reflex-dev/reflex reflex-base-v0.9.11a1

reflex-base@0.9.11a1

on GitHub

Breaking Changes

• Bundled Bun moves to 1.4.0, and the minimum supported Bun version rises to 1.4.0 with it. Bun 1.4 creates new lockfiles at lockfileVersion: 2, which Bun 1.3.x cannot parse at all — so once a project's reflex.lock/bun.lock has been generated under 1.4, everyone building it (teammates, CI, Docker images) needs Bun 1.4 too. An existing lockfileVersion: 1 lockfile is kept at v1 by Bun 1.4, even across dependency changes, so already-initialized projects are unaffected until their lockfile is regenerated from scratch. Reflex installs and manages its own Bun, so this only needs action if you point bun_path at your own Bun or rely on one from PATH. (#7019)

Deprecations

• reflex_base.config._load_config() is deprecated in favor of _get_config(); use get_config() to read the cached config. (#6933)

Features

• Add inert OpenTelemetry trace points and metrics around event handler execution, state acquisition, socket messages and compile stages (reflex_base.otel) and window.__reflex_otel hooks in the frontend event loop and upload helper; they cost one boolean check, and import nothing from opentelemetry, until the reflex-otel package enables them (reflex-base itself does not depend on opentelemetry-api). (#6227)
• hybrid_property remains a property subclass at runtime, but type checkers now resolve class-level access to the frontend var's type instead of the descriptor: without a var function it follows the var equivalent of the getter's return type, and a var function may declare a type of its own. The var function may be a classmethod or staticmethod, may return None to declare that the property has no frontend value on a class, and — like getter, setter and deleter — may be defined under a name of its own instead of shadowing the property's declaration. (#6812)
• reflex_base.utils.log.reserve_stdout() reserves stdout for a machine-readable document, rendering log records, tables, rules, prompts, spinners and progress bars to stderr for as long as it is set. (#6917)

Bug Fixes

• A hybrid property a state inherits from a base class is no longer shadowed by state storage when the state annotates its name, which made such a state fail to instantiate. (#6812)

• Attribute probes on vars (e.g. inspect.iscoroutinefunction via unittest.mock) no longer trigger ForwardRef resolution of unrelated annotations, silencing spurious "Failed to resolve ForwardRefs" warnings and avoiding NameError under PEP 649 lazy annotations on Python 3.14. (#6929)

• Avoid ModuleNotFoundError when loading rxconfig.py in a multi-threaded context. (#6933)

• Auto-memoized components that render identically no longer share a generated memo name, which silently dropped one of the two compiled bodies. The name now accounts for:

  • module-level code emitted by add_custom_code
  • dynamic imports
  • app-wrap components, including rx.text and the other MarkdownComponentMap components that all hashed alike
  • the defining module, so same-named components from different modules stay apart
  • the identity of dataclasses and enum members, which previously hashed by shape and by str()

  (#6947)

• The compatibility delta flush for background handlers that never enter async with self now also runs when the handler raises, so uncached computed vars and preamble-dirty vars (like router_data) reach the client regardless of how the task ended. The exception still propagates to the backend exception handler afterwards; if the flush itself fails in that case, the flush error is logged instead of masking the handler's exception. (#6995)

• rx.Config now rejects a frontend_path whose segments are not plain directory names (.., backslashes, or drive letters), which would otherwise relocate the production build output outside of .web/build/client. (#7044)

• Fix the Safari dev-server cache-busting plugin rendering pages as comma-separated byte values with React Router 8. The rewritten HTML now streams through instead of being buffered, and multibyte characters split across response chunks stay intact. (#7048)

• Keep the frontend runtime stable across hot updates in reflex run. React contexts, event dispatchers, and element refs now survive a recompile, and the state and event-loop providers are no longer remounted on every compile, so a component refreshed before its provider no longer crashes with Cannot read properties of null, drops events, or reconnects the websocket. (#7071)

• Fix the post-eviction rehydrate fallback not running under StateManagerRedis. (#7072)

• Prevent runaway page-load event chains when backend-initiated events encounter expired state. (#7073)

Performance

• Component content hashing, which auto-memoization runs for every memoized component during a compile, encodes roughly 1.2-1.3x faster on large pages. Generated memo module names change as a result; nothing outside the compiled output refers to them. (#6947)
• New opt-in dev-server knobs: REFLEX_DEV_PROD_REACT=1 serves React's production build under the Vite dev server (navigation CPU on a large app 54 → 36 ms, prod build 24 ms; edits become a full reload since Fast Refresh needs dev React), and REFLEX_VITE_WARMUP_ROUTES=1 pre-transforms route modules at startup so the first visit to a page no longer waits on Vite (105–131 → 43–69 ms, or 20–32 ms with both). (#7021)
• Trimmed the framework overhead around every event handler: the state fast-paths its own bookkeeping attributes, foreground handler tasks start eagerly on Python 3.12+, the computed-var expiry check only looks at interval vars, route matching is memoized per path, and socket.io handlers run inline. About 28% less CPU per trivial event and 20% more events per second per worker under concurrent load. (#7025)
• Reduce CLI startup time and memory by loading compiler plugins and optional SQLAlchemy property support only when used. (#7050)

Miscellaneous

• Bump bundled frontend pins: react-router 8.3.1, isbot 5.2.2, postcss 8.5.26, postcss-import 17.0.0, and vite 8.2.2. postcss-import 17 requires Node 22+, which already matches the Reflex minimum. (#7019)