tap: don’t tap deprecated taps.

[MikeMcQuaid]

These no longer have any files in them.

[sjackman]

Tapping the empty tap is needed to provide access to tap_migrations.json so that brew install homebrew/science/bwa installs homebrew/core/bwa. Would you accept a PR to revert this change?

Current behaviour

❯❯❯ brew install homebrew/science/bwa
Error: homebrew/science was deprecated. This tap is now empty as all its formulae were migrated.

Expected behaviour

❯❯❯ brew install homebrew/science/bwa
Warning: homebrew/science was deprecated. This tap is now empty as all its formulae were migrated.
==> Tapping homebrew/science
Cloning into '/Users/sjackman/.homebrew/Homebrew/Library/Taps/homebrew/homebrew-science'...
Warning: Use bwa instead of deprecated homebrew/science/bwa
==> Downloading https://homebrew.bintray.com/bottles/bwa-0.7.17.el_capitan.bottle.tar.gz
Already downloaded: /Users/sjackman/Library/Caches/Homebrew/bwa-0.7.17.el_capitan.bottle.tar.gz
==> Pouring bwa-0.7.17.el_capitan.bottle.tar.gz
🍺  /usr/local/Cellar/bwa/0.7.17: 8 files, 534.2KB

[ilovezfs]

I don't think we want formulae out in the wild still to be able to use

depends_on "homebrew/science/bwa"

successfully.

[MikeMcQuaid]

@sjackman I don't think so, sorry. I think the current error message is more helpful to users and will require them to perform the necessary updates.

[sjackman]

This tap was deprecated on Jan 1 and became a hard error on Feb 6. I feel that a deprecation period is typically longer than a month, before the warning becomes a hard error. My opinion anyway. I don't feel super strong about this issue.