[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Changes by A.M. Kuchling li...@amk.ca: -- keywords: -easy ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7839 ___ ___ Python-bugs-list mailing

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Chris Rebert pyb...@rebertia.com added the comment: Re: Nick's comments: Besides `close_fds`, what other Popen parameters currently have suboptimal defaults? -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7839

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Andrew Svetlov andrew.svet...@gmail.com added the comment: If fylesystem doesn't support unicode (only Windows directly does as I know) str filename should to be converted by `sys.getfilesystemencoding()`. `os.exec` family already does it as well as other fs functions — but they are supports

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Andrew Svetlov andrew.svet...@gmail.com added the comment: What's about test which pass bytes to Popen? Should it be deprecated and should Popen accept only unicode strings only — I mean `str` type? As I know the trend of py3k to get rid of bytes in filesystem names. --

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

R. David Murray rdmur...@bitdance.com added the comment: No, you need to be able to pass bytes to Popen, just like you do to the os.exec[xx] functions. When the OS doesn't fully support unicode, that is sometimes the only option. As for filenames; again, as long as the underlying systems

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Chris Rebert pyb...@rebertia.com added the comment: The reason I'm not a fan is the fact that, with shell=True, you can use the *executable* argument to Popen to select a non-default shell. At that point, passing a list can make sense, even if it isn't useful for the default shell. Modulo

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Andrew Svetlov andrew.svet...@gmail.com added the comment: After trying to make a patch I found what current test suite itself has calls like (str, shell=False), (bytes, shell=True) and (['shell command'], shell=True). We can: 1. Implement Eric's suggestion with fixing/removing broken tests.

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

R. David Murray rdmur...@bitdance.com added the comment: Which just goes to show that using Popen correctly is not obvious, I suppose. Given that adding these errors *would* break backward compatibility, there would have to be a deprecation if it was done. Personally I don't see the point in

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Andrew Svetlov andrew.svet...@gmail.com added the comment: BTW we need to drop win9x and win2000 support, see #14470 -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7839 ___

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Andrew Svetlov andrew.svet...@gmail.com added the comment: I'm +1 for going though deprecation process for Popen args to make parameters combination clean and obvious. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7839

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Nick Coghlan ncogh...@gmail.com added the comment: Everyone missed my other argument in favour of alternate constructor methods: fixing the currently wrong default arguments. There is no good reason to break working code when beginner confusion can be better addressed by telling them to avoid

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Andrew Svetlov andrew.svet...@gmail.com added the comment: I like Eric's proposition, e.g. raising error if (list, shell=True) or (str, shell=False) If nobody object I can try to make initial patch for that. -- ___ Python tracker

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Changes by Chris Rebert pyb...@rebertia.com: -- nosy: +cvrebert ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7839 ___ ___ Python-bugs-list

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Eric V. Smith e...@trueblade.com added the comment: While I still think raising those errors is a good thing, we should also look at Nick's shell-command: http://shell-command.readthedocs.org/en/latest/index.html -- ___ Python tracker

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Andrew Svetlov andrew.svet...@gmail.com added the comment: Nick's library is awesome and I +1 to include it into stdlib if Nick is ready to do. But also I like to prevent obviously bad usage of popen. We cannot and don't want to remove popen shell=True param, so let's add raising exception

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

R. David Murray rdmur...@bitdance.com added the comment: Yes, Nick's library looks good, but that should be a separate issue, it isn't really relevant to this one. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7839

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Nick Coghlan ncogh...@gmail.com added the comment: For the record, my shell access convenience API proposal is in issue 13238. I'm not going to push that for 3.3 though - convenient shell access from Python is currently an area with a lot of active third party development, so I think it's

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Changes by Arfrever Frehtes Taifersar Arahesis arfrever@gmail.com: -- nosy: +Arfrever ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7839 ___

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Changes by Éric Araujo mer...@netwok.org: -- nosy: +eric.araujo versions: +Python 3.3 -Python 3.2 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7839 ___

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Changes by Andrew Svetlov andrew.svet...@gmail.com: -- nosy: +asvetlov ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7839 ___ ___ Python-bugs-list

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Changes by STINNER Victor victor.stin...@haypocalc.com: -- nosy: +haypo ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7839 ___ ___

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Changes by David Stanek dsta...@dstanek.com: -- nosy: +dstanek ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7839 ___ ___ Python-bugs-list mailing

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Steve Holden st...@holdenweb.com added the comment: The test program Larry provided does not appear to function as intended on Windows, and runs without either producing error messages or requiring interactive input. Here's a typical output, in this case from Python 3.1 on Vista:

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

R. David Murray rdmur...@bitdance.com added the comment: See issue 8972 for motivation for accepting this proposal. Maybe I should start working on the patch :) -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7839

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Changes by Giampaolo Rodola' g.rod...@gmail.com: -- nosy: +giampaolo.rodola ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7839 ___ ___

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Larry Hastings la...@hastings.org added the comment: I noticed this a while ago. And FWIW it's not just 3.x; I see this same behavior in 2.6. I've whipped up a test case, attached, which runs in both Python 2 and Python 3. The test runs sys.interpreter -V four times: it tries all the

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Larry Hastings la...@hastings.org added the comment: I realize we're down to the wire, but would it be too late to fix this in 2.7? It is a genuine bug, and it won't break any correct code. -- ___ Python tracker rep...@bugs.python.org

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Changes by Larry Hastings la...@hastings.org: -- versions: +Python 2.7 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7839 ___ ___ Python-bugs-list

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Larry Hastings la...@hastings.org added the comment: Sorry for spamming updates, but here's two more things to consider. 1) What does it do on Windows? For all I know all four combinations work fine there and we should preserve the existing functionality. 2) All four combinations work fine

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

R. David Murray rdmur...@bitdance.com added the comment: Unless we go the proliferating-interfaces route, it does represent a behavior change, and so if accepted would need to go through a deprecation cycle. And if we did go that route, it would be a new feature. So nothing can happen in

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Zsolt Cserna zsolt.cse...@morganstanley.com added the comment: I would say that both string and list should be accepted in args, and depending on the shell parameter, the module should create a list or a string from the specified list/string. We already have a list2cmdline function to convert

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Larry Hastings la...@hastings.org added the comment: Zsolt: an excellent idea! That shouldn't change the semantics of the function, and therefore is strictly a bug fix. Which means we could potentially backport it, yes? Obviously we only need to change it between string / list if we're

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

R. David Murray rdmur...@bitdance.com added the comment: Because we use the versions field to indicate which versions a patch will be applied to, if it is, and I created this bug as a feature request, and as such it is not a candidate for 2.7. Changing list to string for shell=True is a

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Eric Smith e...@trueblade.com added the comment: I agree with David. For the issue raised here, at most I would make (list, shell=True) and (str, shell=False) raise errors. There's an issue (that I can't find right now) for creating functions that convert from str-list and list-str for cases

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

R. David Murray rdmur...@bitdance.com added the comment: Because the shell argument provides important functionality. Or are you suggesting that passing a list implies shell=False and passing a string implies shell=True? That is a possibility, but I think it would not be a good idea,

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Eric Smith e...@trueblade.com added the comment: I think the better design is to have 2 distinct APIs: Popen_shell and Popen_exec. I'm not wild about the name Popen_exec, suggestions welcome. Neither of these would accept a shell parameter. For starters these could be convenience APIs that

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Brian Curtin cur...@acm.org added the comment: That seems reasonable. We already have subprocess.call, the thin wrapper around Popen. Maybe add this as subprocess.call_shell and call_exec? -- nosy: +brian.curtin ___ Python tracker

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

R. David Murray rdmur...@bitdance.com added the comment: Hmm. I liked Eric's idea, and it would be easier to get in, but 'call' is actually an argument against it. It would mean that in addition to PopenExec and PopenShell we'd need call_exec and call_shell, and check_call_exec and

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

New submission from R. David Murray rdmur...@bitdance.com: Currently Popen accepts either a string or a list regardless of the value of 'shell'. In the shell=False case, a string is interpreted as the command name, no matter what it actually is. In the shell=True case, a list is interpreted

[issue7839] Popen should raise ValueError if pass a string when shell=False or a list when shell=True

Changes by Eric Smith e...@trueblade.com: -- nosy: +eric.smith ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7839 ___ ___ Python-bugs-list mailing