ARROW-13784: [Python] Table.from_arrays should raise an error when ar…

…ray is empty but names is not

We already check that the list of arrays and list of names should have the same length in `table.pxi`.
For a special case when a list of arrays is of length 0 but length of list of names is greater than 0 the check fails.
I changed the ordering of checks in `table.pxi` and added a test to `test_table.py`.

Closes #11457 from AlenkaF/ARROW-13784

Authored-by: Alenka Frim <frim.alenka@gmail.com>
Signed-off-by: Joris Van den Bossche <jorisvandenbossche@gmail.com>

python/pyarrow/table.pxi

@@ -572,8 +572,12 @@ cdef _schema_from_arrays(arrays, names, metadata, shared_ptr[CSchema]* schema):
         c_meta = KeyValueMetadata(metadata).unwrap()
 
     if K == 0:
-        schema.reset(new CSchema(c_fields, c_meta))
-        return arrays
+        if names is None or len(names) == 0:
+            schema.reset(new CSchema(c_fields, c_meta))
+            return arrays
+        else:
+            raise ValueError('Length of names ({}) does not match '
+                             'length of arrays ({})'.format(len(names), K))
 
     c_fields.resize(K)
 

python/pyarrow/tests/test_table.py

@@ -1022,6 +1022,23 @@ def test_table_remove_column_empty():
     assert t3.equals(table)
 
 
+def test_empty_table_with_names():
+    # ARROW-13784
+    data = []
+    names = ["a", "b"]
+    message = (
+        'Length of names [(]2[)] does not match length of arrays [(]0[)]')
+    with pytest.raises(ValueError, match=message):
+        pa.Table.from_arrays(data, names=names)
+
+
+def test_empty_table():
+    table = pa.table([])
+
+    assert table.column_names == []
+    assert table.equals(pa.Table.from_arrays([], []))
+
+
 def test_table_rename_columns():
     data = [
         pa.array(range(5)),