Lobsters conformance

Upstream lobsters' own RSpec suite, run against a Roundhouse emit of the same checkout. Most failures name a Rails construct not yet modeled; some are answers that came out wrong, and a few are this harness's own gaps. That makes their tests the worklist generator — so the ranked causes below, not the pass count, are what this page is for.

lobsters 2f385d149e67 · roundhouse 85ce611a88ea · 2026-08-21T07:02:54Z
116/354 examples pass25 of 104 spec filesemit 764 files, 0 errors
116 passing · 238 failing · 1 error(s) outside examples
What this measures. Not whether Roundhouse compiles lobsters — the Ruby target is gap-tolerant and answers that with a zero whether or not the output behaves. Their suite asserts behavior example by example, so a failure here names a construct that was emitted but is wrong or missing. The emit is produced fresh from the same checkout the specs come from, and runs on Ruby 4.0.0, the version their .ruby-version pins.

Current lobsters, not a snapshot. This tracks whatever upstream HEAD is and records its SHA; it deliberately does not pin. A benchmark must freeze its input or its numbers stop being comparable — but this answers a present-tense question, and pinning it would only manufacture a second fossil beside the ruby-bench capture the benchmark page measures.

Each run stands alone. There is no history here and no comparison to previous runs: numbers move when their code moves as well as when ours does, so a delta would attribute upstream's changes to us.

Scope

25 of 104 spec files in their suite are run here — spec/models. Request, feature, mailbox and routing specs are not run. Model specs exercise the compiler surface most densely; the request tier is next, and the capybara/mailbox tier is ledgered rather than attempted.

Todos, by failures blocked

Occurrences churn; causes are the unit of work, so each carries a stable slug you can still refer to after another forty upstream commits. Owner says who can act: most of this is Roundhouse's own modeling debt.

Counts are how many examples are currently stopped by each cause, not how many will pass when it lands: an example is attributed to the first exception it raised, so clearing one cause can reveal another behind it.

BlockedCauseOwner
16
Ran, answered wrong
expectation-mismatch
roundhouse
No exception — the emitted code executed and produced a different answer than Rails does. Each needs individual diagnosis; they cluster by message no better than by coin flip, so this bucket is a count, not a cause. Keep it visible: it is where correctness bugs hide once the crash-shaped failures clear.
5 of 16 examples
  • Category validations does not allow a category with a name too long to be saved
  • Comment extracts links from markdown
  • Comment.accessible_to_user when user is a moderator
  • Comment.accessible_to_user when user does not a moderator
  • Domain origin inserts start-and-end-of-line anchors to
15
Symbol used where an Integer index is expected
symbol-into-integer
roundhouse
Undiagnosed. Shape suggests a Hash emitted as an Array (or a symbol-keyed read lowered to an index) — needs a reduction before it can be ranked honestly.
5 of 15 examples
  • Comment hat can't be worn if user doesn't have that hat
  • Domain origin is invalid for invalid regexp
  • InvitationRequest has a limit on the email field
  • InvitationRequest has a limit on the memo field
  • InvitationRequest has a limit on the name field
2
errors is an Array, not an ActiveModel::Errors
errors-object-api
roundhouse
The runtime errors collection is Array[String]; attribute identity is lost at push, so errors[:attr] and errors.messages have nothing to answer with.
2 examples
  • Moderation validates the length of action
  • Moderation validates the length of reason
1
Nested constant not emitted
nested-constant-missing
roundhouse
Constants nested inside a model class (Hat::Mail, Notification::Notifiable) are dropped rather than emitted alongside the class.
1 example
  • Hat santizes email addresses
204
Not yet triaged
unclassified
untriaged
No rule in bench/lobsters/spec-causes.json matches these. Triage, then add a rule.
10 of 204 examples
  • Category logs modification in moderation log logs on create
    NoMethodError: undefined method 'username_changed?' for an instance of User
  • Category logs modification in moderation log logs on update
    NoMethodError: undefined method 'username_changed?' for an instance of User
  • Comment should get a short id
    NoMethodError: undefined method 'username_changed?' for an instance of User
  • Comment links to users during and after creation
    NoMethodError: undefined method 'username_changed?' for an instance of User
  • Comment subtracts karma if mod intervenes
    NoMethodError: undefined method 'username_changed?' for an instance of User
  • Comment hat can be one of the user's hats
    NoMethodError: undefined method 'username_changed?' for an instance of User
  • Comment hat logs hat use on new comment
    NoMethodError: undefined method 'username_changed?' for an instance of User
  • Comment hat logs hat use on edited comment that adds it
    NoMethodError: undefined method 'username_changed?' for an instance of User
  • Comment hat doesn't relog hat use on edit that doesn't change hat
    NoMethodError: undefined method 'username_changed?' for an instance of User
  • Comment speed limit is not enforced as a regular validation
    NoMethodError: undefined method 'username_changed?' for an instance of User

Rules matching nothing this run — either cleared, or the failure's message changed and is now counted as untriaged: harness-time-helpers, relation-pick, model-class-first, update-attribute, apppath-concat, kernel-bigdecimal, nil-arith-coercion, dirty-saved-change-alias, has-attribute-predicate, scope-not-on-relation, binary-column-text-escape, searchparser-parslet-dsl, keystore-upsert.

By spec file

FileExamplesPassFail
spec/models/story_spec.rb76472
spec/models/search_spec.rb33033
spec/models/user_spec.rb22022
spec/models/domain_spec.rb20119
spec/models/comment_spec.rb24618
spec/models/notification_spec.rb16016
spec/models/link_spec.rb14014
spec/models/vote_spec.rb13013
spec/models/invitation_request_spec.rb624
spec/models/message_spec.rb404
spec/models/mod_note_spec.rb404
spec/models/category_spec.rb633
spec/models/invitation_spec.rb413
spec/models/moderation_spec.rb303
spec/models/tag_spec.rb1073
spec/models/story_image_spec.rb202
spec/models/comment_stat_spec.rb101
spec/models/hat_spec.rb541
spec/models/mod_mail_spec.rb101
spec/models/story_text_spec.rb101
spec/models/username_spec.rb101
spec/models/hat_request_spec.rb330
spec/models/keystore_spec.rb440
spec/models/mastodon_app_spec.rb330
spec/models/search_parser_spec.rb78780

What the harness compensates for

The shim that boots the emit in place of Rails does these things on the emit's behalf. Listed because a pass rate achieved by propping up the subject is not a pass rate about the subject.

CompensationKindWhy
require "net/http" in the shimemit gapapp/models/sponge.rb references Net:: constants but the emit never requires net/http.
Numeric duration builders in the shimby designSpecs and factories are untranspiled plain Ruby; the emit path rewrites n.days at transpile time, so the shared runtime never reopens Numeric.

Errors outside examples

A spec file or hook that failed to run at all. These are not counted as failures above, so the denominator understates by however many examples they would have contributed.

An error occurred in an `after(:context)` hook.
Failure/Error: @comments.each(&:destroy!)

NoMethodError:
  undefined method 'each' for nil
# /home/rubys/lobsters/spec/models/search_spec.rb:60:in 'block (2 levels) in <top (required)>'

Emit diagnostics

From the transpile that produced the tree under test: 764 files, 0 errors, 3,020 warnings. Warnings are a modeling-debt ledger rather than a failure — the Ruby target emits through its gaps — so they are not comparable to the spec failures above.

DiagnosticCount
gradual_untyped1,397
unresolved_type770
lower_residue492
unsupported240
send_dispatch_failed66
ivar_unresolved29
incompatible_binop12
missing_preload12
blank_unlowered2
Artifact: summary.json — every number on this page comes from it.