[client-v2,jdbc-v2] Reading Array(Nullable(String)) with BinaryString enabled

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
58/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Quiet
Tech stack
java
Domain
database

Research direction

Start by tracing readArray and its use of readValue when binaryStringSupport is enabled, focusing on Array(Nullable(String)) and nested String or FixedString values. Confirm the container returns plain String elements rather than StringValue, and verify that the resulting array avoids the reported type mismatch or ArrayStoreException.

Written by the indexing model from the issue text.

Description

area:data-type client-api-v2 jdbc-v2
Description

There is a claim:

Nullable array strings wrong
High Severity

It looks like readArray is using the top-level readValue for nullable array elements when binaryStringSupport is enabled. This means nested String/FixedString inside Array(Nullable(...)) are read as StringValue instead of plain String. This goes against our rule for container types and could lead to ArrayStoreException or unexpected type mismatches.

https://github.com/ClickHouse/clickhouse-java/pull/2952/changes/BASE..c74bd36aae7fd863f0691654f65c87cc9c982415#r3632548114

Dominant language
Java
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Forks
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Avg merge
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Merged PRs (30d)
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