FlushResult Renamed to UARTFlushResult

Apr 9, 2026

The FlushResult enum introduced in ESPHome 2026.3.0 has been renamed to UARTFlushResult with prefixed enum values to follow ESPHome’s naming conventions and avoid macro collisions.

This is a breaking change for external components in ESPHome 2026.4.0 and later.

Background

PR #15101: Rename FlushResult to UARTFlushResult with UART_FLUSH_RESULT_ prefix

The original FlushResult::SUCCESS value collided with the Realtek RTL SDK’s #define SUCCESS 0 macro, requiring ugly #pragma push_macro workarounds. Renaming to UARTFlushResult with UART_FLUSH_RESULT_ prefixed values follows ESPHome’s conventional component-prefix naming style (matching UARTParityOptions / UART_CONFIG_PARITY_NONE) and eliminates the collision entirely.

What’s Changing

Before	After
`FlushResult`	`UARTFlushResult`
`FlushResult::SUCCESS`	`UARTFlushResult::UART_FLUSH_RESULT_SUCCESS`
`FlushResult::TIMEOUT`	`UARTFlushResult::UART_FLUSH_RESULT_TIMEOUT`
`FlushResult::FAILED`	`UARTFlushResult::UART_FLUSH_RESULT_FAILED`
`FlushResult::ASSUMED_SUCCESS`	`UARTFlushResult::UART_FLUSH_RESULT_ASSUMED_SUCCESS`

Who This Affects

External components that implement UARTComponent::flush() and reference the FlushResult type or enum values.

This only affects components updated for the 2026.3.0 flush() return type change. If you haven’t updated your flush() override yet, see the 2026.3.0 UART flush blog post first.

Migration Guide

// Before (2026.3.0)
FlushResult flush() override {
  // ...
  return FlushResult::ASSUMED_SUCCESS;
}

// After (2026.4.0)
UARTFlushResult flush() override {
  // ...
  return UARTFlushResult::UART_FLUSH_RESULT_ASSUMED_SUCCESS;
}

Supporting Multiple ESPHome Versions

#if ESPHOME_VERSION_CODE >= VERSION_CODE(2026, 4, 0)
UARTFlushResult flush() override {
  // ...
  return UARTFlushResult::UART_FLUSH_RESULT_ASSUMED_SUCCESS;
}
#elif ESPHOME_VERSION_CODE >= VERSION_CODE(2026, 3, 0)
FlushResult flush() override {
  // ...
  return FlushResult::ASSUMED_SUCCESS;
}
#else
void flush() override {
  // ...
}
#endif

Timeline

ESPHome 2026.3.0 (March 2026): FlushResult introduced
ESPHome 2026.4.0 (April 2026): Renamed to UARTFlushResult with prefixed values
No deprecation period — this is a rename of a type introduced one release ago

Finding Code That Needs Updates

# Find FlushResult references in your component
grep -rn 'FlushResult' your_component/

Questions?

If you have questions about migrating your external component, please ask in:

ESPHome Discord - #devs channel
ESPHome GitHub Discussions

Comments

Feel free to leave a comment here to discuss this post with others. You can ask questions, share your experience, or suggest improvements. If you have a question about a specific feature or issue, please consider using the ESPHome Discord. Stick to English and follow ESPHome's code of conduct. These comments exist on a discussion on GitHub, so you can also comment there directly if you prefer.