Re: [BUG] Clones from local repositories do not work correctly under Windows

From: Johannes Sixt <j6t@kdbg.org>
Date: Apr 12, 2024, 16:16 UTC
Message-ID: <01cf64db-2ff5-4be5-8968-d280ab0ffc50@kdbg.org>
In-Reply-To: <e25bbce7-8338-430b-865f-690fe3c94fb6@amyspark.me>

Am 12.04.24 um 15:05 schrieb L. E. Segovia:

Show 14 quoted lines

> Under a MSYS2 shell, follow these steps (feel free to replace the choice
> of remote repo with any other supporting a Rust crate):
> 
> 1. `cd` to a directory of your choice (let's call it `dirA`).
> 2. `git clone https://gitlab.gnome.org/GNOME/librsvg.git .`
> 3. `git checkout -b cerbero_build`.
> 4. `cd ..`
> 5. `git clone <full path to dirA> -s -b cerbero_build dirB`
> 6. `cd dirB`
> 7. `git status`
> 
> Now switch to any other shell of your choice, such as Git Bash, CMD, or
> PowerShell, and try issuing commands such as `git status`. It will
> result in a wall of "error: unable to normalize..."

Thanks, that is much more helpful. Here are my assumption, my explanation of the symptoms, and the conclusion (which is basically "if it hurts, don't do it"):

I assume that you have two installations of Git. One installation is used when you use the git command from the MSYS2 shell; it is the MSYS2 version. The other installation is Git for Windows or equivalent that is used by all the other shells.

When you clone a repository with -s, a .git/objects/info/alternates file is initialized that contains the path to the original repository. You can see its contents with `git count-objects -v`. I tested the reproduction recipe with my own build (which is a MinGW build, much like Git for Windows), and it looks like this:

C:\Temp\repoclone>git count-objects -v count: 0 size: 0 in-pack: 0 packs: 0 size-pack: 0 prune-packable: 0 garbage: 0 size-garbage: 0 alternate: C:/Temp/repoorig/.git/objects

See the last line? It begins with a drive letter. When you call the command with the MSYS2 version, it will look more like this:

alternate: /c/Temp/repoorig/.git/objects

This is the MSYS2/Cygwin absolute path with a "drive letter". Unfortunately, this kind of path is unintelligible for Git for Windows. It expects absolute paths to begin with drive letter-colon or a double-slash or double-backslash. For this reason, it reports "unable to normalize alternate object path".

The conclusion is: Do not use two different flavors of Git on a repository that is set up with a link to an alternate repository.

BTW, I did not do the followup test with `git am`. (Actually, I did, but there were no errors.) So, I cannot tell why your MSYS2 version suddenly also reports the "unable to normalize" error.

-- Hannes