Package: ruamel.yaml
ruamel.yamlruamel.yamlis a YAML 1.2 loader/dumper package for Python.version0.18.6updated2024-02-07documentationhttps://yaml.readthedocs.iorepositoryhttps://sourceforge.net/projects/ruamel-yamlpypihttps://pypi.org/project/ruamel.yamlAs announced, in 0.18.0, the old PyYAML functions have been deprecated.
(scan,parse,compose,load,emit,serialize,dumpand their variants
(_all,safe_,round_trip_, etc)). If you only read this after your program has
stopped working: I am sorry to hear that, but that also means you, or the person
developing your program, has not tested with warnings on (which is the recommendation
in PEP 565, and e.g. defaultin when usingpytest). If you have troubles, explicitly usepip install "ruamel.yaml<0.18.0"or put something to that effects in your requirments, to give yourself
some time to solve the issue.There will be at least one more potentially breaking change in the 0.18 series:YAML(typ='unsafe')now has a pending deprecation warning and is going to be deprecated, probably before the end of 2023.
If you only use it to dump, please use the newYAML(typ='full'), the result of that can besafelyloaded with a default  instanceYAML(), as that will get you inspectable, tagged, scalars, instead of
executed Python functions/classes. (You should probably add constructors for what you actually need,
but I do consider adding aruamel.yaml.unsafepackage that will re-add thetyp='unsafe'option.Please adjust/pin your dependencies accordingly if necessary.There seems to be a CVE onruamel.yaml, stating that theload()function could be abused
because of unchecked input.load()was never the default function (that wasround_trip_load()before the new API came into existence. So the creator of that CVE was ill informed and probably lazily assumed that sinceruamel.yamlis a derivative of PyYAML (for which a similar CVE exists), the same problem would still exist, without checking.  So the CVE was always inappriate,  now just more so, as the call to the functionload()with any input will terminate your program with an error message. If you  (have to) care about such things as this CVE, my recommendation is to stop using Python completely, aspickle.load()can be abused in the same way asload()(and like unlikeload()`
is only documented to be unsafe, without development-time warning.Version 0.17.21 was the last one tested to be working on Python 3.5 and 3.6The 0.16.13 release was the last that was tested to be working on Python 2.7.There are two extra plug-in packages
(ruamel.yaml.bytesandruamel.yaml.string)
for those not wanting to do the streaming to aio.BytesIO/StringIObuffer themselves.If your package usesruamel.yamland is not listed on PyPI, drop me an
email, preferably with some information on how you use the package (or a
link to the repository) and I'll keep you informed when the status of
the API is stable enough to make the transition.OverviewInstallingOptional requirementsBasic UsageLoad and dumpMore examplesWorking with Python classesDumping Python classesDataclassDetailsIndentation of block sequencesInconsistently indented YAMLIndenting using `typ="safe"`Positioning ':' in top level mappings, prefixing ':'Document version supportRound trip including commentsConfig file formatsExtendingSmarteningExamplesOutput of `dump()` as a stringDeparture from previous APILoadingDuplicate keysDumping a multi-document YAML streamDumpingControlsTransparent usage of new and old APIReason for API changeDifferences with PyYAMLDefaulting to YAML 1.2 supportPY2/PY3 reintegrationFixesTestingAPIContributingDocumentationCodeFlakeTox/pytestTyping/mypyGenerated filesVulnerabilitiesChangeLog0.18.6 (2024-02-07):fixed an issue with dataclass loading when the fields were collections (bug found as a result of a question byFibroMyAlgebraonStackOverflow)fixed an issue loading dataclasses withInitVarfields whenfrom __future__ import annotationswas used to delay evaluation of typing.0.18.5 (2023-11-03):there is some indication that dependent packages have been pinned to use specific (tested) and just install the latest even in Python versions that have end-of-life0.18.4 (2023-11-01):YAML() instance has adoc_infosattribute which is a cumulative list of DocInfo instances (one forload(), one per document forload_all()). DocInfo instances contain version information (requested, directive) and tag directive informationfix issue that the YAML instance tags attribute was not reset between documents, resulting in mixing of tag directives of multiple documents. Now only provides tag directive information on latest document after loading. This means tags for dumping must be setagainafter a document is loaded with the same instance. (because of this tags will be removed in a favour of a different mechanism in the future)fix issue with multiple document intermixing YAML 1.2 and YAML 1.1, the VersionedResolver now resetsfix issue with disappearing comment when next token was Tag (still can't have both a comment before a tag and after a tag, before node)0.18.3 (2023-10-29):fix issue with spurious newline on first item after comment + nested block sequenceadditional links in the metadata on PyPI (Reported, with pointers how to fix, bySorin).0.18.2 (2023-10-24):calling the deprecated functions now raises anAttributeErrorwith the, somewhat more informative, orginal warning message. Instead of callingsys.exit(1)0.18.1 (2023-10-24):calling the deprecated functions now always displays the warning message. (reported byTrend Lloyd)0.18.0 (2023-10-23):thefunctionsscan,parse,compose,load,emit,serialize,dumpand their variants (_all,safe_,round_trip_, etc) have been deprecated (the same namedmethodsonYAML()instances are, of course, still there.YAML(typ='unsafe')now issues aPendingDeprecationWarning. This will become deprecated in the 0.18 series
(probably before the end of 2023).
You can useYAML(typ='full')to dump unregistered Python classes/functions.
For loading you'll have to register your classes/functions
if you want the old, unsafe, functionality. You can still load any tag, like `!!python/name:posix.system',safelywith the (default) round-trip parser.fix forbytes-like object is required not 'str' while dumping binary streams. This was reported, analysed and a fix provided byVit Zikmund0.17.40 (2023-10-20):flow style sets are now preserved (!!set {a, b, c} ). Any values specified when loading are dropped, including!!null "".potential workaround for issue 484: the long_description_content_type including the variant specificationCommonMarkcan result in problems on Azure. If you can install from.tar.gzusingRUAMEL_NO_LONG_DESCRIPTION=1 pip install ruamel.yaml --no-binary :all:then the long description, and its
offending type, are nog included (in the METADATA).
(Reported byCoury Ditch)links in documentation update (reported byDavid Hoese)Added some__repr__for internally used classes0.17.39 (2023-10-19):update README generation, no code changes0.17.36 (2023-10-19):fixed issue 480, dumping of a loaded empty flow-style mapping with comment failed (Reported byStéphane Brunner)fixed issue 482, caused by DEFAULT_MAPPING_TAG having changes to being aTag()instance, not a string (reported byyan12125)updated documentation to use mkdocs0.17.35 (2023-10-04):support for loading dataclasses withInitVarvariables (some special coding was necessary to get the, unexecpected, default value in the corresponding instance attribute ( example of usage inthis question)0.17.34 (2023-10-03):Python 3.12 also loads C version when usingtyp='safe'initial support for loading invoking__post_init__()on dataclasses that have that
method after loading a registered dataclass.
(Originallyaskedon
Stackoverflow bynyanpasu64and asticketbyPatrick Lehmann)@yaml.register_class
@dataclass
class ...0.17.33 (2023-09-28):addedflow_seq_start,flow_seq_end,flow_seq_separator,flow_map_start,flow_map_end,flow_map_separatorclassattributes to theEmitterclass so flow style output can more easily be influenced (based onthis answeron a StackOverflow question byHuw Walters).0.17.32 (2023-06-17):fix issue with scanner getting stuck in infinite loop0.17.31 (2023-05-31):added tag.setter onScalarEventand onNode, that takes either aTaginstance, or a str (reported bySorin Sbarnea)0.17.30 (2023-05-30):fix issue 467, caused by Tag instances not being hashable (reported byDouglas Raillard)0.17.29 (2023-05-30):changed the internals of the tag property from a string to a class which allows for preservation of the original handle and suffix. This should result in better results using documents with %TAG directives, as well as preserving URI escapes in tag suffixes.0.17.28 (2023-05-26):fix for issue 464: documents ending with document end marker
without final newline fail to load (reported byMariusz
Rusiniak)0.17.27 (2023-05-25):fix issue with inline mappings as value for merge keys (reported by Sirish onStackOverflow)fix for 468, error inserting after accessing merge attribute onCommentedMap(reported byBastien gerard)fix for issue 461 pop + insert on sameCommentedMapkey throwing error (reported byJohn Thorvald Wodder II)0.17.26 (2023-05-09):fix for error on edge cage for issue 4590.17.25 (2023-05-09):fix for regression while dumping wrapped strings with too many backslashes removed (issue 459, reported byLele Gaifax)0.17.24 (2023-05-06):rewrite ofCommentedMap.insert(). If you have a merge key in the YAML document for the mapping you insert to, the position value should be the one as you look at the YAML input. This fixes issue 453 where other keys of a merged in mapping would show up after an insert (reported byAlex Miller). It also fixes a call to.insert()resulting into the merge key to move to be the first key if it wasn't already and it is also now possible to insert a key before a merge key (even if the fist key in the mapping).fix (in the pure Python implementation including default) for issue 447. (reported byJack Cherng, also brought up by brent onStackOverflow)0.17.23 (2023-05-05):fix 458, error on plain scalars starting with word longer than width. (reported byKyle Larose)fix for.update()no longer correctly handling keyword arguments (reported by John Lin onStackOverflow)fix issue 454: high Unicode (emojis) in quoted strings always
escaped (reported byMichal
Čihařbased on a
question on StackOverflow).fix issue with emitter conservatively inserting extra backslashes in wrapped quoted strings (reported by thebenman onStackOverflow)0.17.22 (2023-05-02):fix issue 449 where the second exclamation marks got URL encoded (reported and fixing PR provided byJohn Stark)fix issue with indent != 2 and literal scalars with empty first line (reported by wrdis onStackOverflow)updated__repr__of CommentedMap, now that Python's dict is ordered -> no moreordereddict(list-of-tuples)merge MR 4, handling OctalInt in YAML 1.1 (provided byJacob Floyd)fix loading of!!float 42(reported by Eric onStack overflow)line numbers are now set onCommentedKeySeqandCommentedKeyMap(which are created if you have a sequence resp. mapping as the key in a mapping)plain scalars: put single words longer than width on a line of
their own, instead of after the previous line (issue 427, reported
byAntoine
Cotten). Caveat:
this currently results in a space ending the previous line.fix for folded scalar part of 421: comments after ">" on first
line of folded scalars are now preserved (as were those in the
same position on literal scalars). Issue reported by Jacob Floyd.added stacklevel to warningstyping changed from Py2 compatible comments to Py3, removed various Py2-isms0.17.21 (2022-02-12):fix bug in calling.compose()method withpathlib.Pathinstance.0.17.20 (2022-01-03):fix error in microseconds while rounding datetime fractions >= 9999995 (reported byLuis Ferreira)0.17.19 (2021-12-26):fix mypy problems (reported byArun)0.17.18 (2021-12-24):copy-paste error in folded scalar comment attachment (reported byStephan Geulette)fix 411, indent error comment between key empty seq value (reported byGuillermo Julián)0.17.17 (2021-10-31):extract timestamp matching/creation to util0.17.16 (2021-08-28):398 also handle issue 397 when comment is newline0.17.15 (2021-08-28):fix issue 397, insert comment before key when a comment between key and value exists (reported byBastien gerard)0.17.14 (2021-08-25):fix issue 396, inserting key/val in merged-in dictionary (reported byBastien gerard)0.17.13 (2021-08-21):minor fix in attr handling0.17.12 (2021-08-21):fix issue with anchor on registered class not preserved and those classes using package attrs with@attr.s()(both reported byssph)0.17.11 (2021-08-19):fix error baseclass forDuplicateKeyError(reported byŁukasz Rogalski)fix typo in reader error message, causingKeyErrorduring reader error (reported byMTU)0.17.10 (2021-06-24):fix issue 388, token with old comment structure != two elements (reported byDimitrios Bariamis)0.17.9 (2021-06-10):fix issue with updating CommentedMap (reported by sri onStackOverflow)0.17.8 (2021-06-09):fix for issue 387 where templated anchors on tagged object did get set resulting in potential id reuse. (reported byArtem Ploujnikov)0.17.7 (2021-05-31):issue 385 also affected other deprecated loaders (reported via email by Oren Watson)0.17.6 (2021-05-31):merged type annotations update provided byJochen Sprickerhoffix for issue 385: deprecated round_trip_loader function not
working (reported byMike
Gouline)wasted a few hours getting rid of mypy warnings/errors0.17.5 (2021-05-30):fix for issue 384!!setwith aliased entry resulting in broken YAML on rt reported byWilliam Kimball)0.17.4 (2021-04-07):prevent (empty) comments from throwing assertion error (issue 351 reported byWilliam Kimball) comments (or empty line) will be dropped0.17.3 (2021-04-07):fix for issue 382 caused by an error in a format string (reported byWilliam Kimball)allow expansion of aliases by settingyaml.composer.return_alias = lambda s: copy.deepcopy(s)(as perStackoverflow answer)0.17.2 (2021-03-29):change -py2.py3-none-any.whl to -py3-none-any.whl, and remove 0.17.10.17.1 (2021-03-29):added 'Programming Language :: Python :: 3 :: Only', and
removing 0.17.0 from PyPI (reported byAlasdair
Nicol)0.17.0 (2021-03-26):removed because of incomplete classifiersthis release no longer supports Python 2.7, most if not all Python 2 specific code is removed. The 0.17.x series is the last to support Python 3.5 (this also allowed for removal of the dependency onruamel.std.pathlib)remove Python2 specific code branches and adaptations (u-strings)prepare % code for f-strings using_Fallow PyOxidisation (issue 324resp.issue 171)replaced Python 2 compatible enforcement of keyword arguments with '*'the old top levelfunctionsload,safe_load,round_trip_load,dump,safe_dump,round_trip_dump,scan,parse,compose,emit,serializeas well as their_allvariants for multi-document streams, now issue aPendingDeprecationning(e.g. when run from pytest, but also Python is started with-Wd). Use the methods onYAML(), which have been extended.fix for issue 376: indentation changes could put literal/folded
scalar to start before the#column of a following comment.
Effectively making the comment part of the scalar in the output.
(reported byBence Nagy)For older changes see the fileCHANGES