From 44617295c7db7b4c134f69e69b11bb7d9011ddfe Mon Sep 17 00:00:00 2001
From: Boris Zbarsky <bzbarsky@apple.com>
Date: Mon, 6 Mar 2023 19:30:21 -0500
Subject: [PATCH] Enable -Wconversion in mbed platform code. (#25409)

---
 src/platform/mbed/BUILD.gn                    |  2 ++
 .../mbed/NetworkCommissioningDriver.h         |  5 +++--
 .../mbed/NetworkCommissioningWiFiDriver.cpp   | 21 ++++++++++++++-----
 3 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/src/platform/mbed/BUILD.gn b/src/platform/mbed/BUILD.gn
index 452c1e8f3d7ccf..e8029944beef69 100644
--- a/src/platform/mbed/BUILD.gn
+++ b/src/platform/mbed/BUILD.gn
@@ -47,4 +47,6 @@ static_library("mbed") {
       "NetworkCommissioningWiFiDriver.cpp",
     ]
   }
+
+  cflags = [ "-Wconversion" ]
 }
diff --git a/src/platform/mbed/NetworkCommissioningDriver.h b/src/platform/mbed/NetworkCommissioningDriver.h
index 82d83d73558417..017f69218267a1 100644
--- a/src/platform/mbed/NetworkCommissioningDriver.h
+++ b/src/platform/mbed/NetworkCommissioningDriver.h
@@ -47,8 +47,9 @@ class MbedScanResponseIterator : public Iterator<WiFiScanResponse>
         }
 
         item.security.SetRaw(mScanResults[mIternum].get_security());
-        item.ssidLen  = strnlen(reinterpret_cast<const char *>(mScanResults[mIternum].get_ssid()),
-                               chip::DeviceLayer::Internal::kMaxWiFiSSIDLength);
+        static_assert(chip::DeviceLayer::Internal::kMaxWiFiSSIDLength <= UINT8_MAX, "Our length won't fit in ssidLen");
+        item.ssidLen  = static_cast<uint8_t>(strnlen(reinterpret_cast<const char *>(mScanResults[mIternum].get_ssid()),
+                                                    chip::DeviceLayer::Internal::kMaxWiFiSSIDLength));
         item.channel  = mScanResults[mIternum].get_channel();
         item.wiFiBand = chip::DeviceLayer::NetworkCommissioning::WiFiBand::k2g4;
         item.rssi     = mScanResults[mIternum].get_rssi();
diff --git a/src/platform/mbed/NetworkCommissioningWiFiDriver.cpp b/src/platform/mbed/NetworkCommissioningWiFiDriver.cpp
index ee9f187ad5f98b..d9ddca2e501cae 100644
--- a/src/platform/mbed/NetworkCommissioningWiFiDriver.cpp
+++ b/src/platform/mbed/NetworkCommissioningWiFiDriver.cpp
@@ -69,14 +69,16 @@ CHIP_ERROR WiFiDriverImpl::Init(NetworkStatusChangeCallback * networkStatusChang
     auto err = PersistedStorage::KeyValueStoreMgr().Get(kWiFiSSIDKeyName, mSavedNetwork.ssid, sizeof(mSavedNetwork.ssid), &ssidLen);
     if (err == CHIP_NO_ERROR)
     {
-        mSavedNetwork.ssidLen = ssidLen;
+        static_assert(sizeof(mSavedNetwork.ssid) <= UINT8_MAX, "Our length might not fit in mSavedNetwork.ssidLen");
+        mSavedNetwork.ssidLen = static_cast<uint8_t>(ssidLen);
     }
 
     err = PersistedStorage::KeyValueStoreMgr().Get(kWiFiCredentialsKeyName, mSavedNetwork.credentials,
                                                    sizeof(mSavedNetwork.credentials), &credentialsLen);
     if (err == CHIP_NO_ERROR)
     {
-        mSavedNetwork.credentialsLen = credentialsLen;
+        static_assert(sizeof(mSavedNetwork.credentials) <= UINT8_MAX, "Our length might not fit in mSavedNetwork.credentialsLen");
+        mSavedNetwork.credentialsLen = static_cast<uint8_t>(credentialsLen);
     }
 
     if (mSavedNetwork.ssidLen != 0 && mSavedNetwork.credentialsLen != 0)
@@ -291,10 +293,17 @@ void WiFiDriverImpl::ExecuteScanNetwork()
     MbedScanResponseIterator * scan_resp_iter;
 
     // Get APs number
-    ap_number = mWiFiInterface->scan(nullptr, 0);
-    if (!ap_number)
+    auto scan_result = mWiFiInterface->scan(nullptr, 0);
+    if (scan_result <= 0)
     {
-        ChipLogProgress(DeviceLayer, "No AP found");
+        if (scan_result == 0)
+        {
+            ChipLogProgress(DeviceLayer, "No AP found");
+        }
+        else
+        {
+            ChipLogError(DeviceLayer, "Error scanning for APs: %d", scan_result);
+        }
         if (mScanCallback)
         {
             mScanCallback->OnFinished(Status::kUnknownError, CharSpan(), nullptr);
@@ -302,6 +311,8 @@ void WiFiDriverImpl::ExecuteScanNetwork()
         goto exit;
     }
 
+    ap_number = static_cast<uint16_t>(scan_result);
+
     ap_buffer = new WiFiAccessPoint[ap_number];
     if (ap_buffer == nullptr)
     {