Re: [PATCH 1/2] relative_path should honor dos_drive_prefix

From: Jiang Xin <worldhello.net@gmail.com>
Date: Sep 20, 2013, 01:26 UTC
Message-ID: <CANYiYbGK_KdF5Yvcus5C_cGz3EyGTaFvirsUH5q4Eu=3VC4=Wg@mail.gmail.com>
In-Reply-To: <5238AE60.1010700@kdbg.org>

2013/9/18 Johannes Sixt <j6t@kdbg.org>:

Show 35 quoted lines

> Am 17.09.2013 10:24, schrieb Jiang Xin:
>> I have checked the behavior of UNC path on Windows (msysGit):
>>
>> * I can cd to a UNC path:
>>
>>     cd //server1/share1/path
>>
>> * can cd to other share:
>>
>>     cd ../../share2/path
>>
>> * and can cd to other server's share:
>>
>>     cd ../../../server2/share/path
>>
>> That means relative_path(path1, path2) support UNC paths out of the box.
>> We only need to check both path1 and path2 are UNC paths, or both not.
>
> Your tests are flawed. You issued the commands in bash, which (or rather
> MSYS) does everything for you that you need to make it work. But in
> reality it does not, because the system cannot apply .. to //server/share:
>
> $ git ls-remote //srv/public/../repos/his/setups.git
> fatal: '//srv/public/../repos/his/setups.git' does not appear to be a
> git repository
> fatal: Could not read from remote repository.
>
> Please make sure you have the correct access rights
> and the repository exists.
>
> even though the repository (and //srv/public, let me assure) exists:
>
> $ git ls-remote //srv/repos/his/setups.git
> bea489b0611a72c41f133343fdccbd3e2b9f80b5        HEAD
> ...

After see this link (provided by Torsten):

    <http://msdn.microsoft.com/en-us/library/windows/desktop/aa365247%28v=vs.85%29.aspx>

I find the following commands could work:

    $ git ls-remote //srv/repos/his/setups.git
    $ git ls-remote //srv/repos/his/../his/setups.git
    $ git ls-remote //?/UNC/srv/repos/his/setups.git
    $ git ls-remote //?/UNC/srv/repos/../repos/his/setups.git

But no luck for this one:

    $ git ls-remote //srv/repos/../repos/his/setups.git

I trace it using gdb, and find it failed in "stat()/mingw_stat()" call of function "enter_repo" in path.c. But I can not find out why "git ls-remote //?/UNC/srv/repos/../repos/his/setups.git" could work (success in shell, failed in gdb).

Show 6 quoted lines

> Please let me suggest not to scratch where there is no itch. ;) Your
> round v2 was good enough.
>
> If you really want to check UNC paths, then you must compare two path
> components after the the double-slash, not just one.
>

I have already try this (honor two path components after //) during the reroll for patch v3. But I am not satisfied with it, and it seems like over-engineered: Rename "have_same_root" to "get_common_root_prefix_width", and it return -1 for no same_root found, otherwize return the length of root_prefix_width.

Since restored the default behavior of setup.c in commit ("Use simpler relative_path when set_git_dir"), function "relative_path" are only used in "quote.c" and "builtin/clean.c", and two paths provided to "relative_path" are always (I can not find exception) relative paths. So no itch exist I think.

-- 
Jiang Xin