- `_expand_virtual_packages` now gets a candidate list and will try
all the candidates.
- Good news: If the first virtual in the list conflicts with something else in
the spec, we'll keep trying until we find a good one.
- Bad news: Only looks as far as the next normalize(); can't see
conflicts further ahead than that if they're inevitable
some other virtual expansion.
- Refactor `concretize.py` to keep all the nasty spec graph stitching in
`spec.py`. This is more similar to before externals support.
- `concretize.py` now just returns a list of candidates sorted by
ABI compatibility to `_expand_virtual_packages`, and `spec.py`
handles testing the candidates.
- Refactor the way external paths are handled in `config.py` and `concretize.py`:
- previously, `spec_externals` returned spec/path pairs. Now it
returns specs with `external` set. Makes code in `concretize.py`
more natural.
- Shouldn't call .package from within things like normalize() and
concretize() beacuse spec may be inconsistent.
- Add `.package_class` property so that we can get at package metadata
without constructing a Package with a Spec.
- should be faster than `.package` was, anyway. Use where possible.
- Move `Spec.__cmp__` out of spec, into concretize as `cmp_specs`.
- `Spec.__cmp__` was never called (except explicitly) due to rich
comparison operators from `key_ordering`
- Refactor `_find_other_spec` to free function `find_spec`. Add a test
for it to make sure it works.
- Had attempted to add more functionality by assigning different
meanign None, True, and False values "keep_stage" (where False was
"always delete").
- Turns out that's not really worth the complexity. Having the third
"always delete" sense is hardly ever useful but makes the code hard
to understand.
- Fix bug introduced during merge of stage refactor.
- install prefix was not created before build_environment.fork()
- build_environment.fork() calls setup_dependent_environment
- python's setup_dependent_environment can inadvertently create
the install prefix before directory_layout expects it.
- Clean up Package.do_install:
- simplify control flow: parent process now entirely responsible for
creating/destroying the install prefix. cleanup is now in one place.
- Hoisting cleanup out of the child improves nesting of try/catch in
`real_work`.
- `real_work` renamed to `build_process`
