Closes Homebrew/homebrew#43107.

Signed-off-by: Xu Cheng <xucheng@me.com>

Closes Homebrew/homebrew#43025.

Signed-off-by: Xu Cheng <xucheng@me.com>

Fixes Homebrew/homebrew#43002

Closes Homebrew/homebrew#43058.

Signed-off-by: Xu Cheng <xucheng@me.com>

Also reduce unnecessary disk operations

Closes Homebrew/homebrew#43024.

Signed-off-by: Xu Cheng <xucheng@me.com>

It can be useful when implementing custom https mirror strategy such as Homebrew/homebrew#42955.

Closes Homebrew/homebrew#43020.

Signed-off-by: Xu Cheng <xucheng@me.com>

These are minor perf optimizations.

Closes Homebrew/homebrew#43028.

Signed-off-by: Baptiste Fontaine <batifon@yahoo.fr>

Mixing 'brew remove' with 'brew uninstall' can confuse users.

Closes Homebrew/homebrew#43026.

Signed-off-by: Baptiste Fontaine <batifon@yahoo.fr>

Closes Homebrew/homebrew#43016.

Signed-off-by: Xu Cheng <xucheng@me.com>

Closes Homebrew/homebrew#43014.

Signed-off-by: Xu Cheng <xucheng@me.com>

Before

```
$ time brew cleanup -s
brew cleanup -s  0.73s user 3.52s system 58% cpu 7.297 total
```

After

```
$ time brew cleanup -s
brew cleanup -s  0.69s user 2.57s system 139% cpu 2.341 total
```

Closes Homebrew/homebrew#42968.

Signed-off-by: Xu Cheng <xucheng@me.com>

Closes Homebrew/homebrew#42998.

Signed-off-by: Xu Cheng <xucheng@me.com>

After the formula gets renamed oldname opt is created and
it points to the linked keg. However if we then upgrade newname
oldname opt still points to the same keg it pointed before upgrade.
The commit fixes this behaviour thus that oldname opt links at the
same keg opt point.

Change behavior for `brew cleanup` as follows:

- If `--force` is supplied, remove only outdated keg-only packages.
- If `--prune=<days>` is supplied, remove both logs and cached downloads
  older than the specified number of days. Use `--prune=all` to remove
  all logs and cached downloads irrespective of age.
- By default, remove logs after 14 days and cached downloads never.

Also centralizes handling of `--prune`, thus removing duplicate logic.

This is motivated by commit 17eee232838d4639b25f863aa342b1dda61b81bc
that made `--force` much more aggressive and made it override whatever
was specified via `--prune`, completely removing all:

- outdated keg-only packages
- cached downloads irrespective of age
- logs irrespective of age

This made it impossible to remove outdated keg-only packages without
also deleting all cached downloads, which is at least inconvenient for
people with limited bandwidth wanting to rebuild packages later.

Closes Homebrew/homebrew#42970.

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

Closes Homebrew/homebrew#42954.

Signed-off-by: Baptiste Fontaine <batifon@yahoo.fr>

Ding, dong, the witch is dead...

This reverts commit fd5ca9ba16f5afc181364369210cb94e997a5a5e.

Ref Homebrew/homebrew#38514, Homebrew/homebrew#38735.

Closes Homebrew/homebrew#41843.

If we have lib/python3.4/site-packages, which is a symlink to
HOMEBREW_PREFIX/lib/python3.4/site-packages, link will be confused. This
only appears after unlinking and relinking because this symlink is
created in post_install, which runs after the first link.

Fixes Homebrew/linuxbrew#502.

Closes Homebrew/homebrew#42891.

Closes Homebrew/homebrew#42976.

Link the keg that was linked before migration. Don't use
newformula.installed_prefix to detect keg to link, because it can break
things (i.e. if intalled formula is outdated, then
newformula.installed_prefix can be not the same as installed prefix
before update).

Closes Homebrew/homebrew#42857.

Signed-off-by: Xu Cheng <xucheng@me.com>

- link newname only if oldname used to be linked
- optlink newname only if oldname used to be optlinked.

- check if old_opt_record exist before using realpath
- don’t check old_opt_record.exist? in link_old_opt
  because it doesn’t have to exist.

Moves us towards being able to support formulae that install R bindings,
like nonpareil in homebrew-science.

Some discussion in Homebrew/homebrew-science#2559.

Closes Homebrew/homebrew#42539.

Closes Homebrew/homebrew#42940.

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

Closes Homebrew/homebrew#42938.

Closes Homebrew/homebrew#42934.

Signed-off-by: Baptiste Fontaine <batifon@yahoo.fr>

Closes Homebrew/homebrew#42900.

Signed-off-by: Xu Cheng <xucheng@me.com>

Also exclude symlink when enumerating installed racks.

Closes Homebrew/homebrew#42851.

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