type_id and value_offset are incorrect for sliced UnionArray

[viirya]

Which issue does this PR close?

Closes #2086.

Rationale for this change

What changes are included in this PR?

Are there any user-facing changes?

[codecov-commenter]

Codecov Report

Merging #2087 (781c606) into master (cb7e5b0) will increase coverage by 0.03%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #2087      +/-   ##
==========================================
+ Coverage   83.68%   83.71%   +0.03%     
==========================================
  Files         224      224              
  Lines       58826    59005     +179     
==========================================
+ Hits        49227    49396     +169     
- Misses       9599     9609      +10     

Impacted Files	Coverage Δ
arrow/src/array/array_union.rs	90.89% <100.00%> (+0.74%)	⬆️
arrow/src/datatypes/datatype.rs	64.05% <0.00%> (-0.36%)	⬇️
parquet/src/encodings/encoding.rs	93.43% <0.00%> (-0.20%)	⬇️
parquet_derive/src/parquet_field.rs	65.75% <0.00%> (ø)
parquet/src/arrow/record_reader/mod.rs	89.17% <0.00%> (ø)
parquet/src/arrow/arrow_reader.rs	92.76% <0.00%> (+0.09%)	⬆️
arrow/src/compute/kernels/take.rs	95.46% <0.00%> (+0.19%)	⬆️
arrow/src/ipc/writer.rs	85.46% <0.00%> (+0.41%)	⬆️
parquet/src/arrow/array_reader/byte_array.rs	86.31% <0.00%> (+1.83%)	⬆️

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[tustvold]

?

[viirya]

Hm? I need use RecordBatch, otherwise:

error[E0412]: cannot find type `RecordBatch` in this scope
   --> arrow/src/array/array_union.rs:994:49
    |
994 |         fn test_slice_union(record_batch_slice: RecordBatch) {
    |                                                 ^^^^^^^^^^^ not found in this scope

[tustvold]

Oh, the diff rendered strangely on my phone - made it look like there were no other changes to this file

[ursabot]

Benchmark runs are scheduled for baseline = a6379fe and contender = 54e9181. 54e9181 is a master commit associated with this PR. Results will be available as each benchmark for each run completes.
Conbench compare runs links:
[Skipped ⚠️ Benchmarking of arrow-rs-commits is not supported on ec2-t3-xlarge-us-east-2] ec2-t3-xlarge-us-east-2
[Skipped ⚠️ Benchmarking of arrow-rs-commits is not supported on test-mac-arm] test-mac-arm
[Skipped ⚠️ Benchmarking of arrow-rs-commits is not supported on ursa-i9-9960x] ursa-i9-9960x
[Skipped ⚠️ Benchmarking of arrow-rs-commits is not supported on ursa-thinkcentre-m75q] ursa-thinkcentre-m75q
Buildkite builds:
Supported benchmarks:
ec2-t3-xlarge-us-east-2: Supported benchmark langs: Python, R. Runs only benchmarks with cloud = True
test-mac-arm: Supported benchmark langs: C++, Python, R
ursa-i9-9960x: Supported benchmark langs: Python, R, JavaScript
ursa-thinkcentre-m75q: Supported benchmark langs: C++, Java