Description

zooba

opened on Aug 10, 2016

Issue body actions

BPO	27731
Nosy	@brettcannon, @pfmoore, @vsajip, @pitrou, @vstinner, @tjguk, @zware, @eryksun, @zooba

^{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 = 'https://github.com/zooba'
closed_at = <Date 2016-09-07.05:44:31.528>
created_at = <Date 2016-08-10.23:09:48.215>
labels = ['type-feature', 'OS-windows']
title = 'Opt-out of MAX_PATH on Windows 10'
updated_at = <Date 2016-09-07.05:44:31.527>
user = 'https://github.com/zooba'

bugs.python.org fields:

activity = <Date 2016-09-07.05:44:31.527>
actor = 'steve.dower'
assignee = 'steve.dower'
closed = True
closed_date = <Date 2016-09-07.05:44:31.528>
closer = 'steve.dower'
components = ['Windows']
creation = <Date 2016-08-10.23:09:48.215>
creator = 'steve.dower'
dependencies = []
files = []
hgrepos = []
issue_num = 27731
keywords = []
message_count = 12.0
messages = ['272385', '272939', '272960', '273054', '273060', '273061', '273067', '274312', '274313', '274319', '274631', '274743']
nosy_count = 10.0
nosy_names = ['brett.cannon', 'paul.moore', 'vinay.sajip', 'pitrou', 'vstinner', 'tim.golden', 'python-dev', 'zach.ware', 'eryksun', 'steve.dower']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue27731'
versions = ['Python 3.6']

Activity

1. zooba commented on Aug 10, 2016

   

   zooba

   on Aug 10, 2016

   MemberAuthor

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   According to https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx we can opt-out of MAX_PATH limitations on a selection of functions on the latest version of Windows 10. This will allow unprefixed paths (i.e. no "\\?\") to exceed 260 characters for many common functions.

   I will enable this for Python 3.6.
2. zooba

   self-assigned this

   on Aug 10, 2016
3. zooba

   added

   OS-windows

   type-featureA feature request or enhancementA feature request or enhancement

   on Aug 10, 2016
4. vstinner commented on Aug 17, 2016

   

   vstinner

   on Aug 17, 2016

   Member

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   Hum, but we use the same binary (.exe) for all Windows versions. Does it mean that we drop support for Windows < 10 in Python 3.6?
5. zooba commented on Aug 17, 2016

   

   zooba

   on Aug 17, 2016

   MemberAuthor

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   No, the flag that we add to the binary is backwards compatible. Earlier versions will just ignore it.
6. pitrou commented on Aug 18, 2016

   

   pitrou

   on Aug 18, 2016

   Member

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   This is great! Will it apply to third-party C extensions loaded into Python?
7. vstinner commented on Aug 18, 2016

   

   vstinner

   on Aug 18, 2016

   Member

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   Steve Dower added the comment:

   No, the flag that we add to the binary is backwards compatible. Earlier
   versions will just ignore it.

   Cool.
8. zooba commented on Aug 18, 2016

   

   zooba

   on Aug 18, 2016

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   Will it apply to third-party C extensions loaded into Python?

   Yes, anything running under the python.exe will get it for free.

   (Non-standard entry points will need to add the flag themselves.)
9. eryksun commented on Aug 18, 2016

   

   eryksun

   on Aug 18, 2016

   Contributor

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   anything running under the python.exe will get it for free.

   py.exe may as well get the manifest setting, but it's not critical. It isn't common to store scripts in deeply nested paths. The same goes for the distlib launchers that pip uses for entry points since they have to open themselves.
10. zooba commented on Sep 3, 2016

    

    zooba

    on Sep 3, 2016

    MemberAuthor

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    Just discovered that this actually requires enabling the group policy for long paths - specifically setting HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem@LongPathsEnabled to 1.

    Apparently the manifest is also required, but in my testing the manifest is ignored and we just get long path support for free. So perhaps we should just add a message to file exceptions when the path is >260?
11. zooba commented on Sep 3, 2016

    

    zooba

    on Sep 3, 2016

    MemberAuthor

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    More info at https://blogs.msdn.microsoft.com/jeremykuhne/2016/07/30/net-4-6-2-and-long-paths-on-windows-10/
12. brettcannon commented on Sep 3, 2016

    

    brettcannon

    on Sep 3, 2016

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    SGTM
13. zooba commented on Sep 6, 2016

    

    zooba

    on Sep 6, 2016

    MemberAuthor

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    Just confirmed that the manifest not being required is a bug, so I'll add it, document it and complete this.
14. python-dev commented on Sep 7, 2016

    

    python-devmannequin

    on Sep 7, 2016

    Mannequin

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    New changeset 26601191b368 by Steve Dower in branch 'default':
    Issue bpo-27731: Opt-out of MAX_PATH on Windows 10
    https://hg.python.org/cpython/rev/26601191b368
15. zooba

    closed this as completedon Sep 7, 2016
16. ezio-melotti

    transferred this issue fromon Apr 10, 2022

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