# Python Changelog

This changelog summarizes major changes between GraalVM versions of the Python
language runtime. The main focus is on user-observable behavior of the engine.

## Version 22.0.0
* Added support for `pyexpat` module.
* Added partial support for `PYTHONHASHSEED` environment variable (also available via `HashSeed` context option), currently only affecting hashing in `pyexpat` module.
* Implement `_csv` module.
* Improved compatibility with PyPI packages `wheel` and `click`

## Version 21.3.0

* Remove `PYPY_VERSION` from our C extension emulation, enabling PyGame 2.0 and other extensions to work out of the box.
* Intrinsify and optimize more of the core language for better startup and reduced footprint.
* Implement a new binary compatible backend for HPy 0.0.3, which allows binary HPy wheels to run unmodified on CPython and GraalPython
* Support the `multiprocessing` module via in-process nested contexts, allowing execution on multiple cores within the same process using the Python multiprocessing API
* Add support for the `ctypes` module, enabling more native extensions to run that use the ctypes API
* Fix multiple REPL issues reported on Github, you can now paste blocks of code and use the numpad in the REPL.
* Make our marshal format compatible with CPython, so binary data can now be exchanged between CPython and GraalPython processes.
* Make most `socket` module tests pass in native mode by using a native extension, allowing usage of all POSIX socket APIs where before only those supported on Java could be used.
* Various compatibility fixes to make the `psutil` package work.

## Version 21.2.0

* Support the `dict` type properly in interop using the new hash interop messages.
* Implement `_pickle` as a faster version than the pure Python version for GraalVM Enterprise Edition.
* Support the newer multi-phase C extension module initialization.
* Make many more tests pass: `io`, `crypt`, more functions in `socket`, `OrderedDict`, `time`,
* Improve performance especially during warmup and in shared engine configurations by adding fast paths, intrinsifying functions, and adding optimized representations for common data structures
* Update the supported HPy version to 0.0.2
* Use the new Truffle safepoint mechanism for more efficient GIL releases, signal handlers, and weakref callbacks
* Initial support for the `psutil` and `PyGame` packages
* GraalPython not longer unconditionally creates `__pycache__` if the file name "sitecustomize.py" exists in the current working directory

## Version 21.1.0

* Support multi-threading with a global interpreter lock by default.
* Added SSL/TLS support (the `ssl` module)
* Added subclassing of Java classes in JVM mode
* Support iterating over Python objects from Java and other languages as well as iterating over foreign objects in Python
* Support catching exceptions from other languages or Java with catch-all except blocks
* Support isinstance and issubclass with instances and classes of other languages
* Use native posix functions in the GraalPython Launcher (see [Operating System Interfaces](https://www.graalvm.org/reference-manual/python/OsInterface/) for details)

## Version 21.0.0

* Implement name mangling for private attributes
* Correctly raise an AttributeError when a class defines slots, but not dict
* Fix infinite continuation prompt in REPL when pasting snippets
* Add jarray module for compatiblity with Jython
* Fix multiple memory leaks and crashes when running NumPy in a shared engine
* Improved support for Pandas
* Initial support for Matplotlib
* Many fixes to pass the unittests of standard library types and modules:
  abc, array, builtin, bzip2, decimal, descriptors, difflib, enum, fractions,
  gzip, memoryview, metaclass, pickle, platform, print, reprlib, statistics,
  strftime, strtod, sysconfig, userdict, userlist, userstring, zipfile,
  zipfile64, zlib
* Improve performance in multiple areas:
  array, memoryview, unzipping packages, dictionaries with dynamic string keys,
  string slicing

## Version 20.3.0

* Fix multiple memory leaks when running Python code in a shared engine.
* Update language support target and standard library to 3.8.5
* Hide internal catching frames from tracebacks
* Update HPy support to the latest version with support for piconumpy
* Many fixes to pass the unittests of standard library types and modules:
  complex, bytes, bytearray, subclassing of special descriptors, type layouts,
  float, generators, modules, argument passing corner cases, string literals and
  encodings, import and importlib, decimal, glob, the builtin module, json,
  math, operator, numeric tower, sys, warnings, random, f-strings, struct,
  itertools

## Version 20.2.0

* Escaping Unicode characters using the character names in strings like
  "\N{GREEK CAPITAL LETTER DELTA}".
* When a `*.py` file is imported, `*.pyc` file is created. It contains binary data to speed up parsing.
* Adding option `PyCachePrefix`, which is equivalent to PYTHONPYCACHEPREFIX environment variable, which is also accepted now. 
* Adding optin `DontWriteBytecodeFlag`. Equivalent to the Python -B flag. Don't write bytecode files.
* Command option -B works
* Implement better reference counting for native extensions to fix memory leaks
* Fix a warning in pandas about size of datetime objects
* Make many more CPython unittests pass for core types
* Support parse requests with arguments for embedding Python to light up GraalVM Insight support
* Support basic tox usage when forcing virtualenv to use venv
* No longer support iterables as arrays in interop
* Add initial support for HPy native extensions
* Support magic encoding comments in Python files
* Improve chaining of exception tracebacks - the tracebacks should now be much closer to CPython and more helpful

## Version 20.1.0

* Update language support target and standard library to 3.8.2
* Improve performance of tuples with primitive elements
* Improve performance of using Python sequences from other GraalVM languages
* Improve performance of dictionaries and sets
* Improve performance of allocations for list comprehensions with range iterators
* Support `cProfile` and `trace` modules through the GraalVM CPU sampler and coverage, respectively
* Support NumPy on macOS
* Support setuptools-scm and pytz.timezone
* Support new syntax for iterable unpacking from yield and return statements
* Fix issues with inspection and printing of non-Python numbers in the Chrome debugger
* Fix issues with AST sharing across different contexts, if these context run concurrently on multiple threads
* Fix code serialization and deserialization with pickle
* Fix DirEntry.stat
* Fix passing non-ASCII strings to `gethostbyname`
* Fix `help(numpy)` to work again in the interactive REPL
* Fix multi-line continuation in the REPL for opening parens
* Fix `select.select` for pipes
* Polyglot: Rethrow AttributeError as UnknownIdentifierException in invokeMember
* Jython mode: treat Java `null` as identical to Python `None` when comparing with the `is` operator
* Jython mode: `isinstance` now works with Java classes and objects
* Improve errno handling in `posix` module
* Move all GraalPython specific functions on `sys` or `builtins` to the `__graalpython__` module

## Version 20.0.0

* Jython Compatiblity: Implement `from JavaType import *` to import all static members of a Java class
* Jython Compatiblity: Implement importing Python code from inside JAR files by adding `path/to/jarfile.jar!path/inside/jar` to `sys.path`
* Added support for date and time interop.
* Added support for setting the time zone via `Context.Builder.timeZone`.
* PEP 570 - Python Positional-Only Parameters implemented

## Version 19.3.0

* Implement `gc.{enable,disable,isenabled}` as stubs
* Implement `charmap_build` function
* Implement `hexversion` in sys module
* Implement `_lzma` module
* Implement enough of `socket.socket` to run `graalpython -m http.server` and download non-encrypted http resources
* Fix printing of Pandas data frames
* Fix a bug in `bytes.startswith` for tuple arguments
* Fix destructuring assignments of arbitrary iterators
* Fix `dict.__contains__` for dictionaries with only `str` keys for subclasses of `str`
* Support NumPy 1.16.4 and Pandas 0.25.0
* Support `timeit` module
* Support basic usage of `pytest`
* Improve performance across many Python and C extension benchmarks
* Improve performance of our parser
* Improve performance of catching exceptions when the exception does not leave the handler block and the traceback is not accessed
* Improve performance of Java interop when Python objects are accessed from Java
* Add a new `--python.EmulateJython` flag to support importing Java classes using normal Python import syntax and to catch Java exceptions from Python code
* Update standard library to Python 3.7.4
* Initial implementatin of PEP 498 -- Literal String Interpolation

## Version 19.2.0

* Implement PyStructSequence_* C API functions
* Implement `_functools.partial` as a class instead of a function
* Implement `type.__base__`
* Implement reading C API type attributes `nb_inplace_add`, `nb_remainder`, `nb_subtract`, and `nb_floor_divide` for builtin types
* Implement C API functions `_PyObject_CallFunction_SizeT`, `PyEval_InitThreads`, and `PyEval_ThreadsInitialized`
* Implement writing to a function's `__dict__` field
* Implement the C API thread state fields `overflowed` and `recursion_depth`
* Fix printing of errors in the REPL
* Fix printing full paths in traceback
* Support the C API varargs functions with arbitrary numbers of arguments instead of imposing an upper limit
* Improve performance of attribute reads and reading closure variables

## Version 19.1.0

* Add `java.add_to_classpath` API to dynamically extend the host class path
* Allow write access to main module bindings for embedder
* Swap arguments for `polyglot.export_value` to use the more natural (name, value) order and deprecate the previous argument order.
* Update Python standard library files to Python 3.7.3
* Improve performance of exceptions that do not escape
* Fix str(None) to print "None" instead of an empty string
* Fix error messages on polyglot objects to not leak implementation class names of those objects
* Fix erroneously frozen package paths in pre-initialized python modules
* Fix caching of core sources in a native image with a preinitialized context for pre-built images and libpolyglot fast startup
* Implement pwd.getpwuid
* Implement os.exec, os.execv, and os.execl
* Add some missing C API headers needed for tensorflow compilation

## Version 19.0.0

* Fix an issue preventing use of encodings in the installable binary
* Fix return value of process when `os.exit` is called with a boolean
* Fix interpretation of foreign objects to prefer interpreting them as integer over double
* Fix performance regression when repeatedly creating a new function in a loop

## Version 1.0.0 RC16

* No user-facing changes

## Version 1.0.0 RC15

* Implement PEP 487 `__init_subclass__`
* Implement PEP 560 `__class_getitem__` and `__mro_entries__`
* Migrate to Truffle libraries for interop
* Support the buffer protocol for mmap
* Support importing java classes using normal Python import syntax
* Improve performance of literal dictionary creation when the first but not all keys are strings
* Improve performance of getting the length of a string
* Improve performance of accessing defaults, keyword-defaults, and code of a function
* Fix getting file separator from the Truffle filesystem rather than the operating system
* Fix constructing and calling methods with non-function callables
* Fix execution of subprocesses with non-default python homes on JVM

## Version 1.0.0 RC14

* Mark a subset of the Graal Python launcher options as "stable". All other options are subject to change and need to be unlocked explicitly on the commandline.
* Automatically install pip when creating a venv. The socket and ssl libraries are still not functional, so pip can only install from local sources or wheels.
* Update the standard library to Python 3.7.0 from 3.6.5.
* Support the `-I` flag to ignore the user environment and not add the working directory to `sys.path`
* Fix an error preventing usage of the memtracer tool. If an object raised an exception in it's `__repr__` method, it would abort the execution.
* Fix issues around not being able to modify function defaults, keyword defaults, or re-defining a function with a different closure.
* Fix continuation prompt in the interactive Python shell when an incomplete statement was typed. Before it raised and ignored a SyntaxError.
* Fix frame restarting of Python functions in the Chrome debugger. Before, functions with closures would have their cells accidentally cleared.

## Version 1.0.0 RC13

* Support marshal.dumps and marshal.loads for code objects and some other built-in objects
* Fix installation of NumPy in a venv
* Initial support for module mmap
* Support debugging with workspace files in the Chrome debugger
* Support the PEP 553 breakpoint() message
* Support running weak reference callbacks and signals on the main thread

## Version 1.0.0 RC12

* Support the `__class__` variable in the class scope
* Support module-level docstrings
* Initial support for the `venv` standard-library tool
* Initial support for the built-in `_bz2` module
* Initial support for the `pandas` package
* Initial support for OSError subclasses based on the `errno` of the exception
* Fix bytearray inplace add to return the same object
* Fix access to standard Python methods (`__repr__`, `__str__`, `__len__` and the like) for foreign objects

## Version 1.0.0 RC11

* Support running setuptools to build and install various packages
* Support running a source release version of NumPy out of the box
* Improve performance of member access to C API objects
* Improve performance of binary operations on C API objects
* Add support for `yield from`
* Support assignment to `object.__dict__` and ensure that managed subclasses of native types also have a `__dict__`
* Fix `[]` access with non-integer keys for array-like foreign objects
* Fix various performance regressions introduced in the last RC
* Implement more built-in methods on the `time` module
* Python no longer exposes internal languages through `polyglot.eval`
* Improve performance of `os.scandir` and functions that build on it (such as `glob`)
* More correct implementation of standard streams, including buffering
* Properly support the `-m` switch to run modules
* Support the standard `zipfile` module
* Add the built-in `_cvs` module
* Add support for `__slots__`
* Allow arbitrary callable objects in methods, not only functions
* Report that we have a TTY console if we are launched on a Terminal through our launcher
* Add the `ginstall` custom module to install known packages such as NumPy and setuptools

## Version 1.0.0 RC10

* Improve performance of C API upcalls
* Improve performance of classmethods, staticmethods, `globals()`, and `locals()`
* Improve performance of various string and bytes operations
* Initial support for the `_thread` builtin module (actual multi-threading is still disabled, the API defaults to a dummy implementation)
* Implement the `zipimporter` module
* Support assignment to `object.__class__`
* Use the new Truffle filesystem API to get/set the current working directory
* Attempt our best to report side-effects in KEY_INFO
* The KEYS message now responds with attributes and methods, never dict keys
* Support the `input` builtin
* Add DEBUG launcher options for performance debugging
* Ensure context isolation for file descriptors and child PIDs
* Fix passing custom locals and globals through `exec` and `eval`
* Fixes to builtin `help`

## Version 1.0.0 RC9

* Support `help` in the builtin Python shell
* Add `readline` to enable history and autocompletion in the Python shell
* Add support for the -q, -E, -s, and -S Python launcher flags
* Improve display of foreign array-like objects
* Improve support for string and bytes regular expressions using our TRegex engine
* Support loading site-packages installed with easy_install
* Initial support for the `binascii` module

## Version 1.0.0 RC8

* Report allocations when the `--memtracer` option is used
* Initial support for `pickle` module

## Version 1.0.0 RC7

* Enhance the `java` interop builtin module with introspection utility methods

## Version 1.0.0 RC6

* Support regular expression patterns built from bytes by using CPython's sre module as a fallback engine to our own
* Support LLVM 5+ for C extension modules
* Introduce native sequence storage so that e.g. Python bytes exposed to C can be mutated
* Introduce lazy string concatenation to significantly speed up benchmarks where strings are concatenated repeatedly
* C-API improvements to support more scikit-learn code
* Fix our distinction between builtin functions, functions, and methods to make the classes for builtin functions equivalent to CPython
* Improve set, frozenset, and dict support
* Attach Python exceptions as cause to ImportErrors raised for C extension modules
* Update standard library to CPython 3.6.5
* Support more code object attributes
* Support constant type ids for objects that are interned on CPython
* Add collections.deque
* Document how to contribute
* Improve efficiency of generators
* Enable re-use of ASTs in multiple Contexts in the same Engine

## Version 1.0.0 RC5

* Generator expressions now properly evaluate their first iterator in the definition scope at definition time
* Fixes for embedders to ensure top scopes are stable and local scopes always contain TruffleObjects
* C-API improvements to support simple Cython modules
* Support recognition of Python source files with the polyglot launcher

## Version 1.0.0 RC4

* No changes

## Version 1.0.0 RC3

* Support for more String encodings
* Implement buffered I/O
* Remove our random module substitute and use the standard library implementation
* Fix a potential thread-safety problem with cached parse trees when multiple Python contexts are used from multiple threads
* Complete support for math module builtins
* C-API improvements to run simple scikit-learn and NumPy examples
* Support the buffer protocol to wrap arbitrary Python sequences with no copy into NumPy arrays

## Version 1.0.0 RC2

* Updates to the polyglot and embedding APIs
* Many additions to the language core implementation
* Performance improvements to the parser
* C-API improvements to compile and run simple C extensions
* Support breakpoints on caught and uncaught exceptions in debugger

## Version 1.0.0 RC1

* LICENSE set to The Universal Permissive License (UPL), Version 1.0.
