mix repository URL change undesirable behaviour

[yrashk]

For example, if I

1. had a meh/elixir-socket git repo for dependency socket and then
2. I had to fork it to yrashk/elixir-socket
3. change that in mix.exs

It will currently try to continue working with meh's repo, not mine, until I remove it from deps and get deps again

[bitwalker]

This is because your dependencies are locked. Do mix deps.unlock elixir-socket, and then mix deps.get to refresh that dependency. This seems like normal, expected behaviour to me, but then I'm used to similar behaviour with Ruby and gemfile dependencies.

[yrashk]

Unlocking doesn't help with the fact that git url has changed

[bitwalker]

Yes it does. I just tested this with lager on a random project to be sure. If I change the url to my fork in mix.exs, execute mix deps.unlock lager, then mix deps.get, the first command removes it from my mix.lock file, and the second re-fetches the dependency from my fork, and adds the new url to mix.lock.

What behaviour are you seeing?

[yrashk]

➜  test  cat mix.exs | grep socket
    [{:socket, github: "meh/elixir-socket"}]
➜  test  cat deps/socket/.git/config | grep github
    url = git://github.com/meh/elixir-socket.git
➜  test  vi mix.exs
➜  test  cat mix.exs | grep socket
    [{:socket, github: "yrashk/elixir-socket"}]
➜  test  mix deps.unlock socket
➜  test  mix deps.get
* Getting socket (git://github.com/yrashk/elixir-socket.git)
* Compiling socket
➜  test  cat deps/socket/.git/config | grep github
    url = git://github.com/meh/elixir-socket.git

[bitwalker]

Ah, yeah I see that now. I had to run mix deps.clean lager and then mix deps.get in order to get it to reclone the dependency. Definitely unexpected. It seems like the default behaviour should be to run the clean task if the dependency source changes.

[bitwalker]

After looking deeper at this, it seems the problem is if you change the repo source, but the HEAD commit is the same, it doesn't see the lock as changed, and therefore doesn't clean the old dependency. I'm still digging, but that seems like the source of the problem.

[josevalim]

We actually see that it has changed because we use the source to detect if the repository changed or not:

https://github.com/elixir-lang/elixir/blob/master/lib/mix/lib/mix/scm/git.ex#L33

The problem is that the only time we pass the location is when cloning:

https://github.com/elixir-lang/elixir/blob/master/lib/mix/lib/mix/scm/git.ex#L53

Maybe if we always pass the location to fetch:

https://github.com/elixir-lang/elixir/blob/master/lib/mix/lib/mix/scm/git.ex#L61

And when checking out the branch:

https://github.com/elixir-lang/elixir/blob/master/lib/mix/lib/mix/scm/git.ex#L85

We would solve the problem.