Added check for unique block id

errors.go

@@ -9,6 +9,7 @@ const (
 	ErrRTMGoodbye           = errorsx.String("goodbye detected")
 	ErrRTMDeadman           = errorsx.String("deadman switch triggered")
 	ErrParametersMissing    = errorsx.String("received empty parameters")
+	ErrBlockIDNotUnique     = errorsx.String("Block ID needs to be unique")
 	ErrInvalidConfiguration = errorsx.String("invalid configuration")
 	ErrMissingHeaders       = errorsx.String("missing headers")
 	ErrExpiredTimestamp     = errorsx.String("timestamp is too old")

views.go

@@ -150,6 +150,23 @@ func (api *Client) OpenView(triggerID string, view ModalViewRequest) (*ViewRespo
 	return api.OpenViewContext(context.Background(), triggerID, view)
 }
 
+// ValidateUniqueBlockID will verify if each input block has a unique block ID if set
+func ValidateUniqueBlockID(view ModalViewRequest) bool {
+
+	uniqueBlockID := map[string]bool{}
+
+	for _, b := range view.Blocks.BlockSet {
+		if inputBlock, ok := b.(*InputBlock); ok {
+			if _, ok := uniqueBlockID[inputBlock.BlockID]; ok {
+				return false
+			}
+			uniqueBlockID[inputBlock.BlockID] = true
+		}
+	}
+
+	return true
+}
+
 // OpenViewContext opens a view for a user with a custom context.
 func (api *Client) OpenViewContext(
 	ctx context.Context,
@@ -159,6 +176,11 @@ func (api *Client) OpenViewContext(
 	if triggerID == "" {
 		return nil, ErrParametersMissing
 	}
+
+	if !ValidateUniqueBlockID(view) {
+		return nil, ErrBlockIDNotUnique
+	}
+
 	req := openViewRequest{
 		TriggerID: triggerID,
 		View:      view,

views_test.go

@@ -25,18 +25,39 @@ func TestSlack_OpenView(t *testing.T) {
 	api := New("testing-token", OptionAPIURL("http://"+serverAddr+"/"))
 
 	cases := []struct {
-		caseName     string
-		triggerID    string
-		rawResp      string
-		expectedResp *ViewResponse
-		expectedErr  error
+		caseName         string
+		triggerID        string
+		modalViewRequest ModalViewRequest
+		rawResp          string
+		expectedResp     *ViewResponse
+		expectedErr      error
 	}{
 		{
-			caseName:     "pass empty trigger_id",
-			triggerID:    "",
+			caseName:         "pass empty trigger_id",
+			triggerID:        "",
+			modalViewRequest: ModalViewRequest{},
+			rawResp:          "",
+			expectedResp:     nil,
+			expectedErr:      ErrParametersMissing,
+		},
+		{
+			caseName:  "raise an error for not having a unique block id",
+			triggerID: "dummy_trigger_id",
+			modalViewRequest: ModalViewRequest{
+				Blocks: Blocks{
+					BlockSet: []Block{
+						&InputBlock{
+							BlockID: "example",
+						},
+						&InputBlock{
+							BlockID: "example",
+						},
+					},
+				},
+			},
 			rawResp:      "",
 			expectedResp: nil,
-			expectedErr:  ErrParametersMissing,
+			expectedErr:  ErrBlockIDNotUnique,
 		},
 		{
 			caseName:  "raise an error from Slack API",
@@ -60,8 +81,9 @@ func TestSlack_OpenView(t *testing.T) {
 			expectedErr: dummySlackErr,
 		},
 		{
-			caseName:  "success",
-			triggerID: "dummy_trigger_id",
+			caseName:         "success",
+			triggerID:        "dummy_trigger_id",
+			modalViewRequest: ModalViewRequest{},
 			rawResp: `{
 				"ok": true,
 				"view": {
@@ -126,7 +148,7 @@ func TestSlack_OpenView(t *testing.T) {
 		t.Run(c.caseName, func(t *testing.T) {
 			h.rawResponse = c.rawResp
 
-			resp, err := api.OpenView(c.triggerID, ModalViewRequest{})
+			resp, err := api.OpenView(c.triggerID, c.modalViewRequest)
 			if c.expectedErr == nil && err != nil {
 				t.Errorf("unexpected error: %s\n", err)
 				return