[ARROW-15652] [C++] GDB plugin printer gives error with extension type

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 8.0.0
• Component/s: C++
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/31109
• Assignee: Antoine Pitrou
• Reporter: Joris Van den Bossche
• Created: 10/Feb/22 16:34
• Updated: 11/Jan/23 11:38
• Resolved: 16/Feb/22 12:14

Description

Copying the example from ARROW-9078

import pyarrow as pa
import pyarrow.parquet as pq


class MyStructType(pa.PyExtensionType): 
 
    def __init__(self): 
        pa.PyExtensionType.__init__(self, pa.struct([('left', pa.int64()), ('right', pa.int64())])) 
 
    def __reduce__(self): 
        return MyStructType, () 


struct_array = pa.StructArray.from_arrays(
    [
        pa.array([0, 1], type="int64", from_pandas=True),
        pa.array([1, 2], type="int64", from_pandas=True),
    ],
    names=["left", "right"],
)

mystruct_array = pa.ExtensionArray.from_storage(MyStructType(), struct_array)
table = pa.table({'a': mystruct_array})
pq.write_table(table, "test_struct.parquet")

What I was doing is then reading the table back in, with a breakpoint at ApplyOriginalMetadata. But I suppose any other way to get into the debugger is fine as well (and maybe also with a simpler extension type, i.e. not with a struct type as storage type, I didn't yet try that).

This gives:

(gdb) p origin_field
$3 = (const arrow::Field &) @0x555bbb308190: Python Exception <class 'gdb.error'> A syntax error in expression, near `) (0x555bbb277020)).ToString()'.: 
arrow::field("a", )

for the field/type being extension type

cc apitrou

Issue Links

• links to: GitHub Pull Request #12434