Changelog

Mirrored from the upstream CHANGELOG.md. Last synced: 2026-05-21. Resynced on each Weaverlet release.

0.3.1 (2026-04-30)

Patch release. Fixes the weaverlet[jupyter] extra and WeaverletApp(jupyter_mode=True) path, both of which were broken on arrival in 0.3.0:

• pyproject.toml declared jupyter = ["dash[jupyter]>=4.1"], but Dash 4.x has no jupyter extra (declared extras: async, ci, dev, testing, celery, diskcache, compress, cloud, ag-grid). Installing weaverlet[jupyter] was a silent no-op.
• WeaverletApp(jupyter_mode=True) did from jupyter_dash import JupyterDash, but the standalone jupyter_dash package was archived in 2022 and Dash 4 absorbed Jupyter integration into core (as dash.jupyter_dash, exposed as a singleton instance). The import always failed, even after installing the (non-existent) extra.

Migration

Dash 4 ships built-in Jupyter support that doesn't need a separate JupyterDash class anymore. Construct WeaverletApp normally and pass jupyter_mode='inline' (or 'tab' / 'external') to .app.run():

wapp = WeaverletApp(root_component=...)
wapp.app.run(jupyter_mode='inline')

No extras required.

Breaking changes (vs 0.3.0)

• weaverlet[jupyter] extra removed. It never installed anything useful; pip install weaverlet[jupyter] will now error out, but the migration path above doesn't need any extra at all.
• WeaverletApp(jupyter_mode=True) raises TypeError with a migration message pointing at app.run(jupyter_mode=...). The default jupyter_mode=False (or omitting it) is unchanged.

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0.3.0 (2026-04-29)

First major refresh since 0.2.0 (2024). Modernizes the dependency stack and adds WebGL-safe routing while keeping the public API backwards-compatible where it matters.

Breaking changes

• Drop Python < 3.12. The package no longer installs on older interpreters.
• Drop hard pins on Flask, werkzeug, dash, dash_extensions, jupyter-dash. The triple-pin in 0.2.0 made Weaverlet unresolvable in any modern environment. Dependencies are now declared as open ranges (dash>=4.1.0,<5.0.0, dash-extensions>=1.0.0,<3.0.0); Flask/werkzeug are resolved transitively.
• jupyter-dash is now optional. Install with pip install weaverlet[jupyter] if you pass WeaverletApp(..., jupyter_mode=True). Otherwise importing weaverlet no longer pulls in jupyter-dash.
• Build system switched from setup.py (setuptools) to pyproject.toml (PEP 621 / hatchling). Existing install commands (pip install weaverlet, pip install -e .) continue to work.
• Identifier id format changed from hex_id-name-attr to ClassName_attr_hexInstanceId. IDs are opaque and only used symbolically as self.<identifier>, so user code is unaffected. But any code that compared the string form of an id will break.
• get_page_root() removed. The old per-router tree walk that assigned page roots to each route's children was unused and added complexity. If you relied on it, file an issue.
• StoreComponent requires the dash-extensions multiplexer/group to register multiple callbacks against the same Output. This worked in 0.2 via dash-extensions 0.0.65; in 1.x/2.x it is provided by DashProxy (which Weaverlet now uses by default). No action required if you use WeaverletApp; raw Dash users need to pick up DashProxy themselves.

New features

• SimpleRouterComponent(keep_mounted=True, preserve_path=...) for WebGL-safe multipage. When keep_mounted=True, every route is rendered at startup and the router toggles style instead of unmounting (preserving the canvas state of dash-sylvereye (PixiJS), dash-leaflet, and Plotly WebGL backends across navigation. The preserve_path route uses visibility:hidden (canvas survives even WebGL-strict libraries); other routes use display:none. Default is keep_mounted=False (unchanged behavior) drop-in replacement for 0.2 routers).
• AuthRouterComponent(keep_mounted=True, preserve_path=...): same state-preservation feature for the auth-gated router. Routes are pre-rendered with placeholder values (user=None, protected_route=""); a separate callback re-renders the login wrapper's children with the actual protected_route whenever an unauthenticated visit hits a login-required route, so the legacy login-redirect pattern keeps working in keep_mounted mode. Apps that need the live user value should read flask.session[user_session_key] from inside their callbacks rather than capturing user from get_layout.
• Aliasing under keep_mounted=True. Two paths mapping to the same component instance (e.g. / and /home both pointing to one page_a) no longer raises DuplicateIdError; both paths share a single canonical wrapper. The same generalization underlies the shared-not_found handling.
• Dynamic 404. When keep_mounted=True and the URL doesn't match any route, the not-found wrapper's children are re-rendered with the live pathname. So a template that interpolates the current pathname displays the actual URL the user typed instead of the empty-string placeholder used at startup.
• WebGL-safe shared not_found. If not_found_page_component is the same instance as one of the routes, the router reuses that route's wrapper instead of mounting a duplicate (no more DuplicateIdError).
• WeaverletApp uses dash_extensions.enrich.DashProxy under the hood, which keeps dash_extensions.javascript.assign() functions registered in window.dashExtensions.default.*. This unblocks dash-leaflet style handlers and similar uses without any extra wiring.
• assets_folder auto-resolves to the directory of the user's main script, so dashExtensions_default.js (and any user-authored asset) is served by Dash without configuration. After resolving, WeaverletApp also re-dumps the dash_extensions.javascript.assign() namespace into that directory. Important because assign() writes to a CWD-relative path by default, which doesn't match Dash's served path when the script is run from a different working directory (common with uv run, IDEs, and test runners). Without this re-dump, dash-leaflet style handlers and similar uses fail with "No match for function0". Override with WeaverletApp(..., assets_folder="...") if needed.
• WeaverletApp exposes title, external_stylesheets, assets_folder as named keyword arguments. Other Dash kwargs continue to flow through via **dash_kwargs.
• Routed get_layout() is permissive about its signature. Components no longer have to declare get_layout(self, pathname, hash, href, search) to be routable. Declare just the kwargs you need ((self), (self, pathname), (self, pathname, hash, href, search, user), etc.) and the router will pass only what your signature accepts. Implemented via weaverlet.base._call_with_router_kwargs.
• weaverlet.__version__ exposes the version string.
• Top-level re-exports: from weaverlet import WeaverletComponent, Identifier, WeaverletApp, SimpleRouterComponent, ... now works directly, no need to drill into weaverlet.base / weaverlet.components.

Internal

• Component children are now discovered by introspecting __dict__ on each walk (with cycle detection via visited), instead of pre-computing _children once and walking it four times. The ComponentsList, ComponentsDict, and ComponentsOrderedDict ABCs are still recognized for collection-style children.
• All component modules migrated from import dash_html_components as html / import dash_core_components as dcc to from dash import html, dcc.
• ServersideOutput (dash-extensions 0.0.65) is gone; the helper ServersideSignalOutput() now returns a plain Output and callers wrap the return value with Serverside(...): the dash-extensions 1.x/2.x pattern. Serverside is re-exported from weaverlet.
• DetatchedComponentRef renamed to DetachedComponentRef (typo fix); the original name is preserved as an alias.

Compat

The following public names continue to import and behave the same way as in 0.2.0: WeaverletComponent, Identifier, WeaverletApp, RouterComponent, SimpleRouterComponent, AuthRouterComponent, StoreComponent, StoreComponentOp, SignalComponent, DivSignalComponent, EmptyLayoutComponent, RedirectComponent, WeaverletException, SignalInput, SignalOutput, SignalTrigger, SignalState, SignalGroup, ServersideSignalOutput, ComponentsDict, ComponentsList, ComponentsOrderedDict, DetatchedComponentRef, DEFAULT_COMPONENT_NAME.