> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/shedskin/shedskin/llms.txt
> Use this file to discover all available pages before exploring further.

# Changelog

> Release history and notable changes in Shed Skin

All notable changes to Shed Skin are documented here. The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/), and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).

## Unreleased

Upcoming changes that will be in the next release.

### Fixed

* Fixed dict comprehension code generation crash (`TypeError: 'Tuple' object is not subscriptable`) in `cpp.py` by accessing `node.elt.elts[0]`/`node.elt.elts[1]` instead of `node.elt[0]`/`node.elt[1]`
* Fixed dict comprehension type inference in `graph.py`: `isinstance(node.elt, tuple)` was always `False` for `ast.Tuple` nodes, so key/value type constraints were never set up. Changed to `node in self.gx.dictcomp_to_lc.values()`
* Fixed `runtests --run` executing unbuilt ext tests by aligning ctest regex with the build target suffix in `cmake.py`
* Added missing `WORKING_DIRECTORY` for non-Windows ext tests in CMake configuration

### Changed

* Converted build system to uv, replacing pip/setuptools workflow with `uv` commands in Makefile
* Applied mypy strict mode fixes across core modules (`__init__`, `cmake`, `config`, `cpp`, `graph`, `infer`, `makefile`, `stats`)
* Converted documentation from Sphinx/RST to MkDocs with Markdown
  * Replaced `README.rst` with `README.md`
  * Removed generated Sphinx HTML/JS/CSS assets from `docs/`
  * Added `mkdocs.yml` configuration
* Updated `Makefile` test target to fix test invocation
* Refactored `graph.py` and `infer.py` to resolve type issues

### Removed

* Removed `requirements.txt` (dependencies now managed via `pyproject.toml` and uv)

***

## \[0.9.12] - 2024

Major release introducing local dependency management and significant internal refactoring.

### Added

#### Local Dependency Management

<Note>
  Starting with 0.9.12, `--local-deps` is now the **default** dependency manager, eliminating the need for external package managers.
</Note>

* **Local dependency management** (`--local-deps` flag) with bundled zip archives:
  * Builds bdwgc and pcre2 from compressed sources in `shedskin/ext/`
  * Extracts to platform-specific cache on first use:
    * **macOS**: `~/Library/Caches/shedskin/`
    * **Linux**: `~/.cache/shedskin/`
    * **Windows**: `%LOCALAPPDATA%/shedskin/Cache/`
  * Caches built static libraries for subsequent compilations
  * Works completely **offline** (no network required)
  * Cross-platform support (Linux, macOS, Windows)
* `LocalDependencyManager` class in `cmake.py` for zip-based dependency building
* CLI option `--local-deps` for both `translate` (Makefile) and `build` (CMake) commands

#### Testing

* **Unit tests** for core modules (`tests/unit/`, 74 tests total):
  * `test_config.py`: Tests for GlobalInfo and state objects
  * `test_graph.py`: Tests for constraint graph building
  * `test_infer.py`: Tests for type inference
  * `test_cpp.py`: Tests for C++ code generation config

### Changed

#### Dependency Management

* Made `--local-deps` the **default** dependency manager for `build`, `run`, and `runtests` subcommands
  * Dependencies are now automatically built from bundled `ext/` sources
  * No external package manager required out of the box
* Bundled bdwgc (v8.2.10) and pcre2 (pcre2-10.47) sources as compressed zip archives in `ext/`:
  * Reduced from 25MB (full sources) to **1.2MB** (trimmed and compressed)
  * Removed documentation, tests, CI/CD files, autotools, legacy platform support
  * Removed SLJIT (JIT compiler) from pcre2 as Shed Skin doesn't use JIT features
* Simplified CMake output directories to `${CMAKE_BINARY_DIR}` (executables in `build/`)

#### Architecture Refactoring

* **Refactored `GlobalInfo` class** into focused state objects for better code organization:
  * `FileSystemPaths`: Immutable paths for shedskin installation, resources, and libraries
  * `BuildConfiguration`: Build flags (bounds\_checking, int32/64, nogc, etc.)
  * `NamingContext`: C++ keywords, prefix, and builtin type names
  * `EntityRegistry`: Functions, classes, variables, modules, and inheritance tracking
  * `GraphBuildingContext`: Temporary graph building state (loops, comprehensions, etc.)
  * `TypeInferenceState`: Core type inference data (cnode, types, constraints, etc.)
* Created new `shedskin/state/` package containing the focused state dataclasses
* Maintained **100% backwards compatibility** via property delegation in `GlobalInfo`

#### CLI Improvements

* Consolidated CLI argument definitions using argparse parent parsers:
  * Created `_create_shared_parsers()` method with reusable argument groups
  * Shared parsers: `stats`, `types`, `disable`, `compiler`, `cmake`
  * Reduced code duplication across `translate`, `build`, `run`, `runtests` subcommands

### Security

* Replaced `os.system()` with `subprocess.run()` across all modules:
  * `cmake.py`: shellcmd, cmake config/build/test, pytest
  * `makefile.py`: Command execution in `_execute()`
  * `__init__.py`: Executable running and Windows color output hack

### Documentation

* Documented type inference tuning constants in `infer.py`:
  * `INCREMENTAL`: Enable incremental analysis mode
  * `INCREMENTAL_FUNCS`: Functions to add per round (default: 5)
  * `INCREMENTAL_DATA`: Enable incremental allocation tracking
  * `INCREMENTAL_ALLOCS`: Allocations before restart (default: 1)
  * `MAXITERS`: Maximum iterations per round (default: 30)
  * `CPA_LIMIT`: Initial cartesian product limit (default: 10)
* Added `MAX_TYPE_DEPTH` constant in `typestr.py` for recursion limit (default: 10)

### Fixed

* Fixed CMake build failure when source file path is absolute (e.g., building from a different directory with `../examples/foo.py`). The issue occurred because absolute parent paths were being concatenated with build directories, creating invalid paths like `build/exe/C:/Users/.../file.cpp`
* Resource leaks: Added context manager support to `MakefileWriter` class
* File handling: Use context managers for file operations in `config.py`

### Removed

* **Removed Conan dependency manager** support:
  * Removed `--conan` CLI option
  * Removed `ConanBDWGC`, `ConanPCRE`, and `ConanDependencyManager` classes
  * Removed `ENABLE_CONAN` CMake option
  * Removed `shedskin/resources/conan/` directory
  * Removed conan from `requirements.txt`

***

## Version History

Shed Skin has been in development since 2005. Version 0.9.12 represents a significant milestone in maturity and usability.

### Key Milestones

* **2005**: Initial release by Mark Dufour
* **Various versions**: Gradual improvements in type inference, optimization, and library support
* **0.9.x series**: Focus on stability, usability, and modern Python 3 support
* **0.9.12 (2024)**: Major architectural improvements and simplified dependency management

### Performance Evolution

Shed Skin has consistently improved performance over the years:

```
Sieve benchmark (n=100000000):

CPython 3.10.6:     13.4 seconds
CPython 3.11.0:     11.4 seconds
Nuitka 0.6.16:      11.4 seconds
PyPy 3.9.12:         5.8 seconds
Numba 0.56.4:        2.5 seconds
Shed Skin 0.9.9:     1.9 seconds
Shed Skin 0.9.9:     1.8 seconds (with --nowrap --nobounds)
```

<Tip>
  Note: Numba defaults to int64 as integer type, while Shed Skin defaults to int32. Performance is practically equal when using `shedskin --int64`.
</Tip>

### Example Programs

Shed Skin successfully compiles over **80 non-trivial programs** (at over 25,000 lines in total), including:

* **Games**: DOOM, Othello, Quake, C64 emulator
* **Graphics**: Ray tracer, Voronoi diagrams, 3D rendering
* **Algorithms**: A\*, neural networks, genetic algorithms
* **Utilities**: rsync-like tool, SHA implementations

See the [Examples](/examples/overview) section for more details.

***

## Contributing

Shed Skin is open source and welcomes contributions! See [Contributing](/resources/contributing) for how to get involved.

### Reporting Issues

Found a bug or have a feature request? [Open an issue](https://github.com/shedskin/shedskin/issues) on GitHub.

### Source Code

View the source code and full commit history on [GitHub](https://github.com/shedskin/shedskin).