Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

argparse version action should print to stdout, not stderr #63120

Closed
wm75 mannequin opened this issue Sep 4, 2013 · 13 comments
Closed

argparse version action should print to stdout, not stderr #63120

wm75 mannequin opened this issue Sep 4, 2013 · 13 comments
Labels
easy type-bug An unexpected behavior, bug, or error

Comments

@wm75
Copy link
Mannequin

wm75 mannequin commented Sep 4, 2013

BPO 18920
Nosy @jwilk, @ezio-melotti, @serhiy-storchaka, @wm75
Files
  • issue18920.1.patch
  • Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.

    Show more details

    GitHub fields:

    assignee = None
    closed_at = <Date 2013-09-06.13:57:07.095>
    created_at = <Date 2013-09-04.12:30:47.440>
    labels = ['easy', 'type-bug']
    title = 'argparse version action should print to stdout, not stderr'
    updated_at = <Date 2018-03-24.16:17:16.912>
    user = 'https://github.com/wm75'

    bugs.python.org fields:

    activity = <Date 2018-03-24.16:17:16.912>
    actor = 'serhiy.storchaka'
    assignee = 'none'
    closed = True
    closed_date = <Date 2013-09-06.13:57:07.095>
    closer = 'eli.bendersky'
    components = []
    creation = <Date 2013-09-04.12:30:47.440>
    creator = 'wolma'
    dependencies = []
    files = ['31587']
    hgrepos = []
    issue_num = 18920
    keywords = ['patch', 'easy']
    message_count = 13.0
    messages = ['196905', '196908', '196910', '196911', '196912', '196916', '196918', '196919', '197068', '197069', '197072', '314373', '314374']
    nosy_count = 8.0
    nosy_names = ['bethard', 'jwilk', 'ezio.melotti', 'eli.bendersky', 'python-dev', 'serhiy.storchaka', 'wolma', 'Stefan Sauer']
    pr_nums = []
    priority = 'normal'
    resolution = 'fixed'
    stage = 'resolved'
    status = 'closed'
    superseder = None
    type = 'behavior'
    url = 'https://bugs.python.org/issue18920'
    versions = []

    @wm75
    Copy link
    Mannequin Author

    wm75 mannequin commented Sep 4, 2013

    Hi,
    I just noticed that version output generated via the
    **'version' action** of the **argparse** module
    is routed to stderr. I'd expect regular output to go to stdout instead.
    The current behavior also seems inconsistent to me because --help
    prints to stdout.
    Best,
    Wolfgang

    @wm75 wm75 mannequin added the type-bug An unexpected behavior, bug, or error label Sep 4, 2013
    @elibendersky
    Copy link
    Mannequin

    elibendersky mannequin commented Sep 4, 2013

    Yes, it seems like an oversight to me. Printing --version to stdout is more customary (Python itself does it, and most other tools do too).

    A question comes up about backwards compatibility. I would definitely not change it in 2.x - it's just not worth it. As for 3.x, should this go into 3.3 too or just 3.4?

    @ezio-melotti
    Copy link
    Member

    ezio-melotti commented Sep 4, 2013

    Only on 3.4.
    Python prints the version on stdout since 3.4 -- before it used stderr:
    3.3$ ./python -V 2> /dev/null
    3.3$ ./python -V > /dev/null
    Python 3.3.2+

    3.4$ ./python -V 2> /dev/null
    Python 3.4.0a1+
    3.4$ ./python -V > /dev/null

    This might also explain why argparse uses stderr (other modules/scripts in the stdlib might do the same too).

    @elibendersky
    Copy link
    Mannequin

    elibendersky mannequin commented Sep 4, 2013

    On Wed, Sep 4, 2013 at 6:26 AM, Ezio Melotti <report@bugs.python.org> wrote:

    Ezio Melotti added the comment:

    Only on 3.4.
    Python prints the version on stdout since 3.4 -- before it used stderr:
    3.3$ ./python -V 2> /dev/null
    3.3$ ./python -V > /dev/null
    Python 3.3.2+

    3.4$ ./python -V 2> /dev/null
    Python 3.4.0a1+
    3.4$ ./python -V > /dev/null

    This might also explain why argparse uses stderr (other modules/scripts in
    the stdlib might do the same too).

    Ah, right. On 3.4 Python's main.c uses printf for --version; on earlier
    versions it's fprintf(stderr...)

    I guess it's a no-brainer then; 3.4 has to be changed, but not earlier
    versions. I'll whip up a quick patch.

    @elibendersky
    Copy link
    Mannequin

    elibendersky mannequin commented Sep 4, 2013

    The Python executable change is from bpo-18338

    @elibendersky
    Copy link
    Mannequin

    elibendersky mannequin commented Sep 4, 2013

    Patch attached

    @serhiy-storchaka
    Copy link
    Member

    serhiy-storchaka commented Sep 4, 2013

    This might also explain why argparse uses stderr (other modules/scripts in the stdlib might do the same too).

    Lib/trace.py, Tools/pynche/Main.py, and Tools/i18n/pygettext.py write to the stdout.

    Lib/smtpd.py and Tools/i18n/msgfmt.py write to the stderr.

    The optparse module also writes to the stdout.

    @serhiy-storchaka
    Copy link
    Member

    serhiy-storchaka commented Sep 4, 2013

    You misplace Misc/NEWS entry in wrong section -- "What's New in Python 3.4.0 Alpha 1".

    I think this change (as change of bpo-18338) worths the mentioning in Doc/whatsnew/3.4.rst.

    Did you run all test suite? This change can affect other tests.

    @python-dev
    Copy link
    Mannequin

    python-dev mannequin commented Sep 6, 2013

    New changeset ec9a4b77f37b by Eli Bendersky in branch 'default':
    Issue bpo-18920: argparse's default version action (for -v, --version) should
    http://hg.python.org/cpython/rev/ec9a4b77f37b

    @elibendersky
    Copy link
    Mannequin

    elibendersky mannequin commented Sep 6, 2013

    Thanks, I moved the NEWS entry to the right place. Yes, all tests pass. I'll update whatsnew separately.

    @python-dev
    Copy link
    Mannequin

    python-dev mannequin commented Sep 6, 2013

    New changeset 587bdb940524 by Eli Bendersky in branch 'default':
    Update whatsnew/3.4 wrt. --version going to stdout. bpo-18338, bpo-18920, bpo-18922
    http://hg.python.org/cpython/rev/587bdb940524

    @elibendersky elibendersky mannequin closed this as completed Sep 6, 2013
    @jwilk jwilk mannequin changed the title argparse module version action argparse version action should print to stdout, not stderr Jul 4, 2016
    @StefanSauer
    Copy link
    Mannequin

    StefanSauer mannequin commented Mar 24, 2018

    Is there a workaround for python2? The issue is that autotools is checking that installed tools support --help and --version and it expects those to stdout:

    bad=0; pid=$$; list="gtkdoc-check gtkdoc-depscan gtkdoc-fixxref gtkdoc-mkdb gtkdoc-mkhtml gtkdoc-mkhtml2 gtkdoc-mkman gtkdoc-mkpdf gtkdoc-rebase gtkdoc-scan gtkdoc-scangobj gtkdocize"; for p in $list; do \
      case '  ' in \
       *" $p "* | *" ../../$p "*) continue;; \
      esac; \
      f=`echo "$p" | sed 's,^.*/,,;s,x,x,'`; \
      for opt in --help --version; do \
        if "/home/ensonic/projects/gnome/gtk-doc/gtk-doc-1.27.1/_inst/bin/$f" $opt >c${pid}_.out \
             2>c${pid}_.err </dev/null \
             && test -n "`cat c${pid}_.out`" \
             && test -z "`cat c${pid}_.err`"; then :; \
        else echo "$f does not support $opt" 1>&2; bad=1; fi; \
      done; \
    done; rm -f c${pid}_.???; exit $bad
    gtkdoc-check does not support --version
    gtkdoc-fixxref does not support --version
    gtkdoc-mkdb does not support --version
    gtkdoc-mkhtml does not support --version
    gtkdoc-mkhtml2 does not support --version
    gtkdoc-mkman does not support --version
    gtkdoc-mkpdf does not support --version
    gtkdoc-rebase does not support --version
    gtkdoc-scan does not support --version
    gtkdoc-scangobj does not support --version
    Makefile:637: recipe for target 'installcheck-binSCRIPTS' failed

    @serhiy-storchaka
    Copy link
    Member

    serhiy-storchaka commented Mar 24, 2018

    You can implement your own version action which outputs to stdout and use it for -V and --version.

    @ezio-melotti ezio-melotti transferred this issue from another repository Apr 10, 2022
    Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
    Labels
    easy type-bug An unexpected behavior, bug, or error
    Projects
    None yet
    Development

    No branches or pull requests

    2 participants