From e42736d3bbfbea7bc56006447b955c10a91d78b9 Mon Sep 17 00:00:00 2001
From: Philipp Rudiger <prudiger@anaconda.com>
Date: Mon, 30 Sep 2024 12:34:48 +0200
Subject: [PATCH] Fix regression handling selection on multi-indexed Tabulator
 data (#7336)

---
 panel/tests/ui/widgets/test_tabulator.py | 17 +++++++++++++++++
 panel/tests/widgets/test_tables.py       |  8 ++++----
 panel/widgets/tables.py                  |  7 +++----
 3 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/panel/tests/ui/widgets/test_tabulator.py b/panel/tests/ui/widgets/test_tabulator.py
index fc69cbf8cc..403379be83 100644
--- a/panel/tests/ui/widgets/test_tabulator.py
+++ b/panel/tests/ui/widgets/test_tabulator.py
@@ -1543,6 +1543,23 @@ def test_tabulator_selection_selectable_rows(page, df_mixed):
     assert widget.selected_dataframe.equals(expected_selected)
 
 
+@pytest.mark.parametrize('pagination', ['remote', 'local', None])
+def test_tabulator_selection_on_multi_index(page, pagination):
+    index = pd.MultiIndex.from_tuples([(i, j) for i in range(10) for j in range(10)], names=["A", "B"])
+    df = pd.DataFrame(index=index, data={"C": range(100)})
+
+    widget = Tabulator(df, pagination=pagination, selectable='checkbox')
+
+    serve_component(page, widget)
+
+    checkboxes = page.locator('input[type="checkbox"]')
+    expect(checkboxes).to_have_count(widget.initial_page_size+1 if pagination else len(df)+1)
+    checkboxes.nth(1).check()
+    checkboxes.nth(17).check()
+
+    wait_until(lambda: widget.selection == [0, 16], page)
+
+
 def test_tabulator_row_content(page, df_mixed):
     widget = Tabulator(df_mixed, row_content=lambda i: f"{i['str']}-row-content")
 
diff --git a/panel/tests/widgets/test_tables.py b/panel/tests/widgets/test_tables.py
index 661b7f382f..5d82e41070 100644
--- a/panel/tests/widgets/test_tables.py
+++ b/panel/tests/widgets/test_tables.py
@@ -1817,8 +1817,8 @@ def test_tabulator_constant_scalar_filter_on_index_client_side(document, comm, p
 
 @pytest.mark.parametrize('pagination', ['local', 'remote', None])
 def test_tabulator_constant_scalar_filter_on_multi_index_client_side(document, comm, pagination):
-    df = makeMixedDataFrame()
-    table = Tabulator(df.set_index(['A', 'C']), pagination=pagination)
+    df = makeMixedDataFrame().set_index(['A', 'C'])
+    table = Tabulator(df, pagination=pagination)
 
     table.filters = [
         {'field': 'A', 'sorter': 'number', 'type': '=', 'value': 2},
@@ -1831,9 +1831,9 @@ def test_tabulator_constant_scalar_filter_on_multi_index_client_side(document, c
         'B': np.array([0.]),
         'D': np.array(['2009-01-05T00:00:00.000000000'],
                       dtype='datetime64[ns]')
-    })
+    }).set_index(['A', 'C'])
     pd.testing.assert_frame_equal(
-        table._processed, expected if pagination == 'remote' else df[['A', 'C', 'B', 'D']]
+        table._processed, expected if pagination == 'remote' else df
     )
 
 @pytest.mark.parametrize('pagination', ['local', 'remote', None])
diff --git a/panel/widgets/tables.py b/panel/widgets/tables.py
index dad733ae6c..4f1f5748f9 100644
--- a/panel/widgets/tables.py
+++ b/panel/widgets/tables.py
@@ -642,9 +642,7 @@ def _process_df_and_convert_to_cds(self, df: pd.DataFrame) -> tuple[pd.DataFrame
         else:
             default_index = ('level_0' if 'index' in df.columns else 'index')
             indexes = [df.index.name or default_index]
-        if len(indexes) > 1:
-            df = df.reset_index()
-        data = ColumnDataSource.from_df(df)
+        data = ColumnDataSource.from_df(df.reset_index() if len(indexes) > 1 else df)
         if not self.show_index and len(indexes) > 1:
             data = {k: v for k, v in data.items() if k not in indexes}
         return df, {k if isinstance(k, str) else str(k): self._process_column(v) for k, v in data.items()}
@@ -1440,7 +1438,6 @@ def _get_data(self):
             indexes = [df.index.name or default_index]
         if len(indexes) > 1:
             page_df = page_df.reset_index()
-            df = df.reset_index()
         data = ColumnDataSource.from_df(page_df).items()
         return df, {k if isinstance(k, str) else str(k): v for k, v in data}
 
@@ -1448,6 +1445,8 @@ def _get_style_data(self, recompute=True):
         if self.value is None or self.style is None or self.value.empty:
             return {}
         df = self._processed
+        if len(self.indexes) > 1:
+            df = df.reset_index()
         if recompute:
             try:
                 self._computed_styler = styler = df.style