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Reflex Base

reflex-base Changelog

v0.9.10 (2026-09-01)

Bug Fixes

  • Enqueuing an event chained from a parent event that has already finished no longer raises RuntimeError: Cannot add a child to an EventFuture that is already done.. Such a late-chained event skips registration under the completed parent and is processed normally. (#6801)
  • Compiling unchanged source twice now produces the same files. Import order came from a set, whose iteration order varies with PYTHONHASHSEED, and a library's imports were not deduplicated against themselves; both fed the content hash a memoized component is named from, so each compile renamed those components and invalidated downstream build caches for no reason. (#7012)

Performance

  • Compiling an app with many components is substantially faster. Imports are now deduplicated as they are merged rather than only at the end, so naming a memoized component no longer costs work proportional to the size of its subtree. An app with 80 routes and 42,268 components went from 263s to 48s. (#7012)

v0.9.9 (2026-08-28)

Breaking Changes

  • get_config(reload=True) has been replaced by reload_config(), and the module-level bundled_libraries list in reflex_base.components.dynamic has moved onto the active RegistrationContext (use bundle_library() / reset_bundled_libraries() as before). Reading reflex_base.components.dynamic.bundled_libraries (or DEFAULT_BUNDLED_LIBRARIES) still works as a deprecated shim that resolves against the active context; the shims are removed in 1.0. (#6382)
  • pydantic is no longer a hard dependency; pydantic model support activates when it is installed. Use the reflex-base[pydantic] extra (or reflex[db]) to keep it. (#6786)
  • Upgraded the frontend to React Router 8.3.0 (from 7.18.2). Its new baseline requires Node 22.22.0+, so Node.MIN_VERSION moves from 22.12.0 to 22.22.0; the already-pinned React 19.2.8 and Vite 8.0.16 satisfy the React 19.2.7+ and Vite 7+ floors. React Router 8 dropped the react-router-dom re-export package, so it is no longer installed: components that declare library = "react-router-dom" must import from react-router instead (RouterProvider/HydratedRouter come from react-router/dom). Existing projects have the stale entry pruned from package.json on the next install. (#6854)

Deprecations

  • The console.debug/info/success/log/warn/error/timing helpers are deprecated (removal in 1.0) but keep working as shims; use logging.getLogger(__name__) and the pipeline in reflex_base.utils.log instead. The interactive Rich features (print/rule/status/ask/progress) remain first-class. (#6867)
  • get_config(reload=True) is deprecated (removal in 1.0) but keeps working: passing reload=True emits a deprecation warning and delegates to reload_config(), which forces a fresh load of the config into the current RegistrationContext. (#6985)

Features

  • RegistrationContext now carries the loaded Config, the registered App, decorated pages, and bundled libraries, and provides fork() to derive a fresh context that preserves existing registrations while resetting the app and config. (#6382)
  • Validate incoming state deltas in the frontend before dispatching and report unprocessable updates to the backend via a new client_error socket event instead of failing silently in the browser console. Values reported by a client are escaped and bounded before reaching the backend logs. (#6827)
  • Added reflex_base.utils.log: a standard python logging pipeline with a rich-rendering console handler (legacy colors preserved), a JSON-lines handler behind REFLEX_LOG_JSON, record deduplication, and file logging. LogLevel gained a correct total ordering and to_logging_level(), and the interactive console helpers (print/rule/status/progress) now respect JSON mode. (#6863)
  • Compiled components are now named for React DevTools: memoized components take a displayName from the Python class or @rx.memo function they came from instead of showing as Anonymous, generated contexts are named (StateContext(reflex___state____state.my_state).Provider rather than an unlabelled Context.Provider), pages are labelled with their route (Component(blog/[slug])), and client-only (NoSSRComponent) wrappers render as ClientSide(<Tag>). (#6945)
  • Add the REFLEX_REFERRER_PARAM environment variable, read at compile time to append a ref query parameter to the "Built with Reflex" badge link. (#6951)

Bug Fixes

  • Event handlers marked with @rx.event(supersedes=True) now use latest-wins semantics: enqueuing a new invocation cancels the previous unfinished event chain for the same client token. on_load_internal uses this to cancel stale on_load chains on navigation. (#6593)
  • @rx.memo functions that forward props through rx.RestProp now classify those props the same way a regular component does: a forwarded prop that is not a declared prop of the target (e.g. font_weight=) joins the component's style and renders as css, instead of being passed through as an unrecognized prop and silently dropped. Such props merge with an explicit style= rather than replacing it, and props the target actually declares are still forwarded normally. (#6605)
  • Declare rx.plugins.RadixThemesPlugin() in the rxconfig.py written by reflex init, so freshly scaffolded apps no longer emit the implicit Radix Themes enablement deprecation warning. (#6776)
  • Qualify annotations whose bare builtin name is shadowed by a member of the same class, so Var.create is no longer inferred as LiteralBooleanVar for every argument type. Var.bool, BaseComponent.set and PropsBase.dict shadowed bool, set and dict for annotations elsewhere in their own class bodies, which type checkers resolve against the class namespace. (#6846)
  • The vite preview server that react-router prerendering fetches pages from is now pinned to 127.0.0.1, fixing reflex export failing with Prerender: Request failed for /: ECONNREFUSED in environments where localhost resolves to both IPv4 and IPv6 loopback addresses (such as docker containers). (#6857)
  • Resolve event handler annotations before runtime state-class patches can shadow builtin names on Python 3.14. (#6890)
  • Chained events (those yielded by an event handler) now inherit the routing data of the event being processed, so router and dynamic route args resolve against the view that produced them instead of whichever view the last client-sent event left on the root state. (#6919)
  • Stop background event handlers from computing a delta and cleaning the root state after the state lock is dropped. On a shared state tree (opportunistic locking, in-memory state manager) a concurrent foreground write landing between the background task's dirty-var snapshot and its _clean() was silently discarded and never reached any delta. (#6920)
  • Resolve TypeAliasType annotations (PEP 695 type statements and the typing_extensions backport) to their underlying value in Var.guess_type, _isinstance and typehint_issubclass. A state var annotated with an alias like type Key = Literal["day", "week"] now compiles and can be assigned to, and event handlers with alias-annotated arguments can be passed uncalled to event triggers. Parameterized generic aliases (Keys[str] for type Keys[T] = list[T]) and aliases nested in unions (Key | None) are resolved as well. (#6944, #6986)
  • The generated vite.config.js no longer passes options rejected or deprecated by rolldown-vite 8.x: the no-op rollupOptions.jsx key is dropped and output.advancedChunks migrated to output.codeSplitting (same shape), removing the "Invalid input options" and "advancedChunks option is deprecated" warnings from every prod build/export. (#6987)
  • Console warnings and errors no longer print literal backslash-escaped brackets (e.g. dict\[str, str]). The rich-markup escapes were left over from the legacy console helpers, but the logging pipeline renders messages with markup disabled, so bracketed type names now print verbatim. VarAttributeError messages drop the same escapes. (#6989)
  • A custom component declaring library = "react-router-dom" (including versioned and subpath forms) now fails compilation with an actionable error naming the component, instead of silently installing the removed package — which pulled in a second, unpinned React Router 7 copy that worked in dev by accident and broke production builds. React Router 8 dropped react-router-dom: use library = "react-router" instead, or "react-router/dom" for RouterProvider/HydratedRouter. (#6991)
  • With REFLEX_ENABLE_FULL_LOGGING, granian worker records reach the log file again: the file handler now opens in append mode (truncating once up front), so it reopens after the worker's post-fork logging.config.dictConfig closes it instead of silently dropping every worker-side record. The legacy console file writer follows the reopened stream through a proxy, so its timestamped lines no longer leak to stdout and break --json output. (#6992)

Performance

  • Dev mode no longer pays for React's per-element owner-stack capture: navigation clicks in a large app dropped from ~350ms to ~83ms of main-thread CPU (5.6x prod down to ~1.3x). In exchange React.captureOwnerStack() returns no owner frames in dev, which affects React DevTools' owner-stack view and custom error overlays built on that API; set REFLEX_REACT_OWNER_STACKS=1 to restore them. (#6905)
  • MemoComponent instances no longer opt out of compiler auto-memoization wholesale. Only the passthrough wrappers the auto-memoize pass generates do, tracked by the new auto_memo_wrapper flag on MemoComponentDefinition, so state-bound props and event handlers on a @rx.memo call site compile their hooks into a generated wrapper instead of the enclosing page. (#6949)
  • Speed up prop validation and JSON serialization on hot paths: _isinstance now reads __origin__ once per type, memoizes get_args, and caches the deferred Var/LiteralVar/Field imports instead of re-importing on every call, and json_dumps caches its deferred serializers.serialize lookup. (#6862)
  • vite_config_template declares a resolveId hook filter ({ id: /react-dom\/server/ }) on vite-plugin-always-use-react-dom-server-node. The plugin runs with enforce: "pre", so without a filter rolldown invoked its JS handler for every import specifier in the graph (~15,800 calls on the Reflex docs build) to redirect the one specifier imported by entry.server.node.tsx. The template also imports ./vite-plugin-safari-cachebust.js with its extension, which Vite's configLoader: "native" requires. (#6959)

Miscellaneous

  • Removed the postcss entry from PackageJson.OVERRIDES, leaving that mapping empty. postcss is pinned directly in DEV_DEPENDENCIES (8.5.23), and that top-level pin already dedupes every transitive requirer (autoprefixer, postcss-import, and vite's own ^8.5.15). Projects that already installed 0.9.8 keep an inert "postcss": "8.5.23" override in reflex.lock/package.json; it matches the dev-dependency pin and can be deleted by hand. (#6854)
  • Bump bundled vite from 8.0.16 to 8.2.0. (#6857)
  • Internal logging in reflex-base migrated from the legacy console helpers to standard python logging per-module loggers. (#6864)
  • Property docstrings are now noun phrases rather than "Get the ..." / "Return the ..." (ruff 0.16's new D421). Field.default, Field.default_factory and Field.default_value() now admit None, matching what they already hold for a field whose annotated type has no computed default, and chain_updates() declares its events parameter as Any, matching the runtime validation it delegates to. (#6893)

v0.9.8 (2026-08-04)

Features

  • Add Env.PREVIEW, the VITE_MINIFY and REFLEX_NO_AUTOPREFIXER environment variables, a minify/cssMinify option on the vite config template, and a REFLEX_NO_AUTOPREFIXER toggle in the generated postcss.config.js to support the new preview run mode. (#6663)
  • Add a staged Plugin.register_route hook with add_page and has_app_page capabilities that runs once per app before its first compilation, and rx.plugins.get_plugin() to look up the configured plugin instance by type (raising ConfigError on ambiguous matches). (#6728)

Bug Fixes

  • Preserve runtime value types for unannotated @rx.memo component parameters. (#6659)
  • Compare timezone-aware datetime Vars by their instants instead of their serialized UTC offsets. (#6767)
  • In python 3.13+, the EventProcessor loop was not catching asyncio.QueueShutdown resulting in uncaught exceptions during shutdown. (#6773)
  • Prevented edits to unloaded routes from poisoning React Router's browser-side HMR queue and blocking all later hot updates until a full page reload. (#6774)
  • Drain queued same-token events during graceful event processor shutdown. (#6791)
  • Custom attributes on a Field are now carried onto the rebuilt field by reference instead of deep copy, so stateful callable markers keep their identity and markers holding non-copyable values (locks, clients) no longer crash state class creation. (#6809)

Miscellaneous

  • Bumped bundled frontend dependency pins to their current releases:
    • react / react-dom: 19.2.6 → 19.2.8
    • react-router, react-router-dom, @react-router/node, @react-router/dev, @react-router/fs-routes: 7.15.0 → 7.18.2
    • isbot: 5.1.40 → 5.2.1
    • universal-cookie: 7.2.2 → 8.1.2
    • postcss: 8.5.14 → 8.5.23
    • autoprefixer: 10.5.0 → 10.5.4
    • @tailwindcss/typography: 0.5.19 → 0.5.20
    • Bun: 1.3.13 → 1.3.14
  • Also raised the rich upper bound to <16 (adopting rich 15). Replaced the now-redundant cookie package.json override (universal-cookie 8 and react-router resolve cookie to 1.x on their own) with a postcss override pinning it to 8.5.23 so transitive resolutions stay on a patched release (>= 8.5.18) for a security advisory.
  • (#6678)
  • Remove the unused REFLEX_USE_TURBOPACK environment variable. Turbopack is a Next.js bundler; the flag has had no effect since Reflex moved to React Router and Vite in 0.8. (#6803)

v0.9.7 (2026-07-15)

Deprecations

  • ArrayVar.foreach is deprecated; use ArrayVar.map instead. (#6701)

Features

  • ArrayVar gained map, filter, reduce, and flat_map operations, and StringVar.strip now accepts a chars argument alongside new lstrip/rstrip methods. (#6701)
  • Added default_color_mode to rx.Config ("system", "light", or "dark", also settable via REFLEX_DEFAULT_COLOR_MODE) and moved the shared LiteralColorMode type and color-mode string constants into reflex_base.constants. This lets apps set the initial color mode without depending on the Radix themes appearance prop. (#6716)
  • @rx.memo now accepts a wrapper= argument controlling the JS function that wraps the compiled component definition: keep the default React memo, pass a custom function Var (e.g. an rx.vars.FunctionStringVar carrying its own imports), or pass wrapper=None to export the bare function component. (#6730)
  • Added frozen_lockfile to rx.Config (default True, also settable via REFLEX_FROZEN_LOCKFILE), controlling whether the frontend package manager runs in lockfile-enforcing mode. Reflex still creates, manages, and syncs the lockfile regardless; the option only controls whether a lockfile/package.json mismatch is treated as an error. (#6763)

Bug Fixes

  • Custom attributes set on a Field are now preserved (deep-copied) when the state metaclass rebuilds fields, instead of being silently discarded. The reserved annotation attribute is never carried over so rebuilt fields are not misidentified as pydantic fields. (#6726)
  • Fix _get_all_hooks_internal mutating each component's cached internal hooks with its descendants' hooks, which made memo tag hashes order-dependent and duplicated hooks into memo bodies. (#6741)

Performance

  • Cache framework-path checks in console.deprecate's call-stack walk, making repeat calls ~150x faster (deprecated attributes on hot paths, like RouterData.page, no longer cost multiple milliseconds per access). (#6736)
  • Event chaining (yield OtherState.handler(rows)) no longer deep-copies payload values that are not attached to any state: only state-bound MutableProxy subtrees are copied, making proxy-free payloads ~5x faster to chain. (#6739)
  • Var.to() and Var.guess_type() resolve their target Var subclass through cached registry lookups instead of scanning the full registry with safe_issubclass on every call (~70% of the cost of constructing a var operation). (#6742)

v0.9.6.post1 (2026-06-26)

Features

  • Added the REFLEX_EXTRA_PLUGINS environment variable, a colon-separated list of fully qualified plugin import paths appended to the config's plugins list. Unlike REFLEX_PLUGINS, which replaces the list entirely, this preserves plugins configured in rxconfig.py; an entry is skipped when a plugin of the same type is already present or when its type is listed in disable_plugins. (#6685)

Bug Fixes

  • Stop warning when a non-built-in plugin is listed in disable_plugins, so config can opt out of an env-provided plugin without a spurious warning. (#6685)
  • Improve error message when plugin spec from environment cannot be used. (#6685)

v0.9.6 (2026-06-25)

Features

  • StringVar now includes lstrip and rstrip methods. The strip method now accepts an optional chars argument for consistency with Python’s str API. (#5417)
  • Added reflex_base.utils.memo_paths, which translates a memo's Python source module into the mirrored .web/app_components/ JSX path and $/... library specifier used by the compiler. The memo component and compiler plugin now route each memo's compiled output through these helpers so it lands alongside its source module's layout, falling back to the per-name utils/components/<name> path when the module can't be mirrored. The helpers also derive a per-module-unique JS symbol for each mirrored memo, and the memo registry is keyed by (name, source module) so same-named memos defined in different modules coexist instead of colliding. (#6457)
  • ObjectVar attribute access now resolves HybridProperty descriptors defined on the underlying type, evaluating the property's frontend logic with the object var substituted as self. HybridProperty moved to reflex_base.vars.hybrid_property (still available as rx._x.hybrid_property). (#6617)
  • Add AgentsMd constants (canonical URL, managed-section markers, and CLAUDE.md bridge) supporting reflex init AGENTS.md generation. (#6620)
  • Added HybridPropertyError, raised when a hybrid property's frontend logic accesses a backend (underscore-prefixed) var on a state while building its frontend var. (#6621)
  • package_json_template accepts **additional_keys to include extra fields (e.g. name, packageManager, engines) in the rendered package.json. (#6658)

Bug Fixes

  • Preserve extra bound event arguments when rx.upload_files is used in an upload handler. (#5290)
  • Avoid re-entering config loading when a State subclass is defined in rxconfig.py. (#6662)
  • Bump the bundled vite dev dependency to 8.0.16, fixing a server.fs.deny bypass on Windows alternate paths (CVE-2026-53571) in the dev server of generated apps. (#6665)
  • pyi_hashes.json entries are now computed from the final .pyi content after ruff format / ruff check --fix post-processing, instead of the intermediate generator output. A pyi_generator change that only affects pre-format output no longer flags hash changes for stubs whose final content is identical.

Miscellaneous

  • Component gained a private _get_tag_name() helper returning the JS expression that references the component's tag (quoted for global-scope DOM tags without a library); Component._render and DebounceInput now share it instead of duplicating the quoting logic. (#6637)

v0.9.5 (2026-06-10)

Features

  • Event-argument type checking now treats a mapping-style payload as compatible with a TypedDict-annotated callback parameter, scoped narrowly to on_submit triggers whose payload is a Mapping[str, ...] so unrelated mapping events are unaffected. Adds the FORM_SUBMIT_MAPPING type var (exposed on the event namespace and pyi_generator's default imports) and a Component._is_form_control class marker that a component sets to declare it contributes a named field to form submission data. (#6301)
  • VarData gained an app_wraps field so a Var can declare the app-level wrapper components it requires; the compiler injects them around the app root, deduped by (priority, tag). This is how the state and event-loop providers now reach the React tree, since event dispatch reaches addEvents via a module-level import (Imports.EVENTS) rather than a hoisted hook. The still-reactive connectErrors value moves to its own CONNECT_ERRORS import/hook, and Component deep copies now drop the render cache so compile-time clones (e.g. the app-root wrapper chain) render their mutated children. (#6447)
  • Added a hydrate_fallback config option (settable via the REFLEX_HYDRATE_FALLBACK environment variable), a dotted import path to a callable returning the component shown while the page is hydrating. The app root template now emits a React Router HydrateFallback export when a fallback is provided, and the import-path resolution shared with extra_overlay_function resolves nested module paths correctly. (#6630)
  • Added the REFLEX_HOT_RELOAD_OVERRIDE_PATHS environment variable, a colon-separated list of paths that, when set, fully replaces the paths watched for hot reload in dev mode. (#6639)

Bug Fixes

  • The reflex_base.utils.pyi_generator build-hook entrypoint no longer rewrites pyi_hashes.json: it only emits the .pyi stubs bundled in the wheel, so building a component package (or the build triggered by uv sync) no longer wipes the hash registry down to a single package's entries. The scanner also tolerates source-less modules (e.g. an empty __init__.py) instead of raising OSError on Python < 3.13. (#6614)
  • Fixed State.router.url reflecting a stale query string after the URL was changed with window.history.replaceState/pushState (e.g. from rx.call_script). React Router's location does not observe direct history manipulation, so the query and hash are now read from the live window.location when building router_data, and the next event sent to the backend reports the correct URL (the path stays basename-relative so frontend_path is not applied twice; embedded apps keep using the in-widget memory router). A direct history mutation is intentionally not a navigation and does not itself emit an event — use rx.redirect(..., replace=True) when you need the URL change to update the router reactively and trigger on_load. (#6625)
  • pyi_generator no longer includes underscore-prefixed props in generated .pyi files. (#6628)
  • Frontend-only events (e.g. rx.toast, rx.redirect) returned from a middleware's preprocess are now emitted to the client instead of being enqueued on the backend event queue, where they had no registered handler and raised KeyError. The frontend/backend split that already applied to handler-yielded events is now shared via a _route_events helper and applied to middleware-preprocess updates too. (#6644)

Performance

  • Speed up component creation by resolving field defaults lazily (via class-level descriptors) instead of eagerly on every instance, caching each component class's event triggers, and memoizing to_camel_case. (#6576)

v0.9.4 (2026-06-03)

Deprecations

  • Component-returning @rx.memo again accepts key without an rx.RestProp (with a deprecation warning), so rx.foreach call sites that set the react key keep working; this fallback is removed in 1.0. Other base props (id, class_name, style, custom_attrs, ref) and identity fields like tag/library still raise — declare an rx.RestProp to forward them.

Features

  • Dependency tracking now follows through hybrid properties, so computed vars that read a hybrid_property correctly recompute when the underlying state vars change. (#3806)
  • The component memo implementation now lives in reflex_base.components.memo and is exported as rx.memo. Added EMPTY_VAR_STR and EMPTY_VAR_INT sentinel vars as memo-friendly defaults. (#6517)

Bug Fixes

  • Pin [email protected] via package overrides to work around upstream breakage in recharts and es-toolkit. (#6570)
  • Unpin [email protected] via package overrides and bump vite to 8.0.14 to work around upstream breakage in recharts and es-toolkit. (#6571)

Miscellaneous

  • Removed the Templates.CHOOSE_TEMPLATES and Templates.REFLEX_TEMPLATES_URL constants, which supported the now-removed open-source templates reflex init option. (#6592)
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