fix: tolerate null file and session resource lists

arkruntime/internal/listresponse/normalize.go

@@ -0,0 +1,46 @@
+// Copyright (c) 2026 ByteDance Ltd. and/or its affiliates.
+// SPDX-License-Identifier: Apache-2.0
+
+// Package listresponse adapts legacy null list responses before strict decoding.
+package listresponse
+
+import (
+	"bytes"
+	"encoding/json"
+)
+
+// Normalize changes only top-level data:null tokens, retaining duplicate fields
+// and all other bytes so the generated decoder keeps its validation behavior.
+func Normalize(data []byte, emptyPage string) []byte {
+	if bytes.Equal(bytes.Trim(data, " \t\r\n"), []byte("null")) {
+		return []byte(emptyPage)
+	}
+	decoder := json.NewDecoder(bytes.NewReader(data))
+	first, err := decoder.Token()
+	if err != nil || first != json.Delim('{') {
+		return data
+	}
+	var normalized []byte
+	copied := 0
+	for decoder.More() {
+		key, err := decoder.Token()
+		if err != nil {
+			return data
+		}
+		var value json.RawMessage
+		if err := decoder.Decode(&value); err != nil {
+			return data
+		}
+		if key == "data" && bytes.Equal(value, []byte("null")) {
+			end := int(decoder.InputOffset())
+			start := end - len(value)
+			normalized = append(normalized, data[copied:start]...)
+			normalized = append(normalized, '[', ']')
+			copied = end
+		}
+	}
+	if _, err := decoder.Token(); err != nil || copied == 0 {
+		return data
+	}
+	return append(normalized, data[copied:]...)
+}

arkruntime/list_null_test.go

@@ -0,0 +1,120 @@
+// Copyright (c) 2026 ByteDance Ltd. and/or its affiliates.
+// SPDX-License-Identifier: Apache-2.0
+
+package arkruntime
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+type listResponseCase struct {
+	name      string
+	body      string
+	count     int
+	wantError bool
+}
+
+func TestListFilesNullResponse(t *testing.T) {
+	const fileID = "file-1"
+	const page = `"object":"file","first_id":"file-1","last_id":"file-1","has_more":true`
+	cases := []listResponseCase{
+		{name: "null", body: `null`},
+		{name: "whitespace", body: " \n null \t"},
+		{name: "invalid_whitespace", body: "\vnull", wantError: true},
+		{name: "null_data", body: `{` + page + `,"data":null}`},
+		{name: "null_data_offsets", body: `{` + page + `,"extra":"中文","d\u0061ta":
+ null}`},
+		{name: "empty", body: `{` + page + `,"data":[]}`},
+		{name: "populated", body: `{` + page + `,"data":[{"id":"file-1","object":"file","bytes":1,"created_at":1,"filename":"test.txt","purpose":"user_data","status":"processed","expire_at":0}]}`, count: 1},
+		{name: "invalid", body: `{` + page + `,"data":"invalid"}`, wantError: true},
+		{name: "invalid_duplicate_data", body: `{` + page + `,"data":"invalid","data":null}`, wantError: true},
+		{name: "invalid_duplicate_pagination", body: `{` + page + `,"data":null,"has_more":"invalid","has_more":true}`, wantError: true},
+		{name: "valid_duplicate_data", body: `{` + page + `,"data":[],"data":[]}`},
+		{name: "missing", body: `{` + page + `}`, wantError: true},
+		{name: "wrong_kind", body: `[]`, wantError: true},
+	}
+	runListResponseCases(t, "/files", cases, func(t *testing.T, c *Client, tc listResponseCase) (int, error) {
+		response, err := c.ListFiles(context.Background(), nil)
+		if err != nil {
+			return 0, err
+		}
+		if response == nil || response.Data == nil {
+			t.Fatal("expected non-nil response and list")
+		}
+		if tc.name == "null" || tc.name == "whitespace" {
+			if response.HasMore || response.FirstID != "" || response.LastID != "" {
+				t.Fatalf("empty page has cursors: %+v", response)
+			}
+		} else if response.FirstID != fileID || response.LastID != fileID || !response.HasMore {
+			t.Fatalf("pagination changed: %+v", response)
+		}
+		if len(response.Data) == 1 && response.Data[0].ID != fileID {
+			t.Fatal("file lost")
+		}
+		return len(response.Data), nil
+	})
+}
+
+func TestListSessionResourcesNullResponse(t *testing.T) {
+	cases := []listResponseCase{
+		{name: "null", body: `null`},
+		{name: "whitespace", body: " \n null \t"},
+		{name: "invalid_whitespace", body: "\vnull", wantError: true},
+		{name: "null_data", body: `{"data":null}`},
+		{name: "null_data_offsets", body: `{"extra":"中文","d\u0061ta":
+ null}`},
+		{name: "empty", body: `{"data":[]}`},
+		{name: "populated", body: `{"data":[{"id":"resource-1","type":"file","file_id":"file-1"}]}`, count: 1},
+		{name: "invalid", body: `{"data":"invalid"}`, wantError: true},
+		{name: "invalid_duplicate_data", body: `{"data":"invalid","data":null}`, wantError: true},
+		{name: "valid_duplicate_data", body: `{"data":[],"data":[]}`},
+		{name: "missing", body: `{}`, wantError: true},
+		{name: "wrong_kind", body: `[]`, wantError: true},
+	}
+	runListResponseCases(t, "/sessions/session-1/resources", cases, func(t *testing.T, c *Client, _ listResponseCase) (int, error) {
+		response, err := c.ListSessionResources(context.Background(), "session-1")
+		if err != nil {
+			return 0, err
+		}
+		if response == nil || response.Data == nil {
+			t.Fatal("expected non-nil response and list")
+		}
+		if len(response.Data) == 1 && response.Data[0].ID.Value != "resource-1" {
+			t.Fatal("resource lost")
+		}
+		return len(response.Data), nil
+	})
+}
+
+func runListResponseCases(t *testing.T, path string, cases []listResponseCase, call func(*testing.T, *Client, listResponseCase) (int, error)) {
+	t.Helper()
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			server := listResponseServer(t, path, tc.body)
+			defer server.Close()
+			client := NewClientWithApiKey("test", WithBaseUrl(server.URL))
+			count, err := call(t, client, tc)
+			if (err != nil) != tc.wantError {
+				t.Fatalf("error = %v, wantError = %v", err, tc.wantError)
+			}
+			if count != tc.count {
+				t.Fatalf("got %d items, want %d", count, tc.count)
+			}
+		})
+	}
+}
+
+func listResponseServer(t *testing.T, path, body string) *httptest.Server {
+	t.Helper()
+	return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodGet || r.URL.Path != path {
+			t.Errorf("unexpected request: %s %s", r.Method, r.URL.Path)
+		}
+		w.Header().Set("Content-Type", "application/json")
+		fmt.Fprint(w, body)
+	}))
+}

arkruntime/model/file/file_shim.go

@@ -10,6 +10,7 @@ import (
 	"net/http"
 	"net/url"
 
+	"github.com/volcengine/ark-runtime-go/arkruntime/internal/listresponse"
 	"github.com/volcengine/ark-runtime-go/arkruntime/pkg/apiform"
 	"github.com/volcengine/ark-runtime-go/arkruntime/pkg/apiquery"
 )
@@ -36,6 +37,12 @@ type FileListResponseWrapper struct {
 	httpHeader
 }
 
+// UnmarshalJSON normalizes legacy null pages without changing generated models.
+func (r *FileListResponseWrapper) UnmarshalJSON(data []byte) error {
+	// Keep this empty page aligned with every required field after schema changes.
+	return r.FileListResponse.UnmarshalJSON(listresponse.Normalize(data, `{"object":"file","data":[],"first_id":"","last_id":"","has_more":false}`))
+}
+
 // FileDeletedResponse wraps FileDeleted so it satisfies model.Response.
 type FileDeletedResponse struct {
 	FileDeleted

arkruntime/model/session/session_shim.go

@@ -8,6 +8,7 @@ import (
 	"encoding/json"
 	"net/url"
 
+	"github.com/volcengine/ark-runtime-go/arkruntime/internal/listresponse"
 	"github.com/volcengine/ark-runtime-go/arkruntime/model"
 	"github.com/volcengine/ark-runtime-go/arkruntime/pkg/apiquery"
 )
@@ -122,6 +123,11 @@ type ListSessionResourcesResponseWrapper struct {
 	model.HttpHeader
 }
 
+// UnmarshalJSON normalizes legacy null pages without changing generated models.
+func (r *ListSessionResourcesResponseWrapper) UnmarshalJSON(data []byte) error {
+	return r.ListSessionResourcesResponse.UnmarshalJSON(listresponse.Normalize(data, `{"data":[]}`))
+}
+
 // --- SessionEvent -----------------------------------------------------------
 
 type SendSessionEventsResponseWrapper struct {