Closes Homebrew/homebrew#18169.

`brew untap` without arguments currently errors out (as it should), but the
error message is generic and unhelpful. (The error message is borrowed from
a method in the tap command - `tap_args`.)

Closes Homebrew/homebrew#18186.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>

Closes Homebrew/homebrew#17735.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>

* Remove legacy url syntax.
* Use revision instead of version.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>

The previous fix only looked at the current Homebrew but we should
discard hits from other installations of Homebrew too.

This reverts commit 6963a356510256762e425b5dbe2ee8c9ee0ace68.

When given no arguments, this should return the stable version, but it
hasn't since we stopped setting this direction in the class's @version
variable.

Closes Homebrew/homebrew#17963

This reverts commit dfd4dd12a41e1697ee9d5feac12cc1ea7c3a590e.

Fixes the problems from Homebrew/homebrew#17683 and Homebrew/homebrew#17685.

This reverts commit ac156b36d00ead5f225389f0a1d8069d0c1cce4a.

Actually works properly now.

This reverts commit a0e56345ea55f7ee3c41d6bf13f9cfb3af635323.

This reverts commit c98d50495275ff4951dd126bb88a55e568b64092.

Closes Homebrew/homebrew#17618.
Closes Homebrew/homebrew#17813.

a6324cb forget fix soft link in ENV folder, it cause superenv
use Apple provided git and svn.

Closes Homebrew/homebrew#17927.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>

The form "attr :name, true" is deprecated and causes Ruby to emit a
warning in verbose mode. Using attr_{reader,writer,accessor} is more
clear anyway, so do so.

Make it no longer possible to override e.g. `brew install` with a
script if there is already a built-in Homebrew command named
`brew install`.

References Homebrew/homebrew#17673

Closes Homebrew/homebrew#17843.