Setting "Default Branch" does not update the symbolic ref in .git/HEAD

[vg-c]

• Gitea version (or commit ref): 1.8.3
• Git version: 2.17.2
• Operating system: Amazon Linux 2
• Database (use [x]):
  • PostgreSQL
  • MySQL
  • MSSQL
  • SQLite
• Can you reproduce the bug at https://try.gitea.io:
  • Yes (https://try.gitea.io/vg-c/testdefaultbranch)
  • No
  • Not relevant
• Log gist:

Description

When a repository uses a default branch whose name is not "master", Gitea still maintains the .git/HEAD file with the content: "ref: refs/heads/master", and even if you try to explicitly set or update the default branch using the Settings/Branches page, it does not change the content of the HEAD file. Consequently, when you try to clone such a repository on your local machine, you get a warning from git: "warning: remote HEAD refers to nonexistent ref, unable to checkout." and then you have to explicitly checkout the default branch of the repository.

Exact steps to reproduce the issue are given below (tested and confirmed on https://try.gitea.io/vg-c/testdefaultbranch):

$ mkdir testdefaultbranch
$ cd testdefaultbranch
$ git init
$ touch README
$ git add README
$ git commit
$ git branch -m master newbranch
$ git branch -vv

• newbranch e2b1ee7 init commit
  $ cat .git/HEAD
  ref: refs/heads/newbranch

$ git remote add origin https://try.gitea.io/vg-c/testdefaultbranch.git
$ git push -u origin newbranch
...
Counting objects: 3, done.
Writing objects: 100% (3/3), 192 bytes | 0 bytes/s, done.
Total 3 (delta 0), reused 0 (delta 0)
To https://try.gitea.io/vg-c/testdefaultbranch.git

• [new branch] newbranch -> newbranch
  Branch newbranch set up to track remote branch newbranch from origin.

$ cd ..
$ mkdir t
$ cd t
$ git clone https://try.gitea.io/vg-c/testdefaultbranch.git
Cloning into 'testdefaultbranch'...
remote: Enumerating objects: 3, done.
remote: Counting objects: 100% (3/3), done.
remote: Total 3 (delta 0), reused 0 (delta 0)
Unpacking objects: 100% (3/3), done.
warning: remote HEAD refers to nonexistent ref, unable to checkout.

$ cat testdefaultbranch/.git/HEAD
ref: refs/heads/master

[zeripath]

This is not a fault of Gitea - but rather of Git itself.

Try the following on your local machine from a temporary directory:

git init --bare push-to.git
git init to-push
cd to-push
touch README
git add README
git commit -a -m'Add Readme'
git branch -m master newbranch
git remote add origin ../push-to.git
git push -u origin newbranch
cd ..
git clone push-to.git to-clone

Git push does not update the HEAD on push-to.git and it still points to master therefore the clone will not work.

That is not to say that we cannot add a feature, but this is not a bug.

[vg-c]

At least GitHub does overcome this "bug" of Git. See e.g. https://github.com/vg-c/testdefaultbranch

It would be nice if Gitea could do the same.

[zeripath]

hence #7610