build: support ESP32-S31 and servers without broadcaster role

.github/tests/server-build/.gitignore

@@ -0,0 +1,5 @@
+build*/
+sdkconfig
+sdkconfig.old
+managed_components/
+dependencies.lock

.github/tests/server-build/CMakeLists.txt

@@ -0,0 +1,6 @@
+cmake_minimum_required(VERSION 3.16)
+get_filename_component(NIMBLE_CPP_ROOT "${CMAKE_CURRENT_LIST_DIR}/../../.." ABSOLUTE)
+set(EXTRA_COMPONENT_DIRS "${NIMBLE_CPP_ROOT}")
+set(COMPONENTS main)
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(nimble_server_build)

.github/tests/server-build/main/CMakeLists.txt

@@ -0,0 +1 @@
+idf_component_register(SRCS "main.cpp" REQUIRES esp-nimble-cpp)

.github/tests/server-build/main/main.cpp

@@ -0,0 +1,9 @@
+#include "NimBLEDevice.h"
+
+// Compile/link probe: exercise the server even when advertising is disabled.
+extern "C" void app_main() {
+    NimBLEDevice::init("server-build-probe");
+    auto* server = NimBLEDevice::createServer();
+    server->advertiseOnDisconnect(false);
+    server->createService("180f");
+}

.github/tests/server-build/sdkconfig.defaults

@@ -0,0 +1,7 @@
+CONFIG_BT_ENABLED=y
+CONFIG_BT_NIMBLE_ENABLED=y
+CONFIG_BT_NIMBLE_ROLE_CENTRAL=n
+CONFIG_BT_NIMBLE_ROLE_OBSERVER=n
+CONFIG_BT_NIMBLE_ROLE_PERIPHERAL=y
+CONFIG_BT_NIMBLE_ROLE_BROADCASTER=y
+CONFIG_COMPILER_OPTIMIZATION_PERF=y

.github/tests/server-build/sdkconfig.no-broadcaster

@@ -0,0 +1 @@
+CONFIG_BT_NIMBLE_ROLE_BROADCASTER=n

.github/workflows/s31-build.yml

@@ -0,0 +1,43 @@
+name: S31 and server role builds
+
+on:
+  workflow_dispatch:
+  pull_request:
+  push:
+    branches: [master]
+
+permissions:
+  contents: read
+
+jobs:
+  server-build:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        target: [esp32s3, esp32s31]
+        broadcaster: [enabled, disabled]
+    # ESP-IDF v6.1; S31 still requires --preview. Stable 5.x jobs stay unchanged.
+    container: espressif/idf@sha256:81893c71bb5e570088901f21def8684c25cd2a9020281bd01b843a7655edb18c
+    steps:
+      - uses: actions/checkout@v5
+        with:
+          persist-credentials: false
+          path: esp-nimble-cpp
+      - name: Build server role probe
+        env:
+          IDF_TARGET: ${{ matrix.target }}
+          BROADCASTER: ${{ matrix.broadcaster }}
+        shell: bash
+        run: |
+          . "${IDF_PATH}/export.sh"
+          cd esp-nimble-cpp/.github/tests/server-build
+          defaults="sdkconfig.defaults"
+          if [ "$BROADCASTER" = disabled ]; then defaults="$defaults;sdkconfig.no-broadcaster"; fi
+          idf.py --preview -D "SDKCONFIG_DEFAULTS=$defaults" build
+          python - "$BROADCASTER" <<'PYTHON'
+          import sys
+          from pathlib import Path
+          enabled = "CONFIG_BT_NIMBLE_ROLE_BROADCASTER=y" in Path("sdkconfig").read_text().splitlines()
+          assert enabled == (sys.argv[1] == "enabled"), "role override was not applied"
+          PYTHON

CMakeLists.txt

@@ -33,6 +33,7 @@ idf_component_register(
   REQUIRED_IDF_TARGETS
     "esp32"
     "esp32s3"
+    "esp32s31"
     "esp32c2"
     "esp32c3"
     "esp32c5"

src/NimBLEServer.cpp

@@ -55,7 +55,7 @@ NimBLEServer::NimBLEServer()
       m_svcChanged{false},
       m_deleteCallbacks{false},
       m_registerAppServicesFirst{false},
-# if !MYNEWT_VAL(BLE_EXT_ADV)
+# if !MYNEWT_VAL(BLE_EXT_ADV) && MYNEWT_VAL(BLE_ROLE_BROADCASTER)
       m_advertiseOnDisconnect{false},
 # endif
       m_pServerCallbacks{&defaultCallbacks},
@@ -363,7 +363,11 @@ bool NimBLEServer::disconnect(const NimBLEConnInfo& connInfo, uint8_t reason) co
  * @param [in] enable true == advertise, false == don't advertise.
  */
 void NimBLEServer::advertiseOnDisconnect(bool enable) {
+# if MYNEWT_VAL(BLE_ROLE_BROADCASTER)
     m_advertiseOnDisconnect = enable;
+# else
+    (void)enable;
+# endif
 } // advertiseOnDisconnect
 # endif