msgpack-python/CHANGELOG.md

# 1.2.1

Release Date: 2026-06-19

Fix a segfault when calling `Unpacker.unpack()` or `Unpacker.skip()` after an unpacking failure.
But note that reusing the same `Unpacker` instance after an unpacking failure is not supported.
Please create a new `Unpacker` instance instead. GHSA-6v7p-g79w-8964


# 1.2.0

Release Date: 2026-06-11

- Support free threaded Python. #654, #686
- Dropped support for Python 3.9. #656
- Fix missing error checks in C code. #665, #666, #667, #672
- Fix `strict_map_key` option didn't work for `object_pairs_hook`. #673
- Increase DEFAULT_RECURSE_LIMIT of Unpacker to 1024. #676
- Fix memory leak when Unpacker returns error for invalid input. #671
- Fix `Packer.pack_ext_type()` ignored `autoreset` option. #663
- Fix `Timestamp.from_datetime()` returning wrong value for pre-epoch datetimes. #662
- Fix use-after-free in `unpackb()` and `Unpacker.unpack()` for non-contiguous input. #677
- Fix possible memory leak when calling `Unpacker.__init__()` several times. #687


# 1.1.2

Release Date: 2025-10-08

This release does not change source code. It updates only building
wheels:

- Update Cython to v3.1.4
- Update cibuildwheel to v3.2.0
- Drop Python 3.8
- Add Python 3.14
- Add windows-arm

# 1.1.1

Release Date: 2025-06-13

- No change from 1.1.1rc1.

# 1.1.1rc1

Release Date: 2025-06-06

- Update Cython to 3.1.1 and cibuildwheel to 2.23.3.

# 1.1.0

Release Date: 2024-09-10

- use `PyLong_*` instead of `PyInt_*` for compatibility with future
  Cython. (#620)

# 1.1.0rc2

Release Date: 2024-08-19

- Update Cython to 3.0.11 for better Python 3.13 support.
- Update cibuildwheel to 2.20.0 to build Python 3.13 wheels.

# 1.1.0rc1

Release Date: 2024-05-07

- Update Cython to 3.0.10 to reduce C warnings and future support for
  Python 3.13.
- Stop using C++ mode in Cython to reduce compile error on some
  compilers.
- `Packer()` has `buf_size` option to specify initial size of internal
  buffer to reduce reallocation.
- The default internal buffer size of `Packer()` is reduced from 1MiB to
  256KiB to optimize for common use cases. Use `buf_size` if you are
  packing large data.
- `Timestamp.to_datetime()` and `Timestamp.from_datetime()` become more
  accurate by avoiding floating point calculations. (#591)
- The Cython code for `Unpacker` has been slightly rewritten for
  maintainability.
- The fallback implementation of `Packer()` and `Unpacker()` now uses
  keyword-only arguments to improve compatibility with the Cython
  implementation.

# 1.0.8

Release Date: 2024-03-01

- Update Cython to 3.0.8. This fixes memory leak when iterating
  `Unpacker` object on Python 3.12.
- Do not include C/Cython files in binary wheels.

# 1.0.7

Release Date: 2023-09-28

- Fix build error of extension module on Windows. (#567)
- `setup.py` doesn't skip build error of extension module. (#568)

# 1.0.6

Release Date: 2023-09-21

> [!NOTE]
> v1.0.6 Wheels for Windows don't contain extension module. Please
> upgrade to v1.0.7 or newer.

- Add Python 3.12 wheels (#517)
- Remove Python 2.7, 3.6, and 3.7 support

# 1.0.5

Release Date: 2023-03-08

- Use `__BYTE_ORDER__` instead of `__BYTE_ORDER` for portability. (#513,
  \#514)
- Add Python 3.11 wheels (#517)
- fallback: Fix packing multidimensional memoryview (#527)

# 1.0.4

Release Date: 2022-06-03

- Support Python 3.11 (beta).
- Don't define `__*_ENDIAN__` macro
  on Unix. by @methane in
  <https://github.com/msgpack/msgpack-python/pull/495>
- Use PyFloat_Pack8() on Python 3.11a7 by @vstinner in
  <https://github.com/msgpack/msgpack-python/pull/499>
- Fix Unpacker max_buffer_length handling by @methane in
  <https://github.com/msgpack/msgpack-python/pull/506>

# 1.0.3

Release Date: 2021-11-24 JST

- Fix Docstring (#459)
- Fix error formatting (#463)
- Improve error message about strict_map_key (#485)

# 1.0.2

- Fix year 2038 problem regression in 1.0.1. (#451)

# 1.0.1

- Add Python 3.9 and linux/arm64 wheels. (#439)
- Fixed Unpacker.tell() after read_bytes() (#426)
- Fixed unpacking datetime before epoch on Windows (#433)
- Fixed fallback Packer didn't check DateTime.tzinfo (#434)

# 1.0.0

Release Date: 2020-02-17

- Remove Python 2 support from the `msgpack/_cmsgpack`.
  `msgpack/fallback` still supports Python 2.
- Remove `encoding` option from the Packer and Unpacker.
- Unpacker: The default value of `max_buffer_size` is changed to 100MiB.
- Unpacker: `strict_map_key` is True by default now.
- Unpacker: String map keys are interned.
- Drop old buffer protocol support.
- Support Timestamp type.
- Support serializing and decerializing `datetime` object with tzinfo.
- Unpacker: `Fix Unpacker.read_bytes()` in fallback implementation.
  (#352)

# 0.6.2

Release Date: 2019-09-20

- Support Python 3.8.
- Update Cython to 0.29.13 for support Python 3.8.
- Some small optimizations.

# 0.6.1

Release Date: 2019-01-25

This release is for mitigating pain caused by v0.6.0 reduced max input
limits for security reason.

- `unpackb(data)` configures `max_*_len` options from `len(data)`,
  instead of static default sizes.
- `Unpacker(max_buffer_len=N)` configures `max_*_len` options from `N`,
  instead of static default sizes.
- `max_bin_len`, `max_str_len`, and `max_ext_len` are deprecated. Since
  this is minor release, it's document only deprecation.

# 0.6.0

Release Date: 2018-11-30

This release contains some backward incompatible changes for security
reason (DoS).

## Important changes

- unpacker: Default value of input limits are smaller than before to
  avoid DoS attack. If you need to handle large data, you need to
  specify limits manually. (#319)
- Unpacker doesn't wrap underlying `ValueError` (including
  `UnicodeError`) into `UnpackValueError`. If you want to catch all
  exception during unpack, you need to use `try ... except Exception`
  with minimum try code block. (#323, \#233)
- `PackValueError` and `PackOverflowError` are also removed. You need to
  catch normal `ValueError` and `OverflowError`. (#323, \#233)
- Unpacker has `strict_map_key` option now. When it is true, only bytes
  and str (unicode in Python 2) are allowed for map keys. It is
  recommended to avoid hashdos. Default value of this option is False
  for backward compatibility reason. But it will be changed True in 1.0.
  (#296, \#334)

## Other changes

- Extension modules are merged. There is `msgpack._cmsgpack` instead of
  `msgpack._packer` and `msgpack._unpacker`. (#314, \#328)
- Add `Unpacker.getbuffer()` method. (#320)
- unpacker: `msgpack.StackError` is raised when input data contains too
  nested data. (#331)
- unpacker: `msgpack.FormatError` is raised when input data is not valid
  msgpack format. (#331)

# 0.5.6

- Fix fallback.Unpacker.feed() dropped unused data from buffer (#287)
- Resurrect fallback.unpack() and `unpacker.unpack()`. They were removed
  at 0.5.5 but it breaks backward compatibility. (#288, #290)

# 0.5.5

- Fix memory leak in pure Python Unpacker.feed() (#283)
- Fix unpack() didn't support `raw` option
  (#285)

# 0.5.4

- Undeprecate `unicode_errors` option. (#278)

# 0.5.3

- Fixed regression when passing `unicode_errors` to Packer but not
  `encoding`. (#277)

# 0.5.2

- Add `raw` option to Unpacker. It is preferred way than `encoding`
  option.
- Packer.pack() reset buffer on exception (#274)

# 0.5.1

- Remove FutureWarning about use_bin_type option (#271)

# 0.5.0

There are some deprecations. Please read changes carefully.

## Changes

- Drop Python 2.6 and ~3.4 support. Python 2.7 and 3.5+ are supported.
- Deprecate useless custom exceptions. Use ValueError instead of
  PackValueError, Exception instead of PackException and
  UnpackException, etc... See msgpack/exceptions.py
- Add *strict_types* option to packer. It can be used to serialize
  subclass of builtin types. For example, when packing object which type
  is subclass of dict, `default()` is called. `default()` is called for
  tuple too.
- Pure Python implementation supports packing memoryview object.
- Support packing bytearray.
- Add `Unpacker.tell()`. And `write_bytes` option is deprecated.

## Bugs fixed

- Fixed zero length raw can't be decoded when encoding is specified.
  (#236)

# 0.4.8

Release Date: 2016-07-29

## Bugs fixed

- Calling ext_hook with wrong length. (Only on Windows, maybe. \#203)

# 0.4.7

Release Date: 2016-01-25

## Bugs fixed

- Memory leak when unpack is failed

## Changes

- Reduce compiler warnings while building extension module
- unpack() now accepts ext_hook argument like Unpacker and unpackb()
- Update Cython version to 0.23.4
- default function is called when integer overflow

# 0.4.6

Release Date: 2015-03-13

## Bugs fixed

- fallback.Unpacker: Fix Data corruption when OutOfData. This bug only
  affects "Streaming unpacking."

# 0.4.5

Release Date: 2015-01-25

## Incompatible Changes

## Changes

## Bugs fixed

- Fix test failure on pytest 2.3. (by @ktdreyer)
- Fix typos in ChangeLog. (Thanks to @dmick)
- Improve README.rst (by @msabramo)

# 0.4.4

Release Date: 2015-01-09

## Incompatible Changes

## Changes

## Bugs fixed

- Fix compile error.

# 0.4.3

Release Date: 2015-01-07

## Incompatible Changes

## Changes

## Bugs fixed

- Unpacker may unpack wrong uint32 value on 32bit or LLP64 environment.
  (#101)
- Build failed on Windows Python 2.7.

# 0.4.2

Release Date: 2014-03-26

## Incompatible Changes

## Changes

## Bugs fixed

- Unpacker doesn't increment refcount of ExtType hook.
- Packer raises no exception for inputs doesn't fit to msgpack format.

# 0.4.1

Release Date: 2014-02-17

## Incompatible Changes

## Changes

- fallback.Unpacker.feed() supports bytearray.

## Bugs fixed

- Unpacker doesn't increment refcount of hooks. Hooks may be GCed while
  unpacking.
- Unpacker may read unfilled internal buffer.

# 0.4.0

Release Date: 2013-10-21

## Incompatible Changes

- Raises TypeError instead of ValueError when packer receives
  unsupported type.

## Changes

- Support New msgpack spec.

# 0.3.0

## Incompatible Changes

- Default value of `use_list` is `True` for now. (It was `False` for
  0.2.x) You should pass it explicitly for compatibility to 0.2.x.
- `Unpacker.unpack()` and some unpack methods now raise `OutOfData` instead of
  `StopIteration`. `StopIteration` is used for iterator protocol only.

## Changes

- Pure Python fallback module is added. (thanks to bwesterb)
- Add `.skip()` method to `Unpacker` (thanks to jnothman)
- Add capturing feature. You can pass the writable object to
  `Unpacker.unpack()` as a second parameter.
- Add `Packer.pack_array_header` and `Packer.pack_map_header`. These
  methods only pack header of each type.
- Add `autoreset` option to `Packer` (default: True). Packer doesn't
  return packed bytes and clear internal buffer.
- Add `Packer.pack_map_pairs`. It packs sequence of pair to map type.

# 0.2.4

Release Date: 2012-12-22

## Bugs fixed

- Fix SEGV when object_hook or object_pairs_hook raise Exception. (#39)

# 0.2.3

Release Date: 2012-12-11

## Changes

- Warn when use_list is not specified. It's default value will be
  changed in 0.3.

## Bugs fixed

- Can't pack subclass of dict.

# 0.2.2

Release Date: 2012-09-21

## Changes

- Add `use_single_float` option to `Packer`. When it is true, packs
  float object in single precision format.

## Bugs fixed

- `unpack()` didn't restores gc state when it called with gc disabled.
  `unpack()` doesn't control gc now instead of restoring gc state
  collectly. User can control gc state when gc cause performance issue.
- `Unpacker`'s `read_size` option didn't used.

# 0.2.1

Release Date: 2012-08-20

## Changes

- Add `max_buffer_size` parameter to Unpacker. It limits internal buffer
  size and allows unpack data from untrusted source safely.
- Unpacker's buffer reallocation algorithm is less greedy now. It cause
  performance decrease in rare case but memory efficient and don't
  allocate than `max_buffer_size`.

## Bugs fixed

- Fix msgpack didn't work on SPARC Solaris. It was because choosing
  wrong byteorder on compilation time. Use `sys.byteorder` to get
  correct byte order. Very thanks to Chris Casey for giving test
  environment to me.

# 0.2.0

Release Date: 2012-06-27

## Changes

- Drop supporting Python 2.5 and unify tests for Py2 and Py3.
- Use new version of msgpack-c. It packs correctly on big endian
  platforms.
- Remove deprecated packs and unpacks API.

## Bugs fixed

- \#8 Packing subclass of dict raises TypeError. (Thanks to Steeve
  Morin.)

# 0.1.13

Release Date: 2012-04-21

## New

- Don't accept subtype of list and tuple as msgpack list. (Steeve Morin)
  It allows customize how it serialized with `default` argument.

## Bugs fixed

- Fix wrong error message. (David Wolever)
- Fix memory leak while unpacking when `object_hook` or `list_hook` is
  used. (Steeve Morin)

## Other changes

- setup.py works on Python 2.5 (Steffen Siering)
- Optimization for serializing dict.

# 0.1.12

Release Date: 2011-12-27

## Bugs fixed

- Re-enable packs/unpacks removed at 0.1.11. It will be removed when 0.2
  is released.

# 0.1.11

Release Date: 2011-12-26

## Bugs fixed

- Include test code for Python3 to sdist. (Johan Bergström)
- Fix compilation error on MSVC. (davidgaleano)

# 0.1.10

Release Date: 2011-08-22

## New feature

- Add `encoding` and `unicode_errors` option to packer and unpacker.
  When this option is specified, (un)packs unicode object instead of
  bytes. This enables using msgpack as a replacement of json. (tailhook)

# 0.1.9

Release Date: 2011-01-29

## New feature

- `use_list` option is added to unpack(b) like Unpacker. (Use keyword
  argument because order of parameters are different)

## Bugs fixed

- Fix typo.
- Add MemoryError check.

# 0.1.8

Release Date: 2011-01-10

## New feature

- Support `loads` and `dumps` aliases for API compatibility with
  simplejson and pickle.
- Add *object_hook* and *list_hook* option to unpacker. It allows you to
  hook unpacking mapping type and array type.
- Add *default* option to packer. It allows you to pack unsupported
  types.
- unpacker accepts (old) buffer types.

## Bugs fixed

- Fix segv around `Unpacker.feed` or `Unpacker(file)`.

# 0.1.7

Release Date: 2010-11-02

## New feature

- Add *object_hook* and *list_hook* option to unpacker. It allows you to
  hook unpacking mapping type and array type.
- Add *default* option to packer. It allows you to pack unsupported
  types.
- unpacker accepts (old) buffer types.

## Bugs fixed

- Compilation error on win32.