What does this implement/fix?

The socket abstraction layer on ESP8266/RP2040 (USE_SOCKET_IMPL_LWIP_TCP) only supports TCP. When E1.31 was migrated from WiFiUDP to the socket abstraction in #4832, it silently broke on these platforms — SOCK_DGRAM requests get TCP sockets that never receive UDP data.

This restores WiFiUDP as the UDP transport on LWIP_TCP platforms while keeping the socket-based implementation on BSD/LWIP socket platforms (ESP32, etc.). This follows the same dual-path pattern already used by the udp and wake_on_lan components.

Changes:

• e131.h: Conditionally include socket/socket.h or WiFiUdp.h and declare the appropriate member (socket_ vs udp_)
• e131.cpp: Add #elif dual paths in destructor, setup(), and loop() for socket vs WiFiUDP. The WiFiUDP path uses a while (parsePacket()) loop to drain all pending packets per loop call, matching the original pre-Migrate e131 to use socket instead of WiFiUDP arduino library #4832 behavior.
• e131_packet.cpp: Guard socket_ == nullptr check so it only compiles on platforms that have the socket_ member

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Developer breaking change (an API change that could break external components)
• Code quality improvements to existing code or addition of tests
• Other

Related issue or feature (if applicable):

• fixes E1.31 not responding after update on esp8266 (socket lacks udp support) #14088

Pull request in esphome-docs with documentation (if applicable):

• N/A (no user-facing configuration changes)

Test Environment

• ESP32
• ESP32 IDF
• ESP8266
• RP2040
• BK72xx
• RTL87xx
• LN882x
• nRF52840

Example entry for config.yaml:

esphome:
  name: e131-test

esp8266:
  board: d1_mini

wifi:
  ssid: MySSID
  password: password1

e131:
  method: multicast

light:
  - platform: neopixelbus
    id: led_strip
    type: GRB
    variant: ws2812
    pin: GPIO2
    num_leds: 50
    default_transition_length: 0s
    effects:
      - e131:
          universe: 1
          channels: RGB

Test sender script

Install sacn (pip install sacn) and run to verify E1.31 reception. Sweeps red, green, blue at 50 FPS:

"""Simple E1.31 (sACN) test sender for testing the ESPHome e131 component.

Usage:
    pip install sacn
    python test_e131_sender.py [--universe 1] [--unicast 192.168.1.100] [--leds 50]
"""

import argparse
import time

import sacn


def main():
    parser = argparse.ArgumentParser(description="E1.31 test sender")
    parser.add_argument("--universe", type=int, default=1)
    parser.add_argument("--unicast", type=str, default=None, help="Device IP for unicast (default: multicast)")
    parser.add_argument("--leds", type=int, default=50)
    args = parser.parse_args()

    sender = sacn.sACNsender()
    sender.start()
    sender.activate_output(args.universe)

    if args.unicast:
        sender[args.universe].destination = args.unicast
    else:
        sender[args.universe].multicast = True

    channels = args.leds * 3  # RGB
    print(f"Sending to universe {args.universe}, {args.leds} LEDs, {'unicast ' + args.unicast if args.unicast else 'multicast'}")
    print("Ctrl+C to stop")

    try:
        while True:
            # Red sweep
            for i in range(256):
                data = tuple([i, 0, 0] * args.leds)[:channels]
                sender[args.universe].dmx_data = data
                time.sleep(0.02)
            # Green sweep
            for i in range(256):
                data = tuple([0, i, 0] * args.leds)[:channels]
                sender[args.universe].dmx_data = data
                time.sleep(0.02)
            # Blue sweep
            for i in range(256):
                data = tuple([0, 0, i] * args.leds)[:channels]
                sender[args.universe].dmx_data = data
                time.sleep(0.02)
    except KeyboardInterrupt:
        print("\nStopping")
    finally:
        sender.stop()


if __name__ == "__main__":
    main()

Checklist:

• The code change is tested and works locally.
• Tests have been added to verify that the new code works (under tests/ folder).

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in esphome-docs.