Installers have cloned with --filter=tree:0 since c3e9ac87a7. A treeless
clone keeps commits only, and git requests a missing tree without telling
the server which trees it already has, so every checkout and every
path-filtered history walk re-downloads complete directory snapshots
(~0.58 MB per commit for this repo). GitHub's own guidance is that
treeless clones are for throwaway CI builds, not long-lived checkouts;
the blobless layout keeps every commit and tree local and fetches only
file contents on demand.
- install.sh / install.ps1 clone --filter=blob:none (same release tags,
--commit pins and ancestor checks the treeless switch was made for).
- hermes update (post-update step) converts an existing tree:0 checkout once with
`git fetch --refetch --filter=blob:none origin` (~120 MB, ~8 s
from GitHub) and records the new filter only after it succeeds, so a
failed refetch retries next update.
- The shallow-heal conversion unshallows as blob:none instead of tree:0.
- checkout_contains asks git with GIT_NO_LAZY_FETCH: a recorded SHA the
checkout lacks is "not contained", never a download of that commit's
whole history.
1d9bb51f6b