fix(selectel): nil-guard в ApplyChanges + тесты пагинации rrset и nil-diff

internal/provider/selectel/selectel.go

@@ -159,10 +159,16 @@ func (c *Client) ApplyChanges(ctx context.Context, creds provider.Credentials, z
 		}
 		switch d.Kind {
 		case diff.Add:
+			if d.Desired == nil {
+				return fmt.Errorf("selectel: add/update diff without Desired record")
+			}
 			if err := c.do(ctx, http.MethodPost, base, creds.Secret, toRRSet(*d.Desired), nil); err != nil {
 				return err
 			}
 		case diff.Update:
+			if d.Desired == nil {
+				return fmt.Errorf("selectel: add/update diff without Desired record")
+			}
 			id, ok := idByKey[d.Desired.Key()]
 			if !ok {
 				return fmt.Errorf("cannot update: rrset %s not found in zone", d.Desired.Key())
@@ -171,6 +177,9 @@ func (c *Client) ApplyChanges(ctx context.Context, creds provider.Credentials, z
 				return err
 			}
 		case diff.Delete:
+			if d.Actual == nil {
+				return fmt.Errorf("selectel: delete diff without Actual record")
+			}
 			id, ok := idByKey[d.Actual.Key()]
 			if !ok {
 				return fmt.Errorf("cannot delete: rrset %s not found in zone", d.Actual.Key())

internal/provider/selectel/selectel_test.go

@@ -266,6 +266,84 @@ func TestListZonesPaginatesAcrossMultiplePages(t *testing.T) {
 	}
 }
 
+// Global Constraint: listRRSets (via GetRecords) must paginate across multiple pages,
+// accumulating records from every page, and must stop as soon as next_offset is 0 —
+// no third request should ever be issued.
+func TestGetRecordsPaginatesAcrossMultiplePages(t *testing.T) {
+	var offsets []string
+	c, srv := newTestClient(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		offset := r.URL.Query().Get("offset")
+		offsets = append(offsets, offset)
+		if len(offsets) > 2 {
+			t.Fatalf("too many requests, possible infinite pagination loop: %v", offsets)
+		}
+		switch offset {
+		case "0":
+			json.NewEncoder(w).Encode(map[string]any{
+				"result": []map[string]any{
+					{"id": "r1", "name": "a.example.com.", "type": "A", "ttl": 300,
+						"records": []map[string]any{{"content": "1.1.1.1"}}},
+				},
+				"next_offset": 1000,
+			})
+		case "1000":
+			json.NewEncoder(w).Encode(map[string]any{
+				"result": []map[string]any{
+					{"id": "r2", "name": "b.example.com.", "type": "A", "ttl": 300,
+						"records": []map[string]any{{"content": "2.2.2.2"}}},
+				},
+				"next_offset": 0,
+			})
+		default:
+			t.Fatalf("unexpected offset %q", offset)
+		}
+	}))
+	defer srv.Close()
+
+	recs, err := c.GetRecords(context.Background(), creds(), "z1")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(offsets) != 2 {
+		t.Fatalf("expected exactly 2 page requests, got %d: %v", len(offsets), offsets)
+	}
+	if len(recs) != 2 {
+		t.Fatalf("expected accumulated records from both pages, got %+v", recs)
+	}
+	names := map[string]bool{recs[0].Name: true, recs[1].Name: true}
+	if !names["a.example.com."] || !names["b.example.com."] {
+		t.Fatalf("expected records from both pages, got %+v", recs)
+	}
+}
+
+// Global Constraint: ApplyChanges must not panic on a Changeset with a nil Desired
+// record for Add/Update, and must instead return a clear error.
+func TestApplyChangesAddWithNilDesiredReturnsErrorNoPanic(t *testing.T) {
+	c, srv := newTestClient(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Method == http.MethodGet {
+			json.NewEncoder(w).Encode(map[string]any{"result": []map[string]any{}, "next_offset": 0})
+			return
+		}
+		t.Fatalf("unexpected mutating call %s %s, nil Desired should have errored before reaching HTTP", r.Method, r.URL.Path)
+	}))
+	defer srv.Close()
+
+	cs := diff.Changeset{Diffs: []diff.RecordDiff{
+		{Kind: diff.Add, Type: model.A, Name: "nil-desired.example.com.", Desired: nil},
+	}}
+
+	defer func() {
+		if r := recover(); r != nil {
+			t.Fatalf("ApplyChanges panicked on nil Desired: %v", r)
+		}
+	}()
+
+	err := c.ApplyChanges(context.Background(), creds(), "z1", cs)
+	if err == nil {
+		t.Fatal("expected non-nil error for Add diff with nil Desired")
+	}
+}
+
 // Global Constraint: HTTP errors (status >= 300) must surface a non-nil error whose text
 // includes the method/path/status (or response body) for diagnosability.
 func TestListZonesHTTPErrorIncludesMethodPathStatus(t *testing.T) {