Re: windows: error cannot lock ref ... unable to create lock

[Philip Oakley <philipoakley@iee.org>]

On 18/06/2019 18:01, Eric Sunshine wrote:
> On Tue, Jun 18, 2019 at 12:39 PM Anthony Sottile <asottile@umich.edu> wrote:
>> + git fetch origin --tags
>> Unpacking objects: 100% (10/10), done.
>>  From https://github.com/asottile-archive/git-windows-branch-test
>>   * [new branch]      master     -> origin/master
>> error: cannot lock ref 'refs/remotes/origin/pr/aux': Unable to create
>> 'C:/Users/IEUser/x/x/.git/refs/remotes/origin/pr/aux.lock': No such
>> file or directory
>>   ! [new branch]      pr/aux     -> origin/pr/aux  (unable to update local ref)
> AUX is a reserved[1] filename on Windows. Quoting from that source:
>
>      Do not use the following reserved names for the name of a file:
>      CON, PRN, AUX, NUL, COM1, COM2, COM3, COM4, COM5, COM6, COM7,
>      COM8, COM9, LPT1, LPT2, LPT3, LPT4, LPT5, LPT6, LPT7, LPT8, and
>      LPT9. Also avoid these names followed immediately by an
>      extension...
>
> The default Git "ref store" is filesystem-based, so a branch named
> "aux" is problematic. Other ref store implementations would not be
> subject to this limitation (though I'm not sure what the state of the
> others is -- someone with more knowledge can probably answer that).
>
> [1]: https://docs.microsoft.com/en-us/windows/desktop/FileIO/naming-a-file#naming-conventions
This sounds interesting. I thought (but I'm not certain) that Git for 
Windows avoided creating files in the working tree with such problematic 
names, so that a clone of a repo that contained a file "AUX" (any case, 
any extension IIRC), would be bypassed with possibly a warning message.

However this looks to be a slightly different case where a _branch_ 
called "AUX" (lower cased) has been created within the clone, and it's a 
problem not trapped. Maybe worth creating a proper issue on the 
Git-for-Windows repo. Also cc'ing Dscho who may remember better than I.
--
Philip