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https://issues.apache.org/jira/browse/ARROW-3790?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16696236#comment-16696236
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Francois Saint-Jacques commented on ARROW-3790:
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I'm currently working on this, the problem turned out to be a bigger than
expected. While the pointed line is indeed wrong, the actual problem lies
somewhere else. [~wesmckinn] can you assign this task to me?
> [C++] Signed to unsigned integer cast yields incorrect results when type
> sizes are the same
> -------------------------------------------------------------------------------------------
>
> Key: ARROW-3790
> URL: https://issues.apache.org/jira/browse/ARROW-3790
> Project: Apache Arrow
> Issue Type: Bug
> Components: C++
> Reporter: Wes McKinney
> Priority: Major
> Fix For: 0.12.0
>
>
> In
> https://github.com/apache/arrow/blob/master/cpp/src/arrow/compute/kernels/cast.cc#L239,
> an {{int32_t}} is overflows in
> {code}
> constexpr in_type kMax =
> static_cast<in_type>(std::numeric_limits<out_type>::max());
> {code}
> resulting in safety checks not being correctly performed
> {code}
> In [2]: arr = pa.array([-1, -2, -3], type='int32')
> In [3]: arr.cast('uint32')
> Out[3]:
> <pyarrow.lib.UInt32Array object at 0x7f4889457b88>
> [
> 4294967295,
> 4294967294,
> 4294967293
> ]
> {code}
> This would be expected to error when {{safe=True}}
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