WebServer::authenticate uses wrong braces in malloc

[TD-er]

Board

Any

Device Description

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Hardware Configuration

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Version

latest master (checkout manually)

IDE Name

PlatformIO

Operating System

Windows 11

Flash frequency

40MHz

PSRAM enabled

yes

Upload speed

115200

Description

C:/Users/gijsn/.platformio/packages/framework-arduinoespressif32/libraries/WebServer/src/WebServer.cpp:138:54: warning: pointer to a function used in arithmetic [-Wpointer-arith]
  138 |       char *toencode = (char *)malloc[toencodeLen + 1];
      |                                                      ^
cc1plus.exe: warning: pointer to a function used in arithmetic [-Wpointer-arith]

Took a while to see what was wrong here, but the code uses malloc[] instead of malloc()

At the end of the compile run, it also states other resulting errors:

C:/Users/gijsn/.platformio/packages/framework-arduinoespressif32/libraries/WebServer/src/WebServer.cpp: In member function 'authenticate':
C:/Users/gijsn/.platformio/packages/framework-arduinoespressif32/libraries/WebServer/src/WebServer.cpp:146:13: warning: 'free' called on unallocated object 'malloc' [-Wfree-nonheap-object]
  146 |         free(toencode);
      |             ^
c:\users\gijsn\.platformio\packages\toolchain-xtensa-esp32\xtensa-esp32-elf\sys-include\stdlib.h:112:10: note: declared here
  112 | void    *malloc(size_t) __malloc_like __result_use_check __alloc_size(1) _NOTHROW;
      |          ^
C:/Users/gijsn/.platformio/packages/framework-arduinoespressif32/libraries/WebServer/src/WebServer.cpp:152:13: warning: 'free' called on unallocated object 'malloc' [-Wfree-nonheap-object]
  152 |         free(toencode);
      |             ^
c:\users\gijsn\.platformio\packages\toolchain-xtensa-esp32\xtensa-esp32-elf\sys-include\stdlib.h:112:10: note: declared here
  112 | void    *malloc(size_t) __malloc_like __result_use_check __alloc_size(1) _NOTHROW;
      |          ^
C:/Users/gijsn/.platformio/packages/framework-arduinoespressif32/libraries/WebServer/src/WebServer.cpp:156:11: warning: 'free' called on unallocated object 'malloc' [-Wfree-nonheap-object]
  156 |       free(toencode);
      |           ^
c:\users\gijsn\.platformio\packages\toolchain-xtensa-esp32\xtensa-esp32-elf\sys-include\stdlib.h:112:10: note: declared here
  112 | void    *malloc(size_t) __malloc_like __result_use_check __alloc_size(1) _NOTHROW;
      |          ^

Sketch

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Debug Message

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Other Steps to Reproduce

No response

I have checked existing issues, online documentation and the Troubleshooting Guide

• I confirm I have checked existing issues, online documentation and Troubleshooting guide.

[robertlipe]

Nice catch. That's subtle. This is why enabling and acting on warnings helps!

This is One More Reason no code in a cpp file should be calling malloc and free anyway. Simplifying that chain of 'if allocated, call free..." could only help the maintainability of that code. Letting all that files's strings be in a std::string or even (ick) a String would really help.

Even the 'minimally correct' approach of using the 'right' form of braces should fix this issue, though.

(Disclaimer: I don't use this code - I'm just reading recent issues while looking for something else in ESP32-land.)

[TD-er]

Yep, totally agree that we should move away from doing the low-level memory allocation ourselves.

I always try to write code which has "no warnings", so I have all warnings enabled.
To be honest, I had never seen this warning, so had to look through the code several times to see what was actually wrong here.

[SuGlider]

Thanks @TD-er !! Nice catch for sure!