[border-agent] fix BorderAgentId compile and enable it in CI tests (#9030)

script/cmake-build

@@ -73,6 +73,7 @@ readonly OT_PLATFORMS
 OT_POSIX_SIM_COMMON_OPTIONS=(
     "-DOT_ANYCAST_LOCATOR=ON"
     "-DOT_BORDER_AGENT=ON"
+    "-DOT_BORDER_AGENT_ID=ON"
     "-DOT_BORDER_ROUTER=ON"
     "-DOT_CHANNEL_MANAGER=ON"
     "-DOT_CHANNEL_MONITOR=ON"

src/core/common/settings.hpp

@@ -36,6 +36,7 @@
 
 #include "openthread-core-config.h"
 
+#include <openthread/border_agent.h>
 #include <openthread/platform/settings.h>
 
 #include "common/clearable.hpp"
@@ -47,7 +48,6 @@
 #include "common/settings_driver.hpp"
 #include "crypto/ecdsa.hpp"
 #include "mac/mac_types.hpp"
-#include "meshcop/border_agent.hpp"
 #include "meshcop/dataset.hpp"
 #include "net/ip6_address.hpp"
 #include "thread/version.hpp"
@@ -779,7 +779,8 @@ public:
         friend class Clearable<BorderAgentId>;
 
     public:
-        static constexpr Key kKey = kKeyBorderAgentId; ///< The associated key.
+        static constexpr Key     kKey    = kKeyBorderAgentId; ///< The associated key.
+        static constexpr uint8_t kLength = OT_BORDER_AGENT_ID_LENGTH;
 
         /**
          * This method initializes the `BorderAgentId` object.
@@ -815,7 +816,7 @@ public:
     private:
         void Log(Action aAction) const;
 
-        uint8_t mId[MeshCoP::BorderAgent::kIdLength];
+        uint8_t mId[kLength];
     } OT_TOOL_PACKED_END;
 #endif // OPENTHREAD_CONFIG_BORDER_AGENT_ID_ENABLE
 

src/core/meshcop/border_agent.cpp

@@ -237,8 +237,6 @@ Error BorderAgent::GetId(uint8_t *aId, uint16_t &aLength)
 {
     Error error = kErrorNone;
 
-    static_assert(sizeof(mId) == kIdLength, "Invalid Border Agent ID size");
-
     VerifyOrExit(aLength >= sizeof(mId), error = kErrorInvalidArgs);
     VerifyOrExit(!mIdInitialized, error = kErrorNone);
 

src/core/meshcop/border_agent.hpp

@@ -44,6 +44,7 @@
 #include "common/locator.hpp"
 #include "common/non_copyable.hpp"
 #include "common/notifier.hpp"
+#include "common/settings.hpp"
 #include "net/udp6.hpp"
 #include "thread/tmf.hpp"
 #include "thread/uri_paths.hpp"
@@ -59,10 +60,6 @@ class BorderAgent : public InstanceLocator, private NonCopyable
     friend class Tmf::SecureAgent;
 
 public:
-#if OPENTHREAD_CONFIG_BORDER_AGENT_ID_ENABLE
-    static constexpr uint8_t kIdLength = OT_BORDER_AGENT_ID_LENGTH;
-#endif
-
     /**
      * This enumeration defines the Border Agent state.
      *