Fixes from code review

esphome/components/packet_interface/packet_interface.h

@@ -44,8 +44,8 @@ class PacketMetaData {
  *
  * The operations defined are:
  *
- * Transmit: the function transmit() takes a PacketBuffer of bytes, and returns when all bytes are queued for
- * transmission at least.
+ * Transmit: the function send_to_interface() takes a PacketBuffer of bytes, and returns when all data is
+ * written or buffered for transmission.
  *
  * Receive: The callbacks for an instance of this class are called with currently received data.
  */
@@ -119,7 +119,7 @@ class PacketInterface : public Component {
     lower->upper_ = this;
     this->inherit_from_(lower, capability);
   }
-  /// Takes the name and capabilities of \p lower without becoming its top, for one of several stacks on a link.
+  /// Takes the name and capabilities of `lower` without becoming its top, for one of several stacks on a link.
   void inherit_from_(PacketInterface *lower, Capability capability) {
     this->name_ = lower->name_;
     this->capabilities_ = lower->capabilities_ | capability;

esphome/components/packet_interface/packet_transport/packet_interface_transport.cpp

@@ -13,19 +13,12 @@ void PacketInterfaceTransport::setup() {
 }
 
 void PacketInterfaceTransport::receive_(const PacketBuffer &data) {
-  if (data.is_contiguous()) {
-    this->process_(data.as_span());
+  // Packet interface layers deliver packets in one piece
+  if (!data.is_contiguous()) {
+    ESP_LOGW(TAG, "Packet split across buffers is not supported");
     return;
   }
-  size_t max_size = this->interface_->get_max_packet_size();
-  if (data.size() > max_size) {
-    ESP_LOGW(TAG, "Received packet of %zu bytes is larger than %zu", data.size(), max_size);
-    return;
-  }
-  if (!this->rx_copy_)
-    this->rx_copy_ = std::make_unique<uint8_t[]>(max_size);
-  size_t len = data.copy_to(this->rx_copy_.get(), max_size);
-  this->process_(std::span<const uint8_t>(this->rx_copy_.get(), len));
+  this->process_(data.as_span());
 }
 
 void PacketInterfaceTransport::send_packet(const std::vector<uint8_t> &buf) const {

tests/components/packet_interface/packet_buffer.cpp

@@ -3,9 +3,7 @@
 #include <cstdint>
 #include "esphome/components/packet_interface/packet_buffer.h"
 
-namespace esphome {
-namespace packet_interface {
-namespace testing {
+namespace esphome::packet_interface::testing {
 
 // Test default constructor
 TEST(PacketBufferTest, DefaultConstructor) {
@@ -243,6 +241,4 @@ TEST(PacketBufferTest, LargeBuffer) {
   EXPECT_EQ(buffer[999], 231);  // 999 % 256 = 231
 }
 
-}  // namespace testing
-}  // namespace packet_interface
-}  // namespace esphome
+}  // namespace esphome::packet_interface::testing