mini-racer

• Improve performance of function calls by exposing Array.prototype.push (avoiding two round trips to get array size and then slice it, for function call argv construction).
• Various internal simplifications intended to improve maintainability. None of these should be externally visible.

• Fix MacOS wheels to not require MacOS 15.

• Upgrade to V8 14.3 from 12.6.
• Add Windows Arm support!
• Alpine support is now reduced to using gcompat and LD_PRELOAD="/lib/libgcompat.so.0".
• Crank up strictness of ruff and mypy, fixing uncovered typing issues.
• Internally: Switch from Hatch and pre-commit to uv, Justfile, and Prettier.
• Internally: Cross compile for arm (testing on the new native Github runners!) instead of using emulation + sccache. This cuts the build time about 10x!

• Upgrade to V8 12.6 from 12.4.

See https://bpcreech.com/PyMiniRacer/history/#0123-2024-05-25

See https://bpcreech.com/PyMiniRacer/history/#0122-2024-05-20

Switch from tags to branches for releases

• Added support for installing callbacks from JS back into Python, using MiniRacer.wrap_py_function.

• Refactored the Python implementation into many internal files. This should mostly not present a breaking change, except for code which reaches into internal (_-prefixed) variables.

• Fixed Python crash on long-running microtasks, introduced in v0.8.1 (before which long-running microtasks would probably not run at all).

• Fixed memory leak on the exception object reported when an eval times out.

• Hardened the memory management of JS value interchange, context tracking, and asynchronous task tracking between C++ and Python.

• Added exhaustive typing (now with a MyPy pre-commit to verify!)

• Added a test asserting that the v8 sandbox is enabled on all platforms we build wheels for.

• Added a MutableMapping (dict-like) interface for all derivatives of JS Objects, and a MutableSequence (list-like) interface for JS Arrays. You can now use Pythonic idioms to read and write Object properties and Array elements in Python, including recursively (i.e., you can read Objects embedded in other objects, and embed your own).

• Added ability to directly call JSFunction objects from Python. E.g., mr.eval("a => a*a")(4) parses the given number-squaring code into a function, returns a handle to that function to Python, calls it with the number 4, and recieves the result of 16.

• Added a JSUndefined Python object to model JavaScript undefined. This is needed to properly implement the above interface for reading Object and Array elements. Unfortunately, this may present a breaking change for users who assume JavaScript undefined is modeled as Python None.

• Removed an old optimization for eval on simple no-argument function calls (i.e., myfunc()). The optimization only delivered about a 17% speedup on no-op calls (and helped relatively less on calls which actually did work), and for the purpose of optimizing repeated calls to the same function, it's now redundant with extracting and calling the function from Python, e.g., mr.eval("myfunc")().

• Hardening (meaning "fixing potential but not-yet-seen bugs") related to freeing Value instances (which convey data from C++ to Python).

• More hardening related to race conditions on teardown of the MiniRacer object in the unlikely condition that eval operations are still executing on the C++ side, and abandoned on the Python side, when Python attempts to garbage collect the MiniRacer object.

• Updated to V8 12.3 from V8 12.2 now that Chromium stable is on 12.3.

• Added Python-side support for JS Promises. You can now return a JS Promise from code executed by MiniRacer.eval, and PyMiniRacer will convert it to a Python object which has a blocking promise.get() method, and also supports await promise in async Python functions.

• Added a setTimeout and clearTimeout. These common functions live in the Web API standard, not the ECMAScript standard, and thus don't come with V8, but they're so ubiquitious we now ship an implemention with PyMiniRacer.

• Revamped JS execution model to be out-of-thread. Python/C++ interaction now happens via callbacks.

• Consequently, Control+C (KeyboardInterrupt) now interrupts JS execution.

• Hardened C++-side thread safety model, resolving potential race conditions introduced in v0.8.1 (but not actually reported as happening anywhere).

• Further improved JS exception reporting; exception reports now show the offending code where possible.

• Introduced timeout_sec parameter to eval, call, and execute to replace the timeout, which unfortunately uses milliseconds (unlike the Python standard library). In the future we may emit deprecation warnings for use of timeout.

• A series of C++ changes which should not impact the behavior of PyMiniRacer:
• Refactoring how we use V8 by inverting the control flow. Before we had function evaluations which ran and drained the message loop. Now we have an always-running message loop into which we inject function evaluations. This seems to be the preferred way to use V8. This is not expected to cause any behavior changes (but, in tests, makes microtask competion more consistent).
• Refactoring the C++ implementation into multiple components to make startup and teardown logic more robust.
• Added tests for the existing fast-function-call path.
• Also, simplified Python conversion of C++ evaluation results.

• General overhaul of C++ implementation to better adhere to modern best practice. This should have no visible impact except for the following notes...
• Exposed the hard memory limit as a context-specific (as opposed to eval-specific) limit, since that's how it worked all along anyway. The max_memory eval argument still works for backwards compatibility purposes.
• Correct message type of some exceptions to str instead of bytes (they should all be str now).
• Added better messages for JS parse errors.
• Added backtraces for more JS errors.
• Added some really basic Python typing.

• Update V8 to 12.2
• Drop Python 2 support
• Fix small Python 3.12 issue and add testing for Python 3.9-3.12
• Add aarch64 support for Mac and Linux
• Revamp DLL loading to be compliant with Python 3.9-style resource loading. This may present a small breaking change for advanced usage; the EXTENSION_PATH and EXTENSION_NAME module variables, and MiniRacer.v8_flags and MiniRacer.ext class variable have all been removed.
• Add support for the ECMAScript internalization API and thus the ECMA Intl API
• Use fast startup snapshots
• Switch from setuptools to Hatch
• Switch from tox to Hatch
• Switch from flake8 and isort to Hatch's wrapper of Ruff
• Switch from Sphinx to mkdocs (and hatch-mkdocs)
• Switch from unittest to pytest
• Add ARCHITECTURE.md and lots of code comments