nicegui 3.12.0

v3.12.0

on Python PyPI

Security

• ⚠️ Prevent local file disclosure in ui.restructured_text via Docutils file insertion directives (GHSA-jfrm-rx66-g536 by @dennyabrahamsinaga, @h3ri0s, @falkoschindler, @evnchn)
• ⚠️ Prevent unauthenticated log-volume denial of service in dynamic resource and ESM module routes (GHSA-pq7c-x8g4-rvp6 by @bitinerant, @evnchn, @falkoschindler)

New features and enhancements

• Make enable(), disable(), set_enabled(), set_visibility() and many more methods chainable (#6014, #6016 by @stragrothsk, @falkoschindler, @evnchn)
• Auto-dedent ui.mermaid content like ui.markdown does (#6011, #6012 by @BasementSociety, @falkoschindler, @evnchn)
• Suppress alarming KeyboardInterrupt traceback from run.cpu_bound workers on Ctrl-C (#6025, #6027 by @justus2510, @falkoschindler, @evnchn)

Bugfixes

• Fix RuntimeError: A SemLock created in a fork context is being shared with a process in a spawn context in ui.run(native=True, reload=True) on CPython ≥ 3.11.5 (#1841, #6045 by @swrpug, @evnchn, @falkoschindler, @rodja, @JensOgorek, @yuanxion, @electronstudio, @knoppmyth, @Qhawaq, @sagarbehere, @frankhuurman, @MrGibus, @BanDroid)
• Fix KeyError: 'error' when calling ValidationElement.validate() after the error prop was removed via props(remove=...) (#5977, #6042 by @manu-ns, @falkoschindler, @evnchn)
• Fix silent window.location.reload() on every WebSocket reconnect (#6018, #6019 by @arodidev, @falkoschindler, @evnchn)
• Resolve ElementFilter.DEFAULT_LOCAL_SCOPE at runtime so changing the class variable actually affects new instances (#6005, #6013 by @gzu300, @DarkRiddle1212, @falkoschindler)
• Fix duplicate app.timer and lifecycle handler (on_connect, on_disconnect, on_delete, on_shutdown, on_exception) registration in script mode (#6003, #6006 by @EchterTimo, @falkoschindler, @evnchn)
• Preserve a meaningful DataFrame index in ui.aggrid.from_pandas and ui.table.from_pandas (#5995, #6002 by @NichtJens, @DarkRiddle1212, @falkoschindler, @evnchn)
  Note: DataFrames with an informative index now produce additional column(s) in the resulting grid/table. To restore the previous "drop the index" behavior, call df.reset_index(drop=True) before passing the DataFrame.
• Bracket IPv6 hosts and omit default ports in printed URLs (#5996 by @bulletmark, @falkoschindler, @evnchn)
• Fix ui.code reporting the wrong language and throwing a ReferenceError in the CodeMirror findLanguage error path (#5982 by @Jepson2k, @falkoschindler)
• Fix material settings not applying to GLTF models in ui.scene (#3515, #5708 by @maria-korosteleva, @evnchn, @falkoschindler, @fabian0702)

Documentation

• Add llms.md — a self-contained LLM reference covering NiceGUI's API surface, mental models, and common anti-patterns for AI-assisted development (#6021, #6049 by @joko-zauberzeug, @falkoschindler, @evnchn, @rodja)
• Restructure CONTRIBUTING.md around the contributor journey, drop rule duplication, and split out a new "For maintainers" section (#6029 by @falkoschindler, @evnchn)
• Restructure AI agent instructions: extract code-review guidance into REVIEW.md, trim AGENTS.md, and tighten Cursor/Copilot prompts (#6030 by @falkoschindler, @evnchn)
• Document packaging with Nuitka (#6009, #6010 by @SHDocter, @falkoschindler, @evnchn)
• Improve authentication example (#6046 by @NichtJens, @evnchn, @falkoschindler)
• Improve Sortable documentation (#6017 by @falkoschindler, @denniswittich)
• Clarify the client_id security model and add an "Examples Are Starting Points" callout (#6004 by @evnchn, @falkoschindler)
• Fix Nested ui.sub_pages doc demo link target and label (#5999, #6008 by @aisartag, @falkoschindler, @evnchn)

Testing

• Fix click handler dispatch in user simulation (#6043 by @Jepson2k, @falkoschindler, @evnchn)
  Note 1: Click handlers on ui.checkbox and ui.switch now receive e.args = None instead of not element.value; read e.sender.value (or use on_value_change) for the post-toggle value.
  Note 2: Also, find(...).click() no longer broadcasts to every matched element — it picks the lowest-ID enabled match and dispatches once. Tests that relied on simultaneous multi-match clicks need to issue separate calls.
• Implement ui.sub_pages navigation in user-simulated tests (#5193 by @rodja, @falkoschindler)

Dependencies

• Bump Mermaid from 11.12.2 to 11.15.0 to consume upstream security patches (#6047 by @falkoschindler, @evnchn)

Infrastructure

• Use uv sync --locked in CI workflows so lockfile drift fails fast with a clear diagnostic (#6036 by @evnchn, @falkoschindler)
• Use uv sync --locked in Copilot setup steps for deterministic agent boot environments (#6040 by @evnchn, @falkoschindler)
• Switch Dependabot from the pip ecosystem to uv (#6037 by @evnchn, @falkoschindler)
• Declare PyPI trove classifiers so NiceGUI appears in PyPI's faceted search (#6041 by @evnchn, @falkoschindler)
• Expand [project.urls] with PEP 753 well-known labels (#6039 by @evnchn, @falkoschindler)

Special thanks to our top sponsors TestMu AI, Lechler GmbH and joet-s ✨

and all our other sponsors and contributors for supporting this project!

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