ESP8266WiFi.h redeclaration of lwip/tcp.h contents

[mcspr]

Basic Infos

• This issue complies with the issue POLICY doc.
• I have read the documentation at readthedocs and the issue is not addressed there.
• I have tested that the issue is present in current master branch (aka latest git).
• I have searched the issue tracker for a similar issue.
• If there is a stack dump, I have decoded it.
• I have filled out all fields below.

Platform

• Hardware: [ESP-12|ESP-01|ESP-07|ESP8285 device|other]
• Core Version: [l1bb5ccf71e0e028a593238b68513aac553a00886]
• Development Env: Platformio
• Operating System: Windows / WSL

Settings in IDE

• Module: Wemos D1 mini r2
• Flash Mode: default
• Flash Size: 4MB
• lwip Variant: ** v2 Lower Memory (default) **
• Reset Method: [ck|nodemcu]
• Flash Frequency: [40Mhz]
• CPU Frequency: [80Mhz|160MHz]
• Upload Using: [OTA|SERIAL]
• Upload Speed: [115200|other] (serial upload only)

Problem Description

1. Include "lwip/tcp.h" after ESP8266WiFi.h
2. Observe the redeclaration issue below

Inspecting the source of WiFiClient, I found this entry:

Arduino/libraries/ESP8266WiFi/src/WiFiClient.cpp

Line 23 in 1bb5ccf

#define LWIP_INTERNAL

This guards these enum values:

Arduino/libraries/ESP8266WiFi/src/include/wl_definitions.h

Lines 71 to 85 in 1bb5ccf

	#if !defined(LWIP_INTERNAL) && !defined(__LWIP_TCP_H__)
	enum wl_tcp_state {
	CLOSED = 0,
	LISTEN = 1,
	SYN_SENT = 2,
	SYN_RCVD = 3,
	ESTABLISHED = 4,
	FIN_WAIT_1 = 5,
	FIN_WAIT_2 = 6,
	CLOSE_WAIT = 7,
	CLOSING = 8,
	LAST_ACK = 9,
	TIME_WAIT = 10
	};
	#endif

Which is a possible workaround for this issue.

git grep wl_tcp_state does not show anything but this enum wl_tcp_state line :/

MCVE Sketch

Consider, I want to use lwip active pcb list in the app
(following is just a means to try to access tcp_pcb struct members, as we only forward-declare it by default as struct tcp_pcb; in esp8266wifi user-side header, so I must add tcp.h)

#include <Arduino.h>
#include <ESP8266WiFi.h>

extern "C" {
    #include <lwip/init.h>
    #include <lwip/opt.h>
    #include <lwip/tcp.h>
    #include <lwip/inet.h>
}

extern struct tcp_pcb *tcp_active_pcbs;

void setup() {}

void loop() {
    char remote_ip[32] = {0};
    char local_ip[32] = {0};
    for (tcp_pcb* pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
        inet_ntoa_r((pcb->local_ip), local_ip, sizeof(local_ip));
        inet_ntoa_r((pcb->remote_ip), remote_ip, sizeof(remote_ip));
        Serial.printf("%s<->%s\n", remote_ip, local_ip);
    }
}

Debug Messages

In file included from /home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/tools/sdk/lwip2/include/lwip/tcp.h:45:0,
                 from src/main.cpp:7:
/home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/tools/sdk/lwip2/include/lwip/tcpbase.h:57:17: error: redeclaration of 'CLOSED'
   CLOSED      = 0,
                 ^
In file included from /home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/libraries/ESP8266WiFi/src/ESP8266WiFi.h:28:0,
                 from src/main.cpp:2:
/home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/libraries/ESP8266WiFi/src/include/wl_definitions.h:73:3: note: previous declaration 'wl_tcp_state CLOSED'
   CLOSED      = 0,
   ^
In file included from /home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/tools/sdk/lwip2/include/lwip/tcp.h:45:0,
                 from src/main.cpp:7:
/home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/tools/sdk/lwip2/include/lwip/tcpbase.h:58:17: error: redeclaration of 'LISTEN'
   LISTEN      = 1,
                 ^
In file included from /home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/libraries/ESP8266WiFi/src/ESP8266WiFi.h:28:0,
                 from src/main.cpp:2:
/home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/libraries/ESP8266WiFi/src/include/wl_definitions.h:74:3: note: previous declaration 'wl_tcp_state LISTEN'
   LISTEN      = 1,
   ^
In file included from /home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/tools/sdk/lwip2/include/lwip/tcp.h:45:0,
                 from src/main.cpp:7:
/home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/tools/sdk/lwip2/include/lwip/tcpbase.h:59:17: error: redeclaration of 'SYN_SENT'
   SYN_SENT    = 2,
                 ^
In file included from /home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/libraries/ESP8266WiFi/src/ESP8266WiFi.h:28:0,
                 from src/main.cpp:2:
/home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/libraries/ESP8266WiFi/src/include/wl_definitions.h:75:3: note: previous declaration 'wl_tcp_state SYN_SENT'
   SYN_SENT    = 2,
   ^
In file included from /home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/tools/sdk/lwip2/include/lwip/tcp.h:45:0,
                 from src/main.cpp:7:
/home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/tools/sdk/lwip2/include/lwip/tcpbase.h:60:17: error: redeclaration of 'SYN_RCVD'
   SYN_RCVD    = 3,
                 ^
In file included from /home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/libraries/ESP8266WiFi/src/ESP8266WiFi.h:28:0,
                 from src/main.cpp:2:
/home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/libraries/ESP8266WiFi/src/include/wl_definitions.h:76:3: note: previous declaration 'wl_tcp_state SYN_RCVD'
   SYN_RCVD    = 3,
   ^
In file included from /home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/tools/sdk/lwip2/include/lwip/tcp.h:45:0,
                 from src/main.cpp:7:
/home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/tools/sdk/lwip2/include/lwip/tcpbase.h:61:17: error: redeclaration of 'ESTABLISHED'
   ESTABLISHED = 4,
                 ^
In file included from /home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/libraries/ESP8266WiFi/src/ESP8266WiFi.h:28:0,
                 from src/main.cpp:2:
/home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/libraries/ESP8266WiFi/src/include/wl_definitions.h:77:3: note: previous declaration 'wl_tcp_state ESTABLISHED'
   ESTABLISHED = 4,
   ^
In file included from /home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/tools/sdk/lwip2/include/lwip/tcp.h:45:0,
                 from src/main.cpp:7:
/home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/tools/sdk/lwip2/include/lwip/tcpbase.h:62:17: error: redeclaration of 'FIN_WAIT_1'
   FIN_WAIT_1  = 5,
                 ^
In file included from /home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/libraries/ESP8266WiFi/src/ESP8266WiFi.h:28:0,
                 from src/main.cpp:2:
/home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/libraries/ESP8266WiFi/src/include/wl_definitions.h:78:3: note: previous declaration 'wl_tcp_state FIN_WAIT_1'
   FIN_WAIT_1  = 5,
   ^
In file included from /home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/tools/sdk/lwip2/include/lwip/tcp.h:45:0,
                 from src/main.cpp:7:
/home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/tools/sdk/lwip2/include/lwip/tcpbase.h:63:17: error: redeclaration of 'FIN_WAIT_2'
   FIN_WAIT_2  = 6,
                 ^
In file included from /home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/libraries/ESP8266WiFi/src/ESP8266WiFi.h:28:0,
                 from src/main.cpp:2:
/home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/libraries/ESP8266WiFi/src/include/wl_definitions.h:79:3: note: previous declaration 'wl_tcp_state FIN_WAIT_2'
   FIN_WAIT_2  = 6,
   ^
In file included from /home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/tools/sdk/lwip2/include/lwip/tcp.h:45:0,
                 from src/main.cpp:7:
/home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/tools/sdk/lwip2/include/lwip/tcpbase.h:64:17: error: redeclaration of 'CLOSE_WAIT'
   CLOSE_WAIT  = 7,
                 ^
In file included from /home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/libraries/ESP8266WiFi/src/ESP8266WiFi.h:28:0,
                 from src/main.cpp:2:
/home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/libraries/ESP8266WiFi/src/include/wl_definitions.h:80:3: note: previous declaration 'wl_tcp_state CLOSE_WAIT'
   CLOSE_WAIT  = 7,
   ^
In file included from /home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/tools/sdk/lwip2/include/lwip/tcp.h:45:0,
                 from src/main.cpp:7:
/home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/tools/sdk/lwip2/include/lwip/tcpbase.h:65:17: error: redeclaration of 'CLOSING'
   CLOSING     = 8,
                 ^
In file included from /home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/libraries/ESP8266WiFi/src/ESP8266WiFi.h:28:0,
                 from src/main.cpp:2:
/home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/libraries/ESP8266WiFi/src/include/wl_definitions.h:81:3: note: previous declaration 'wl_tcp_state CLOSING'
   CLOSING     = 8,
   ^
In file included from /home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/tools/sdk/lwip2/include/lwip/tcp.h:45:0,
                 from src/main.cpp:7:
/home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/tools/sdk/lwip2/include/lwip/tcpbase.h:66:17: error: redeclaration of 'LAST_ACK'
   LAST_ACK    = 9,
                 ^
In file included from /home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/libraries/ESP8266WiFi/src/ESP8266WiFi.h:28:0,
                 from src/main.cpp:2:
/home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/libraries/ESP8266WiFi/src/include/wl_definitions.h:82:3: note: previous declaration 'wl_tcp_state LAST_ACK'
   LAST_ACK    = 9,
   ^
In file included from /home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/tools/sdk/lwip2/include/lwip/tcp.h:45:0,
                 from src/main.cpp:7:
/home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/tools/sdk/lwip2/include/lwip/tcpbase.h:67:17: error: redeclaration of 'TIME_WAIT'
   TIME_WAIT   = 10
                 ^
In file included from /home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/libraries/ESP8266WiFi/src/ESP8266WiFi.h:28:0,
                 from src/main.cpp:2:
/home/builder/.platformio/packages/framework-arduinoespressif8266@src-31d658a59f41540201fc3726a1394910/libraries/ESP8266WiFi/src/include/wl_definitions.h:83:3: note: previous declaration 'wl_tcp_state TIME_WAIT'
   TIME_WAIT   = 10
   ^
*** [.pio/build/d1_mini/src/main.cpp.o] Error 1
========================== [FAILED] Took 2.80 seconds ==========================