FLUSH_IN_EFFECT_CALLBACK
flush() from an effect callback (no-op; the drain is already running).
What you saw
- Kind:
lifecycle - Severity:
warn(code that works but is structurally wrong or expensive)
The console report opens with [FLUSH_IN_EFFECT_CALLBACK] and the message, then an in line naming the owners that enclose the subject, root first, and an at line with the source location when the code was compiled with one.
In a captured artifact the same finding is an event with code: "FLUSH_IN_EFFECT_CALLBACK", ownerPath, and loc.
Diagnostics explains each line.
Why it fires
flush() was called inside an effect callback, where it is a no-op (the flush running effects is already in progress).
Writes made there are handled in the same flush's continuation.
How to fix it
If you truly need a drain afterwards, defer it: queueMicrotask(() => flush()).
Usually the right fix is deleting the call.
In tests
captureArtifact from @solidjs/diagnostics runs a scenario with the diagnostics channel open and returns the events it saw.
expectNoDiagnostics(artifact) fails while FLUSH_IN_EFFECT_CALLBACK is among them, with the events as evidence; after the fix, the code is gone from artifact.diagnostics.
Check for regressions in tests shows the loop and the Vitest matcher form.
Learn more
- Diagnostics: every code, with its kind, severity, and trigger.
- Debugging reactivity: how to read a report and what each group of codes points at.