Misc #22275: Ruby::Box support plan for RubyGems and Bundler

• Status: Open
• Assignee: -

[hsbt (Hiroshi SHIBATA)]

This is a tracking issue for making RubyGems and Bundler work with Ruby::Box, so that reviewers can see the whole picture and what to look at next in one place.

Goal

The goal is to realize Feature #13847 with Ruby::Box: loading a specific version of a gem, including default gems and C extensions, isolated from the copy that RubyGems/Bundler themselves use. Vendoring with namespace rewriting has been our workaround for pure-Ruby gems for years; Box removes that limitation.

As a further step, we want RubyGems/Bundler to activate different gem versions per box, which enables the use cases already proposed around Box: gradual dependency upgrades, plugin systems with conflicting dependencies, and multiple applications in one process.

First milestone

Before designing such APIs, Box needs to leave experimental status. Our first milestone is that Rails and RubyGems/Bundler themselves work under RUBY_BOX=1, and that the ruby/rubygems repository runs its test suites with Box enabled continuously so we do not regress.

Current status

Both suites now run under RUBY_BOX=1 with the pull requests below applied. The rubygems suite is at 0 failures (ruby/rubygems#9826, open). The bundler suite runs 3957 examples with box and non-box at parity; the single remaining failure is an unrelated upstream problem in a Rust extension test. Pending marks reference the unfixed core bugs below.

Fixed

ruby/ruby

• ruby/ruby#18218 / ruby/ruby#18219 — BUNDLER_SETUP was consumed outside the main box (Bug #22123). Shipped in 4.0.7.
• ruby/ruby#18509 — box-local extension DLLs on Windows were unloaded too early; now deferred.
• ruby/ruby#18534 — autoload-triggered require bypassed the box's Kernel#require (Bug #21830). This alone took Rails from 500 on every request to fully working.
• ruby/ruby#18535 — with --disable=gems, modules prepended to Kernel in a user box ended up behind Kernel in the ancestry (Bug #22270).
• ruby/ruby#18536 — the box extension copy embedded the full path in the temporary filename, exceeding NAME_MAX on deep paths, and the name was predictable (Bug #22110, Bug #22271).
• ruby/ruby#18578 — the process-private directory added by the previous fix did not survive fork; a forked child removed it at exit (Bug #22271).

ruby/rubygems

• ruby/rubygems#9809 — Bundler evaluated gemspecs through TOPLEVEL_BINDING, which always belongs to the main box. It now uses a binding in the box Bundler is loaded in, so gemspecs resolve the right Gem::Specification.
• ruby/rubygems#9810 — the gem CLI died under RUBY_BOX=1. Marshal-based deep copies could not resolve Gem:: constants across boxes and were replaced with a plain deep dup, and RUBY_BOX is now stripped from extension build subprocesses, where mkmf have_devel? recurses until SystemStackError (Bug #22283). Includes a CLI canary test that runs under RUBY_BOX=1.

Open pull requests

All review-requested to @tagomoris (Satoshi Tagomori):

• ruby/ruby#18546 — Symbol#to_proc ignores box-local method definitions (Bug #22015, revives ruby/ruby#16865). This alone unblocks Bundler's spec harness, which dies in rspec-core's &:shellsplit before running a single spec.
• ruby/ruby#18544 — Marshal.load resolves classes in the root box (Bug #22090); an in-process round-trip of Gem::Version fails today.
• ruby/ruby#18575 — box resolution crashes on an IFUNC frame (Bug #21977).
• ruby/ruby#18574 — reassigning $stdout/$stderr is invisible to builtin writers (Bug #21867), which breaks output-capturing test helpers everywhere.
• ruby/ruby#18577 — $? is uninitialized after Kernel#system and IO.popen (Bug #22280).
• ruby/ruby#18579 — assignments to $VERBOSE and $DEBUG have no effect (Bug #22282).
• ruby/ruby#18586 — defined? does not see global variables assigned in a box (Bug #22283). This is why mkmf have_devel? never memoizes and recurses until the stack is exhausted, which is the "stack level too deep in extconf.rb" entry under Known issues in doc/language/box.md.

Remaining problems without a fix

• ruby -r<gem> and RUBYOPT=-r<gem> do not activate gems under Box. require_libraries_in_main_box() calls rb_require_string() directly, bypassing the RubyGems Kernel#require override. The closest existing report is item 3 of Bug #21760.
• Stubbing a core class does not reach code already loaded in the root box, so existing test suites change behaviour under Box without failing loudly. allow(File).to receive(:expand_path) in the main box leaves Pathname#expand_path calling the real method, and the suite then takes a different path than it does without Box. We hit this in the Bundler suite and scoped the stub as a workaround, but existing test code cannot be expected to know the rule. If this is intended box semantics, it should at least be documented as a known limitation, because rspec-mocks style stubbing of core classes is everywhere.

Critical path

The most critical items are ruby/ruby#18546, ruby/ruby#18544 and ruby/ruby#18575. The first gates Bundler's entire spec suite, the second makes the artifice-based install specs fail wholesale, and without the third the suite dies with [BUG] and the dead workers cascade into unrelated failures. With those three the bundler suite runs end to end and the rest can be marked pending. ruby/ruby#18574 and ruby/ruby#18577 then let us drop most of the pending marks.

[hsbt (Hiroshi SHIBATA)]

• Description updated (diff)

[hsbt (Hiroshi SHIBATA)]

• Related to Feature #13847: Gem activated problem for default gems added

[hsbt (Hiroshi SHIBATA)]

• Related to Bug #22123: Ruby::Box + `BUNDLER_SETUP` can evaluate gemspecs before main-box RubyGems initialization added

[hsbt (Hiroshi SHIBATA)]

• Related to Bug #21830: Ruby::Box and Kernel#require added

[hsbt (Hiroshi SHIBATA)]

• Related to Bug #22015: Success without RUBY_BOX=1, Failure with RUBY_BOX=1 added

[hsbt (Hiroshi SHIBATA)]

• Related to Bug #22090: Enabling Ruby::Box breaks Marshal.load added

[hsbt (Hiroshi SHIBATA)]

• Related to Bug #22110: Ruby::Box C-extension loading can be denied by predictable temporary filename added

[hsbt (Hiroshi SHIBATA)]

• Related to Bug #21867: enabling Ruby::Box changes puts/warn to no longer use $stdout/$stderr added

[hsbt (Hiroshi SHIBATA)]

• Related to Bug #22271: Ruby::Box fails to load C extensions from deep paths (temporary file name exceeds NAME_MAX) added

[Eregon (Benoit Daloze)]

(for some reason this didn't get sent to the ruby-core mailing list. Other recent Misc tickets didn't have the issue, so unclear what happened)

[hsbt (Hiroshi SHIBATA)]

• Description updated (diff)

[hsbt (Hiroshi SHIBATA)]

Status update. ruby/ruby#18534, ruby/ruby#18535, ruby/ruby#18536 and ruby/ruby#18578 have been merged since this issue was filed, and three more core bugs were found and reported along the way (Bug #22271, Bug #22280, Bug #22282).

The Bundler spec suite now runs under RUBY_BOX=1 at parity with a non-box run: 3957 examples, with the same single failure in both modes, which is an unrelated upstream problem in a Rust extension test. The rubygems suite stays at 0 failures. Six core pull requests are waiting for review, and ruby/ruby#18546, ruby/ruby#18544 and ruby/ruby#18575 are the ones that gate the suite.

The next milestone is to land those three, add a RUBY_BOX=1 lane to the ruby/rubygems CI so we stop regressing, and drop the pending marks as the rest land. After that we can discuss what is left before Box can lose the experimental label.

[hsbt (Hiroshi SHIBATA)]

• Related to Bug #22282: $VERBOSE and $DEBUG assignments have no effect under RUBY_BOX=1 added

[hsbt (Hiroshi SHIBATA)]

• Related to Bug #21977: Ruby::Box crash with `RUBY_BOX=1` via `Binding` refinement, `UnboundMethod#bind_call`, and `Symbol#to_proc` added

[hsbt (Hiroshi SHIBATA)]

• Related to Bug #22280: Ruby::Box breaks $? after Kernel#system / IO.popen added

[hsbt (Hiroshi SHIBATA)]

• Related to Bug #21760: Ruby::Box: a couple of require-related problems added

[hsbt (Hiroshi SHIBATA)]

• Description updated (diff)

[hsbt (Hiroshi SHIBATA)]

• Related to Bug #22283: `defined?` does not see global variables assigned in a box added