Preselect current index in go command so that first keystroke replaces it

Author: FrancescAlted

src/blosc2/b2view/app.py

@@ -351,6 +351,9 @@ def on_mount(self) -> None:
         input_widget = self.query_one("#goto-input", Input)
         input_widget.value = str(self.current)
         input_widget.focus()
+        # Pre-select the current value so the first keystroke replaces it (typing
+        # a fresh number is the common case); arrows/edits still work as usual.
+        input_widget.select_all()
 
     def on_input_submitted(self, event: Input.Submitted) -> None:
         value = event.value.strip().replace("_", "")
@@ -408,6 +411,9 @@ def on_mount(self) -> None:
         input_widget = self.query_one("#gotocol-input", Input)
         input_widget.value = str(self.current)
         input_widget.focus()
+        # Pre-select the current index so typing a column name (or a new index)
+        # replaces it instead of appending (e.g. "0" + "payment.fare").
+        input_widget.select_all()
 
     def _fail(self, message: str) -> None:
         self.query_one("#gotocol-title", Static).update(message)

tests/b2view/test_basics.py

@@ -529,6 +529,21 @@ async def test_ctable_column_paging(store_path):
         assert page["start"] + table.cursor_row == 150
         _assert_ctable_window_values(page, expected)
 
+        # Typing a name replaces the pre-filled current index (not appends): the
+        # modal opens with the current column index selected, so the first
+        # keystroke overwrites it instead of producing e.g. "0v12".
+        await pilot.press("c")
+        await pilot.pause()
+        gotocol_input = app.screen.query_one("#gotocol-input", Input)
+        assert gotocol_input.value == str(app.table_page["col_start"])  # pre-filled
+        for ch in "v12":
+            await pilot.press(ch)
+        assert gotocol_input.value == "v12"  # replaced, not "<index>v12"
+        await pilot.press("enter")
+        await wait_for_table(pilot)
+        assert app.table_page["col_start"] == all_names.index("v12")
+        assert app.table_page["columns"][0] == "v12"
+
         # An ambiguous name prefix keeps the modal open; escape cancels
         await pilot.press("c")
         await pilot.pause()