[TW#13494] Compilation fails with -O3 optimization - vfs_fat.c specifically

[benpeoples]

CC src/vfs_fat.o
/Users/ben/esp/esp-idf/components/fatfs/src/vfs_fat.c: In function 'vfs_fat_readdir':
/Users/ben/esp/esp-idf/components/fatfs/src/vfs_fat.c:546:20: error: 'out_dirent' may be used uninitialized in this function [-Werror=maybe-uninitialized]
     struct dirent* out_dirent;
                    ^
cc1: some warnings being treated as errors
make[1]: *** [src/vfs_fat.o] Error 1
make: *** [fatfs-build] Error 2

I have not dug into the issue beyond this. Compiles fine with -O2.

[igrr]

This probably means that there is a possibility that vfs_fat_readdir_r will return 0 while not initializing out_dirent. The code looks like this:

    FRESULT res = f_readdir(&fat_dir->ffdir, &fat_dir->filinfo);
    if (res != FR_OK) {
        ESP_LOGD(TAG, "%s: fresult=%d", __func__, res);
        return fresult_to_errno(res);
    }

Unless I'm missing something, fresult_to_errno can only return 0 if res is FR_OK. On the other hand, the compiler is rarely wrong about such things. Will run this through a static analyzer...

[FayeY]

Hi @benpeoples , is this problem solved now?

[igrr]

@FayeY Not yet, please assign to me.