enable_fts(): materialize columns so a one-shot iterator works

sqlite_utils/db.py

@@ -3770,6 +3770,9 @@ class Table(Queryable):
         :param tokenize: Custom SQLite tokenizer to use, for example ``"porter"`` to enable Porter stemming.
         :param replace: Should any existing FTS index for this table be replaced by the new one?
         """
+        # columns is used several times below, so a one-shot iterator
+        # would be exhausted after the CREATE VIRTUAL TABLE statement
+        columns = list(columns)
         create_fts_sql = (
             textwrap.dedent("""
             CREATE VIRTUAL TABLE {table_fts} USING {fts_version} (

tests/test_fts.py

@@ -51,6 +51,19 @@ def test_enable_fts(fresh_db):
     assert [] == list(table.search("bar"))
 
 
+@pytest.mark.parametrize("create_triggers", [True, False])
+def test_enable_fts_columns_iterator(fresh_db, create_triggers):
+    # columns is typed Iterable[str], so a one-shot iterator has to work
+    table = fresh_db.table("searchable")
+    table.insert_all(search_records)
+    table.enable_fts(iter(["text", "country"]), create_triggers=create_triggers)
+    assert [row["rowid"] for row in table.search("tanuki")] == [1]
+    assert [row["rowid"] for row in table.search("usa")] == [2]
+    if create_triggers:
+        table.insert({"text": "kitsune", "country": "Japan", "not_searchable": "x"})
+        assert [row["rowid"] for row in table.search("kitsune")] == [3]
+
+
 def test_enable_fts_escape_table_names(fresh_db):
     # Table names with restricted chars are handled correctly.
     # colons and dots are restricted characters for table names.