[ARROW-6704] [C++] Cast from timestamp to higher resolution does not check out of bounds timestamps

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.16.0
• Component/s: C++
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/23049
• Assignee: Joris Van den Bossche
• Reporter: Joris Van den Bossche
• Created: 26/Sep/19 08:08
• Updated: 11/Jan/23 07:48
• Resolved: 24/Oct/19 13:19

Description

When casting eg timestamp('s') to timestamp('ns'), we do not check for out of bounds timestamps, giving "garbage" timestamps in the result:

In [74]: a_np = np.array(["2012-01-01", "2412-01-01"], dtype="datetime64[s]")                                                                                                                                      

In [75]: arr = pa.array(a_np)                                                                                                                                                                                      

In [76]: arr                                                                                                                                                                                                       
Out[76]: 
<pyarrow.lib.TimestampArray object at 0x7f3d1f07cb88>
[
  2012-01-01 00:00:00,
  2412-01-01 00:00:00
]

In [77]: arr.cast(pa.timestamp('ns'))                                                                                                                                                                              
Out[77]: 
<pyarrow.lib.TimestampArray object at 0x7f3d1f07cfa8>
[
  2012-01-01 00:00:00.000000000,
  1827-06-13 00:25:26.290448384
]

Now, this is the same behaviour as numpy, so not sure we should do this. However, since we have a safe=True/False, I would expect that for safe=True we check this and for safe=False we do not check this.
(numpy has a similiar casting='safe' but also does not raise an error in that case).

Issue Links

• links to: GitHub Pull Request #5623