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os.path.normpath over-normalizes #46542

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os.path.normpath over-normalizes#46542
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type-featureA feature request or enhancement

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@eljay451
eljay451
mannequin
opened on Mar 14, 2008
BPO 2289
Nosy @birkenfeld, @abalkin

Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.

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GitHub fields:

assignee = None
closed_at = <Date 2008-03-16.21:53:19.689>
created_at = <Date 2008-03-14.18:43:44.486>
labels = ['type-feature']
title = 'os.path.normpath over-normalizes'
updated_at = <Date 2008-03-16.21:53:19.687>
user = 'https://bugs.python.org/eljay451'

bugs.python.org fields:

activity = <Date 2008-03-16.21:53:19.687>
actor = 'georg.brandl'
assignee = 'none'
closed = True
closed_date = <Date 2008-03-16.21:53:19.689>
closer = 'georg.brandl'
components = []
creation = <Date 2008-03-14.18:43:44.486>
creator = 'eljay451'
dependencies = []
files = []
hgrepos = []
issue_num = 2289
keywords = []
message_count = 3.0
messages = ['63533', '63586', '63605']
nosy_count = 3.0
nosy_names = ['georg.brandl', 'belopolsky', 'eljay451']
pr_nums = []
priority = 'normal'
resolution = 'wont fix'
stage = None
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue2289'
versions = ['Python 2.4']

Activity

  1. eljay451 commented on Mar 14, 2008

    @eljay451
    eljay451mannequin
    on Mar 14, 2008
    MannequinAuthor

    I found a bug (or at least a shortcoming) in Python's os.path.normpath routine.

    It overly normalizes, at least for Unix and Unix-like systems (including Mac), and
    Windows.

    Example:

    x = os.path.join(".", "dog", "..", "cupcake.txt")
print x
x = os.path.normpath(x)
print x

    If say "dog" is a symlink (any flavor of Unix (including OS X), or Win), there is a
    difference between ./dog/../cupcake.txt and ./cupcake.txt.

    In the OS, if dog is a symlink to fire/fly, the .. resolves relative to fire/fly.

    It should be safe to normalize this:
    ././././././././cupcake.txt --> ./cupcake.txt

    It should be safe to normalize this:
    .////////////////cupcake.txt --> ./cupcake.txt

    But this is not safe to normalize:
    ./x/../x/../x/../cupcake.txt --> ./cupcake.txt

    For example, if the directories look like this:
    ./cupcake.txt
    ./over/yonder/back/cupcake.txt
    ./x --> over/there
    ./over/there
    ./over/x --> yonder/aways
    ./over/yonder/aways
    ./over/yonder/x --> back/again
    ./over/yonder/back/again

    ./cupcake.txt refers to first cupcake.
    ./x/../x/../x/../cupcake.txt refers to the second cupcake.

    The os.path.realpath does the resolve, but sometimes the path-in-hand is for some
    arbitrary path, and not necessarily one on the local system, or if on the local
    files system may be relative based off from a different cwd.

  2. eljay451
    added
    type-bugAn unexpected behavior, bug, or error
    on Mar 14, 2008

  3. abalkin commented on Mar 16, 2008

    @abalkin
    abalkin
    on Mar 16, 2008
    Member

    This is a documented feature:

    """
    normpath(path)

    Normalize a pathname. ... It should be understood that this may change
    the meaning of the path if it contains symbolic links!
    """

    See http://docs.python.org/lib/module-os.path.html .

  4. abalkin
    added
    type-featureA feature request or enhancement
    and removed
    type-bugAn unexpected behavior, bug, or error
    on Mar 16, 2008

  5. birkenfeld commented on Mar 16, 2008

    @birkenfeld
    birkenfeld
    on Mar 16, 2008
    Member

    Closing as "Won't fix".

  6. birkenfeld
    closed this as completedon Mar 16, 2008
  7. ezio-melotti
    transferred this issue fromon Apr 10, 2022
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