A version's integrity is a single value shared by every archive cached
for it, but a dev branch caches one archive per commit. Recording the
listed head's shasum made a cache hit for an older pinned commit fail its
check, so its archive was discarded and fetched again, which cleared the
head's recorded shasum in turn. The listed shasum only ever describes the
current head, and Composer checks dist.shasum itself.
- Skip the shasum for dev versions
- Test a pinned commit, then the head, then both again from the cache
npm versions published before dist.integrity existed carry only a SHA-1
dist.shasum, and Composer metadata lists only a SHA-1 dist.shasum, so
neither could be checked.
- Accept native integrity given as an algorithm-prefixed hex checksum,
verified with integrity's exact-digest check, so a recorded "sha1-<hex>"
is also checked on cache hits
- npm: fall back to dist.shasum when dist.integrity is missing or cannot
be parsed; a usable dist.integrity still takes precedence
- Composer: verify an archive against its dist.shasum, except another
commit of a branch fetched in place of the listed one, which the listed
shasum does not describe
- Fetch unverified as before when no shasum is listed, as Packagist does
for GitHub archives, or it is not a SHA-1 digest
