Skip to content

Suboptimal stacklevel of deprecation warnings for formatter and imp modules #67998

Closed

Description

@Arfrever
mannequin
BPO 23810
Nosy @brettcannon, @ncoghlan, @larryhastings, @ericsnowcurrently, @berkerpeksag, @serhiy-storchaka
Superseder
  • bpo-24305: The new import system makes it inconvenient to correctly issue a deprecation warning for a module
  • Files
  • better_stacklevel.diff
  • deprecated_module_stacklevel.diff
  • 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 = 'https://github.com/brettcannon'
    closed_at = <Date 2015-08-14.18:18:33.979>
    created_at = <Date 2015-03-30.01:54:14.679>
    labels = ['deferred-blocker', 'type-bug', 'library']
    title = 'Suboptimal stacklevel of deprecation warnings for formatter and imp modules'
    updated_at = <Date 2015-08-14.18:18:57.969>
    user = 'https://bugs.python.org/Arfrever'

    bugs.python.org fields:

    activity = <Date 2015-08-14.18:18:57.969>
    actor = 'brett.cannon'
    assignee = 'brett.cannon'
    closed = True
    closed_date = <Date 2015-08-14.18:18:33.979>
    closer = 'brett.cannon'
    components = ['Library (Lib)']
    creation = <Date 2015-03-30.01:54:14.679>
    creator = 'Arfrever'
    dependencies = []
    files = ['39196', '39550']
    hgrepos = []
    issue_num = 23810
    keywords = ['patch']
    message_count = 11.0
    messages = ['239554', '239607', '239610', '241944', '241968', '242015', '244260', '244304', '244396', '246285', '248600']
    nosy_count = 7.0
    nosy_names = ['brett.cannon', 'ncoghlan', 'larry', 'Arfrever', 'eric.snow', 'berker.peksag', 'serhiy.storchaka']
    pr_nums = []
    priority = 'deferred blocker'
    resolution = 'duplicate'
    stage = 'patch review'
    status = 'closed'
    superseder = '24305'
    type = 'behavior'
    url = 'https://bugs.python.org/issue23810'
    versions = ['Python 3.5', 'Python 3.6']

    Activity

    1. Arfrever commented on Mar 30, 2015

      Arfrevermannequin
      MannequinAuthor

      https://hg.python.org/cpython/rev/2a336cc29282 changed stacklevel of some deprecation warnings.
      However new value is still not useful, because either _frozen_importlib or importlib/_bootstrap.py is now mentioned in deprecation warnings:

      $ cat test.py
      import formatter
      import imp
      $ python3.4 -Wd test.py
      /usr/lib64/python3.4/formatter.py:24: PendingDeprecationWarning: the formatter module is deprecated and will be removed in Python 3.6
        'Python 3.6', PendingDeprecationWarning)
      /usr/lib64/python3.4/imp.py:32: PendingDeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
        PendingDeprecationWarning)
      $ python3.5 -Wd test.py
      _frozen_importlib:321: DeprecationWarning: the formatter module is deprecated and will be removed in Python 3.6
      /usr/lib64/python3.5/importlib/_bootstrap.py:321: PendingDeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
        return f(*args, **kwds)
    2. added
      stdlibStandard Library Python modules in the Lib/ directory
      on Mar 30, 2015
    3. brettcannon commented on Mar 30, 2015

      @brettcannon
      Member

      Probably need to introduce a new keyword argument just for deprecated imports or some helper function in importlib to get the stack depth right (else there is a risk of breaking the stack depth in any minor release whenever importlib's depth shifts). Something like the following should be enough (obviously done in warnings instead of per-file):

      try:
      level = 1
      while True:
      frame = sys._getframe(level)
      print(frame.f_code.co_filename)
      if '_bootstrap' not in frame.f_code.co_filename:
      break
      level += 1
      except ValueError:
      pass
      print(sys._getframe(2).f_code.co_filename)
      warnings.warn("the imp module is deprecated in favour of importlib; "
      "see the module's documentation for alternative uses",
      PendingDeprecationWarning, stacklevel=level+1)

      Otherwise the depths should just go back to what they were at.

    4. serhiy-storchaka commented on Mar 30, 2015

      @serhiy-storchaka
      Member

      Similar feature is needed for warnings in the re module. Methods of regular expression pattern can be called directly or from module-level wrappers. In these case the stack level differs by 1. And sometimes warnings are emitted in recursive parser, when stack level is variable.

    5. brettcannon commented on Apr 24, 2015

      @brettcannon
      Member

      Here is a private function in warnings for calculating the stack depth to the first frame not referencing some key string. Can someone look at it to make sure it looks reasonable?

      I'm starting with it being private since it uses sys._getframe() and I don't know how widely needed it is.

    6. serhiy-storchaka commented on Apr 24, 2015

      @serhiy-storchaka
      Member

      Unfortunately this will not help for re, because the trace passes through three files: Lib/sre_parse.py, Lib/sre_compile.py and Lib/re.py.

    7. brettcannon commented on Apr 25, 2015

      @brettcannon
      Member

      OK, I'll look at making it more general for multiple names to skip.

    8. ncoghlan commented on May 28, 2015

      @ncoghlan
      Contributor

      bpo-24305 covers either making this a public API for general use, or else just making module level deprecation warnings skip the import machinery automatically.

      I also wonder whether Eric's _boostrap_external changes might have broken any of the frame hiding tricks for tracebacks.

    9. ericsnowcurrently commented on May 28, 2015

      @ericsnowcurrently
      Member

      I had a similar concern, Nick, but don't think I did anything that would have broken the frame hiding logic. That said, I did not take stacklevel for warnings into account.

    10. brettcannon commented on May 29, 2015

      @brettcannon
      Member

      Latest patch should work for Serhiy's needs by taking a container of names to compare against the filename instead of a single argument.

    11. larryhastings commented on Jul 5, 2015

      @larryhastings
      Contributor

      This regression isn't thrilling, but it's not the kind of "OMG we can't release with this bug" level of escalation I associate with an actual release blocker. Let's at least defer it for now, and maybe we'll even reduce it further later.

    12. brettcannon commented on Aug 14, 2015

      @brettcannon
      Member

      Merging with the other issue so there is a single place to track this

    13. transferred this issue fromon Apr 10, 2022
    Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

    Metadata

    Metadata

    Assignees

    Labels

    deferred-blockerstdlibStandard Library Python modules in the Lib/ directorytype-bugAn unexpected behavior, bug, or error

    Projects

    No projects

      Milestone

      No milestone

      Relationships

      None yet

      Development

      No branches or pull requests

      Issue actions