refactor: split MeshTables::hasSeen into pure query + markSeen

hasSeen() was simultaneously a predicate and a mutator — it inserted the
packet hash on every miss, making five call sites that only wanted to mark
a packet as sent call it with the return value discarded.

Split into:
- wasSeen()   — pure predicate, no side effects
- markSeen()  — explicit insert

All query sites now call markSeen() immediately after wasSeen() returns
false, preserving identical runtime behaviour. The five mark-only send
sites (sendFlood, sendDirect, sendZeroHop x2) now call markSeen directly.

Also fixes three bridge sites (BridgeBase, ESPNowBridge, RS232Bridge)
that had the same query+implicit-insert pattern.

Tests: add test/test_mesh_tables/ covering wasSeen purity, markSeen,
dup stats, and clear. Update SHA256 mock to produce deterministic output
(previously finalize() was a no-op). Add Packet.cpp to native build filter.

platformio.ini

@@ -165,5 +165,6 @@ test_build_src = yes
 build_src_filter =
   -<*>
   +<../src/Utils.cpp>
+  +<../src/Packet.cpp>
 lib_deps =
   google/googletest @ 1.17.0

src/Mesh.cpp

@@ -55,7 +55,8 @@ DispatcherAction Mesh::onRecvPacket(Packet* pkt) {
       uint16_t offset = (uint16_t)pkt->path_len << path_sz;
       if (offset >= len) {   // TRACE has reached end of given path
         onTraceRecv(pkt, trace_tag, auth_code, flags, pkt->path, &pkt->payload[i], len);
-      } else if (self_id.isHashMatch(&pkt->payload[i + offset], 1 << path_sz) && allowPacketForward(pkt) && !_tables->hasSeen(pkt)) {
+      } else if (self_id.isHashMatch(&pkt->payload[i + offset], 1 << path_sz) && allowPacketForward(pkt) && !_tables->wasSeen(pkt)) {
+        _tables->markSeen(pkt);
         // append SNR (Not hash!)
         pkt->path[pkt->path_len++] = (int8_t) (pkt->getSNR()*4);
 
@@ -89,14 +90,16 @@ DispatcherAction Mesh::onRecvPacket(Packet* pkt) {
       if (pkt->getPayloadType() == PAYLOAD_TYPE_MULTIPART) {
         return forwardMultipartDirect(pkt);
       } else if (pkt->getPayloadType() == PAYLOAD_TYPE_ACK) {
-        if (!_tables->hasSeen(pkt)) {  // don't retransmit!
+        if (!_tables->wasSeen(pkt)) {  // don't retransmit!
+          _tables->markSeen(pkt);
           removeSelfFromPath(pkt);
           routeDirectRecvAcks(pkt, 0);
         }
         return ACTION_RELEASE;
       }
 
-      if (!_tables->hasSeen(pkt)) {
+      if (!_tables->wasSeen(pkt)) {
+        _tables->markSeen(pkt);
         removeSelfFromPath(pkt);
 
         uint32_t d = getDirectRetransmitDelay(pkt);
@@ -117,7 +120,8 @@ DispatcherAction Mesh::onRecvPacket(Packet* pkt) {
       memcpy(&ack_crc, &pkt->payload[i], 4); i += 4;
       if (i > pkt->payload_len) {
         MESH_DEBUG_PRINTLN("%s Mesh::onRecvPacket(): incomplete ACK packet", getLogDateTime());
-      } else if (!_tables->hasSeen(pkt)) {
+      } else if (!_tables->wasSeen(pkt)) {
+        _tables->markSeen(pkt);
         onAckRecv(pkt, ack_crc);
         action = routeRecvPacket(pkt);
       }
@@ -134,7 +138,8 @@ DispatcherAction Mesh::onRecvPacket(Packet* pkt) {
       uint8_t* macAndData = &pkt->payload[i];   // MAC + encrypted data 
       if (i + CIPHER_MAC_SIZE >= pkt->payload_len) {
         MESH_DEBUG_PRINTLN("%s Mesh::onRecvPacket(): incomplete data packet", getLogDateTime());
-      } else if (!_tables->hasSeen(pkt)) {
+      } else if (!_tables->wasSeen(pkt)) {
+        _tables->markSeen(pkt);
         // NOTE: this is a 'first packet wins' impl. When receiving from multiple paths, the first to arrive wins.
         //       For flood mode, the path may not be the 'best' in terms of hops.
         // FUTURE: could send back multiple paths, using createPathReturn(), and let sender choose which to use(?)
@@ -197,7 +202,8 @@ DispatcherAction Mesh::onRecvPacket(Packet* pkt) {
       uint8_t* macAndData = &pkt->payload[i];   // MAC + encrypted data 
       if (i + 2 >= pkt->payload_len) {
         MESH_DEBUG_PRINTLN("%s Mesh::onRecvPacket(): incomplete data packet", getLogDateTime());
-      } else if (!_tables->hasSeen(pkt)) {
+      } else if (!_tables->wasSeen(pkt)) {
+        _tables->markSeen(pkt);
         if (self_id.isHashMatch(&dest_hash)) {
           Identity sender(sender_pub_key);
 
@@ -224,7 +230,8 @@ DispatcherAction Mesh::onRecvPacket(Packet* pkt) {
       uint8_t* macAndData = &pkt->payload[i];   // MAC + encrypted data 
       if (i + 2 >= pkt->payload_len) {
         MESH_DEBUG_PRINTLN("%s Mesh::onRecvPacket(): incomplete data packet", getLogDateTime());
-      } else if (!_tables->hasSeen(pkt)) {
+      } else if (!_tables->wasSeen(pkt)) {
+        _tables->markSeen(pkt);
         // scan channels DB, for all matching hashes of 'channel_hash' (max 4 matches supported ATM)
         GroupChannel channels[4];
         int num = searchChannelsByHash(&channel_hash, channels, 4);
@@ -255,7 +262,8 @@ DispatcherAction Mesh::onRecvPacket(Packet* pkt) {
         MESH_DEBUG_PRINTLN("%s Mesh::onRecvPacket(): incomplete advertisement packet", getLogDateTime());
       } else if (self_id.matches(id.pub_key)) {
         MESH_DEBUG_PRINTLN("%s Mesh::onRecvPacket(): receiving SELF advert packet", getLogDateTime());
-      } else if (!_tables->hasSeen(pkt)) {
+      } else if (!_tables->wasSeen(pkt)) {
+        _tables->markSeen(pkt);
         uint8_t* app_data = &pkt->payload[i];
         int app_data_len = pkt->payload_len - i;
         if (app_data_len > MAX_ADVERT_DATA_SIZE) { app_data_len = MAX_ADVERT_DATA_SIZE; }
@@ -282,7 +290,8 @@ DispatcherAction Mesh::onRecvPacket(Packet* pkt) {
       break;
     }
     case PAYLOAD_TYPE_RAW_CUSTOM: {
-      if (pkt->isRouteDirect() && !_tables->hasSeen(pkt)) {
+      if (pkt->isRouteDirect() && !_tables->wasSeen(pkt)) {
+        _tables->markSeen(pkt);
         onRawDataRecv(pkt);
         //action = routeRecvPacket(pkt);    don't flood route these (yet)
       }
@@ -300,7 +309,8 @@ DispatcherAction Mesh::onRecvPacket(Packet* pkt) {
           tmp.payload_len = pkt->payload_len - 1;
           memcpy(tmp.payload, &pkt->payload[1], tmp.payload_len);
 
-          if (!_tables->hasSeen(&tmp)) {
+          if (!_tables->wasSeen(&tmp)) {
+            _tables->markSeen(&tmp);
             uint32_t ack_crc;
             memcpy(&ack_crc, tmp.payload, 4);
 
@@ -357,7 +367,8 @@ DispatcherAction Mesh::forwardMultipartDirect(Packet* pkt) {
     tmp.payload_len = pkt->payload_len - 1;
     memcpy(tmp.payload, &pkt->payload[1], tmp.payload_len);
 
-    if (!_tables->hasSeen(&tmp)) {   // don't retransmit!
+    if (!_tables->wasSeen(&tmp)) {   // don't retransmit!
+      _tables->markSeen(&tmp);
       removeSelfFromPath(&tmp);
       routeDirectRecvAcks(&tmp, ((uint32_t)remaining + 1) * 300);  // expect multipart ACKs 300ms apart (x2)
     }
@@ -637,7 +648,7 @@ void Mesh::sendFlood(Packet* packet, uint32_t delay_millis, uint8_t path_hash_si
   packet->header |= ROUTE_TYPE_FLOOD;
   packet->setPathHashSizeAndCount(path_hash_size, 0);
 
-  _tables->hasSeen(packet); // mark this packet as already sent in case it is rebroadcast back to us
+  _tables->markSeen(packet); // mark this packet as already sent in case it is rebroadcast back to us
 
   uint8_t pri;
   if (packet->getPayloadType() == PAYLOAD_TYPE_PATH) {
@@ -666,7 +677,7 @@ void Mesh::sendFlood(Packet* packet, uint16_t* transport_codes, uint32_t delay_m
   packet->transport_codes[1] = transport_codes[1];
   packet->setPathHashSizeAndCount(path_hash_size, 0);
 
-  _tables->hasSeen(packet); // mark this packet as already sent in case it is rebroadcast back to us
+  _tables->markSeen(packet); // mark this packet as already sent in case it is rebroadcast back to us
 
   uint8_t pri;
   if (packet->getPayloadType() == PAYLOAD_TYPE_PATH) {
@@ -699,7 +710,7 @@ void Mesh::sendDirect(Packet* packet, const uint8_t* path, uint8_t path_len, uin
       pri = 0;
     }
   }
-  _tables->hasSeen(packet); // mark this packet as already sent in case it is rebroadcast back to us
+  _tables->markSeen(packet); // mark this packet as already sent in case it is rebroadcast back to us
   sendPacket(packet, pri, delay_millis);
 }
 
@@ -709,7 +720,7 @@ void Mesh::sendZeroHop(Packet* packet, uint32_t delay_millis) {
 
   packet->path_len = 0;  // path_len of zero means Zero Hop
 
-  _tables->hasSeen(packet); // mark this packet as already sent in case it is rebroadcast back to us
+  _tables->markSeen(packet); // mark this packet as already sent in case it is rebroadcast back to us
 
   sendPacket(packet, 0, delay_millis);
 }
@@ -722,7 +733,7 @@ void Mesh::sendZeroHop(Packet* packet, uint16_t* transport_codes, uint32_t delay
 
   packet->path_len = 0;  // path_len of zero means Zero Hop
 
-  _tables->hasSeen(packet); // mark this packet as already sent in case it is rebroadcast back to us
+  _tables->markSeen(packet); // mark this packet as already sent in case it is rebroadcast back to us
 
   sendPacket(packet, 0, delay_millis);
 }

src/Mesh.h

@@ -15,8 +15,9 @@ public:
 */
 class MeshTables {
 public:
-  virtual bool hasSeen(const Packet* packet) = 0;
-  virtual void clear(const Packet* packet) = 0;   // remove this packet hash from table
+  virtual bool wasSeen(const Packet* packet) = 0;
+  virtual void markSeen(const Packet* packet) = 0;
+  virtual void clear(const Packet* packet) = 0;    // remove this packet hash from table
 };
 
 /**

src/helpers/SimpleMeshTables.h

@@ -31,27 +31,31 @@ public:
   }
 #endif
 
-  bool hasSeen(const mesh::Packet* packet) override {
+  bool wasSeen(const mesh::Packet* packet) override {
     uint8_t hash[MAX_HASH_SIZE];
     packet->calculatePacketHash(hash);
 
     const uint8_t* sp = _hashes;
     for (int i = 0; i < MAX_PACKET_HASHES; i++, sp += MAX_HASH_SIZE) {
-      if (memcmp(hash, sp, MAX_HASH_SIZE) == 0) { 
+      if (memcmp(hash, sp, MAX_HASH_SIZE) == 0) {
         if (packet->isRouteDirect()) {
-          _direct_dups++;   // keep some stats
+          _direct_dups++;
         } else {
           _flood_dups++;
         }
         return true;
       }
     }
-
-    memcpy(&_hashes[_next_idx*MAX_HASH_SIZE], hash, MAX_HASH_SIZE);
-    _next_idx = (_next_idx + 1) % MAX_PACKET_HASHES;  // cyclic table
     return false;
   }
 
+  void markSeen(const mesh::Packet* packet) override {
+    uint8_t hash[MAX_HASH_SIZE];
+    packet->calculatePacketHash(hash);
+    memcpy(&_hashes[_next_idx * MAX_HASH_SIZE], hash, MAX_HASH_SIZE);
+    _next_idx = (_next_idx + 1) % MAX_PACKET_HASHES;
+  }
+
   void clear(const mesh::Packet* packet) override {
     uint8_t hash[MAX_HASH_SIZE];
     packet->calculatePacketHash(hash);

src/helpers/bridges/BridgeBase.cpp

@@ -39,7 +39,8 @@ void BridgeBase::handleReceivedPacket(mesh::Packet *packet) {
     return;
   }
 
-  if (!_seen_packets.hasSeen(packet)) {
+  if (!_seen_packets.wasSeen(packet)) {
+    _seen_packets.markSeen(packet);
     // bridge_delay provides a buffer to prevent immediate processing conflicts in the mesh network.
     _mgr->queueInbound(packet, millis() + _prefs->bridge_delay);
   } else {

src/helpers/bridges/BridgeBase.h

@@ -110,7 +110,7 @@ protected:
    * @brief Common packet handling for received packets
    *
    * Implements the standard pattern used by all bridges:
-   * - Check if packet was seen before using _seen_packets.hasSeen()
+   * - Check if packet was seen before using _seen_packets.wasSeen()
    * - Queue packet for mesh processing if not seen before
    * - Free packet if already seen to prevent duplicates
    *

src/helpers/bridges/ESPNowBridge.cpp

@@ -167,7 +167,8 @@ void ESPNowBridge::sendPacket(mesh::Packet *packet) {
     return;
   }
 
-  if (!_seen_packets.hasSeen(packet)) {
+  if (!_seen_packets.wasSeen(packet)) {
+    _seen_packets.markSeen(packet);
     // Create a temporary buffer just for size calculation and reuse for actual writing
     uint8_t sizingBuffer[MAX_PAYLOAD_SIZE];
     uint16_t meshPacketLen = packet->writeTo(sizingBuffer);

src/helpers/bridges/RS232Bridge.cpp

@@ -115,7 +115,8 @@ void RS232Bridge::sendPacket(mesh::Packet *packet) {
     return;
   }
 
-  if (!_seen_packets.hasSeen(packet)) {
+  if (!_seen_packets.wasSeen(packet)) {
+    _seen_packets.markSeen(packet);
 
     uint8_t buffer[MAX_SERIAL_PACKET_SIZE];
     uint16_t len = packet->writeTo(buffer + 4);

test/mocks/SHA256.h

@@ -3,12 +3,33 @@
 #include <stdint.h>
 #include <stddef.h>
 
-// Mock SHA256 class for testing
-// Provides minimal interface to allow Utils.cpp to compile
+// Mock SHA256 for native testing — deterministic but not cryptographic.
+// finalize() writes real (non-garbage) output so calculatePacketHash() produces
+// distinguishable results for packets with different payloads.
+#include <string.h>
+
 class SHA256 {
+  uint8_t _state[32];
+  size_t _len;
 public:
-  void update(const uint8_t* data, size_t len) {}
-  void finalize(uint8_t* hash, size_t hashLen) {}
+  SHA256() : _len(0) { memset(_state, 0, sizeof(_state)); }
+
+  void update(const void* data, size_t len) {
+    const uint8_t* bytes = static_cast<const uint8_t*>(data);
+    for (size_t i = 0; i < len; i++) {
+      uint8_t b = bytes[i];
+      _state[_len % 32] ^= b;
+      _state[(_len + 1) % 32] += (uint8_t)((b >> 1) | (b << 7));
+      _len++;
+    }
+  }
+
+  void finalize(uint8_t* hash, size_t hashLen) {
+    for (size_t i = 0; i < hashLen; i++) {
+      hash[i] = _state[i % 32];
+    }
+  }
+
   void resetHMAC(const uint8_t* key, size_t keyLen) {}
   void finalizeHMAC(const uint8_t* key, size_t keyLen, uint8_t* hash, size_t hashLen) {}
 };

test/test_mesh_tables/test_simple_mesh_tables.cpp

@@ -0,0 +1,103 @@
+#include <gtest/gtest.h>
+#include "helpers/SimpleMeshTables.h"
+
+using namespace mesh;
+
+// Build a packet that calculatePacketHash() distinguishes by payload content.
+// header selects ROUTE_TYPE_FLOOD so isRouteDirect() returns false.
+static Packet makeFloodPacket(uint8_t seed) {
+    Packet p;
+    p.header = ROUTE_TYPE_FLOOD | (PAYLOAD_TYPE_ACK << PH_TYPE_SHIFT);
+    p.payload[0] = seed;
+    p.payload_len = 1;
+    p.path_len = 0;
+    return p;
+}
+
+static Packet makeDirectPacket(uint8_t seed) {
+    Packet p;
+    p.header = ROUTE_TYPE_DIRECT | (PAYLOAD_TYPE_ACK << PH_TYPE_SHIFT);
+    p.payload[0] = seed;
+    p.payload_len = 1;
+    p.path_len = 0;
+    return p;
+}
+
+// ── wasSeen: pure query ───────────────────────────────────────────────────────
+
+TEST(SimpleMeshTables, WasSeen_ReturnsFalseForUnseen) {
+    SimpleMeshTables t;
+    Packet p = makeFloodPacket(0x01);
+    EXPECT_FALSE(t.wasSeen(&p));
+}
+
+// wasSeen shouldn't change state
+TEST(SimpleMeshTables, WasSeen_IsPureQuery_DoesNotInsert) {
+    SimpleMeshTables t;
+    Packet p = makeFloodPacket(0x01);
+    EXPECT_FALSE(t.wasSeen(&p));
+    EXPECT_FALSE(t.wasSeen(&p));
+}
+
+// ── markSeen + wasSeen ───────────────────────────────────────────────────────
+
+TEST(SimpleMeshTables, MarkSeen_MakesWasSeenReturnTrue) {
+    SimpleMeshTables t;
+    Packet p = makeFloodPacket(0x01);
+    t.markSeen(&p);
+    EXPECT_TRUE(t.wasSeen(&p));
+}
+
+TEST(SimpleMeshTables, MarkSeen_DoesNotAffectOtherPackets) {
+    SimpleMeshTables t;
+    Packet p1 = makeFloodPacket(0x01);
+    Packet p2 = makeFloodPacket(0x02);
+    t.markSeen(&p1);
+    EXPECT_FALSE(t.wasSeen(&p2));
+}
+
+// Canonical pattern used at every onRecvPacket call site:
+//   if (!wasSeen(pkt)) { markSeen(pkt); process(pkt); }
+TEST(SimpleMeshTables, QueryThenMark_WorksCorrectly) {
+    SimpleMeshTables t;
+    Packet p = makeFloodPacket(0x01);
+    EXPECT_FALSE(t.wasSeen(&p));
+    t.markSeen(&p);
+    EXPECT_TRUE(t.wasSeen(&p));
+}
+
+// ── dup stats ────────────────────────────────────────────────────────────────
+
+TEST(SimpleMeshTables, WasSeen_IncrementsFloodDupStat) {
+    SimpleMeshTables t;
+    Packet p = makeFloodPacket(0x01);
+    t.markSeen(&p);
+    t.wasSeen(&p);
+    EXPECT_EQ(1u, t.getNumFloodDups());
+    EXPECT_EQ(0u, t.getNumDirectDups());
+}
+
+TEST(SimpleMeshTables, WasSeen_IncrementsDirectDupStat) {
+    SimpleMeshTables t;
+    Packet p = makeDirectPacket(0x01);
+    t.markSeen(&p);
+    t.wasSeen(&p);
+    EXPECT_EQ(0u, t.getNumFloodDups());
+    EXPECT_EQ(1u, t.getNumDirectDups());
+}
+
+// ── clear ────────────────────────────────────────────────────────────────────
+
+TEST(SimpleMeshTables, Clear_RemovesSeenPacket) {
+    SimpleMeshTables t;
+    Packet p = makeFloodPacket(0x01);
+    t.markSeen(&p);
+    ASSERT_TRUE(t.wasSeen(&p));
+    t.clear(&p);
+    EXPECT_FALSE(t.wasSeen(&p));
+}
+
+int main(int argc, char** argv) {
+    ::testing::InitGoogleTest(&argc, argv);
+    return RUN_ALL_TESTS();
+}