Libraries are included but compiler complains a variable is missing from scope

Libraries
1

I’m trying to add the WebSerial library to my PlatformIO project. I’ve added it to the library manager, and the library is present in my dependency graph when I build. However, I keep getting an error that the instance variable ‘WebSerial’ was not declared in this scope.

I’ve confirmed that:

  • The library exists in .pio/libdeps
  • It exists in my platformio.ini file under lib_deps
  • I’ve tried lib_ldf_mode = chain+ and deep+
  • I have an extra lib/ directory with the source .cpp and .h files, yet the compiler can’t find it

Poking around through the .pio/build directory, I noticed object files for the other libraries. But none for WebSerial. I wonder if there’s a manual build step that I’m missing? Maybe the dependencies are out of order?

My file structure is as follows (unimportant files have been omitted):

.pio/libdeps/esp32dev/
|-- WebSerial/  // contents are from https://github.com/ayushsharma82/WebSerial
include/
|-- webserial.h  // My own wrapper. This has the directive #include <WebSerial.h>
src/
|-- webserial.cpp  // Has directive #include "webserial.h". COMPILER ERRORS HERE
lib/
|-- WebSerial/
|  |-- WebSerial.h
|  |-- WebSerial.cpp
|  |-- webserial_webpage.cpp

platformio.ini:

[env:esp32dev]
platform = espressif32
board = esp32dev
framework = arduino
lib_ldf_mode = deep+
lib_deps = 
	https://github.com/me-no-dev/ESPAsyncWebServer.git
	bblanchon/ArduinoJson@^6.19.4
	ayushsharma82/WebSerial@^1.3.0
lib_extra_dirs = 
	./lib/WebSerial/
monitor_speed = 115200

Here is the raw dump:

CONFIGURATION: https://docs.platformio.org/page/boards/espressif32/esp32dev.html
PLATFORM: Espressif 32 (5.3.0) > Espressif ESP32 Dev Module
HARDWARE: ESP32 240MHz, 320KB RAM, 4MB Flash
DEBUG: Current (cmsis-dap) External (cmsis-dap, esp-bridge, esp-prog, iot-bus-jtag, jlink, minimodule, olimex-arm-usb-ocd, olimex-arm-usb-ocd-h, olimex-arm-usb-tiny-h, olimex-jtag-tiny, tumpa)
PACKAGES: 
 - framework-arduinoespressif32 @ 3.20006.221224 (2.0.6) 
 - tool-esptoolpy @ 1.40400.0 (4.4.0) 
 - tool-openocd-esp32 @ 2.1100.20220706 (11.0) 
 - toolchain-xtensa-esp32 @ 8.4.0+2021r2-patch5
LDF: Library Dependency Finder -> https://bit.ly/configure-pio-ldf
LDF Modes: Finder ~ deep+, Compatibility ~ soft
Found 40 compatible libraries
Scanning dependencies...
Dependency Graph
|-- ESP Async WebServer @ 1.2.3+sha.f71e3d4
|   |-- AsyncTCP @ 1.1.1
|   |-- FS @ 2.0.0
|   |-- WiFi @ 2.0.0
|-- ArduinoJson @ 6.20.0
|-- WebSerial @ 1.3.0
|   |-- WiFi @ 2.0.0
|   |-- AsyncTCP @ 1.1.1
|   |-- ESP Async WebServer @ 1.2.3+sha.f71e3d4
|   |   |-- AsyncTCP @ 1.1.1
|   |   |-- FS @ 2.0.0
|   |   |-- WiFi @ 2.0.0
|   |-- FS @ 2.0.0
|-- WiFi @ 2.0.0
|-- Preferences @ 2.0.0
|-- FS @ 2.0.0
|-- AsyncTCP @ 1.1.1
|-- AsyncElegantOTA
|   |-- WiFi @ 2.0.0
|   |-- AsyncTCP @ 1.1.1
|   |-- Update @ 2.0.0
|   |-- ESP Async WebServer @ 1.2.3+sha.f71e3d4
|   |   |-- AsyncTCP @ 1.1.1
|   |   |-- FS @ 2.0.0
|   |   |-- WiFi @ 2.0.0
|   |-- FS @ 2.0.0
|-- Update @ 2.0.0

src/webserial.cpp: In function 'void recvMsg(uint8_t*, size_t)':
src/webserial.cpp:22:3: error: 'WebSerial' was not declared in this scope
   WebSerial.println("Received data...");
   ^~~~~~~~~
src/webserial.cpp:22:3: note: suggested alternative: 'Serial'
   WebSerial.println("Received data...");
   ^~~~~~~~~
   Serial
src/webserial.cpp: In function 'void initWebSerial(AsyncWebServer&)':
src/webserial.cpp:43:3: error: 'WebSerial' was not declared in this scope
   WebSerial.begin(server);
   ^~~~~~~~~
src/webserial.cpp:43:3: note: suggested alternative: 'Serial'
   WebSerial.begin(server);
   ^~~~~~~~~
   Serial
2

Having both webserial.h and WebSerial.h in the project is a deathblow to compilation on Windows which has a case-insensitive filesystem, it won’t know which file you mean. There may be a chance that PlatformIO gets confused too. Can you rename your wrapper header and c files to a distinct name, like webserial_wrapper.h etc and retry?

That’s not the right usage of lib_extra_dirs, which expectes to be given a folder under which there is one or multiple library folders. So if anything, it would have to be lib_extra_dirs = lib, but since lib already is the default library directory, the directive should be deleted completely.

3

Renaming to webserial_wrapper.h fixed the issue. I’m used to developing on Unix so the naming conflict didn’t even cross my mind as a possibility.

I’ve also removed the redundant lib_extra_dirs as you pointed out.

Thanks!