The denylist kept the PURL namespace, but the Debian and RPM handlers
build pkg:deb/{name} and pkg:rpm/{name} without a vendor, while Alpine
and Arch build pkg:apk/alpine/{name} and pkg:alpm/arch/{name} with one.
So standard entries such as pkg:deb/debian/curl@... or
pkg:rpm/fedora/curl@..., and pkg:apk/busybox@... or pkg:alpm/glibc@...,
never matched. Drop the namespace of distro types on both sides, as
retention and the inventory already do, using packageurl's list of
those types.
Debian and RPM handlers read versions from filenames, which leave out
the epoch, so an entry such as pkg:deb/foo@1:2.3-1 never matched
foo_2.3-1_amd64.deb. An entry with an epoch now also covers the
version without it.
Denylist entries now also match Composer versions with Packagist's
leading v, OCI repositories written as a path, Swift registry packages
in either form (also when streaming), Go versions with escaped uppercase
letters, and gems whose names contain a dash followed by a digit. OCI
manifests are checked by tag and digest, and denied blobs and Swift
archives answer 403 instead of 500 or 502.
Denylist entries were compared as plain PURL strings, but handlers build
PURLs from download URLs that spell packages differently, so some denied
versions were still served. Entries and checked PURLs now go through one
per-ecosystem comparison form: PyPI names follow PEP 503 (case and runs of
-, _ and . are equivalent), NuGet ids and versions ignore case, a gem
version also matches its platform builds, and a conda entry matches the
package in every channel unless it carries a channel qualifier. Cache keys
are unchanged.
