Deterministic failure-preserving testcase reduction for MoonBit projects

testing

reducer

delta-debugging

cli

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Author

Ag108

Version

0.2.0

License

Apache-2.0

Last updated

last month

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moonbitlang/async0.20.4

#MoonReduce

A MoonBit testcase reducer and native CLI. It removes irrelevant project files, declarations, statements and tokens in independent copies while preserving a user-defined failure predicate.

中文 · Project mode · Predicates · Library API

#Quick start

Use the pinned MoonBit toolchain and a native C compiler. The native runtime uses moonbitlang/async 0.20.4.

moon update
moon run cmd/main -- reduce --project --config testdata/final/compile_diagnostic/predicate.json --workspace testdata/final/compile_diagnostic/input --output ./compile-result
moon run cmd/main -- replay ./compile-result/report.json

Use a fresh output directory outside the input, with an existing parent. Replay checks SHA-256 and executes uncached final trials in new copies.

moon build --target native --release cmd/main
moon install ./cmd/main --bin ./local-bin
moon run examples/custom_pass --target native

#Features

Single-file and multi-file reduction, protected glob selection and package edits.
Text/token passes and 16 structured families with conservative syntax fallback.
Exit/timeout/output predicates, bounded regex, diagnostic fingerprints, wrappers, differential commands, repeated quorum and inconclusive decisions.
Deterministic candidate batches with configurable workers and strict scoring.
Checkpoints, resume, run-scoped cache, budgets and uncached final verification.
Checksummed evidence bundles, environment summaries, diff and standalone replay.
Pure evaluator/pass/event extension contracts and check/reduce library facade.

Commands: check, reduce, resume, replay, diff, explain, passes, config validate, cache stats and cache clean. Run --help for all options. JSON defaults are validated and overridden by CLI arguments. The twelve examples in examples/ include a runnable custom library extension.

#Verification and boundaries

Run scripts/verify.ps1, scripts/benchmark-final.ps1 and scripts/determinism-final.ps1 from PowerShell. Pure packages support native, JavaScript and wasm-gc; process/workspace/CLI packages require native. See testing, benchmarks, compatibility and the acceptance record.

Only trusted commands/projects are supported. Copies are not a sandbox. The scanner is not a complete MoonBit parser. Snapshot limits are 1000 files/16 MiB, 1 MiB per file and 64 KiB per MoonBit source. Private checkpoints retain explicit environment overrides; ordinary reports omit values. Do not put secrets in argv or share private checkpoints. SHA-256 detects corruption, not a malicious author. See security and limitations.

Apache-2.0. Dependencies and owned fixture provenance are in THIRD_PARTY.md and each fixture's LICENSE.

CandidateEvaluator

source

pub(open) trait CandidateEvaluator {
  fn evaluate(Self, @Ag108/MoonReduce/workspace/manifest.Snapshot
Snapshot) -> Result[@Ag108/MoonReduce/predicate/stability.Decision
Decision, String]
}

Synchronous pure-driver evaluation contract. Each call is one uncached trial. Return Unresolved for inconclusive observations, Err for execution failures.

EventSink

source

pub(open) trait EventSink {
  fn emit(Self, Event) -> Unit
}

Event delivery is synchronous; sinks may record evidence or update a UI.

Event

source

pub(all) struct Event {
  schema_version : Int
  candidate_id : Int
  phase : String
  trial : Int
  decision : @Ag108/MoonReduce/predicate/stability.Decision
Decision
} derive(ToJson)

Immutable versioned observation delivered in deterministic candidate order.

ReduceConfig

source

pub(all) struct ReduceConfig {
  max_tests : Int
  repeat : Int
  quorum : Int
  consecutive : Bool
  final_repeat : Int
  final_quorum : Int
  score : String
  includes : Array[String]
  protects : Array[String]
  ignores : Array[String]
  pass_include : Array[String]
  pass_exclude : Array[String]
  extra_passes : Array[&@Ag108/MoonReduce/passes/api.ReductionPass
ReductionPass]
}

Pure reduction options. Native CLI time/process controls belong to app.Config.

check

source

fn check(original : @Ag108/MoonReduce/workspace/manifest.Snapshot
Snapshot, evaluator : &CandidateEvaluator, config? : ReduceConfig, sink? : &EventSink) -> Result[@Ag108/MoonReduce/predicate/stability.Statistics
Statistics, String]

Validate only the baseline; no pass runs and no original data is changed.

default_config

source

fn default_config() -> ReduceConfig

Defaults match the deterministic project engine: 2 baseline, 3 final trials.

default_passes

source

fn default_passes() -> Array[&@Ag108/MoonReduce/passes/api.ReductionPass
ReductionPass]

Built-in pure passes, in the same order as the native project CLI.

reduce

source

fn reduce(original : @Ag108/MoonReduce/workspace/manifest.Snapshot
Snapshot, evaluator : &CandidateEvaluator, config? : ReduceConfig, sink? : &EventSink) -> Result[@Ag108/MoonReduce/reducer/project.ResultSummary
ResultSummary, String]