Concurrency conformance: eager, shareable themes and configuration; canary + audit + probes #42

Child of EPIC_REF (concurrency conformance across the zoolutions gems). Depends on conformance-kit (Phase 0 of the epic).

Problem / Goal

phlex-forms keeps its component maps and configuration in lazy class ivars — Theme.@daisy ||= / @plain ||= (lib/phlex_forms/theme.rb:56,74), PhlexForms.@configuration ||= (lib/phlex_forms.rb:42-56), Configuration lazies incl. an icon_renderer lambda (configuration.rb:50,58,68) — idempotent races today, unreadable from a non-main Ractor. Goal: Tier 1–2 gates green; PhlexForms.finalize! builds both themes and the configuration eagerly and Ractor.make_shareables them (the icon_renderer default becomes a method object / Ractor.shareable_lambda on 4.0, a capture-free lambda below); the kit's canary runs field inference (Forms::Field option resolution from a literal model-like Struct) inside a non-main Ractor on Ruby 4.0; rendering stays pending on yippee-fun/phlex#1055 (per-Ractor attribute cache; tag() registries are a further follow-up); audit passes; probes report-only. Floor 3.4 (store_if_absent available; still reach it through the kit shim for uniformity). Add a 4.0 lane (matrix is ["3.4"]).

Context

• lib/phlex_forms.rb:42-56,65-95 (configuration memo, reset_configuration!, manual Zeitwerk loader, require "phlex/reactive" rescue), lib/phlex_forms/theme.rb:56,74 + reactive_roles (defined?(Phlex::Reactive) probe), lib/phlex_forms/configuration.rb:50,58,68, lib/forms/base.rb:24-40 (form_options class ivars, class-body time), lib/phlex_forms/inline_icons.rb:14-16 (frozen SVG constants — already shareable), lib/phlex_forms/engine.rb:31.
• Labels: core, theme, devops.

Decision

Finalize-at-boot (engine after_initialize, or end of configure when Rails is absent); themes become frozen, shareable Hashes of classes; configuration frozen; reset_configuration! stays for tests. The daisyui/phlex-reactive defined? probes are evaluated once at finalize.

Steps (TDD)

1. Kit dev dep + rubocop inherit. 2. spec/phlex_forms/finalize_spec.rb ("a boot-finalized configuration" over Theme.daisy, Theme.plain, every Configuration reader) RED → GREEN. 3. spec/phlex_forms/contention_spec.rb (thread + Async examples over Theme.component_for). 4. spec/phlex_forms/ractor_canary_spec.rb (:ractor; pending render canary with the Phlex reason). 5. .conformance.yml (Forms::Base class-body ivars → main_only). 6. CI callers + 4.0 lane; CHANGELOG.

Gates

bundle exec rspec green (3.4/4.0; --tag ractor on 4.0); rubocop clean; conformance-audit --strict 0; probes artifact.

Out of scope

Rendering in a Ractor (Phlex upstream); the validation→Stimulus client bridge.

Execution

/lfg <this issue> after the kit exists.

Update 2026-10-14: conformance-kit 0.1.0 is on RubyGems; the Gemfile reference (gem "conformance-kit", "~> 0.1", require: false, plus require "conformance_kit/rspec" where RSpec is used) is in #43 (open until the branch ruleset's CodeQL requirement is sorted). Start from the remaining steps.

Update 2026-10-14 (conformance-kit 0.2.0, zoolutions/conformance-kit#6): this supersedes the CI step above ("call the kit's ractor.yml + probes.yml" / "CI callers"). 0.2 removed those workflows: one zoolutions org ruleset now requires the kit's conformance.yml on every repo whose conformance property is enforced, and this repo is flipped once this issue closes clean. Instead:

• Write .conformance.yml 0.2: audit.require (must eager-load the gem), audit.namespace, audit.strict_autoloads: true, ractor.test_command, probes.gem_name.
• Bump to gem "conformance-kit", "~> 0.2" (plus gem "rubocop-thread_safety", ">= 0.8", and inherit_gem: { conformance-kit: config/rubocop.yml } in .rubocop.yml; conformance-kit doctor checks all three).
• bundle exec conformance-kit check green on Ruby 4.0.
• Do not add caller jobs.

Update 2026-10-15 (supersedes the 2026-10-14 conformance-kit 0.2.0 note above; zoolutions/conformance-kit#10): there will be no org ruleset. Each repo calls the kit's workflow itself, so this replaces "Do not add caller jobs". Once conformance-kit v0.3.0 is released:

• Add .github/workflows/conformance.yml with the caller from the kit README's Enforcement section: uses: zoolutions/conformance-kit/.github/workflows/conformance.yml@v0.3.0 on pull_request + merge_group, permissions: contents: read.
• Bump to gem "conformance-kit", "~> 0.3". The workflow's version check fails while the lockfile resolves anything older than the caller's tag.
• Add .github/dependabot.yml with the github-actions and bundler ecosystems, as in the kit README's "Staying current", so both pins keep moving.
• Once bundle exec conformance-kit check is green on Ruby 4.0, add conformance / Conformance settings and conformance / Conformance (Ruby 4.0) to this repo's branch ruleset as required status checks.
• The rest of the 0.2 note still applies: the .conformance.yml 0.2 keys, rubocop-thread_safety >= 0.8, inherit_gem, and the repo-specific line.