An AST cache entry is keyed by its own file's content, so after
pkg/slice.py is renamed or deleted, the unchanged importer pkg/user.py
is a hit and replays its import edges resolved while slice.py existed:
a target id minted from the absolute path and a target_file stamp to
the old file. extract() maps a stamped target to a portable id only
when it exists, so the edge kept the absolute-path id and the #2873
stub was minted with it: graph.json held the checkout folder and OS
username, and a warm update differed from a cold build (pkg_slice).
save_cached now records the target_file stamps that name an existing
file when an AST entry is written (made portable like the entry's
ids). load_cached returns a miss when any recorded file is gone, so
the importer is extracted again exactly as on a cold build. Stamps
that did not exist at write time are not recorded and never cause a
miss; entries without the list load as before.
A no-change warm rebuild of graphify's own repo has the same 16 cache
misses as before, and its cold build is unchanged.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
(cherry picked from commit 48578d04f1)
