Toast provider not included in production builds when used with sync events

[clemlesne]

Describe the bug

When toasts are included in sync events, build error appears only in prod mode.

To reproduce

VERSION = "v0.0.0"

# ...

rx.text(
    f"v{VERSION} ({rx.config.environment.REFLEX_ENV_MODE.get().value})",
    on_mouse_up=rx.set_clipboard(
        f"v{VERSION}"
    ),  # On Safari, async func are not allowed to access clipboard (see: https://github.com/reflex-dev/reflex/issues/4757#issue-2832833845)
    on_click=lambda: rx.toast.success(
        "Version copied to clipboard"
    ),
)

Expected behavior

App builds.

Logs

Builds logs without rx.toast.provider():

File "/[root]/app/pages/template.py", line 140, in _wrapper
  rx.text(
  ~~~~~~~^
      f"v{VERSION} ({rx.config.environment.REFLEX_ENV_MODE.get().value})",
      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  ...<7 lines>...
      size="1",
      ^^^^^^^^^
  ),
  ^
File "/[root]/.venv/lib/python3.13/site-packages/reflex/components/radix/themes/base.py", line 139, in create
  component = super().create(*children, **props)
File "/[root]/.venv/lib/python3.13/site-packages/reflex/components/component.py", line 736, in create
  return cls(children=children, **props)
File "/[root]/.venv/lib/python3.13/site-packages/reflex/components/component.py", line 491, in __init__
  kwargs["event_triggers"][key] = EventChain.create(
                                  ~~~~~~~~~~~~~~~~~^
      value=value,
      ^^^^^^^^^^^^
      args_spec=component_specific_triggers[key],
      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
      key=key,
      ^^^^^^^^
  )
  ^
File "/[root]/.venv/lib/python3.13/site-packages/reflex/event.py", line 484, in create
  result = call_event_fn(value, args_spec, key=key)
File "/[root]/.venv/lib/python3.13/site-packages/reflex/event.py", line 1494, in call_event_fn
  out = fn(*[*parsed_args][:number_of_fn_args])
File "/[root]/app/pages/template.py", line 146, in <lambda>
  on_click=lambda: rx.toast.success(
                    ~~~~~~~~~~~~~~~~^
      "Version copied to clipboard"
      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  ),
  ^
File "/[root]/.venv/lib/python3.13/site-packages/reflex/components/sonner/toast.py", line 328, in toast_success
  return Toaster.send_toast(message, level="success", **kwargs)
          ~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/[root]/.venv/lib/python3.13/site-packages/reflex/components/sonner/toast.py", line 256, in send_toast
  raise ValueError(
      "Toaster component must be created before sending a toast. (use `rx.toast.provider()`)"
  )
ValueError: Toaster component must be created before sending a toast. (use `rx.toast.provider()`)

Builds logs with rx.toast.provider():

Creating Production Build failed with exit code 1

> export-sitemap
> next build && next-sitemap

   ▲ Next.js 15.1.6

   Linting and checking validity of types ...
   Creating an optimized production build ...
 ✓ Compiled successfully
   Collecting page data ...
   Generating static pages (0/8) ...
ReferenceError: useEffect is not defined
    at E (.next/server/pages/demo//review/edit.js:1:8700)
ReferenceError: useEffect is not defined
    at y (.next/server/pages/user.js:1:2006)
Error occurred prerendering page "/demo//review/edit". Read more: 
https://nextjs.org/docs/messages/prerender-error
ReferenceError: useEffect is not defined
[...]
Error occurred prerendering page "/user". Read more: 
https://nextjs.org/docs/messages/prerender-error
ReferenceError: useEffect is not defined
[...]
Export encountered an error on /demo//review/edit, exiting the build.
 ⨯ Static worker exited with code: 1 and signal: null

Specifics (please complete the following information)

• Python version: 3.13
• Reflex Version: 0.7.0
• OS: macOS 15.3 (24D60) plus Ubuntu 24.04

[linear]

ENG-4727 Toast provider not included in production builds when used with sync events

[adhami3310]

can you test it with latest release of reflex?