`run-task` is taught a --sparse-profile argument to be passed down
to `hg robustcheckout` for the main source checkout. It does what
you expect: performs a sparse checkout using the named profile.
The Taskgraph YAML for run-task is taught a "sparse-profile"
property to define the sparse profile. When defined, --sparse-profile
will be passed down to `run-task` and the cache name will be updated
to reflect the use of sparse checkout.
Our cache checking transform is updated to audit for the use of
--sparse-profile without the corresponding "-sparse" cache name
variation.
The reason we need a distinct cache name for sparse is because
clients that aren't sparse aware will be unable to read checkouts
that are sparse. By forcing sparse and non-sparse into different
cache pools, we avoid compatibility issues.
In the ideal world, we probably support sparse profiles on all the
VCS checkouts that `run-task` supports (e.g. --tools-checkout).
Perfect is the enemy of done. All of this is defined in-tree and
it is easy enough to change atomically.
MozReview-Commit-ID: 79k7Vul0hHO
--HG--
extra : rebase_source : babe9b42e2796c2341bffc6ecfe829f4daff9e0f
22bae15639