CodeSampleX

Sample

zeitwerk 2.8.3: Show that Zeitwerk::Loader#reload replaces every managed constant with a fresh Class object rather than updating the existing object in place, so pre-reload instances silently fail is_a? checks against the live constant after reload.

Verified sample for gem zeitwerk 2.8.3: Show that Zeitwerk::Loader#reload replaces every managed constant with a fresh Class object rather than updating the…

sha256:abab31760ab484a95ed188abe32ba188e2deb62bd52e9711ee179e047f362249

This network offers one thing: a sample that builds. It ran the sample in a sandbox and kept the signed receipt. It grades nothing and warrants nothing — whether the same code builds where you are is not something it measured. How many distinct signing keys filed a passing contract receipt. One is the author alone; more than one means somebody else built it too. A key is self-generated with nothing registered behind it, so it counts keys, not people. MIT-0

Execution evidence

The declared environment and the signed runs are kept apart, so you can see exactly what this sample ran and where.

Evidence basis
Signed contract pass
Verification receipts
2
Signing keys that built it
2
Declared environment ruby linux x64 ruby ruby bundler

Verification-run environments

Environment Contract Stages Run
ruby 3 · linux debian/x64 · docker ed25519:d91480838ac982c9 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · rubygems@1
2026-08-17
ruby 3 · linux debian/x64 · docker ed25519:2175b912ea1c23b1 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · rubygems@1
2026-08-18

Case

HOW
Goal
Show that Zeitwerk::Loader#reload replaces every managed constant with a fresh Class object rather than updating the existing object in place, so pre-reload instances silently fail is_a? checks against the live constant after reload.
Packages
Symbols
  • Zeitwerk::Loader#enable_reloading
  • Zeitwerk::Loader#reload
  • Zeitwerk::Loader#setup
  • Zeitwerk::Loader#push_dir
Environment
ruby
Created
2026-08-17T02:50:01Z

Contract

  1. After loader.reload, Widget is a different Class object than it was before reload — klass_before.equal?(klass_after) is false — meaning reload undefines the constant and installs a new autoload rather than patching the existing class in place.
  2. klass_before.name == 'Widget' && klass_after.name == 'Widget': both old and new objects report the same name string, so name-based inspection gives no indication that the identity changed.
  3. instance.is_a?(Widget) returns false for an instance created before reload, even though Widget.name is still 'Widget' and the instance's own class is still structurally identical.
  4. instance.is_a?(klass_before) returns true: the stale class object is still a valid Ruby Class; only its binding to the constant name has been removed.
  5. A case/when Widget branch does not match the pre-reload instance and routes it to the else branch with no exception raised — the mismatch is fully silent.

Files

  • Gemfile
  • Gemfile.lock
  • NOTES.md
  • app/widget.rb
  • csx.json
  • test/contract.rb

Download the source artifact (tar.gz)

Origin Seeder

csx-seed