From: Johannes Sixt <j6t@kdbg.org>
Date: Sun, 20 Aug 2017 08:20:47 GMT
Subject: Re: Git *accepts* a branch name, it can't identity in the future?
Message-ID: <829ac9ed-857d-84bf-2374-6a36b1d0aff1@kdbg.org>
In-Reply-To: <1503215489.5824.4.camel@gmail.com>

Am 20.08.2017 um 09:51 schrieb Kaartic Sivaraam:
> I made a small assumption in the script which turned out to be false. I
> thought the unicode prefixes I used corresponded to only two bytes.
> This lead to the issue. The unicode character '✓' corresponds to three
> characters and as a result instead of removing it, my script replaced
> it with the unknown character '�'. So, the branch named '✓doc-fix'
> became 'done/�doc-fix'. Here's the issue. I couldn't use
> 
>      $ git branch -m done/�doc-fix done/dic-fix
> 
> to rename the branch. Nor could I refer to it in anyway. Git simply
> says,
> 
>      error: pathspec 'done/�doc-fix' did not match any file(s) known to git.
> 
> It's not a big issue as I haven't lost anything out of it. The branches
> have been merged into 'master'.
> 
> I just wanted to know why git accepted a branch name which it can't
> identify later?
> 
> If it had rejected that name in the first place it would have been
> better. In case you would like to know how I got that weird name,
> here's a way to get that
> 
>      $ echo '✓doc-fix' | cut -c3-100
> 

See, these two are different:

$ echo '✓doc-fix' | cut -c3-100 | od -t x1
0000000 93 64 6f 63 2d 66 69 78 0a
0000011
$ echo '�doc-fix' | od -t x1
0000000 64 6f bd 64 6f 63 2d 66 69 78 0a
0000013

It is not Git's fault that your terminal converts an invalid UTF-8 
sequence (that your script produces) to �. Nor is it when you paste that 
character onto the command line, that it is passed as a (correct) UTF-8 
character.

Perhaps this helps (untested):

$ git branch -m done/$(printf '\x93')doc-fix done/dic-fix

In Git's database, branch names are just sequences of bytes. It is 
outside the scope to verify that all input is encoded correctly.

-- Hannes