Closes Homebrew/homebrew#29294.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

This commit supports "-" and "_" in names of user and repository.

Closes Homebrew/homebrew#28203.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Handle formula URLs with query parameters. This is useful for fetching formulas from cgit repositories, which uses ?h= to choose branches.

Closes Homebrew/homebrew#28314.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Fixes Homebrew/homebrew#28234.

This means that tapped formula will always have the correct path, and we
can stop calling realpath everywhere.

`brew install ./foo` treats `./foo` like `./foo.rb`. This requires
a confusing special case in the name resolution logic and doesn't make
a whole lot of sense from a UX perspective.

Drop support for this. The argument should be an absolute path,
a relative path, or a formula name, rather than a hybrid.

cf. https://github.com/Homebrew/homebrew/issues/23430#issuecomment-26776962

Now we can avoid computing the path twice in the common case.

Much of the name resolution done in Formula.canonical_name is repeated
Formulary.factory. Here we eliminate the repeated work by duplicating
the code from canonical_name. Later we will refactor it so that both
methods can share the bulk of the logic.

When the path argument to the Formula constructor is omitted, the
instance's path attribute is created using the Formula.path class
method. However, we have already done this work, so we can just pass it
into the constructor.

This translates to one less call to Pathname#to_s per formula, or about
2600 calls when running `brew readall`.

Before:

  f1 = Formula.factory('tree')
  f1.versions
  f2 = Formula.factory('tree')
  f1.class == f2.class # => false

After:

  f1 = Formula.factory('tree')
  f1.versions
  f2 = Formula.factory('tree')
  f1.class == f2.class # => true

Closes Homebrew/homebrew#22833.

Closes Homebrew/homebrew#21680.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Closes Homebrew/homebrew#19177.

Closes Homebrew/homebrew#20926.

Closes Homebrew/homebrew#20920.