Each build stages the runtime artifacts it links from the runtime pack and
hashes each one with SHA-256 unless the build cache records that it was
verified with the file identity it still has. A build with an empty cache
therefore hashed every artifact again: on Linux x64, 40 objects and 4.3 MB
for a Benchmarks Game program, about 25 ms of a 300-1100 ms build.
Staging now also reads and writes runtime-pack.verified.json beside the
pack. It lists each verified artifact with its digest and file identity
(device, inode, size, mtime and ctime), as the cache's record does:
- An artifact is trusted only when one of the two records lists it with
the manifest's digest and size and the identity its file has during the
read. Any change to the file means hashing it again.
- A missing, unreadable or malformed record, or a malformed entry, is
treated as absent.
- The record is written to a new file and renamed over the old one, so a
reader sees a whole record. A write merges the record as it is then.
- When the pack directory cannot be written, the cache's record is the only
one, as before.
The runtime pack packages do not publish the file. The native CLI build
removes the record its probe builds leave in the bundled pack, and
verify-native-cli.mjs rejects a distribution that has one.
Chris Tate
c12f2d64f3