Changelog

Copy Markdown View Source

All notable changes to this project are documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

Unreleased

0.1.2 - 2026-09-07

Fixed

  • The kept sandbox preserves empty directories. The incremental materialisation that the default kept sandbox uses mirrored files and symlinks only, so a directory with nothing in it never reached the sandbox — and a shallow git checkout under deps/ keeps .git/refs/heads and .git/refs/tags empty. git then no longer recognised the checkout and Mix reported every git dependency as a lock mismatch before the metamutant could compile; a freshly generated Phoenix 1.8 app (heroicons, daisyui) could not run Mutare at all.
  • Rendering no longer consults the target project's .formatter.exs. Sourceror reads locals_without_parens from it through Mix.Tasks.Format on every render — evaluating its import_deps and plugins inside Mutare's own process — and Mix could refuse the lookup mid-scan ("Unknown dependency :ecto_sql given to :import_deps"). Every render now pins the option (Mutare.AST.render_opts/1); a parsed call keeps the spelling its metadata records, and a node built without metadata renders with parentheses.
  • mix igniter.install mutare fetches the companion packages it adds. The companions are chosen from the project's own deps at run time, and Igniter writes a dep added that way to mix.exs without fetching it — so the generated .mutare.exs named modules of packages that were never fetched or locked. The installer now applies the mix.exs change and runs deps.get before writing .mutare.exs.

0.1.1 - 2026-09-07

Fixed

  • Unit-return classification exempts behaviour callbacks. A function that is a callback of one of its module's declared behaviours (direct @behaviour or use-injected, read through the behaviour's behaviour_info/1 when it is loadable), or whose first clause carries an @impl other than @impl false, is never classified unit-returning, however its body reads. Its caller is the behaviour's runtime, which the source never shows and which may treat a lone :ok as one contract outcome among several — Oban.Worker.perform/1's :ok is one of six. 0.1.0 silenced the :ok return mutants of every such callback, including mutare_oban's worker-return family.

0.1.0 - 2026-09-07

Initial release.

Added

  • Compile-once metamutant. Source under lib/ is rewritten into a single program that embeds every mutant behind a :persistent_term runtime switch, compiled once; the suite then runs once per mutant by flipping MUTARE_ACTIVE_MUTANT — no per-mutant recompilation.
  • A broad built-in mutator set (all on by default): arithmetic/operator and operand swaps, relational and logical swaps, strict-equality relaxation, literals of every kind (integer/float/string/charlist/atom/sigil/regex/ bitstring/date-time), collection/string/map/keyword call rewrites, pattern and clause restructurings, guard/default/call drops, and more. See Mutare.Mutators.
  • Unit-return classification — a function (or anonymous function) whose every return path is literally :ok or nil returns no data, so its tails draw no return-value constant and no :ok → :error swap. Syntactic, and one-sided: it can miss a unit function, never silence a data-returning one.
  • Coverage-guided test selection — coverage is self-recorded by the metamutant at runtime and keyed by mutant id; each mutant runs only the test cases that cover it (--per-file widens that to the covering test files, for stateful async: false suites; --full runs the whole suite every time). Uncovered mutants are skipped and excluded from the score.
  • Parallel workers with per-mutant timeouts — mutants run :workers at a time, each capped by a wall-clock deadline; a mutation that hangs halts itself and counts as a kill (no process-tree killing).
  • Compile-poison recovery — a mutant that won't compile is identified from the compile error, dropped (reported as poisoned, excluded from the score), and the build retried, for a bounded number of rounds; only a compile error that can't be attributed to any mutant (or that outlasts the bound) aborts the run, with a copy-pasteable :skip snippet.
  • # mutare:ignore directive — suppress a known-equivalent mutant per line, per span (-start/-end), or per file (-file), with an optional free-text reason and an optional [family] / [family:label] filter; ineffective directives are surfaced (--strict-ignores escalates).
  • Reporters — human (default, survivor diffs + score), plus machine-readable json (Stryker / mutation-testing-elements schema), html (interactive viewer), and sarif (GitHub code scanning) via --report FORMAT[:PATH] (repeatable) or :reporters.
  • Live progress on stderr; the detailed report and score print to stdout.
  • CI integration — --since <ref> to scope to the lines changed against a git ref, --min-score to gate, --line to target lines, and a kept sandbox (the default) so the compiled build carries across runs; --sandbox <path> pins it at a CI cache, --no-keep-sandbox opts back into a throwaway copy.
  • Umbrella-aware — target one app, several, or the whole workspace.
  • Extension surface — Mutare.Mutator (custom mutators), independent Mutare.CallRouting and Mutare.UseExpansion capabilities, :extensions for non-mutating integrations, declarative :call_routes configuration (user-tier treatments only; the adapter-grade treatments must come from a module implementing Mutare.CallRouting), the Mutare.AST node constructors that discharge Sourceror's emission invariants for plugins, and the Mutare.Calls call-resolution readers (resolved_call_to/3, module_key/1) so plugins match calls without building core's key representation, and a declarative environment guard (required_modules/0, on mutators and extensions): the modules a DSL plugin routes are checked loadable once at startup, aborting with Mutare.EnvironmentError instead of silently registering routes against nothing on an external-source run.
  • mix igniter.install mutare installer that detects frameworks and wires up the matching companion packages and .mutare.exs.
  • Call routes (call_routes: / --skip-call Module.fun/arity) — leave a call alone: :skip makes a whole call an inert leaf (functions, macros, and the construct special forms alike — Kernel.if/2 or case included; a piped receiver and the enclosing function's return-value mutants are unaffected), :raw leaves an argument as written, :interior mutates an argument's contents but never its own node, and a keyed refinement ([:expression, timeout: :raw]) reaches one option of a literal keyword argument. The forms Mutare analyzes structurally (if, case, the boolean operators, …) take :skip only, and definitions (def, defmodule, …) and literal syntax ({}, %{}, =, …) take no route. Routes match qualified, aliased, imported, and piped forms, and an entry that matches no call in a full scan is warned about.
  • Argument marks (argument_marks:) — extend the built-in timeout table (or any label a mutator declares) to your own functions, with the mutators' value-aware reaction: {MyApp.Http, :get, 2, [{:keyword, :recv_timeout}], :timeout}.