#527: remove global caching for fb/github_graph, inject octo into over?

[VasilevNStas]

This is a new PR replacing the closed #535. The approach was changed after @yegor256 rejected GLOBAL_MUTEX ("global state is pure evil in OOP").

Problem

lib/fbe/octo.rb:53, lib/fbe/fb.rb:34, lib/fbe/github_graph.rb:18 use global[:x] ||= begin...end — a non-atomic read-then-write. Under concurrent access (e.g., multiple judges running in parallel), two threads can both evaluate the block and overwrite each other's result.

Solution

Changes made:

1. lib/fbe/fb.rb — removed global[:fb] ||=. Each call to Fbe.fb() creates a fresh decorator stack. Thread-safe by definition, no global state.

2. lib/fbe/github_graph.rb — removed global[:github_graph] ||=. Same approach — each call creates a new GraphQL client.

3. lib/fbe/octo.rb — kept global[:octo] ||=. Without caching, rate limit tracking breaks: Fbe::Middleware::RateLimit stores state per middleware instance. Different clients don't share request history, so off_quota? always returns false on a fresh client.

4. lib/fbe/over.rb — added optional octo: parameter. When provided, uses it for off_quota? check; otherwise falls back to Fbe.octo() (backward compatibility).

5. lib/fbe/iterate.rb — passes octo: oct (its internal client) to all Fbe.over? calls. Proper OOP: dependency injection instead of global cache.

6. lib/fbe/unmask_repos.rb — creates octo before the first Fbe.over? call and passes it via octo:.

Why not remove caching from octo.rb entirely?

Fbe::Middleware::RateLimit is a Faraday middleware living inside each Octokit client's Faraday stack. It tracks @remaining (requests left before hitting rate limit) and decrements it on each request. If every Fbe.octo call creates a new client with fresh middleware, rate limit tracking stops working — off_quota? always sees a fresh /rate_limit response.

The clean OOP fix would be full DI (create the client once and pass it everywhere), but that requires changing the judge API. Our compromise: octo.rb remains a cached factory, while all internal callers (iterate, unmask_repos, over?) accept and pass octo: explicitly.

Tests

• 283 tests pass, 0 failures, 0 errors
• RuboCop — 0 offenses
• Code coverage: 94%

[VasilevNStas]

@yegor256 please re-review

[VasilevNStas]

The xcop CI failure is a Docker Hub connectivity issue (i/o timeout pulling ruby:3.0 from docker.io), not related to this PR. The rake jobs (macos-15 + ubuntu-24.04, Ruby 3.3) pass successfully. Could someone with admin rights re-run the failed job?

[bibonix]

The branch sits on top of 8e52719, 17 commits behind master, and the resulting diff folds in unrelated history rather than only the #527 change. Concretely, the diff shows lib/fbe/fake_octokit.rb being removed (1797 lines) and re-inlined into lib/fbe/octo.rb (~1791 additions), because fake_octokit was extracted on master in #534 after this branch forked off. The same staleness pulls test deletions in test_delete.rb, test_delete_one.rb, test_overwrite.rb, test_just_one.rb, test_kill_if.rb, test_repeatedly.rb, test_sec.rb, test_unmask_repos.rb, test_octo.rb, and test_sqlite_store.rb that revert improvements already landed in #503, #517, #521, #531, #532, #533, #534, #541, #543, #545, and #548, plus README, .gitignore, .github/workflows/actionlint.yml, and .github/workflows/codecov.yml changes that have nothing to do with #527. xcop is red on the current head. Rebase onto current master and drop everything outside lib/fbe/fb.rb, lib/fbe/github_graph.rb, lib/fbe/octo.rb, lib/fbe/over.rb, lib/fbe/iterate.rb, lib/fbe/unmask_repos.rb, then resubmit. No inline comments yet because the rebase will rewrite the diff.

[VasilevNStas]

Rebased onto current master per review. Diff now contains only the 6 relevant files for #527. RuboCop — 0 offenses, 338 tests — 0 failures.

@bibonix @yegor256 please re-review

[yegor256]

@VasilevNStas again, a wrong move. we do need caching and we do need mutex. I suggest keeping mutex inside the global hash

[yegor256]

@VasilevNStas merge conflicts here

[yegor256]

Please fix the merge conflicts so this pull request can be merged.