fix(ios): stop dump ui from timing out after 10s on heavy screens

devices/devicekit/requests.go

@@ -34,7 +34,12 @@ type jsonRPCError struct {
 	Message string `json:"message"`
 }
 
-const defaultRPCTimeout = 10 * time.Second
+// a var so tests can shorten it
+var defaultRPCTimeout = 10 * time.Second
+
+// dumpUITimeout gives the agent time to snapshot a heavy screen, while keeping
+// the request below the http client's own timeout
+const dumpUITimeout = 55 * time.Second
 
 func (c *DeviceKitClient) CallRPC(method string, params any) (json.RawMessage, error) {
 	return c.CallRPCWithTimeout(method, params, defaultRPCTimeout)

devices/devicekit/source.go

@@ -129,7 +129,7 @@ func filterSourceElements(source sourceTreeElement) []types.ScreenElement {
 func (c *DeviceKitClient) GetSourceRaw() (any, error) {
 	startTime := time.Now()
 
-	result, err := c.CallRPC("device.dump.ui", map[string]string{"format": "raw"})
+	result, err := c.CallRPCWithTimeout("device.dump.ui", map[string]string{"format": "raw"}, dumpUITimeout)
 	if err != nil {
 		return nil, fmt.Errorf("failed to get source: %w", err)
 	}
@@ -148,7 +148,7 @@ func (c *DeviceKitClient) GetSourceRaw() (any, error) {
 func (c *DeviceKitClient) GetSourceElements() ([]types.ScreenElement, error) {
 	startTime := time.Now()
 
-	result, err := c.CallRPC("device.dump.ui", map[string]string{"format": "json"})
+	result, err := c.CallRPCWithTimeout("device.dump.ui", map[string]string{"format": "json"}, dumpUITimeout)
 	if err != nil {
 		return nil, err
 	}

devices/devicekit/source_test.go

@@ -1,7 +1,10 @@
 package devicekit
 
 import (
+	"net/http"
+	"net/http/httptest"
 	"testing"
+	"time"
 
 	"github.com/mobile-next/mobilecli/types"
 )
@@ -543,3 +546,36 @@ func TestFilterSourceElementsDoesNotMarkNonSwitchAsChecked(t *testing.T) {
 		t.Errorf("expected checked to be unset, got %v", *output[0].Checked)
 	}
 }
+
+// Snapshotting a heavy screen can take the agent longer than the default RPC
+// timeout; dump ui has to wait for it instead of failing with "context
+// deadline exceeded", see https://github.com/mobile-next/mobilecli/issues/448
+func TestDumpUIWaitsForAnAgentSlowerThanTheDefaultRPCTimeout(t *testing.T) {
+	previous := defaultRPCTimeout
+	defaultRPCTimeout = 50 * time.Millisecond
+	t.Cleanup(func() { defaultRPCTimeout = previous })
+
+	slowAgent := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		time.Sleep(200 * time.Millisecond)
+		_, _ = w.Write([]byte(`{"jsonrpc":"2.0","id":1,"result":{"type":"XCUIElementTypeApplication","rect":{"x":0,"y":0,"width":390,"height":844},"children":[{"type":"XCUIElementTypeButton","label":"Done","rect":{"x":16,"y":62,"width":44,"height":44}}]}}`))
+	}))
+	defer slowAgent.Close()
+
+	client := NewDeviceKitClient(slowAgent.URL)
+
+	if _, err := client.CallRPC("device.info", nil); err == nil {
+		t.Fatal("expected the agent to be slower than the default RPC timeout")
+	}
+
+	elements, err := client.GetSourceElements()
+	if err != nil {
+		t.Fatalf("GetSourceElements: %v", err)
+	}
+	if len(elements) != 1 || elementLabel(elements[0]) != "Done" {
+		t.Errorf("expected the Done button, got %+v", elements)
+	}
+
+	if _, err := client.GetSourceRaw(); err != nil {
+		t.Fatalf("GetSourceRaw: %v", err)
+	}
+}

server/deadline_test.go

@@ -16,6 +16,7 @@ func TestExtendedWriteDeadlineForSlowMethods(t *testing.T) {
 		"device.apps.install":      3 * time.Minute,
 		"device.apps.uninstall":    3 * time.Minute,
 		"device.screenrecord.stop": 35 * time.Second,
+		"device.dump.ui":           60 * time.Second,
 	}
 
 	for method, want := range slowMethods {

server/server.go

@@ -294,6 +294,8 @@ func extendedWriteDeadline(method string) (time.Duration, bool) {
 		return 3 * time.Minute, true
 	case "device.screenrecord.stop":
 		return 35 * time.Second, true
+	case "device.dump.ui":
+		return 60 * time.Second, true
 	}
 	return 0, false
 }