Skip to content

Onion Practical-Quality Bar

"Practical quality" is intentionally vague, so this file pins it to a set of objectively measurable indicators. Each row has a measurement you can run and a threshold; the language has reached the bar when every row passes.

Baseline figures are the ground-truth values as of 2026-07-26 (develop @ c2126299), re-measured rather than carried forward — the previous baseline (2026-07-26 @ 871fe5a1) had already drifted after the effect-table / tool-capability / tool-contracts work (#356,

357, #358) landed: it recorded 2590 tests against an actual 2644, 14/14 guides against

15/15 (docs/guide/tools.md shipped with #357), and 77 diagnostic codes against 80 (E0077–E0079 added by the capability boundary).

# Dimension How to measure Current (2026-08-13) Pass threshold
1 Test suite sbt -batch -Duser.language=en test 3410 pass / 0 fail / 1 cancelled 0 failed, 0 skipped
2 Sample health SampleCompilesSpec / SampleProgramsSpec (both compile every run/*.on) 169 / 169 compile all compile, no rot
3 Large programs count of run/*.on ≥ 100 lines that run end-to-end as-is 112 (AccessLogAnalyzer, AirlineReservation, AuctionHouse, Automaton, BankLedger, BankSystem, Blackjack, BookClub, BrokenLogDemo, BudgetTracker, BugTracker, CarRentalFleet, CensusAnalyzer, ChemCalculator, CinemaBooking, CipherSuite, ClinicRecords, CodeContest, ConferenceSchedule, ConwayLife, CourseRegistration, CryptoPortfolio, DependencyResolver, DnaAnalyzer, DoctorScheduler, ElevatorDispatcher, EmployeeManager, EspressoShop, EventTicketing, ExpenseAuditor, FitnessTracker, FleetManager, GameOfLife, GameStore, GenericLeaderboard, GeneticSequencer, GradeBook, GradeReport, GraphAlgorithms, GraphSearch, HospitalWard, HotelReservation, HRSystem, HuffmanCoding, InsuranceClaims, Inventory, InventoryManager, InventoryReport, JobScheduler, KaraokeNight, KingdomSim, LibraryCatalog, LibrarySystem, LogAnalytics, MarkdownConverter, MathParser, MatrixCalc, MazeSolver, MiniRpg, MiniTypeChecker, MovieRecommender, MuseumCollection, MusicFestival, MusicLibrary, NationalParkTracker, NetworkMonitor, NutritionTracker, OrderReport, ParkingGarage, PayrollReport, PerfReview, PetShelter, PharmacySystem, PlantCare, PlaylistManager, PokerHands, PropertyManager, RankedChoice, RecipeBook, RecipeManager, RecipeVault, RestaurantOrders, RuleEngine, ShapeProcessor, ShipmentTracker, ShoppingCart, SnippetLibrary, SocialNetwork, SortAlgorithms, SortingShowcase, SpaceMission, SpellCheck, SprintPlanner, StatsApp, StockPortfolio, StudentGradeBook, Sudoku, SudokuSolver, SupplyChain, TaskPlanner, TextAnalytics, TextAnalyzer, TicTacToe, TimesheetTracker, TodoManager, ToolDemo, TournamentStandings, TournamentTracker, TransitPlanner, VirtualMachine, VirtualShell, WeatherReport) ≥ 5
4 Feature coverage checklist below demonstrated inside the large samples complete every item ✓
5 Known usability bugs implemented-but-unreachable / broken features still open 0 0
6 Docs parity docs/guide vs docs/ja/guide count + every code block compiles 15 / 15 parity + all blocks verified
7 Diagnostics distinct E00xx codes with EN+JA messages 84 every common error has a dedicated code

Do not set SBT_OPTS to a heap below the project default. .jvmopts pins the default to -Xmx10g (raised from 4g as the run/ sample corpus grew — see CHANGELOG 0.10.18). Any SBT_OPTS heap lower than that — -Xmx2g was one previous bad recommendation, -Xmx4G is another one seen in the wild — lowers the effective heap below what the full suite needs and makes it die with an OutOfMemoryError partway through (see #691). If you need to override SBT_OPTS for another flag, keep the heap at -Xmx10G or higher.

-Duser.language=en matters: error messages are bilingual and resolved from the JVM default locale, so a test asserting on message text passes in a Japanese locale and fails in release CI, which runs in English. Assert on error codes, not localized text.

The one cancelled test is the distribution smoke test, gated behind -Donion.dist.path.

Practical quality is reached when rows 1–7 all pass. This turns the open-ended goal "reach practical quality" into a checkable state.

Row 4 — feature coverage checklist

A feature counts as covered once it runs inside at least one large sample (run/), not just a micro-test:

  • records (plain) and data-carrying enums
  • plain enums
  • classes with constructors and methods
  • interfaces + polymorphic dispatch (ExprEval)
  • top-level def with block and expression bodies
  • recursion (incl. tail position)
  • collection pipelines: map / filter / fold / reduce / sortedBy / groupBy / find / distinct / partition / zip / flatten
  • select / pattern matching
  • if / else if expressions
  • while, foreach over ranges and over Map (k, v)
  • nullable types with null checks
  • closures stored in vals
  • string interpolation #{}
  • try / catch
  • generics used non-trivially in a large sample (StatsApp — SafeBox[T], Pair[A,B], generic countMatches)
  • extension methods used in a large sample (StatsApp, ShapeProcessor, TextAnalyzer, TodoManager)

Row 5 — currently open usability bugs (tracked)

None open.

Previously tracked and resolved:

  1. Primitive-type extensions — fixed. extension Int { def double(): Int = self * 2 } and (5).double() now work. Extension methods on primitive receivers are registered under the boxed class name and the call target is unboxed before invoking the backing static method.
  2. Top-level function called from a class method — fixed. Top-level val/var and functions are emitted as static members of the synthetic top-level class, and bare identifiers / unqualified calls in class methods fall back to these static members.
  3. Constant narrowing does not reach constructor arguments. val b: Byte = 100 narrows, but new R(..., -3) against a Short component was E0021 ("constructor applicable for R(..., Int) is not found") and needed (-3 as Short). Fixed for constructors (#374); the same gap in ordinary method/function overload resolution (takesShort(-3) against a Short parameter, reported as E0005) was found and fixed alongside it — both now share the ConstantNarrowing helper.