chatllm: do not attempt to serialize incompatible state (#1742)

gpt4all-backend/llamamodel.cpp

@@ -163,6 +163,10 @@ bool LLamaModel::loadModel(const std::string &modelPath)
     d_ptr->ctx_params.seed   = params.seed;
     d_ptr->ctx_params.f16_kv = params.memory_f16;
 
+    // The new batch API provides space for n_vocab*n_tokens logits. Tell llama.cpp early
+    // that we want this many logits so the state serializes consistently.
+    d_ptr->ctx_params.logits_all = true;
+
     d_ptr->n_threads = std::min(4, (int32_t) std::thread::hardware_concurrency());
     d_ptr->ctx_params.n_threads       = d_ptr->n_threads;
     d_ptr->ctx_params.n_threads_batch = d_ptr->n_threads;

gpt4all-chat/chat.cpp

@@ -435,7 +435,6 @@ bool Chat::deserialize(QDataStream &stream, int version)
     if (!m_chatModel->deserialize(stream, version))
         return false;
 
-    if (!deserializeKV || discardKV)
     m_llmodel->setStateFromText(m_chatModel->text());
 
     emit chatModelChanged();

gpt4all-chat/chatllm.cpp

@@ -863,11 +863,11 @@ bool ChatLLM::deserialize(QDataStream &stream, int version, bool deserializeKV,
         if (!discardKV)
             m_state = qUncompress(compressed);
     } else {
-        if (!discardKV)
+        if (!discardKV) {
             stream >> m_state;
-        else {
+        } else {
             QByteArray state;
-            stream >> m_state;
+            stream >> state;
         }
     }
 
@@ -912,7 +912,7 @@ void ChatLLM::restoreState()
         stream >> context;
         chatGPT->setContext(context);
         m_state.clear();
-        m_state.resize(0);
+        m_state.squeeze();
         return;
     }
 
@@ -923,10 +923,16 @@ void ChatLLM::restoreState()
     if (m_state.isEmpty())
         return;
 
-    m_processedSystemPrompt = true;
+    if (m_llModelInfo.model->stateSize() == m_state.size()) {
         m_llModelInfo.model->restoreState(static_cast<const uint8_t*>(reinterpret_cast<void*>(m_state.data())));
+        m_processedSystemPrompt = true;
+    } else {
+        qWarning() << "restoring state from text because" << m_llModelInfo.model->stateSize() << "!=" << m_state.size() << "\n";
+        m_restoreStateFromText = true;
+    }
+
     m_state.clear();
-    m_state.resize(0);
+    m_state.squeeze();
 }
 
 void ChatLLM::processSystemPrompt()