ble_store_config_cccds referenced even with CCCD persistence disabled (IDFGH-12372)

[therealergo]

Answers checklist.

• I have read the documentation ESP-IDF Programming Guide and the issue is not addressed there.
• I have updated my IDF branch (master or release) to the latest version and checked that the issue is present there.
• I have searched the issue tracker for a similar issue and not found a similar issue.

IDF version.

v5.1.2

Espressif SoC revision.

ESP32

Operating System used.

Windows

How did you build your project?

VS Code IDE

If you are using Windows, please specify command line type.

PowerShell

Development Kit.

Custom Board

Power Supply used.

USB

What is the expected behavior?

Esp-Idf to compile with CONFIG_BT_NIMBLE_MAX_CCCDS=0

What is the actual behavior?

Compilation fails, since ble_store_config_cccds is referenced even when it is undefined.

Steps to reproduce.

1. Set CONFIG_BT_NIMBLE_MAX_CCCDS to 0 to disable CCCD persistence with Esp-Idf v5.1.2 or newer.
2. Attempt to compile any project.

Debug Logs.

ld.exe: esp-idf/bt/libbt.a(ble_store_nvs.c.obj):(.literal.ble_store_config_conf_init+0x8): undefined reference to `ble_store_config_cccds'
collect2.exe: error: ld returned 1 exit status
ninja: build stopped: subcommand failed

More Information.

As of commit b85d99d, NimBLE better supports setting CONFIG_BT_NIMBLE_MAX_CCCDS to 0 to disable CCCD persistence. This is desirable in some circumstances, e.g. see this previous issue where another person uses this configuration value. When this configuration is set, newer versions of NimBLE do not define the ble_store_config_cccds array, since it is not used by the implementation. Unfortunately, the Esp-Idf implementation of CCCD persistence always references the ble_store_config_cccds array in ble_store_config_conf.c and ble_store_nvs.c. As a result, Esp-Idf v5.1.2 will fail to compile if CONFIG_BT_NIMBLE_MAX_CCCDS is set to 0. Checks like #if MYNEWT_VAL(BLE_STORE_MAX_CCCDS) should be added around references to this array to ensure that it is not referenced while undefined.

[rahult-github]

Hi @therealergo ,

I tried the mentioned version at my end and i do not observe the failure you have mentioned.

Anyways, i have tried to make a fix based on usage. Can you please help check if attached patch works ok for you ? The patch has to be applied in $IDF_PATH/components/bt/host/nimble/nimble path

fix_cccd_zero_usage.txt

[therealergo]

Hi @rahult-github

Thanks for looking into this. I suspect you do not see the compilation failure because you have the entire persistence module disabled. You have to set CONFIG_BT_NIMBLE_NVS_PERSIST to y to enable the persistence feature at all. This includes persistence for bonding data, CCCD's, and encoded advertisement data. I have attached a minimal sdkconfig that exhibits this problem.
sdkconfig.txt

Regardless, the patch fixes the issue. Hope it can be merged in soon!

[rahult-github]

Change has been merged. Closing