cloud: don't error sending empty messages (ollama#12724)

Author: pdevine

server/routes.go

@@ -1874,10 +1874,14 @@ func (s *Server) ChatHandler(c *gin.Context) {
 			req.Options = map[string]any{}
 		}
 
-		msgs := append(m.Messages, req.Messages...)
-		if req.Messages[0].Role != "system" && m.System != "" {
-			msgs = append([]api.Message{{Role: "system", Content: m.System}}, msgs...)
+		var msgs []api.Message
+		if len(req.Messages) > 0 {
+			msgs = append(m.Messages, req.Messages...)
+			if req.Messages[0].Role != "system" && m.System != "" {
+				msgs = append([]api.Message{{Role: "system", Content: m.System}}, msgs...)
+			}
 		}
+
 		msgs = filterThinkTags(msgs, m)
 		req.Messages = msgs
 

server/routes_generate_test.go

@@ -6,6 +6,8 @@ import (
 	"encoding/json"
 	"io"
 	"net/http"
+	"net/http/httptest"
+	"net/url"
 	"strings"
 	"sync"
 	"testing"
@@ -52,6 +54,86 @@ func newMockServer(mock *mockRunner) func(discover.GpuInfoList, string, *ggml.GG
 	}
 }
 
+func TestGenerateChatRemote(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	rs := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodPost {
+			t.Errorf("Expected POST request, got %s", r.Method)
+		}
+		if r.URL.Path != "/api/chat" {
+			t.Errorf("Expected path '/api/chat', got %s", r.URL.Path)
+		}
+
+		w.WriteHeader(http.StatusOK)
+		w.Header().Set("Content-Type", "application/json")
+		resp := api.ChatResponse{
+			Model:      "test",
+			Done:       true,
+			DoneReason: "load",
+		}
+		if err := json.NewEncoder(w).Encode(&resp); err != nil {
+			t.Fatal(err)
+		}
+	}))
+	defer rs.Close()
+
+	p, err := url.Parse(rs.URL)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	t.Setenv("OLLAMA_REMOTES", p.Hostname())
+	s := Server{}
+	w := createRequest(t, s.CreateHandler, api.CreateRequest{
+		Model:      "test-cloud",
+		RemoteHost: rs.URL,
+		From:       "test",
+		Info: map[string]any{
+			"capabilities": []string{"completion", "thinking"},
+		},
+		Stream: &stream,
+	})
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("expected status 200, got %d", w.Code)
+	}
+
+	t.Run("missing messages", func(t *testing.T) {
+		w := createRequest(t, s.ChatHandler, api.ChatRequest{
+			Model: "test-cloud",
+		})
+		if w.Code != http.StatusOK {
+			t.Errorf("expected status 200, got %d", w.Code)
+		}
+
+		var actual api.ChatResponse
+		if err := json.NewDecoder(w.Body).Decode(&actual); err != nil {
+			t.Fatal(err)
+		}
+
+		if actual.Model != "test-cloud" {
+			t.Errorf("expected model test-cloud, got %s", actual.Model)
+		}
+
+		if actual.RemoteModel != "test" {
+			t.Errorf("expected remote model test, got %s", actual.RemoteModel)
+		}
+
+		if actual.RemoteHost != rs.URL {
+			t.Errorf("expected remote host '%s', got %s", rs.URL, actual.RemoteHost)
+		}
+
+		if !actual.Done {
+			t.Errorf("expected done true, got false")
+		}
+
+		if actual.DoneReason != "load" {
+			t.Errorf("expected done reason load, got %s", actual.DoneReason)
+		}
+	})
+}
+
 func TestGenerateChat(t *testing.T) {
 	gin.SetMode(gin.TestMode)