Ensure follow behavior works when streaming to paginated Tabulator

panel/models/tabulator.ts

@@ -1034,25 +1034,36 @@ export class DataTabulatorView extends HTMLBoxView {
  }
 
  // Update table
- setData(): void {
+ setData(): Promise<void> {
  if (this._initializing || this._building || !this.tabulator.initialized) {
- return
+ return Promise.resolve(undefined)
  }
  const data = this.getData()
  if (this.model.pagination != null) {
- this.tabulator.rowManager.setData(data, true, false)
+ return this.tabulator.rowManager.setData(data, true, false)
  } else {
- this.tabulator.setData(data)
+ return this.tabulator.setData(data)
  }
  }
 
  addData(): void {
  const rows = this.tabulator.rowManager.getRows()
  const last_row = rows[rows.length-1]
  const start = ((last_row?.data._index) || 0)
- this.setData()
- if (this.model.follow && last_row) {
- this.tabulator.scrollToRow(start, "top", false)
+ this._updating_page = true
+ const promise = this.setData()
+ if (this.model.follow) {
+ promise.then(() => {
+ if (this.model.pagination) {
+ this.tabulator.setPage(Math.ceil(this.tabulator.rowManager.getDataCount() / (this.model.page_size || 20)))
+ }
+ if (last_row) {
+ this.tabulator.scrollToRow(start, "top", false)
+ }
+ this._updating_page = false
+ })
+ } else {
+ this._updating_page = true
  }
  }
 
@@ -1099,7 +1110,7 @@ export class DataTabulatorView extends HTMLBoxView {
  }
 
  updatePage(pageno: number): void {
- if (this.model.pagination === "local" && this.model.page !== pageno) {
+ if (this.model.pagination === "local" && this.model.page !== pageno && !this._updating_page) {
  this._updating_page = true
  this.model.page = pageno
  this._updating_page = false

panel/tests/ui/widgets/test_tabulator.py

@@ -170,7 +170,7 @@
  widget.param.trigger('value')
  wait_until(lambda: page.locator('text="AA"') is not None, page)
  changed_cell = page.locator('text="AA"')
  expect(changed_cell).to_have_count(1)
 
 
 def test_tabulator_disabled(page, df_mixed):
@@ -2116,7 +2116,6 @@
 
  height_start = page.locator('.pnx-tabulator.tabulator').bounding_box()['height']
 
-
  def stream_data():
  widget.stream(df) # follow is True by default
 
@@ -2131,6 +2130,24 @@
  assert page.locator('.pnx-tabulator.tabulator').bounding_box()['height'] > height_start
 
 
+@pytest.mark.parametrize('pagination', ['remote', 'local'])
+def test_tabulator_streaming_follow_pagination(page, pagination):
+ df = pd.DataFrame(np.random.random((3, 2)), columns=['A', 'B'])
+ widget = Tabulator(df, pagination=pagination, page_size=3)
+
+ serve_component(page, widget)
+
+ expect(page.locator('.tabulator-row')).to_have_count(len(df))
+
+ widget.stream(df)
+
+ expect(page.locator('.tabulator-page.active')).to_have_text('2')
+
+ widget.stream(df)
+
+ expect(page.locator('.tabulator-page.active')).to_have_text('3')
+
+
 def test_tabulator_streaming_no_follow(page):
  nrows1 = 10
  arr = np.random.randint(10, 20, (nrows1, 2))
@@ -3332,7 +3349,7 @@
  assert table_values == list(df2['x'].sort_values(ascending=False))
  else:
  return False
  wait_until(x_values, page)
 
 
 def test_tabulator_update_hidden_columns(page):

panel/widgets/tables.py

@@ -1565,8 +1565,10 @@ def _stream(self, stream, rollover=None, follow=True):
  length = self._length
  nrows = self.page_size or self.initial_page_size
  max_page = max(length//nrows + bool(length%nrows), 1)
- if self.page != max_page:
+ if self.page != max_page and not follow:
  return
+ self._processed, _ = self._get_data()
+ return
  super()._stream(stream, rollover)
  self._update_style()
  self._update_selectable()
@@ -1575,13 +1577,13 @@ def _stream(self, stream, rollover=None, follow=True):
  def stream(self, stream_value, rollover=None, reset_index=True, follow=True):
  for ref, (model, _) in self._models.items():
  self._apply_update([], {'follow': follow}, model, ref)
+ super().stream(stream_value, rollover, reset_index)
+ if follow and self.pagination:
+ self._update_max_page()
  if follow and self.pagination:
  length = self._length
  nrows = self.page_size or self.initial_page_size
  self.page = max(length//nrows + bool(length%nrows), 1)
- super().stream(stream_value, rollover, reset_index)
- if follow and self.pagination:
- self._update_max_page()
 
  @updating
  def _patch(self, patch):