## Summary
The basic idea here is that we can (should) reuse a build environment
across resolution (`prepare_metadata_for_build_wheel`) and installation.
This also happens to solve the build-PyTorch-from-source problem, since
we use a consistent build environment between the invocations.
Since `SourceDistributionBuilder` is stateless, we instead store the
builds on `BuildContext`, and we key them by various properties: the
underlying interpreter, the configuration settings, etc. This just
ensures that if we build the same package twice within a process, we
don't accidentally reuse an incompatible build (virtual) environment.
(Note that still drop build environments at the end of the command, and
don't attempt to reuse them across processes.)
Closes#14269.
## Summary
We now persist the `ResolverInstallerOptions` when writing out a tool
receipt. When upgrading, we grab the saved options, and merge with the
command-line arguments and user-level filesystem settings (CLI > receipt
> filesystem).
Charlie Marsh