kconfiglib: Allow CONFIG_xxx= to disable booleans

But replace all sdkconfig.defaults to use the explicit =n (more correct)

examples/bluetooth/a2dp_gatts_coex/sdkconfig.defaults

@@ -2,29 +2,29 @@
 # Classic BT is enabled and BT_DRAM_RELEASE is disabled
 CONFIG_BT_ENABLED=y
 CONFIG_BTDM_CONTROLLER_PINNED_TO_CORE_0=y
-CONFIG_BTDM_CONTROLLER_PINNED_TO_CORE_1=
+CONFIG_BTDM_CONTROLLER_PINNED_TO_CORE_1=n
 CONFIG_BTDM_CONTROLLER_PINNED_TO_CORE=0
 CONFIG_BTDM_CONTROLLER_HCI_MODE_VHCI=y
-CONFIG_BTDM_CONTROLLER_HCI_MODE_UART_H4=
+CONFIG_BTDM_CONTROLLER_HCI_MODE_UART_H4=n
 CONFIG_BLUEDROID_ENABLED=y
 CONFIG_BLUEDROID_PINNED_TO_CORE_0=y
-CONFIG_BLUEDROID_PINNED_TO_CORE_1=
+CONFIG_BLUEDROID_PINNED_TO_CORE_1=n
 CONFIG_BLUEDROID_PINNED_TO_CORE=0
 CONFIG_BTC_TASK_STACK_SIZE=3072
-CONFIG_BLUEDROID_MEM_DEBUG=
+CONFIG_BLUEDROID_MEM_DEBUG=n
 CONFIG_CLASSIC_BT_ENABLED=y
 CONFIG_A2DP_ENABLE=y
 CONFIG_A2DP_SINK_ENABLE=y
-CONFIG_A2DP_SRC_ENABLE=
+CONFIG_A2DP_SRC_ENABLE=n
 CONFIG_A2DP_SINK_TASK_STACK_SIZE=2048
-CONFIG_BT_SPP_ENABLED=
+CONFIG_BT_SPP_ENABLED=n
 CONFIG_GATTS_ENABLE=y
-CONFIG_GATTC_ENABLE=
-CONFIG_BLE_SMP_ENABLE=
+CONFIG_GATTC_ENABLE=n
+CONFIG_BLE_SMP_ENABLE=n
 CONFIG_BLE_ENABLE_SRVCHG_REG=y
-CONFIG_BT_STACK_NO_LOG=
+CONFIG_BT_STACK_NO_LOG=n
 CONFIG_BT_ACL_CONNECTIONS=4
-CONFIG_BT_ALLOCATION_FROM_SPIRAM_FIRST=
-CONFIG_BT_BLE_DYNAMIC_ENV_MEMORY=
+CONFIG_BT_ALLOCATION_FROM_SPIRAM_FIRST=n
+CONFIG_BT_BLE_DYNAMIC_ENV_MEMORY=n
 CONFIG_SMP_ENABLE=y
 CONFIG_BT_RESERVE_DRAM=0x10000

examples/bluetooth/a2dp_sink/sdkconfig.defaults

@@ -4,7 +4,7 @@ CONFIG_BT_ENABLED=y
 CONFIG_BLUEDROID_ENABLED=y
 CONFIG_CLASSIC_BT_ENABLED=y
 CONFIG_A2DP_ENABLE=y
-CONFIG_BT_SPP_ENABLED=
-CONFIG_GATTS_ENABLE=
-CONFIG_GATTC_ENABLE=
-CONFIG_BLE_SMP_ENABLE=
+CONFIG_BT_SPP_ENABLED=n
+CONFIG_GATTS_ENABLE=n
+CONFIG_GATTC_ENABLE=n
+CONFIG_BLE_SMP_ENABLE=n

examples/bluetooth/a2dp_source/sdkconfig.defaults

@@ -4,7 +4,7 @@ CONFIG_BT_ENABLED=y
 CONFIG_BLUEDROID_ENABLED=y
 CONFIG_CLASSIC_BT_ENABLED=y
 CONFIG_A2DP_ENABLE=y
-CONFIG_BT_SPP_ENABLED=
-CONFIG_GATTS_ENABLE=
-CONFIG_GATTC_ENABLE=
-CONFIG_BLE_SMP_ENABLE=
+CONFIG_BT_SPP_ENABLED=n
+CONFIG_GATTS_ENABLE=n
+CONFIG_GATTC_ENABLE=n
+CONFIG_BLE_SMP_ENABLE=n

examples/bluetooth/blufi/sdkconfig.defaults

@@ -6,24 +6,24 @@
 #
 CONFIG_BT_ENABLED=y
 CONFIG_BTDM_CONTROLLER_PINNED_TO_CORE_0=y
-CONFIG_BTDM_CONTROLLER_PINNED_TO_CORE_1=
+CONFIG_BTDM_CONTROLLER_PINNED_TO_CORE_1=n
 CONFIG_BTDM_CONTROLLER_PINNED_TO_CORE=0
 CONFIG_BTDM_CONTROLLER_HCI_MODE_VHCI=y
-CONFIG_BTDM_CONTROLLER_HCI_MODE_UART_H4=
+CONFIG_BTDM_CONTROLLER_HCI_MODE_UART_H4=n
 CONFIG_BLUEDROID_ENABLED=y
 CONFIG_BLUEDROID_PINNED_TO_CORE_0=y
-CONFIG_BLUEDROID_PINNED_TO_CORE_1=
+CONFIG_BLUEDROID_PINNED_TO_CORE_1=n
 CONFIG_BLUEDROID_PINNED_TO_CORE=0
 CONFIG_BTC_TASK_STACK_SIZE=3072
-CONFIG_BLUEDROID_MEM_DEBUG=
-CONFIG_CLASSIC_BT_ENABLED=
+CONFIG_BLUEDROID_MEM_DEBUG=n
+CONFIG_CLASSIC_BT_ENABLED=n
 CONFIG_GATTS_ENABLE=y
-CONFIG_GATTC_ENABLE=
-CONFIG_BLE_SMP_ENABLE=
+CONFIG_GATTC_ENABLE=n
+CONFIG_BLE_SMP_ENABLE=n
 CONFIG_BLE_ENABLE_SRVCHG_REG=y
-CONFIG_BT_STACK_NO_LOG=
+CONFIG_BT_STACK_NO_LOG=n
 CONFIG_BT_ACL_CONNECTIONS=4
-CONFIG_BT_ALLOCATION_FROM_SPIRAM_FIRST=
-CONFIG_BT_BLE_DYNAMIC_ENV_MEMORY=
-CONFIG_SMP_ENABLE=
+CONFIG_BT_ALLOCATION_FROM_SPIRAM_FIRST=n
+CONFIG_BT_BLE_DYNAMIC_ENV_MEMORY=n
+CONFIG_SMP_ENABLE=n
 CONFIG_BT_RESERVE_DRAM=0x10000

examples/bluetooth/bt_discovery/sdkconfig.defaults

@@ -2,7 +2,7 @@
 # Classic BT is enabled and BT_DRAM_RELEASE is disabled
 CONFIG_BT_ENABLED=y
 CONFIG_CLASSIC_BT_ENABLED=y
-CONFIG_A2DP_ENABLE=
-CONFIG_GATTS_ENABLE=
-CONFIG_GATTC_ENABLE=
-CONFIG_BLE_SMP_ENABLE=
+CONFIG_A2DP_ENABLE=n
+CONFIG_GATTS_ENABLE=n
+CONFIG_GATTC_ENABLE=n
+CONFIG_BLE_SMP_ENABLE=n

examples/wifi/iperf/sdkconfig.defaults

@@ -12,18 +12,18 @@ CONFIG_ESP32_WIFI_TX_BA_WIN=32
 CONFIG_ESP32_WIFI_AMPDU_RX_ENABLED=y
 CONFIG_ESP32_WIFI_RX_BA_WIN=32
 
-CONFIG_FREERTOS_UNICORE=
+CONFIG_FREERTOS_UNICORE=n
 CONFIG_FREERTOS_HZ=1000
 
-CONFIG_INT_WDT=
-CONFIG_TASK_WDT=
+CONFIG_INT_WDT=n
+CONFIG_TASK_WDT=n
 
 CONFIG_TCP_SND_BUF_DEFAULT=65535
 CONFIG_TCP_WND_DEFAULT=65535
 CONFIG_TCP_RECVMBOX_SIZE=64
 CONFIG_UDP_RECVMBOX_SIZE=64
 CONFIG_TCPIP_RECVMBOX_SIZE=64
-CONFIG_LWIP_ETHARP_TRUST_IP_MAC=
+CONFIG_LWIP_ETHARP_TRUST_IP_MAC=n
 
 CONFIG_FLASHMODE_QIO=y
 CONFIG_ESPTOOLPY_FLASHFREQ_40M=y

tools/kconfig_new/kconfiglib.py

@@ -754,6 +754,9 @@ class Kconfig(object):
                         continue
 
                     if sym.orig_type in (BOOL, TRISTATE):
+                        if val == "":
+                            val = "n"  # C implementation allows 'blank' for 'no'
+
                         # The C implementation only checks the first character
                         # to the right of '=', for whatever reason
                         if not ((sym.orig_type == BOOL and