{
"format": "promptkb-evidence-brief",
"version": 1,
"title": "Python 3.11 → 3.14: a scoped tomllib migration brief",
"question": "For a maintainer moving a TOML-reading utility from Python 3.11 to Python 3.14, what should be checked about file input, decimal values and error handling? Can tomllib itself write edited configuration? Compare the pinned 3.11.0 and 3.14.0 documentation; distinguish the separate local CPython 3.14.4 probe from evidence about other runtimes. Do not claim performance or migration success.",
"sources": [
{
"id": "S1",
"title": "CPython 3.11.0 tomllib documentation (raw RST)",
"locator": "https://raw.githubusercontent.com/python/cpython/deaf509e8fc6e0363bd6f26d52ad42f976ec42f2/Doc/library/tomllib.rst",
"text": ":mod:`tomllib` --- Parse TOML files\n===================================\n\n.. module:: tomllib\n :synopsis: Parse TOML files.\n\n.. versionadded:: 3.11\n\n.. moduleauthor:: Taneli Hukkinen\n.. sectionauthor:: Taneli Hukkinen\n\n**Source code:** :source:`Lib/tomllib`\n\n--------------\n\nThis module provides an interface for parsing TOML (Tom's Obvious Minimal\nLanguage, `https://toml.io `_). This module does not\nsupport writing TOML.\n\n.. seealso::\n\n The `Tomli-W package `__\n is a TOML writer that can be used in conjunction with this module,\n providing a write API familiar to users of the standard library\n :mod:`marshal` and :mod:`pickle` modules.\n\n.. seealso::\n\n The `TOML Kit package `__\n is a style-preserving TOML library with both read and write capability.\n It is a recommended replacement for this module for editing already\n existing TOML files.\n\n\nThis module defines the following functions:\n\n.. function:: load(fp, /, *, parse_float=float)\n\n Read a TOML file. The first argument should be a readable and binary file object.\n Return a :class:`dict`. Convert TOML types to Python using this\n :ref:`conversion table `.\n\n *parse_float* will be called with the string of every TOML\n float to be decoded. By default, this is equivalent to ``float(num_str)``.\n This can be used to use another datatype or parser for TOML floats\n (e.g. :class:`decimal.Decimal`). The callable must not return a\n :class:`dict` or a :class:`list`, else a :exc:`ValueError` is raised.\n\n A :exc:`TOMLDecodeError` will be raised on an invalid TOML document.\n\n\n.. function:: loads(s, /, *, parse_float=float)\n\n Load TOML from a :class:`str` object. Return a :class:`dict`. Convert TOML\n types to Python using this :ref:`conversion table `. The\n *parse_float* argument has the same meaning as in :func:`load`.\n\n A :exc:`TOMLDecodeError` will be raised on an invalid TOML document.\n\n\nThe following exceptions are available:\n\n.. exception:: TOMLDecodeError\n\n Subclass of :exc:`ValueError`.\n\n\nExamples\n--------\n\nParsing a TOML file::\n\n import tomllib\n\n with open(\"pyproject.toml\", \"rb\") as f:\n data = tomllib.load(f)\n\nParsing a TOML string::\n\n import tomllib\n\n toml_str = \"\"\"\n python-version = \"3.11.0\"\n python-implementation = \"CPython\"\n \"\"\"\n\n data = tomllib.loads(toml_str)\n\n\nConversion Table\n----------------\n\n.. _toml-to-py-table:\n\n+------------------+--------------------------------------------------------------------------------------+\n| TOML | Python |\n+==================+======================================================================================+\n| table | dict |\n+------------------+--------------------------------------------------------------------------------------+\n| string | str |\n+------------------+--------------------------------------------------------------------------------------+\n| integer | int |\n+------------------+--------------------------------------------------------------------------------------+\n| float | float (configurable with *parse_float*) |\n+------------------+--------------------------------------------------------------------------------------+\n| boolean | bool |\n+------------------+--------------------------------------------------------------------------------------+\n| offset date-time | datetime.datetime (``tzinfo`` attribute set to an instance of ``datetime.timezone``) |\n+------------------+--------------------------------------------------------------------------------------+\n| local date-time | datetime.datetime (``tzinfo`` attribute set to ``None``) |\n+------------------+--------------------------------------------------------------------------------------+\n| local date | datetime.date |\n+------------------+--------------------------------------------------------------------------------------+\n| local time | datetime.time |\n+------------------+--------------------------------------------------------------------------------------+\n| array | list |\n+------------------+--------------------------------------------------------------------------------------+\n",
"rights": "Copyright (c) 2001 Python Software Foundation; All Rights Reserved. Source RST is reproduced unchanged; this brief adds selected quotations and agent-authored interpretation, not changes to Python. No PSF endorsement. Full license from the same release follows.\n\nA. HISTORY OF THE SOFTWARE\n==========================\n\nPython was created in the early 1990s by Guido van Rossum at Stichting\nMathematisch Centrum (CWI, see http://www.cwi.nl) in the Netherlands\nas a successor of a language called ABC. Guido remains Python's\nprincipal author, although it includes many contributions from others.\n\nIn 1995, Guido continued his work on Python at the Corporation for\nNational Research Initiatives (CNRI, see http://www.cnri.reston.va.us)\nin Reston, Virginia where he released several versions of the\nsoftware.\n\nIn May 2000, Guido and the Python core development team moved to\nBeOpen.com to form the BeOpen PythonLabs team. In October of the same\nyear, the PythonLabs team moved to Digital Creations, which became\nZope Corporation. In 2001, the Python Software Foundation (PSF, see\nhttps://www.python.org/psf/) was formed, a non-profit organization\ncreated specifically to own Python-related Intellectual Property.\nZope Corporation was a sponsoring member of the PSF.\n\nAll Python releases are Open Source (see http://www.opensource.org for\nthe Open Source Definition). Historically, most, but not all, Python\nreleases have also been GPL-compatible; the table below summarizes\nthe various releases.\n\n Release Derived Year Owner GPL-\n from compatible? (1)\n\n 0.9.0 thru 1.2 1991-1995 CWI yes\n 1.3 thru 1.5.2 1.2 1995-1999 CNRI yes\n 1.6 1.5.2 2000 CNRI no\n 2.0 1.6 2000 BeOpen.com no\n 1.6.1 1.6 2001 CNRI yes (2)\n 2.1 2.0+1.6.1 2001 PSF no\n 2.0.1 2.0+1.6.1 2001 PSF yes\n 2.1.1 2.1+2.0.1 2001 PSF yes\n 2.1.2 2.1.1 2002 PSF yes\n 2.1.3 2.1.2 2002 PSF yes\n 2.2 and above 2.1.1 2001-now PSF yes\n\nFootnotes:\n\n(1) GPL-compatible doesn't mean that we're distributing Python under\n the GPL. All Python licenses, unlike the GPL, let you distribute\n a modified version without making your changes open source. The\n GPL-compatible licenses make it possible to combine Python with\n other software that is released under the GPL; the others don't.\n\n(2) According to Richard Stallman, 1.6.1 is not GPL-compatible,\n because its license has a choice of law clause. According to\n CNRI, however, Stallman's lawyer has told CNRI's lawyer that 1.6.1\n is \"not incompatible\" with the GPL.\n\nThanks to the many outside volunteers who have worked under Guido's\ndirection to make these releases possible.\n\n\nB. TERMS AND CONDITIONS FOR ACCESSING OR OTHERWISE USING PYTHON\n===============================================================\n\nPython software and documentation are licensed under the\nPython Software Foundation License Version 2.\n\nStarting with Python 3.8.6, examples, recipes, and other code in\nthe documentation are dual licensed under the PSF License Version 2\nand the Zero-Clause BSD license.\n\nSome software incorporated into Python is under different licenses.\nThe licenses are listed with code falling under that license.\n\n\nPYTHON SOFTWARE FOUNDATION LICENSE VERSION 2\n--------------------------------------------\n\n1. This LICENSE AGREEMENT is between the Python Software Foundation\n(\"PSF\"), and the Individual or Organization (\"Licensee\") accessing and\notherwise using this software (\"Python\") in source or binary form and\nits associated documentation.\n\n2. Subject to the terms and conditions of this License Agreement, PSF hereby\ngrants Licensee a nonexclusive, royalty-free, world-wide license to reproduce,\nanalyze, test, perform and/or display publicly, prepare derivative works,\ndistribute, and otherwise use Python alone or in any derivative version,\nprovided, however, that PSF's License Agreement and PSF's notice of copyright,\ni.e., \"Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,\n2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022 Python Software Foundation;\nAll Rights Reserved\" are retained in Python alone or in any derivative version\nprepared by Licensee.\n\n3. In the event Licensee prepares a derivative work that is based on\nor incorporates Python or any part thereof, and wants to make\nthe derivative work available to others as provided herein, then\nLicensee hereby agrees to include in any such work a brief summary of\nthe changes made to Python.\n\n4. PSF is making Python available to Licensee on an \"AS IS\"\nbasis. PSF MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR\nIMPLIED. BY WAY OF EXAMPLE, BUT NOT LIMITATION, PSF MAKES NO AND\nDISCLAIMS ANY REPRESENTATION OR WARRANTY OF MERCHANTABILITY OR FITNESS\nFOR ANY PARTICULAR PURPOSE OR THAT THE USE OF PYTHON WILL NOT\nINFRINGE ANY THIRD PARTY RIGHTS.\n\n5. PSF SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF PYTHON\nFOR ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS\nA RESULT OF MODIFYING, DISTRIBUTING, OR OTHERWISE USING PYTHON,\nOR ANY DERIVATIVE THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF.\n\n6. This License Agreement will automatically terminate upon a material\nbreach of its terms and conditions.\n\n7. Nothing in this License Agreement shall be deemed to create any\nrelationship of agency, partnership, or joint venture between PSF and\nLicensee. This License Agreement does not grant permission to use PSF\ntrademarks or trade name in a trademark sense to endorse or promote\nproducts or services of Licensee, or any third party.\n\n8. By copying, installing or otherwise using Python, Licensee\nagrees to be bound by the terms and conditions of this License\nAgreement.\n\n\nBEOPEN.COM LICENSE AGREEMENT FOR PYTHON 2.0\n-------------------------------------------\n\nBEOPEN PYTHON OPEN SOURCE LICENSE AGREEMENT VERSION 1\n\n1. This LICENSE AGREEMENT is between BeOpen.com (\"BeOpen\"), having an\noffice at 160 Saratoga Avenue, Santa Clara, CA 95051, and the\nIndividual or Organization (\"Licensee\") accessing and otherwise using\nthis software in source or binary form and its associated\ndocumentation (\"the Software\").\n\n2. Subject to the terms and conditions of this BeOpen Python License\nAgreement, BeOpen hereby grants Licensee a non-exclusive,\nroyalty-free, world-wide license to reproduce, analyze, test, perform\nand/or display publicly, prepare derivative works, distribute, and\notherwise use the Software alone or in any derivative version,\nprovided, however, that the BeOpen Python License is retained in the\nSoftware, alone or in any derivative version prepared by Licensee.\n\n3. BeOpen is making the Software available to Licensee on an \"AS IS\"\nbasis. BEOPEN MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR\nIMPLIED. BY WAY OF EXAMPLE, BUT NOT LIMITATION, BEOPEN MAKES NO AND\nDISCLAIMS ANY REPRESENTATION OR WARRANTY OF MERCHANTABILITY OR FITNESS\nFOR ANY PARTICULAR PURPOSE OR THAT THE USE OF THE SOFTWARE WILL NOT\nINFRINGE ANY THIRD PARTY RIGHTS.\n\n4. BEOPEN SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF THE\nSOFTWARE FOR ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS\nAS A RESULT OF USING, MODIFYING OR DISTRIBUTING THE SOFTWARE, OR ANY\nDERIVATIVE THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF.\n\n5. This License Agreement will automatically terminate upon a material\nbreach of its terms and conditions.\n\n6. This License Agreement shall be governed by and interpreted in all\nrespects by the law of the State of California, excluding conflict of\nlaw provisions. Nothing in this License Agreement shall be deemed to\ncreate any relationship of agency, partnership, or joint venture\nbetween BeOpen and Licensee. This License Agreement does not grant\npermission to use BeOpen trademarks or trade names in a trademark\nsense to endorse or promote products or services of Licensee, or any\nthird party. As an exception, the \"BeOpen Python\" logos available at\nhttp://www.pythonlabs.com/logos.html may be used according to the\npermissions granted on that web page.\n\n7. By copying, installing or otherwise using the software, Licensee\nagrees to be bound by the terms and conditions of this License\nAgreement.\n\n\nCNRI LICENSE AGREEMENT FOR PYTHON 1.6.1\n---------------------------------------\n\n1. This LICENSE AGREEMENT is between the Corporation for National\nResearch Initiatives, having an office at 1895 Preston White Drive,\nReston, VA 20191 (\"CNRI\"), and the Individual or Organization\n(\"Licensee\") accessing and otherwise using Python 1.6.1 software in\nsource or binary form and its associated documentation.\n\n2. Subject to the terms and conditions of this License Agreement, CNRI\nhereby grants Licensee a nonexclusive, royalty-free, world-wide\nlicense to reproduce, analyze, test, perform and/or display publicly,\nprepare derivative works, distribute, and otherwise use Python 1.6.1\nalone or in any derivative version, provided, however, that CNRI's\nLicense Agreement and CNRI's notice of copyright, i.e., \"Copyright (c)\n1995-2001 Corporation for National Research Initiatives; All Rights\nReserved\" are retained in Python 1.6.1 alone or in any derivative\nversion prepared by Licensee. Alternately, in lieu of CNRI's License\nAgreement, Licensee may substitute the following text (omitting the\nquotes): \"Python 1.6.1 is made available subject to the terms and\nconditions in CNRI's License Agreement. This Agreement together with\nPython 1.6.1 may be located on the internet using the following\nunique, persistent identifier (known as a handle): 1895.22/1013. This\nAgreement may also be obtained from a proxy server on the internet\nusing the following URL: http://hdl.handle.net/1895.22/1013\".\n\n3. In the event Licensee prepares a derivative work that is based on\nor incorporates Python 1.6.1 or any part thereof, and wants to make\nthe derivative work available to others as provided herein, then\nLicensee hereby agrees to include in any such work a brief summary of\nthe changes made to Python 1.6.1.\n\n4. CNRI is making Python 1.6.1 available to Licensee on an \"AS IS\"\nbasis. CNRI MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR\nIMPLIED. BY WAY OF EXAMPLE, BUT NOT LIMITATION, CNRI MAKES NO AND\nDISCLAIMS ANY REPRESENTATION OR WARRANTY OF MERCHANTABILITY OR FITNESS\nFOR ANY PARTICULAR PURPOSE OR THAT THE USE OF PYTHON 1.6.1 WILL NOT\nINFRINGE ANY THIRD PARTY RIGHTS.\n\n5. CNRI SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF PYTHON\n1.6.1 FOR ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS\nA RESULT OF MODIFYING, DISTRIBUTING, OR OTHERWISE USING PYTHON 1.6.1,\nOR ANY DERIVATIVE THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF.\n\n6. This License Agreement will automatically terminate upon a material\nbreach of its terms and conditions.\n\n7. This License Agreement shall be governed by the federal\nintellectual property law of the United States, including without\nlimitation the federal copyright law, and, to the extent such\nU.S. federal law does not apply, by the law of the Commonwealth of\nVirginia, excluding Virginia's conflict of law provisions.\nNotwithstanding the foregoing, with regard to derivative works based\non Python 1.6.1 that incorporate non-separable material that was\npreviously distributed under the GNU General Public License (GPL), the\nlaw of the Commonwealth of Virginia shall govern this License\nAgreement only as to issues arising under or with respect to\nParagraphs 4, 5, and 7 of this License Agreement. Nothing in this\nLicense Agreement shall be deemed to create any relationship of\nagency, partnership, or joint venture between CNRI and Licensee. This\nLicense Agreement does not grant permission to use CNRI trademarks or\ntrade name in a trademark sense to endorse or promote products or\nservices of Licensee, or any third party.\n\n8. By clicking on the \"ACCEPT\" button where indicated, or by copying,\ninstalling or otherwise using Python 1.6.1, Licensee agrees to be\nbound by the terms and conditions of this License Agreement.\n\n ACCEPT\n\n\nCWI LICENSE AGREEMENT FOR PYTHON 0.9.0 THROUGH 1.2\n--------------------------------------------------\n\nCopyright (c) 1991 - 1995, Stichting Mathematisch Centrum Amsterdam,\nThe Netherlands. All rights reserved.\n\nPermission to use, copy, modify, and distribute this software and its\ndocumentation for any purpose and without fee is hereby granted,\nprovided that the above copyright notice appear in all copies and that\nboth that copyright notice and this permission notice appear in\nsupporting documentation, and that the name of Stichting Mathematisch\nCentrum or CWI not be used in advertising or publicity pertaining to\ndistribution of the software without specific, written prior\npermission.\n\nSTICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO\nTHIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND\nFITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE\nFOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES\nWHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN\nACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT\nOF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.\n\nZERO-CLAUSE BSD LICENSE FOR CODE IN THE PYTHON DOCUMENTATION\n----------------------------------------------------------------------\n\nPermission to use, copy, modify, and/or distribute this software for any\npurpose with or without fee is hereby granted.\n\nTHE SOFTWARE IS PROVIDED \"AS IS\" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH\nREGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY\nAND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,\nINDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM\nLOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR\nOTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR\nPERFORMANCE OF THIS SOFTWARE.\n"
},
{
"id": "S2",
"title": "CPython 3.14.0 tomllib documentation (raw RST)",
"locator": "https://raw.githubusercontent.com/python/cpython/ebf955df7a89ed0c7968f79faec1de49f61ed7cb/Doc/library/tomllib.rst",
"text": ":mod:`!tomllib` --- Parse TOML files\n====================================\n\n.. module:: tomllib\n :synopsis: Parse TOML files.\n\n.. versionadded:: 3.11\n\n.. moduleauthor:: Taneli Hukkinen\n.. sectionauthor:: Taneli Hukkinen\n\n**Source code:** :source:`Lib/tomllib`\n\n--------------\n\nThis module provides an interface for parsing TOML 1.0.0 (Tom's Obvious Minimal\nLanguage, `https://toml.io `_). This module does not\nsupport writing TOML.\n\n.. seealso::\n\n The :pypi:`Tomli-W package `\n is a TOML writer that can be used in conjunction with this module,\n providing a write API familiar to users of the standard library\n :mod:`marshal` and :mod:`pickle` modules.\n\n.. seealso::\n\n The :pypi:`TOML Kit package `\n is a style-preserving TOML library with both read and write capability.\n It is a recommended replacement for this module for editing already\n existing TOML files.\n\n\nThis module defines the following functions:\n\n.. function:: load(fp, /, *, parse_float=float)\n\n Read a TOML file. The first argument should be a readable and binary file object.\n Return a :class:`dict`. Convert TOML types to Python using this\n :ref:`conversion table `.\n\n *parse_float* will be called with the string of every TOML\n float to be decoded. By default, this is equivalent to ``float(num_str)``.\n This can be used to use another datatype or parser for TOML floats\n (e.g. :class:`decimal.Decimal`). The callable must not return a\n :class:`dict` or a :class:`list`, else a :exc:`ValueError` is raised.\n\n A :exc:`TOMLDecodeError` will be raised on an invalid TOML document.\n\n\n.. function:: loads(s, /, *, parse_float=float)\n\n Load TOML from a :class:`str` object. Return a :class:`dict`. Convert TOML\n types to Python using this :ref:`conversion table `. The\n *parse_float* argument has the same meaning as in :func:`load`.\n\n A :exc:`TOMLDecodeError` will be raised on an invalid TOML document.\n\n\nThe following exceptions are available:\n\n.. exception:: TOMLDecodeError(msg, doc, pos)\n\n Subclass of :exc:`ValueError` with the following additional attributes:\n\n .. attribute:: msg\n\n The unformatted error message.\n\n .. attribute:: doc\n\n The TOML document being parsed.\n\n .. attribute:: pos\n\n The index of *doc* where parsing failed.\n\n .. attribute:: lineno\n\n The line corresponding to *pos*.\n\n .. attribute:: colno\n\n The column corresponding to *pos*.\n\n .. versionchanged:: 3.14\n Added the *msg*, *doc* and *pos* parameters.\n Added the :attr:`msg`, :attr:`doc`, :attr:`pos`, :attr:`lineno` and :attr:`colno` attributes.\n\n .. deprecated:: 3.14\n Passing free-form positional arguments is deprecated.\n\n\nExamples\n--------\n\nParsing a TOML file::\n\n import tomllib\n\n with open(\"pyproject.toml\", \"rb\") as f:\n data = tomllib.load(f)\n\nParsing a TOML string::\n\n import tomllib\n\n toml_str = \"\"\"\n python-version = \"3.11.0\"\n python-implementation = \"CPython\"\n \"\"\"\n\n data = tomllib.loads(toml_str)\n\n\nConversion Table\n----------------\n\n.. _toml-to-py-table:\n\n+------------------+--------------------------------------------------------------------------------------+\n| TOML | Python |\n+==================+======================================================================================+\n| TOML document | dict |\n+------------------+--------------------------------------------------------------------------------------+\n| string | str |\n+------------------+--------------------------------------------------------------------------------------+\n| integer | int |\n+------------------+--------------------------------------------------------------------------------------+\n| float | float (configurable with *parse_float*) |\n+------------------+--------------------------------------------------------------------------------------+\n| boolean | bool |\n+------------------+--------------------------------------------------------------------------------------+\n| offset date-time | datetime.datetime (``tzinfo`` attribute set to an instance of ``datetime.timezone``) |\n+------------------+--------------------------------------------------------------------------------------+\n| local date-time | datetime.datetime (``tzinfo`` attribute set to ``None``) |\n+------------------+--------------------------------------------------------------------------------------+\n| local date | datetime.date |\n+------------------+--------------------------------------------------------------------------------------+\n| local time | datetime.time |\n+------------------+--------------------------------------------------------------------------------------+\n| array | list |\n+------------------+--------------------------------------------------------------------------------------+\n| table | dict |\n+------------------+--------------------------------------------------------------------------------------+\n| inline table | dict |\n+------------------+--------------------------------------------------------------------------------------+\n| array of tables | list of dicts |\n+------------------+--------------------------------------------------------------------------------------+\n",
"rights": "Copyright (c) 2001 Python Software Foundation; All Rights Reserved. Source RST is reproduced unchanged; this brief adds selected quotations and agent-authored interpretation, not changes to Python. No PSF endorsement. Full license from the same release follows.\n\nA. HISTORY OF THE SOFTWARE\n==========================\n\nPython was created in the early 1990s by Guido van Rossum at Stichting\nMathematisch Centrum (CWI, see https://www.cwi.nl) in the Netherlands\nas a successor of a language called ABC. Guido remains Python's\nprincipal author, although it includes many contributions from others.\n\nIn 1995, Guido continued his work on Python at the Corporation for\nNational Research Initiatives (CNRI, see https://www.cnri.reston.va.us)\nin Reston, Virginia where he released several versions of the\nsoftware.\n\nIn May 2000, Guido and the Python core development team moved to\nBeOpen.com to form the BeOpen PythonLabs team. In October of the same\nyear, the PythonLabs team moved to Digital Creations, which became\nZope Corporation. In 2001, the Python Software Foundation (PSF, see\nhttps://www.python.org/psf/) was formed, a non-profit organization\ncreated specifically to own Python-related Intellectual Property.\nZope Corporation was a sponsoring member of the PSF.\n\nAll Python releases are Open Source (see https://opensource.org for\nthe Open Source Definition). Historically, most, but not all, Python\nreleases have also been GPL-compatible; the table below summarizes\nthe various releases.\n\n Release Derived Year Owner GPL-\n from compatible? (1)\n\n 0.9.0 thru 1.2 1991-1995 CWI yes\n 1.3 thru 1.5.2 1.2 1995-1999 CNRI yes\n 1.6 1.5.2 2000 CNRI no\n 2.0 1.6 2000 BeOpen.com no\n 1.6.1 1.6 2001 CNRI yes (2)\n 2.1 2.0+1.6.1 2001 PSF no\n 2.0.1 2.0+1.6.1 2001 PSF yes\n 2.1.1 2.1+2.0.1 2001 PSF yes\n 2.1.2 2.1.1 2002 PSF yes\n 2.1.3 2.1.2 2002 PSF yes\n 2.2 and above 2.1.1 2001-now PSF yes\n\nFootnotes:\n\n(1) GPL-compatible doesn't mean that we're distributing Python under\n the GPL. All Python licenses, unlike the GPL, let you distribute\n a modified version without making your changes open source. The\n GPL-compatible licenses make it possible to combine Python with\n other software that is released under the GPL; the others don't.\n\n(2) According to Richard Stallman, 1.6.1 is not GPL-compatible,\n because its license has a choice of law clause. According to\n CNRI, however, Stallman's lawyer has told CNRI's lawyer that 1.6.1\n is \"not incompatible\" with the GPL.\n\nThanks to the many outside volunteers who have worked under Guido's\ndirection to make these releases possible.\n\n\nB. TERMS AND CONDITIONS FOR ACCESSING OR OTHERWISE USING PYTHON\n===============================================================\n\nPython software and documentation are licensed under the\nPython Software Foundation License Version 2.\n\nStarting with Python 3.8.6, examples, recipes, and other code in\nthe documentation are dual licensed under the PSF License Version 2\nand the Zero-Clause BSD license.\n\nSome software incorporated into Python is under different licenses.\nThe licenses are listed with code falling under that license.\n\n\nPYTHON SOFTWARE FOUNDATION LICENSE VERSION 2\n--------------------------------------------\n\n1. This LICENSE AGREEMENT is between the Python Software Foundation\n(\"PSF\"), and the Individual or Organization (\"Licensee\") accessing and\notherwise using this software (\"Python\") in source or binary form and\nits associated documentation.\n\n2. Subject to the terms and conditions of this License Agreement, PSF hereby\ngrants Licensee a nonexclusive, royalty-free, world-wide license to reproduce,\nanalyze, test, perform and/or display publicly, prepare derivative works,\ndistribute, and otherwise use Python alone or in any derivative version,\nprovided, however, that PSF's License Agreement and PSF's notice of copyright,\ni.e., \"Copyright (c) 2001 Python Software Foundation; All Rights Reserved\"\nare retained in Python alone or in any derivative version prepared by Licensee.\n\n3. In the event Licensee prepares a derivative work that is based on\nor incorporates Python or any part thereof, and wants to make\nthe derivative work available to others as provided herein, then\nLicensee hereby agrees to include in any such work a brief summary of\nthe changes made to Python.\n\n4. PSF is making Python available to Licensee on an \"AS IS\"\nbasis. PSF MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR\nIMPLIED. BY WAY OF EXAMPLE, BUT NOT LIMITATION, PSF MAKES NO AND\nDISCLAIMS ANY REPRESENTATION OR WARRANTY OF MERCHANTABILITY OR FITNESS\nFOR ANY PARTICULAR PURPOSE OR THAT THE USE OF PYTHON WILL NOT\nINFRINGE ANY THIRD PARTY RIGHTS.\n\n5. PSF SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF PYTHON\nFOR ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS\nA RESULT OF MODIFYING, DISTRIBUTING, OR OTHERWISE USING PYTHON,\nOR ANY DERIVATIVE THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF.\n\n6. This License Agreement will automatically terminate upon a material\nbreach of its terms and conditions.\n\n7. Nothing in this License Agreement shall be deemed to create any\nrelationship of agency, partnership, or joint venture between PSF and\nLicensee. This License Agreement does not grant permission to use PSF\ntrademarks or trade name in a trademark sense to endorse or promote\nproducts or services of Licensee, or any third party.\n\n8. By copying, installing or otherwise using Python, Licensee\nagrees to be bound by the terms and conditions of this License\nAgreement.\n\n\nBEOPEN.COM LICENSE AGREEMENT FOR PYTHON 2.0\n-------------------------------------------\n\nBEOPEN PYTHON OPEN SOURCE LICENSE AGREEMENT VERSION 1\n\n1. This LICENSE AGREEMENT is between BeOpen.com (\"BeOpen\"), having an\noffice at 160 Saratoga Avenue, Santa Clara, CA 95051, and the\nIndividual or Organization (\"Licensee\") accessing and otherwise using\nthis software in source or binary form and its associated\ndocumentation (\"the Software\").\n\n2. Subject to the terms and conditions of this BeOpen Python License\nAgreement, BeOpen hereby grants Licensee a non-exclusive,\nroyalty-free, world-wide license to reproduce, analyze, test, perform\nand/or display publicly, prepare derivative works, distribute, and\notherwise use the Software alone or in any derivative version,\nprovided, however, that the BeOpen Python License is retained in the\nSoftware, alone or in any derivative version prepared by Licensee.\n\n3. BeOpen is making the Software available to Licensee on an \"AS IS\"\nbasis. BEOPEN MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR\nIMPLIED. BY WAY OF EXAMPLE, BUT NOT LIMITATION, BEOPEN MAKES NO AND\nDISCLAIMS ANY REPRESENTATION OR WARRANTY OF MERCHANTABILITY OR FITNESS\nFOR ANY PARTICULAR PURPOSE OR THAT THE USE OF THE SOFTWARE WILL NOT\nINFRINGE ANY THIRD PARTY RIGHTS.\n\n4. BEOPEN SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF THE\nSOFTWARE FOR ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS\nAS A RESULT OF USING, MODIFYING OR DISTRIBUTING THE SOFTWARE, OR ANY\nDERIVATIVE THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF.\n\n5. This License Agreement will automatically terminate upon a material\nbreach of its terms and conditions.\n\n6. This License Agreement shall be governed by and interpreted in all\nrespects by the law of the State of California, excluding conflict of\nlaw provisions. Nothing in this License Agreement shall be deemed to\ncreate any relationship of agency, partnership, or joint venture\nbetween BeOpen and Licensee. This License Agreement does not grant\npermission to use BeOpen trademarks or trade names in a trademark\nsense to endorse or promote products or services of Licensee, or any\nthird party. As an exception, the \"BeOpen Python\" logos available at\nhttp://www.pythonlabs.com/logos.html may be used according to the\npermissions granted on that web page.\n\n7. By copying, installing or otherwise using the software, Licensee\nagrees to be bound by the terms and conditions of this License\nAgreement.\n\n\nCNRI LICENSE AGREEMENT FOR PYTHON 1.6.1\n---------------------------------------\n\n1. This LICENSE AGREEMENT is between the Corporation for National\nResearch Initiatives, having an office at 1895 Preston White Drive,\nReston, VA 20191 (\"CNRI\"), and the Individual or Organization\n(\"Licensee\") accessing and otherwise using Python 1.6.1 software in\nsource or binary form and its associated documentation.\n\n2. Subject to the terms and conditions of this License Agreement, CNRI\nhereby grants Licensee a nonexclusive, royalty-free, world-wide\nlicense to reproduce, analyze, test, perform and/or display publicly,\nprepare derivative works, distribute, and otherwise use Python 1.6.1\nalone or in any derivative version, provided, however, that CNRI's\nLicense Agreement and CNRI's notice of copyright, i.e., \"Copyright (c)\n1995-2001 Corporation for National Research Initiatives; All Rights\nReserved\" are retained in Python 1.6.1 alone or in any derivative\nversion prepared by Licensee. Alternately, in lieu of CNRI's License\nAgreement, Licensee may substitute the following text (omitting the\nquotes): \"Python 1.6.1 is made available subject to the terms and\nconditions in CNRI's License Agreement. This Agreement together with\nPython 1.6.1 may be located on the internet using the following\nunique, persistent identifier (known as a handle): 1895.22/1013. This\nAgreement may also be obtained from a proxy server on the internet\nusing the following URL: http://hdl.handle.net/1895.22/1013\".\n\n3. In the event Licensee prepares a derivative work that is based on\nor incorporates Python 1.6.1 or any part thereof, and wants to make\nthe derivative work available to others as provided herein, then\nLicensee hereby agrees to include in any such work a brief summary of\nthe changes made to Python 1.6.1.\n\n4. CNRI is making Python 1.6.1 available to Licensee on an \"AS IS\"\nbasis. CNRI MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR\nIMPLIED. BY WAY OF EXAMPLE, BUT NOT LIMITATION, CNRI MAKES NO AND\nDISCLAIMS ANY REPRESENTATION OR WARRANTY OF MERCHANTABILITY OR FITNESS\nFOR ANY PARTICULAR PURPOSE OR THAT THE USE OF PYTHON 1.6.1 WILL NOT\nINFRINGE ANY THIRD PARTY RIGHTS.\n\n5. CNRI SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF PYTHON\n1.6.1 FOR ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS\nA RESULT OF MODIFYING, DISTRIBUTING, OR OTHERWISE USING PYTHON 1.6.1,\nOR ANY DERIVATIVE THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF.\n\n6. This License Agreement will automatically terminate upon a material\nbreach of its terms and conditions.\n\n7. This License Agreement shall be governed by the federal\nintellectual property law of the United States, including without\nlimitation the federal copyright law, and, to the extent such\nU.S. federal law does not apply, by the law of the Commonwealth of\nVirginia, excluding Virginia's conflict of law provisions.\nNotwithstanding the foregoing, with regard to derivative works based\non Python 1.6.1 that incorporate non-separable material that was\npreviously distributed under the GNU General Public License (GPL), the\nlaw of the Commonwealth of Virginia shall govern this License\nAgreement only as to issues arising under or with respect to\nParagraphs 4, 5, and 7 of this License Agreement. Nothing in this\nLicense Agreement shall be deemed to create any relationship of\nagency, partnership, or joint venture between CNRI and Licensee. This\nLicense Agreement does not grant permission to use CNRI trademarks or\ntrade name in a trademark sense to endorse or promote products or\nservices of Licensee, or any third party.\n\n8. By clicking on the \"ACCEPT\" button where indicated, or by copying,\ninstalling or otherwise using Python 1.6.1, Licensee agrees to be\nbound by the terms and conditions of this License Agreement.\n\n ACCEPT\n\n\nCWI LICENSE AGREEMENT FOR PYTHON 0.9.0 THROUGH 1.2\n--------------------------------------------------\n\nCopyright (c) 1991 - 1995, Stichting Mathematisch Centrum Amsterdam,\nThe Netherlands. All rights reserved.\n\nPermission to use, copy, modify, and distribute this software and its\ndocumentation for any purpose and without fee is hereby granted,\nprovided that the above copyright notice appear in all copies and that\nboth that copyright notice and this permission notice appear in\nsupporting documentation, and that the name of Stichting Mathematisch\nCentrum or CWI not be used in advertising or publicity pertaining to\ndistribution of the software without specific, written prior\npermission.\n\nSTICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO\nTHIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND\nFITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE\nFOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES\nWHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN\nACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT\nOF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.\n\nZERO-CLAUSE BSD LICENSE FOR CODE IN THE PYTHON DOCUMENTATION\n----------------------------------------------------------------------\n\nPermission to use, copy, modify, and/or distribute this software for any\npurpose with or without fee is hereby granted.\n\nTHE SOFTWARE IS PROVIDED \"AS IS\" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH\nREGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY\nAND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,\nINDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM\nLOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR\nOTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR\nPERFORMANCE OF THIS SOFTWARE.\n"
},
{
"id": "S3",
"title": "Local CPython 3.14.4 runtime probe",
"locator": "PromptKB, observed 2026-11-04T10:04:55.325813+00:00; probe.py and runtime-probe.json in this example directory.",
"text": "{\n \"observed_at\": \"2026-11-04T10:04:55.325813+00:00\",\n \"runtime\": \"CPython 3.14.4\",\n \"scope\": \"One local Python runtime. No Python 3.11 run, performance measurement, cross-version guarantee, real configuration migration or third-party writer test.\",\n \"results\": {\n \"binary_load\": {\n \"amount\": 1.2\n },\n \"decimal_loads\": {\n \"type\": \"Decimal\",\n \"value\": \"1.20\"\n },\n \"text_stream\": {\n \"exception\": \"TypeError\",\n \"message\": \"File must be opened in binary mode, e.g. use `open('foo.toml', 'rb')`\"\n },\n \"list_parse_float\": {\n \"exception\": \"ValueError\",\n \"message\": \"parse_float must not return dicts or lists\"\n },\n \"invalid_toml\": {\n \"exception\": \"TOMLDecodeError\",\n \"message\": \"Invalid value (at line 1, column 10)\",\n \"attributes\": {\n \"msg\": \"Invalid value\",\n \"doc\": \"amount = ]\",\n \"pos\": 9,\n \"lineno\": 1,\n \"colno\": 10\n }\n },\n \"has_dumps\": false\n }\n}\n",
"rights": "Agent-authored probe and observation. You may use, copy, modify and redistribute these additions, including commercially, without attribution or warranty. This permission does not replace the Python source licenses. No claim of independent review."
}
],
"response": "{\n \"claims\": [\n {\n \"id\": \"C1\",\n \"text\": \"Keep file inputs binary when using tomllib.load; both pinned documentation versions require a readable binary file object and document a dict result. This is not a newly introduced 3.14 requirement.\",\n \"citations\": [\n {\n \"source\": \"S1\",\n \"quote\": \"Read a TOML file. The first argument should be a readable and binary file object.\\n Return a :class:`dict`.\"\n },\n {\n \"source\": \"S2\",\n \"quote\": \"Read a TOML file. The first argument should be a readable and binary file object.\\n Return a :class:`dict`.\"\n }\n ]\n },\n {\n \"id\": \"C2\",\n \"text\": \"For explicit decimal handling, both versions document parse_float as a hook that can use decimal.Decimal. A hook returning a dict or list raises ValueError. Decimal support is not new in the 3.14 document.\",\n \"citations\": [\n {\n \"source\": \"S1\",\n \"quote\": \"This can be used to use another datatype or parser for TOML floats\\n (e.g. :class:`decimal.Decimal`). The callable must not return a\\n :class:`dict` or a :class:`list`, else a :exc:`ValueError` is raised.\"\n },\n {\n \"source\": \"S2\",\n \"quote\": \"This can be used to use another datatype or parser for TOML floats\\n (e.g. :class:`decimal.Decimal`). The callable must not return a\\n :class:`dict` or a :class:`list`, else a :exc:`ValueError` is raised.\"\n }\n ]\n },\n {\n \"id\": \"C3\",\n \"text\": \"Audit exception construction and inspection when migrating: the 3.14 document marks msg/doc/pos parameters and msg/doc/pos/lineno/colno attributes as added in 3.14, and deprecates passing free-form positional arguments. This documentation does not establish how every existing application handles those changes.\",\n \"citations\": [\n {\n \"source\": \"S2\",\n \"quote\": \".. versionchanged:: 3.14\\n Added the *msg*, *doc* and *pos* parameters.\\n Added the :attr:`msg`, :attr:`doc`, :attr:`pos`, :attr:`lineno` and :attr:`colno` attributes.\\n\\n .. deprecated:: 3.14\\n Passing free-form positional arguments is deprecated.\"\n }\n ]\n },\n {\n \"id\": \"C4\",\n \"text\": \"Do not plan to write edited configuration with tomllib itself: both documentation versions explicitly say it does not support writing TOML. A separate writer needs evaluation; this brief does not test one.\",\n \"citations\": [\n {\n \"source\": \"S1\",\n \"quote\": \"This module does not\\nsupport writing TOML.\"\n },\n {\n \"source\": \"S2\",\n \"quote\": \"This module does not\\nsupport writing TOML.\"\n }\n ]\n },\n {\n \"id\": \"C5\",\n \"text\": \"In the single local CPython 3.14.4 probe, Decimal parsing retained the value string 1.20. This is a narrow runtime observation, not a Python 3.11 run or a complete configuration-migration test.\",\n \"citations\": [\n {\n \"source\": \"S3\",\n \"quote\": \"\\\"runtime\\\": \\\"CPython 3.14.4\\\"\"\n },\n {\n \"source\": \"S3\",\n \"quote\": \"\\\"decimal_loads\\\": {\\n \\\"type\\\": \\\"Decimal\\\",\\n \\\"value\\\": \\\"1.20\\\"\\n }\"\n },\n {\n \"source\": \"S3\",\n \"quote\": \"\\\"scope\\\": \\\"One local Python runtime. No Python 3.11 run, performance measurement, cross-version guarantee, real configuration migration or third-party writer test.\\\"\"\n }\n ]\n },\n {\n \"id\": \"C6\",\n \"text\": \"Python 3.14 tomllib can write edited TOML files without a separate writer.\",\n \"citations\": [\n {\n \"source\": \"S2\",\n \"quote\": \"This module does not\\nsupport writing TOML.\"\n }\n ]\n }\n ],\n \"questions\": [\n \"Which supported Python versions and exception-construction patterns occur in the real application? Inspect its code and test all required runtimes before changing error handling.\",\n \"If configuration editing is required, which writer preserves the formatting and comments the application needs? Evaluate a writer separately; no writer was tested here.\",\n \"Does the real configuration corpus contain non-finite floats, dates or malformed documents that need additional policy/tests? This probe covers only tiny authored inputs.\"\n ]\n}",
"notes": "Editorial exercise, not model execution: the agent authored all six claims and these reviews using the same source context. C1–C5 are selected for this limited migration brief. C6 is a deliberately authored counterexample: its quote matches exactly but explicitly contradicts its claim; reject it. The cited PSF documentation is real and commit-pinned, not current-live documentation. S3 is a real local runtime observation on CPython 3.14.4, not a 3.11/3.14.0 compatibility comparison. No actual application was migrated, no performance measured, and no third-party writer tested. Next: inspect the application’s actual version floor, error handling and configuration corpus. This is not an independent review or demonstrated human time saving."
}