Amber 2.0.0-beta.8

Amber 2.0.0-beta.8 compiles on every Crystal version its shard.yml
declares, starting at 1.20.0, and lets an application choose the cache
policy for the static files it serves.

What changed

• Builds on Crystal 1.20 (#1434). Beta.7 did not compile on Crystal
  1.20.x (no parameter named 'writable'), although it declares
  crystal: ">= 1.20.0". Both IO::Memory calls now pass the read-only
  flag positionally, and CI runs the full suite on Crystal 1.20.0 next to
  1.22.1 and crystal-alpha.

• Static files follow the application's cache policy (#1435).
  Amber::Pipe::Static keeps a Cache-Control that an earlier handler
  already set. An application with its own fingerprint scheme overrides
  #cache_control in a subclass; the hook runs only for a file the pipe
  serves:

  class AppStatic < Amber::Pipe::Static
    SHORT_FINGERPRINT = /-[0-9a-f]{8}\.[^\/]+$/i
  
    protected def cache_control(request_path : String) : String
      return IMMUTABLE_CACHE_CONTROL if request_path.matches?(SHORT_FINGERPRINT)
      super
    end
  end

  Asset headers now go on GET and HEAD responses only.

Upgrade

dependencies:
  amber:
    github: amberframework/amber
    version: 2.0.0-beta.8

Then run minecart update amber. An application that re-applied its own
Cache-Control after super in an apply_asset_headers override can move
that policy into #cache_control.

Amber CLI 2.0.8 generates projects on 2.0.0-beta.7; change version: to
2.0.0-beta.8 after amber new.

Release

The tag is v2.0.0-beta.8. The GitHub release for the tag states the tagged
commit hash, its tree hash, and the sha256 of the source tarball attached to
the release (scripts/release_checksums.sh v2.0.0-beta.8 produces all three).
A file cannot carry its own tarball's hash, so they live in the release.

Verify this release

Commit: 1a787cee4490f1252665667e2b31121dd54977e9
Tree: 39e2c8b49d7cb1ec7efa90e9f003dff944894f56
Tarball: amber-2.0.0-beta.8.tar.gz (git archive --format=tar.gz --prefix=amber-2.0.0-beta.8/ 1a787cee4490f1252665667e2b31121dd54977e9)
Tarball sha256: 7d59d318978df678bb73fac2353ea5e6279e8c6f16e506a0fe8339c114361831