In order to allow kegs built with the same version but differing formula
revisions to coexist, we must encode the revision as part of the keg's
name. This is necessary to actually perform an upgrade, as we cannot
upgrade a keg in-place, and temporarily moving it pending the result of
the upgrade is error-prone and potentially slow.
To accomplish this, we introduce a new Formula#pkg_version method that
concatenates the active_spec version with the formula revision. An
exception is made for a formula that has no revision: the tag is
omitted. This preserves compatibility with existing installations.
Declarations of dependencies, options, and resources in the DSL only
apply to specs that have already been initialized. For example, given
this snippet:
url ...
sha1 ...
depends_on 'foo'
devel do
url ...
sha1 ...
end
The dependency 'foo' will be recorded for the stable spec, but not the
devel spec, since it was not initialized prior to the call to
depends_on.
While it is considered best practice to declare all specs (stable,
devel, head, and bottle) prior to other declarations, there is nothing
that enforces this ordering, so when it happens it can be confusing and
hard to debug.
To prevent this, we can initialize all specs up front. This comes with
a performance penalty for commands that load all formulae into memory,
but that is probably outweighed by what we gain in correctness.
FixesHomebrew/homebrew#23425.
Comparing two objects should not raise an exception, even if they have
different types.
The semantics of #== are now the same as #eql?, so make one an alias.
The initializer for Formula does a number of validations, but it does
them in a weird order, and some attributes aren't validated under
certain circumstances. This became even more of a mess when most
software package attributes were moved into the SoftwareSpec class.
This commit removes the last vestiges of storing these attributes as
instance variables. In particular, it eliminates #set_instance_variable
and #validate_variable, replacing them with methods that operate on
SoftwareSpec instances, and generate more useful errors.
Doing these validations unconditionally in the initializer means we bail
out much earlier if the formula has invalid attributes or is not fully
specified, and no longer need to validate in #prefix.
Technically we don't need to validate in #brew either, but we continue
to do so anyway as a safety measure, and because we cannot enforce calls
to super in subclasses.
