'--HEAD' does not install HEAD

[mybuddymichael]

In installing rbenv with "--HEAD", brew does not install the actual HEAD, but instead installs the most recently tagged commit, despite a "head" url being declared in the formula.

[Sharpie]

Looks like the latest commit is being fetched to me:

grendel:~ sharpie$ brew fetch rbenv --HEAD
==> Cloning https://github.com/sstephenson/rbenv.git
Cloning into /Users/sharpie/Library/Caches/Homebrew/rbenv--git...
remote: Counting objects: 139, done.
remote: Compressing objects: 100% (109/109), done.
remote: Total 139 (delta 66), reused 73 (delta 24)
Receiving objects: 100% (139/139), 45.01 KiB, done.
Resolving deltas: 100% (66/66), done.
grendel:~ sharpie$ git ls-remote https://github.com/sstephenson/rbenv.git HEAD
b4f8906b246711db4c5116a12b6d9b0772084b97    HEAD
grendel:~ sharpie$ cd `brew --cache`/rbenv--git && git log --oneline | head -n 1
b4f8906 Update zsh completion adapter

What are you seeing that suggests the latest version is not being used?

[mybuddymichael]

The problem was that there were previous versions of rbenv in my brew --cache. Even with the --HEAD flag, it still used the cached tar files. Once I removed those cached tar files, brew installed HEAD fine. So perhaps this issue should now be, "brew doesn't respect the --HEAD flag if there are cached tars."

[jacknagel]

Ah, found the bug.

When updating a git checkout, Homebrew does a git reset --hard without specifying a revision, so it just resets to what is currently in HEAD. Which isn't what it just fetched. It should probably be git reset --hard origin/HEAD.