Branch name rules should be enforced instead of erring out

[masecla22]

Version

0.20.4

Operating System

Linux

Distribution Method

deb (Linux)

Describe the issue

There are certain restrictions on how branches should be named enforced by Git. For now, the only one I can think of is that a branch name cannot have a trailing slash.

I think Butler should warn you about this, preventing you from ever naming the branch.

Currently, it simply errs out with a semi-cryptic error:

Of course, reading the error you can quite clearly tell what's happening and why Git is upset, but still, Butler should probably prevent you from ever doing this anyhow.

How to reproduce (Optional)

1. Make a branch ending in /
2. View error

Expected behavior (Optional)

I would expect Butler to stop me from doing this instead of dumping a git error log.

[slarse]

Hi!

I think that this is a conflation of errors due to an unclear error message. GitButler normalizes names you pass in, so if you try to create or rename a branch to mm/, the actual name of the ref is normalized to mm. Creating a branch looks like this, note the notice below the input window of what the name actually will be:

Renaming a branch does not have that convenience it seems, and even more is that there appears to be a rendering bug on updating where the / actually sticks around in the UI until you click again (then it's refreshed). But the response from the backend is very clear that the / has been stripped away so at no point is a ref created with a trailing /. This wouldn't even be possible on a standard UNIX-like file system as / is the path separator, so it cannot be included in the name of a file by definition.

I do however recognize the error you posted a screenshot of, it occurs when a reference you're trying to create collides with a path prefix of an existing reference. For example, if you create the reference mm/hello, that creates a ref file at .git/refs/heads/mm/hello, i.e. mm is a directory. If you then try to create ref named mm/, the normalized name mm collides with the directory mm/, causing this error. You'd get the same error when just trying to create mm without the trailing slash.

Can you confirm that you do indeed have some ref named mm/... already, and you actually get the exact same error regardless of if you try to create mm/ or mm?

[masecla22]

Indeed, I do have other mm branches, and just mm without the slashes crashes as well! So the err message was unclear enough that I even misunderstood the original cause!

[Byron]

Thanks everyone for sharing.

For what I can tell, the branch name normalization function removes slashes, which is why the UI preview of the final branch name does not seem to change or update.

The other issue was pointed out by @slarse and there is nothing that can effectively be done except for catching the problem to provide a clearer error. While this can be done, I keep thinking it's best to wait for reftables and switch to that as soon as it's available, which should be in September.