holoviz/panel v1.10.0

Version 1.10.0

on GitHub

Panel 1.10.0 is a major step towards Panel 2.0. The headline is panel.ui, a single namespace that combines the Material UI components from panel-material-ui with the classic Panel components that have no Material equivalent, together with a panel migrate codemod that rewrites existing apps to use it. Panel now also ships its own native ASGI server, replacing bokeh-fastapi and bokeh-django, so panel serve --server fastapi|asgi works out of the box and OAuth behaves identically across transports.

Components no longer have to be declared up front: a component that wraps a JavaScript library now loads its resources on demand the first time it renders, so forgetting pn.extension('tabulator') no longer results in a blank component. The server pages (index, login, logout and error pages) and the /admin dashboard have been restyled to match panel-material-ui and can be branded with the new pn.config.page_config, and the admin dashboard can now be secured independently of the apps it monitors.

The release also contains significant performance improvements: rendering of JSComponent and ReactComponent (and therefore all of panel-material-ui) no longer scales quadratically with the number of components, streaming into Markdown and HTML panes has a roughly constant rendering cost per token so long responses stream at a steady rate, and Tabulator no longer pulls in the 500 KB bokeh-tables bundle. It also includes a long list of robustness fixes, including for Tabulator edits, busy state tracking, notebook resource loading under RequireJS, caching and periodic callbacks.

This release requires Bokeh 3.10 and drops support for Python 3.10 and 3.11, while adding support for Python 3.15. It also deprecates the REST providers, pn.state.publish and pn.widgets.DataFrame, and removes the long-deprecated LangChain callback handler.

Many thanks to the contributors to this release: @philippjfr, @hoxbro, @chiruu12, @MohammadHijjawi97, @ebarkhordar, @Kayvan-Zahiri, @ghostiee-11, @Azaya89, @rimsha152007-dotcom, @EltonChang1, @Bortlesboat, @ATL2001, @ZainnQureshii, @vignesh-chaturvedi, @IDavinciCode, @mvanhorn, @SatvikMishra08, @YashAnand69, @Cherith1222, @anshurajbisoyi98-ctrl, @Coderambling, @Jojoussef and @wolfgang-aura.

🚀 Features

• Add the panel.ui namespace, which exports every Material component from panel-material-ui and the classic components without a Material equivalent (e.g. Tabulator, CodeEditor, Terminal), both at the top level (pn.ui.Button) and through widgets, layout, pane, chat, indicators, template and wrappers submodules. The namespace is loaded lazily so import panel stays as light-weight as before, and using it selects the MaterialUIDesign for the current session unless a design was chosen explicitly (#8752, #8877)
• Add Material implementations of Modal, WidgetBox and Debugger that retain the classic API (#8752)
• Add pn.ui.Param, pn.ui.HoloViews and pn.ui.panel, which always generate Material UI widgets regardless of the active design, while pn.Param and pn.pane.HoloViews keep generating widgets for the active design (#8883)
• Add the panel migrate command (installed with the panel[migrate] extra), which rewrites classic imports to pn.ui, name= to label=, button_type/button_style to color/variant, MenuButton(split=True) to SplitButton and compatible templates to pn.ui.Page, and reports anything it cannot rewrite safely. --check and --diff preview the changes without writing them (#8752)
• Add native ASGI server implementations for FastAPI and Django built on Bokeh 3.10's transport-neutral server layer, dropping the bokeh-fastapi and bokeh-django dependencies. panel serve gains a --server option accepting tornado (the default), fastapi and asgi, and wildcard routes, pn.state.route_params, static directories and OAuth work the same on every server (#8722)
• Load component resources on demand, so components such as Tabulator, ECharts or Perspective render without first being declared via pn.extension(...), including when they are created in a callback after the page has loaded. Declaring an extension is now only a preloading and bundling hint (#8745)
• Support template="page" in pn.extension and pn.config.template, resolving to pn.ui.Page, with .servable(target=...) routing into its main, sidebar, header and contextbar areas (#8808)
• Add pn.config.page_config (also settable with panel serve --page-config and the PANEL_PAGE_CONFIG environment variable) to enable branding of the server index, login, logout and error pages with the same theme, logo, favicon and title options as pn.ui.Page. Pages also fall back to the class defaults of Page, so a brand module passed to --setup themes apps and server pages at once (#8802)
• Add access control for the admin dashboard with --admin-password (PANEL_ADMIN_PASSWORD), which secures only the admin endpoint behind a login page, and --admin-users (PANEL_ADMIN_USERS), which restricts it to specific users of --basic-auth or --oauth-provider (#8805)
• Render any DataFrame-like object supported by Narwhals (polars, pyarrow, modin, cuDF, ...) in the DataFrame pane (#8744)
• Add a Jupyter server extension resource endpoint so notebooks running a plain kernel can load Panel and component resources without access to a public CDN, falling back to the CDN with a visible warning if the endpoint is unreachable (#8762)
• Allow configuring the CDN that converted apps load Pyodide from with pn.config.pyodide_cdn_root and the PANEL_PYODIDE_CDN_ROOT environment variable, enabling panel convert apps in air-gapped environments (#8784)
• Add an approximate argument to pn.cache; setting approximate=False hashes all of a large DataFrame or array instead of a sample of 100,000 rows (#8759)

✨ Enhancements

• Rebuild the /admin dashboard with panel.ui as a Page with sidebar navigation, lazily built pages, per-session log filters, literal case-insensitive text filtering, Clear filters and Download log buttons, and page_config theming (#8805)
• Add Design.component_mapping and Design.widget_mapping so designs can substitute the widgets Panel generates in Param, interact and HoloViews widgets (#8752)
• Route the loading indicator through the Design, allowing designs to declare their own spinner, and add a material spinner whose overlay follows the theme so dark themes no longer flash white (#8752)
• Add config.set_if_unset(), panel.theme.resolve_design() and string values for config.design (e.g. config.design = 'material-ui') (#8752)
• Select the MaterialUIDesign per session when an app uses panel.ui, so classic apps served from the same process keep their design, and resolve the design and theme of components without an explicit design when they render rather than when they are created (#8877)
• Expose the generate_palette and linear_gradient palette helpers in panel.ui.theme (#8868)
• Rename size to icon_size on ToggleIcon and ButtonIcon in panel migrate, flagging calls that size the icon through width or height for review (#8854)
• Theme classic components such as Tabulator, CodeEditor, JSONEditor, Markdown, Terminal, Dial, Gauge and LinearGauge from the MUI palette under the MaterialUIDesign (#8752)
• Share and reference count a single model per root when the same component is rendered in several places, so every view keeps receiving updates and removing it from one parent no longer breaks the others (#8830)
• Serve session info from a built-in /session_info endpoint on every server implementation instead of via the param REST provider (#8828)
• Update value_throttled when a slider value is set from Python (#8712)
• Yield to the event loop when a periodic callback overruns its period (#8755)
• Keep the count and timeout budgets of a periodic callback across a period change (#8757)
• Converted Pyodide apps no longer install and patch pyodide-http, since current Pyodide supports requests and urllib3 natively; the --disable-http-patch option was removed (#8777)

⚡ Performance

• Speed up ReactiveESM and ReactComponent rendering, eliminating layout work that scaled with the square of the number of components and React subtree remounts on re-render; this benefits every panel-material-ui app (#8795)
• Make streaming into Markdown and HTML panes roughly constant in rendering cost per token by coalescing updates, re-rendering only the trailing Markdown block and sending HTML splices rather than re-sending the tail (#8800)
• Render Tabulator without the bokeh-tables bundle (507 KB minified), which is now only loaded when a DataTable or DataCube is rendered, in notebooks or when requested with pn.extension('bokeh-tables') (#8837)
• Lay out ESM children once per mount instead of once per child (#8786)
• Replace the gl-matrix dependency in the VTK axes with two small helpers (#8835)

🎨 UI Improvements

• Restyle the server index, panel convert index, error, kernel error, login and logout pages to match panel-material-ui, so they share one stylesheet that follows the operating system's dark mode. Search on the index page now also matches paths and ?search= is applied on load (#8802)
• Restyle the DataFrame pane following Material Design table conventions with theme-aware hover and divider colors (#8744)
• Improve Dial rendering and theming (#8796)
• Keep Tabulator hidden until it is built and styled to avoid a flash of unstyled content (#8799)
• Use a single loading indicator in converted apps (#8827)

🐛 Bug Fixes

• Make Tabulator edits robust by sending the edited value and old value with the edit event, fixing on_edit callbacks that reported stale values and edits under remote pagination that could corrupt a sibling row (#8731)
• Ignore stale Tabulator data and server-side stream echoes (#8797)
• Prevent Tabulator page reset when clicking Last on a shrunk container (#8738)
• Fix the Tabulator keywords header filter raising an error when header_filters=True (#8726)
• Honor matchAll in Tabulator keywords header filters when pagination is not remote (#8842)
• Show the Tabulator loading spinner when the table has no columns (#8807)
• Re-measure Tabulator columns once web fonts have loaded, so headers are no longer truncated in apps with a custom font, and stop the container_popup spacer column from showing a sort arrow (#8896)
• Fix component libraries (Tabulator, ECharts, Vega, KaTeX, DeckGL, JSONEditor) failing to load in notebooks with RequireJS, i.e. classic Jupyter notebook and VS Code, including on networks that block the public CDNs, where the bundled copies of the libraries are now loaded instead (#8762, #8848)
• Stop busy state from echoing between server and client and from leaking across threads, which left busy indicators such as the Page progress bar visible while the server was idle (#8780)
• Make busy state cleanup robust to state resets, missing event loops and failed submits (#8838)
• Fix several cache hashing collisions: reordered DataFrame rows, frames differing only in dtypes, same-named closures and scalars of different types (e.g. 0 and False) no longer share cache entries (#8759)
• Hash value-type arguments such as UUID, Decimal, Fraction, IP addresses, enums and dataclasses by value in pn.cache instead of by id(), which could return another call's result (#8821, #8843)
• Cache functions that have no module file (#8770)
• Ensure stylesheet models are not reused across sessions (#8740)
• Scope reactive stylesheets to their document (#8769)
• Keep notebook stylesheets inline after updates (#8787)
• Stop shared ESM watchers when they are no longer used (#8775)
• Stop the reset of a param.Event on a ReactiveESM component from re-triggering watchers, which made functions bound to a pn.ui.Button run a second time with False (#8890)
• Freeze ReactiveHTML _scripts at class creation so instances no longer share and overwrite each other's scripts (#8861)
• Skip JS callbacks on properties the rendered model does not have (#8825)
• Ignore click events on disabled buttons (#8823)
• Notify MenuButton callbacks when the same item is selected repeatedly (#8810)
• Keep TextInput value_input in sync when value is set from Python, so pressing Enter no longer reverts the value (#8782)
• Fix DatetimeSlider when start and end fall on the same day (#8743)
• Allow setting DateRangeSlider and DatetimeRangeSlider value to None (#8901)
• Serialize string values of LiteralInput as JSON when serializer='json' (#8894)
• Restore rejected boundary values on repeated throttled Param slider changes (#8851)
• Fix nested Plotly arrays being lost when syncing across clients (#8758)
• Clean up GridSpec children when deleting cells (#8736)
• Parse negative integers in URL query parameters as integers (#8790)
• Keep URL query values as strings when syncing String parameters (#8814)
• Raise a ValueError when pn.state.location.sync is asked to sync a constant parameter such as value_throttled, instead of silently ignoring the URL value (#8902)
• Abbreviate Parameterized objects inside lists in reprs (#8792)
• Reject unparsable schedule_task periods instead of looping (#8812)
• Strip IPython line magics when serving notebooks (#8781)
• Use CDN resources in exported notebooks (#8776)
• Treat converted Pyodide apps as served (#8833)
• Deliver every message, including binary data, to Python in apps converted with --to pyodide-worker (#8844)
• Handle the Windows ProactorEventLoop (#8815)
• Ensure the server thread shuts down fully before exiting (#8741)
• Resolve the design from the document each model was rendered into when a parameter changes, so a component shown in sessions with different designs no longer receives another session's stylesheets (#8879)
• Only load resources from the Jupyter server extension endpoint when Panel's server extension launched the kernel, fixing 404s for Panel's JS and component resources in other notebook frontends such as nteract (#8863)
• Dispatch changes made inside hold() to subscribers of a sessionless Document, so embedders that sync the Document over their own transport receive updates to ReactiveESM components and layout children (#8862)
• Detect the format of raw image bytes from the file signature, so JPEG, GIF and WebP bytes passed to pn.pane.Image are no longer encoded as PNG with nonsensical dimensions, and fix the dimensions of lossy WebP images (#8875)
• Detect local media files with uppercase extensions, e.g. pn.pane.Video('CLIP.MP4') (#8867)
• Fix an off-by-one error in Player in notebooks (#8860)
• Fix the inverted apple_icon condition in the base template that emitted an empty apple-touch-icon link (#8752)

⚙️ Compatibility

• Add compatibility with Bokeh 3.10, which is now the minimum supported version, and drop support for Python 3.10 and 3.11 (#8716)
• Add compatibility with the upcoming Bokeh 3.10.2 (#8898)
• Require panel-material-ui 0.16.6 or later (#8899)
• Add support for Python 3.15 (#8767, #8850)
• Upgrade to the latest JupyterLite and Pyodide (v314.0.7) (#8763)
• Ignore the NumPy 2.5 ndarray.shape deprecation warning raised by VTK (#8729)
• Annotate subclasses in _descendents for mypy with Param 2.4 (#8801)

⚠️ Deprecations and Removals

• --rest-provider, --rest-endpoint, pn.state.publish and the panel.io.rest module are deprecated and will be removed in Panel 2.0; use --plugins to add custom endpoints instead. /rest/session_info is kept as a deprecated alias of /session_info, and --rest-provider is not supported on the ASGI servers (#8828)
• pn.widgets.DataFrame is deprecated in favor of Tabulator and will be removed in Panel 2.0; Param now always maps param.DataFrame parameters to Tabulator (#8752)
• The LangChain callback handler, deprecated since 1.8.0, has been removed (#8689)
• The bokeh-fastapi and bokeh-django dependencies have been dropped; see the upgrade guide for migrating Django integrations (#8722)
• The --disable-http-patch option of panel convert has been removed (#8777)
• PercentEditor and TimeEditor on Tabulator now use Tabulator's native input editor, and in served apps a DataFrame widget or hv.Table that first appears after the page has loaded requires pn.extension('bokeh-tables') (#8837)
• Components without an explicit design now have design=None and use the configured design when they render, so a design configured after a component is created but before it is rendered applies to it (#8877)
• Calling .servable() with an unknown target on the page template now raises a ValueError instead of being silently dropped (#8808)

📚 Documentation

• Add a new homepage and versioned documentation (#8753)
• Use pn.ui throughout the docs and gallery, generate the Component Gallery from the panel-material-ui reference notebooks and move the classic reference to reference/classic/ (#8752)
• Move the narrative docs to pn.ui.Page and rewrite the getting started, core concepts and templates guides around it (#8808)
• Migrate the tutorials to pn.ui and fix broken examples (#8891)
• Add pn.ui how-to guides for theming, palettes, typography, dark mode, branding, icons and building Material UI components (#8892)
• Modernize the gallery examples and add new apps, including a Gaia million star atlas, a model serving monitor and a storm surge studio (#8798)
• Add a how-to guide for theming server pages with page_config (#8802)
• Document the admin dashboard pages, plugins and access control (#8805)
• Document the --server option and per-server differences for endpoints, wildcard routes and static files (#8722)
• Document approximate hashing of large inputs in the caching guide (#8759)
• Document the Markdown docs and llms.txt (#8715, #8730)
• Add a note on configuring the Param mypy plugin (#8734)
• Surface the guide on using Panel with an AI assistant in the How-to section (#8846)
• Explain running UI tests with Firefox and WebKit in the developer guide (#8809)
• Note that cell editing takes precedence over row-click selection in the Tabulator reference (#8817)
• Bring the parameter lists of the pane and layout reference notebooks in line with the code and add examples for many undocumented features (#8882)
• Only show the Material version banner on classic reference pages (#8845)
• Fix links to the Tabler icons site (#8765)
• Fix dead Extensions links in the gallery and use label= in the README example (#8855)
• Fix broken relative links in how-to guides (#8773)
• Fix unresolved cross-page anchor links (#8836)
• Fix the broken Troubleshooting card icon (#8865)