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Releases: holoviz/param

Version 1.12.3

09 Dec 08:38
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The 1.12.3 release adds support for Python 3.11. Many thanks to @musicinmybrain (first contribution!) and @maximlt for contributing to this release.


  • Preserve existing Random seed behavior in Python 3.11 (#638)
  • Add support for Python 3.11 (#658)

Version 1.12.2

24 Jun 09:47
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The 1.12.2 release fixes a number of bugs and adds support again for Python 2.7, which was unfortunately no longer supported in the last release. Note however that Param 2.0 will still drop support of Python 2.7 as already announced. Many thanks to @Hoxbro and the maintainers @jbednar, @jlstevens, @maximlt and @philippjfr for contributing to this release.

Bug fixes:

  • Match against complete spec name when determining dynamic watchers (615)
  • Ensure async functionality does not cause python2 syntax errors (624)
  • Allow (de)serializing CalendarRange and DateRange Parameters (625)
  • Improve DateRange validation (627)
  • Fix regression in @param.depends execution ordering (628)
  • Ensure named_objs does not fail on unhashable objects (632)
  • Support comparing date-like objects (629)
  • Fixed BinaryPower example in the docs to use the correct name EvenInteger(634)

Version 1.12.1

31 Mar 15:43
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The 1.12.1 release fixes a number of bugs related to async callback handling when using param.depends and and a number of documentation and error messages. Many thanks to @Hoxbro and the maintainers @jbednar, @jlstevens, @maximlt and @philippjfr for contributing to this release.

Error handling and documentation:

  • Fixed description of shared_parameters (#568)
  • Improve the error messages of Date and DateRange (#579)
  • Clarified step error messages and other docs and links (#604)

Bug fixes:

  • Make iscoroutinefunction more robust (#572)
  • Fix for handling misspelled parameter (#575)
  • Handle None serialization for Date, CalendarDate, Tuple, Array, and DataFrame (#582)
  • Support async coroutines in param.depends (#591)
  • Handle async functions in depends with watch=True (#611)
  • Avoid equality check on Watcher (#612)


  • Fix binder (#564)
  • Fixed description of shared_parameters (#568)

Version 1.12.0

21 Oct 21:42
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Version 1.12.0 introduces a complete user manual and website (for the first time since 2003!) along with extensive API improvements gearing up for the 2.0 release (which will be Python3 only).

The pre-2.0 API is still being preserved and no new warnings are added in this release, so the older API can continue to be used with this release, but the next 1.x release is expected to enable warnings for deprecated API. If you have older code using the deprecated Param features below, please update your API calls as described below to be compatible with the 2.0 release when it comes out (or pin to param<2 if you don't need any new Param features). For new users, just use the API documented on the website, and you should be ready to go for either 1.12+ or 2.0+.

Thanks to James A. Bednar for the user guide and 2.0 API support, to Philipp Rudiger for improvements and new capabilities for handling dependencies on subobjects, and to Maxime Liquet and Philipp Rudiger for extensive improvements to the website/docs/package-building/testing.

New features:

  • Added future-facing API for certain Parameterized().param methods (see Compatibility below; #556, #558, #559)
  • New option on_init=True for @depends decorator, to run the method in the constructor to ensure initial state is consistent when appropriate (#540)
  • Now resolves subobject dependencies dynamically, allowing dependencies on internal parameters of subobjects to resolve appropriately as those objects are replaced. (#552)
  • Added prettyprinting for numbergen expressions (#525)
  • Improved JSON schema generation (#458)
  • Added more-usable script_repr command, availabie in param namespace, with default values, and showing imports (#522)
  • Added Parameterized.param.pprint(); underlying implementation of script_repr but with defaults suitable for interactive usage rather than generating a .py script. (#522)
  • Watchers can now declare precedence so that events are triggered in the desired order (#552, #557)

Bug fixes:

  • Fix bug setting attributes in some cases before class is initialized (#544)
  • Ensure None is supported on ListSelector (#511)
  • Switched from deprecated inspect.getargspec to the py3 version inspect.getfullargspec, which is similar but splits keyword args into varkw (**) and kw-only args. Falls back to getargspec on Python2. (#521)

Doc improvements (including complete user guide for the first time!):

  • Misc comments/docstrings/docs cleanup (#507, #518, #528, #553)
  • Added comparison with pydantic (#523)
  • Added new user guide sections:
    • Dependencies_and_Watchers user guide (#536)
    • Dynamic Parameters (#525)
    • Outputs (#523)
    • Serialization and Persistence (#523)


Compatibility (see #543 for the complete list):

  • Calendardate now accepts date values only (#517)

  • No longer allows modifying name of a Parameter once it is in a Parameterized class, to avoid confusion (#541)

  • Renamed (with old name still accepted for compatibility until 2.0):

    • .param._add_parameter(): Now public .param.add_parameter(); too useful to keep private! (#559)
    • .param.params_depended_on: Now .param.method_dependencies to indicate that it accepts a method name and returns its dependencies (#559)
    • .pprint: Now private ._pprint; use public .param.pprint instead (#559)
    • batch_watch: Now batch_call_watchers, to declare that it does not set up watching, it just invokes it. Removed unused operation argument (#536)
  • Deprecated (but not yet warning unless noted):

    • .param.debug(): Use .param.log(param.DEBUG, ...) instead (#556)
    • .param.verbose(): Use .param.log(param.VERBOSE, ...) instead (#556)
    • .param.message(): Use .param.log(param.MESSAGE, ...) instead (#556)
    • .param.defaults(): Use {k:v.default for k,v in p.param.objects().items()} instead (#559)
    • .param.deprecate(): To be repurposed or deleted after 2.0 (#559)
    • .param.params(): Use .param.values() or .param['param'] instead (#559)
    • .param.print_param_defaults(): Use for k,v in p.param.objects().items(): print(f"{}.{k}={repr(v.default)}") instead (#559)
    • .param.print_param_values(): Use for k,v in p.param.values().items(): print(f"{}.{k}={v}") instead (#559)
    • .param.set_default(): Use p.param.default= instead (#559)
    • .param.set_param(): Had tricky API; use .param.update instead (#558)
    • .param.get_param_values(): Use .param.values().items() instead (or .param.values() for the common case of dict(....param.get_param_values())) (#559)
    • .state_pop(): Will be renamed to ._state_pop to make private
    • .state_push(): Will be renamed to ._state_push to make private
    • .initialized: Will be renamed to ._initialized to make private
    • Most methods on Parameterized itself have already been deprecated and warning for some time now; see #543 for the list. Use the corresponding method on the .param accessor instead.
  • Added:

    • .param.watchers: Read-only version of private _watchers (#559)
    • .param.log(): Subsumes .debug/verbose/message; all are logging calls. (#556)
    • .param.update(): Dictionary-style updates to parameter values, as a drop-in replacement for set_param except for its optional legacy positional-arg syntax (#558)
    • .values(): Dictionary of name:value pairs for parameter values, replacing get_param_values but now a dict since python3 preserves order (#558)
    • .param.log(): General-purpose interface to the logging module functionailty; replaces .debug, .verbose, .message (#556)

Version 1.11.1

06 Jul 01:02
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(including changes in 1.11.0; 1.11.1 adds only a minor change to fix param.List(None).)

Version 1.11 contains entirely new documentation, plus various enhancements and bugfixess. Thanks to James A. Bednar for the documentation, Philipp Rudiger for the website setup and for many of the other fixes and improvements below, and others as noted below.


  • Brand-new website, with getting started, user manual, reference manual, and more! Some user guide sections are still under construction. (#428,#464,#479,#483,#501,#502,#503,#504)
  • New intro video with examples/Promo.ipynb notebook, thanks to Marc Skov Madsen and Egbert Ammicht (#488)
  • Sort docstring by definition order and precedence, thanks to Andrew Huang (#445)


  • Allow printing representations for recursively nested Parameterized objects (#499)
  • Allow named colors for param.Color (#472)
  • Allow FileSelector and MultiFileSelector to accept initial values (#497)
  • Add Step slot to Range, thanks to Simon Hansen (#467)
  • Update FileSelector and MultiFileSelector parameters when setting path (#476)
  • Improved error messages (#475)

Bug Fixes:

  • Fix Path to allow folders, as documented but previously not supported (#495)
  • Fix previously unimplemented Parameter._on_set (#484)
  • Fix Python2 IPython output parameter precedence (#477)
  • Fix allow_None for param.Series and param.DataFrame (#473)
  • Fix behavior when both instantiate and constant are True (#474)
  • Fix for versioning when param is inside a separate git-controlled repo (port of fix from autover/pull/67) (#469)


  • Swapped ObjectSelector and Selector in the inheritance hierarchy, to allow ObjectSelector to be deprecated. (#497)
  • Now get_soft_boundssilently crops softbounds to any hard bounds supplied ; previously soft bounds would be returned even if they were outside the hard bounds (#498)
  • Rename class_ to item_type in List parameter, to avoid clashing semantics with ClassSelector and others with a class_ slot. class_ is still accepted as a keyword but is stored in item_type. (#456)

Version 1.10.1

10 May 15:57
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Minor release for Panel-related bugfixes and minor features, from @philippjfr.

  • Fix serialization of Tuple, for use in Panel (#446)
  • Declare asynchronous executor for Panel to use (#449)
  • Switch to GitHub Actions (#450)

Version 1.10.0

06 Jan 18:38
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Version 1.10.0

Version 1.9.3

26 Jan 21:03
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  • Fixed ClassSelector.get_range when a tuple of types is supplied (#360)

Version 1.9.2

23 Jan 21:02
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  • Compatibility with Python 3.8
  • Add eager option to watch calls (#351)
  • Add Calendar and CalendarDateRange for real date types (#348)

Version 1.9.1

08 Oct 12:39
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  • Allow param.depends to annotate functions (#334)
  • Add context managers to manage events and edit constant parameters

Bug fixes:

  • Ensure that Select constructor does not rely on truthiness (#337)
  • Ensure that param.depends allows mixed Parameter types (#338)
  • Date and DateRange now allow type (#341)
  • Ensure events aren't dropped in batched mode (#343)