Changelog for mockcat

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to the Haskell Package Versioning Policy.

[1.3.3.0] - 2026-01-04

Added

• Type Families Support: deriveMockInstances now supports type classes containing Associated Type Families.
• Improved withMockIO: withMockIO now enables direct execution of IO actions within mock contexts without liftIO.

[1.3.2.0] - 2026-01-04

Added

• New Derivation Macros:
  • deriveMockInstances: Automatically derives MockT instances for user-defined "Capability" type classes (e.g., MonadLogger). It lifts operations to the base monad.
    • Note: Type Families are currently not supported.
  • deriveNoopInstance: Generates "No-op" instances where methods (returning m ()) do nothing. Useful for ignoring specific interactions (e.g., MonadAuditor).

Improved

• Compile-Time Verification: Enhanced robustness of internal verification scripts (verify_th_errors.sh) to ensure consistent error reporting across GHC versions.
• Documentation: Clarified "Capability vs. Control" design philosophy and limitations regarding Type Families in deriveMockInstances.

[1.3.1.0] - 2026-01-03

Added

• New Parameter Matcher: Introduced when and when_ as the primary functions for condition-based matching.
  • These replace expect and expect_ to improve readability (e.g., mock (when (>5) ~> True) reads naturally as "mock when > 5").

Changed

• Renaming / Deprecation: expect and expect_ have been renamed to when and when_.
  • The old expect and expect_ are now DEPRECATED and will trigger a compiler warning. They will be removed in a future major release.
• Documentation: Updated when / when_ usage and added guidance on resolving name collisions with Control.Monad.when.

[1.3.0.0] - 2026-01-03

Added

• Type-Safe Verification Result: Generated mock helpers now return MockResult params. This type carries parameter information, enabling robust type inference and compile-time safety checks when using declarative verification (expects).
  • This change is part of an ongoing effort to make misuse of mocks impossible at the type level.

Changed

• Breaking Change: Due to the introduction of MockResult, generated mock helpers (e.g., _myMethod) no longer return the mock function itself (MockT m (FunctionType)).
  • Code that previously relied on capturing the returned function (e.g., fn <- _myMethod ...) will need to be updated.
• Refactoring: Reorganized internal test verification logic to utilize MockResult properties.
• Internal: Refactored test suite organization for better maintainability.

[1.2.1.0] - 2026-01-01

Added

• Dynamic Language Extension Detection: mockcat now automatically identifies and requests only necessary extensions (e.g., MultiParamTypeClasses, UndecidableInstances) based on the target class definition.
• Granular Extension Optimization: Simple multi-parameter type classes no longer require AllowAmbiguousTypes or FunctionalDependencies unless they are actually used.

Fixed

• Resolved NoVerification scope issues in Template Haskell generated code.
• Resolved ambiguous any occurrences in internal Template Haskell logic.
• Fixed several typos in Template Haskell error messages.

[1.2.0.0] - 2025-12-31

Changed

• Breaking Change: Changed the fixity of expects operator to infixl 0 to resolve precedence issues with $.
  • Impact: Code using mock $ ... expects ... will now fail to compile.
  • Migration: Wrap the mock definition in parentheses: mock (... ~> ...) expects ....
• Breaking Change: expects now strictly enforces that it can only be applied to a mock creation action (m fn).
  • Attempting to apply expects directly to a MockSpec (e.g. (any ~> 1) expects ...) or an already instantiated function will result in a compile-time TypeError.
• Removed redundant Typeable constraints from expects, enabling cleaner builds on GHC 9.8+.

[1.1.0.0] - 2025-12-29

Added

• HPC Coverage Support: Verification logic now robustly handles unstable StableNames caused by HPC instrumentation (stack test --coverage).
• Optimization Hardening: Protected verification logic against GHC optimizations (CSE/LICM) to ensure stable tests in optimized builds.

Changed

• Automatic History Reset: runMockT and withMock now strictly scope mock history. History is automatically reset to prevent interference between sequential tests or Property-Based Testing iterations.

[1.0.0.0] - 2025-12-24

Changed

• DSL Reboot: Replaced |> with ~> as the primary parameter chain operator (representing the "mock arrow").
• Terminology Shift: Standardized terminology to "called" instead of "applied" throughout the library and error messages.
• Simplified creating/stubbing API: f <- mock $ ... is now the canonical way.
• Expanded structural diffing support for nested records and lists.
• Unified verification API: All verification is now handled via shouldBeCalled.
• Strict by Default: makeMock and makePartialMock now default to strict return values (implicit monadic return is disabled). makeAutoLiftMock was introduced for the previous behavior.

Added

• Deep Structural Diff: Enhanced error messages with precise caret pointers for complex nested data structures.
• STM-based concurrency for mock registration and call recording.
• Infinite arity support for mock/stub building.

Removed

• Backward compatibility with 0.x.x APIs (stubFn, createMock, applied, etc.).
• makeMockWithOptions, makePartialMockWithOptions, and MockOptions (internalized to simplify API).

Migration Guide (0.x -> 1.0)

This release is a complete reboot. Previous code will break.

1. Operator Change: Replace |> with ~>.

   -- Old
   createStubFn $ "arg" |> "result"
   
   -- New
   stub $ "arg" ~> "result"
   

2. Mock Creation: Use mock / stub instead of createMock / createStubFn.

   -- Old
   f <- createMock $ "arg" |> "result"
   
   -- New
   f <- mock $ "arg" ~> "result"
   

3. Verification: Use shouldBeCalled (unified API).

   -- Old
   f `shouldApplyTo` "arg"
   
   -- New
   f `shouldBeCalled` "arg"
   

4. Template Haskell Generics: makeMock is now strict by default (requires explicit pure for IO actions).

   • Use makeAutoLiftMock for old implicit behavior.
   • Or stick to makeMock and add pure to your return values.

0.6.0.0

Changed

• Removed the upper limit on variable arguments when creating stub functions. Previously, there was a restriction on the maximum number of arguments, but this limitation has been removed, allowing stub functions to accept an arbitrary number of arguments.

0.5.5.0

Added

• Aliases expectApplyTimes and expectNever (preferred names) for pre-run expectation declarations.

Documentation

• README (EN/JA) now recommends expectApplyTimes / expectNever over legacy applyTimesIs / neverApply.
• Clarified that expectApplyTimes n is the canonical form; expectNever is sugar for expectApplyTimes 0.

Notes

• Legacy names remain exported for backward compatibility (no deprecation pragma yet). They may receive a soft deprecation notice in a future minor release after community feedback.

0.5.4.0

Added

• Parallel execution support (verified counting under concurrency, stress tests).
• Verification helpers: applyTimesIs, neverApply.

Changed

• Refactored MockT from StateT to ReaderT (TVar [Definition]) architecture.
• Simplified Template Haskell generated constraints.

Fixed

• Race causing lost/double count in concurrent stub applications (strict modifyTVar').

Removed

• unsafePerformIO in TH-generated code.

Internal

• Introduced MonadMockDefs abstraction.

0.5.3.0

Added

• MonadUnliftIO instance for MockT (initial groundwork for later parallel support).