect.spawn(which(command), list(args))
+        os.execv(which(command), [command] + list(args))
+        # c = pexpect.spawn(which(command), list(args))
     except pexpect.exceptions.ExceptionPexpect:
         click.echo(crayons.red('The command ({0}) was not found within the virtualenv!'.format(which(command))))
         sys.exit(1)

$ python3 -m pipenv run python3 -c "print('foo')" | grep foo
foo
$ python3 -m pipenv run python3 -c "print('foo')" > bar.txt
$ cat bar.txt
foo

Can you add exec subcommand like bundler, or change run command to use os.exec ?

version

3.5.6, or current master (7b17058)

[nateprewitt]

Hey everyone, sorry this hasn’t been addressed yet. We’re trying to work through tickets as time permits. I don’t see a particular reason that pipenv run needs to be a subprocess, and we have a whole list of tickets that pertain to problems because of this model. I’d like to see some formal verification that this approach doesn’t break anything the subprocess currently supports though.

Using os.exec seems like it will help the honcho/coverage issues we’ve had in the past too. I’ll need to investigate that further (or anyone with some spare time could verify that pipenv run honcho/pipenv run coverage [params] works with the os.exec model.)

@kennethreitz, do you have any particular reasoning that we need to be spawning off subprocesses for pipenv run?

[nonylene]

@kennethreitz OK, I will fix this !