reflex-dev/reflex reflex-base-v0.10.1a1

reflex-base@0.10.1a1

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Deprecations

• VarData(position=...) and Hooks.HookPosition are deprecated and ignored: hooks render in declaration order. Remove the position argument; to place a hook after another one, put the one it reads in its VarData(hooks=...). (#7586)
• reflex_base.utils.format.format_data_editor_column is deprecated and will be removed in 1.0; rx.data_editor applies the column defaults itself. (#7607)

Features

• Add the experimental react_compiler configuration option, also available as REFLEX_REACT_COMPILER, to opt in to automatic React component memoization. (#7234)
• Event props and the events an event handler returns accept any sequence of events, e.g. a tuple or a variable typed list[EventSpec], not only a list literal. The new reflex_base.event.event_sequence helper returns such a value as a sequence of events, wrapping a single event in a list. (#7402)
• The compiled context module exports stateSchema, a hash of the state tree the frontend was built for, and the frontend sends it in the socket.io CONNECT auth payload under the state_schema key. The backend answers a mismatch with the new state_mismatch socket event; in production, the frontend then reloads once per cooldown window or shows a "new version available" banner, while in development it only warns in the console. (#7553)
• Add reflex_base.vars.get_leaf_vars, which returns the vars a var reads by unwrapping var operations, casts, literal containers and function bodies, for example to list a derived var's dependencies in a React hook's dependency array. (#7606)
• Add the trusted_proxy_hops configuration option for safely resolving client IPs from trusted proxy headers. (#7614)

Bug Fixes

• TypedDict form data honors Required and NotRequired, including inside Annotated, in modules using from __future__ import annotations: a NotRequired field no longer needs a matching form control. (#7386)
• An event handler stored outside a state, e.g. in a component or dataclass field, now type-checks as the handler instead of a bound function, and a handler read through a state instance is typed as a function returning Any. (#7401)
• LiteralObjectVar.create is typed to take any value that serializes to a mapping, such as a dataclass, as it does at runtime, not only a mapping. (#7403)
• The CDN fallback for an unbundled sub-path dynamic import now puts the sub-path before jsdelivr's /+esm, so it resolves instead of returning 404. (#7405)
• ty now reads an optional model, dataclass or mapping field (rx.Field[X | None]) on the state class as ObjectVar[X], as pyright already did, instead of ObjectVar[X | None]. (#7413)
• Cancel pending hydration and page-load event chains when their client disconnects. (#7415)
• Calling an upload handler with rx.upload_files(...) or rx.upload_files_chunk(...) as its only argument, as the upload docs show, now type-checks under pyright and ty, for a handler taking list[rx.UploadFile] or rx.UploadChunkIterator. (#7419)
• Frontend updates and events now keep working when a backend update names a substate the compiled frontend does not know. Reflex skips that substate and reports it once per connection. (#7435)
• Fix a blank page with Maximum call stack size exceeded in apps with thousands of state classes. State is now read from one shared store, so the React provider tree no longer grows with the number of states. (#7441)
• Raise descriptive errors when page or compile contexts are accessed outside compilation. (#7517)
• Make StringVar length, indexing, and slicing count Unicode code points so operations do not split valid surrogate pairs. On a None string these operations now behave as if it were empty. (#7518)
• A frontend error event that carries no Error object, such as the benign ResizeObserver loop notification, no longer throws inside window.onerror and is now reported to handle_frontend_exception. (#7544)
• Editing one tab no longer leaves other sync=True browser storage vars that share its storage name stale in other tabs; every such var is now synced, not only the last one declared. (#7545)
• A state var annotation that names an undefined symbol, such as items: list[Item] = [] under from __future__ import annotations, raises NameError: name 'Item' is not defined again instead of an unrelated TypeError or AttributeError. This also covers vars without a default, backend vars, and Python 3.14 annotations without the __future__ import. (#7547)
• Report a hydrate message that exceeds the server's message size limit, with its size and the limit, instead of sending it and retrying. Reduce browser storage data and reload to recover. (#7551)
• On POSIX, reflex run --json forwards SIGINT to its child process, so supervisors that signal only the Reflex PID can stop the app cleanly. (#7558)
• Raising a negative number or a negated var to a power, such as (-State.x) ** 2, now compiles to valid JavaScript instead of failing the frontend build with "A unary expression with the '-' operator cannot be used as the left operand of an exponentiation expression". (#7565)
• Write the Tailwind important option to the generated tailwind.config.js under the important key. It was emitted as importants, so Tailwind ignored it. (#7573)
• A background task that re-enters an expired session now rehydrates the loaded states. The browser drops their stale values and keeps its route and browser storage; its next event runs the current page's on_load. (#7585)
• Component hooks render in the order they are declared and merged, so a hook always comes after the hooks it reads. Before, a component whose prop and add_hooks Var read the same state could render a hook before the state declaration it reads and fail with a ReferenceError. A hook that reads state must carry it: return rx.Var(f"const x = {State.value}") from add_hooks, not a plain string built with str(State.value). (#7586)
• Passing a plain dict to format_prop no longer raises AttributeError; the dict is JSON-encoded like any other literal. (#7587)
• Resolve Pydantic v2 model field types without emitting deprecation warnings, while retaining Pydantic v1 compatibility. (#7592)
• Retry with backoff and show the connection error when the server or a proxy closes the connection before it is established, for example when browser storage makes the hydrate message too large, instead of reconnecting in a tight loop. (#7605)
• Event handler arguments hinted as an rx.Model no longer emit a PydanticDeprecatedSince20 warning for every key of the payload. (#7636)
• Upgrade the default Bun version to 1.4.4, which removes compromised emSign certificate authorities from its bundled trust store. (#7639)

Performance

• Add the REFLEX_BACKEND_START_METHOD environment variable to choose how production backend workers are started (fork, spawn, or forkserver). (#7079)
• Unchanged objects and arrays in state updates now keep their previous identity on the frontend, so memoized components skip re-rendering them, and an update that changes nothing no longer re-renders at all. (#7273)
• A running background event handler no longer keeps the state tree it was dispatched with alive once it has entered async with self. With the Redis state manager, every long-running background task used to hold an extra copy of the session's state. (#7447)

Documentation

• Document the supported BaseStateMeta contract for custom state metaclasses, including the state_root and mixin class keywords and the reserved _reflex_state_root attribute. (#7626)

Miscellaneous

• Update generated apps to React 19.3.1, Vite 8.3.4, PostCSS 8.5.30, and postcss-import 17.0.1. (#7645)