Print path of first detected Git instead of executing it. This is hidden
behind a `--homebrew=print-path` argument that is unlikely to conflict
with any existing or future Git flags.
Using `git` from `Formula#install` can cause an exec bomb if used in a
formula with `env :userpaths` because that causes both `Library/ENV/4.3`
and `Library/ENV/scm` to be in PATH, both of which contain a `git`
binary that is the same SCM wrapper. Those will mutually exec each other
indefinitely as they fail to detect that they are the same wrapper.
Extend the exec-bomb protection to check the paths after all symbolic
links have been expanded to prevent this situation.
Fixes#43.
FixesHomebrew/homebrew-core#133.
FixedHomebrew/homebrew-core#143.
Closes#46.
Signed-off-by: Martin Afanasjew <martin@afanasjew.de>
`/usr/bin/<tool>` will be a popup stub under such configuration.
The idea is to let `scm/git` to handle all of git location resolution
throughout Homebrew codebase.
Some things can break in hard to debug ways if users or build scripts
set these variables, causing our otherwise quite robust Ruby wrappers
to fail. In theory, we could also use `--disable-rubyopt`, but this is
not supported in Ruby 1.8 (and we still care about it).
Use the same interpreter for the shims that is also used to run the main
Homebrew process (the one invoked via `brew`). The magic basically lies
in executing `ruby` with the `-x` option (supported since at least 1.8)
and in the following shebang line.
This strategy is only used in one formula, so we can just replace it
with a dependency. It could be done with a requirement, but since this
is a low-impact change (it only matters for head builds on Leopard), I'm
not sure it's worth the effort.
The constant is retained for compatibility, though I could find only one
other reference to it on GitHub, in a formula that was removed from core
almost two years ago.
