Fix result mapping string size in SQL Server string aggregate translator #29231
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ajcvickers
reviewed
Sep 29, 2022
| @@ -61,21 +61,21 @@ public class SqlServerStringAggregateMethodTranslator : IAggregateMethodCallTran | |||
| var resultTypeMapping = sqlExpression.TypeMapping; | |||
| if (resultTypeMapping?.Size != null) | |||
| { | |||
| if (resultTypeMapping.IsUnicode && resultTypeMapping.Size < 8000) | |||
| if (resultTypeMapping.IsUnicode && resultTypeMapping.Size < 4000) | |||
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I think that if it's equal to 4000 (for unicode), it's OK to just retain the original mapping of the operand expression (assigned just above), bubbling it up, no?
ajcvickers
approved these changes
Sep 29, 2022
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Fixes #29229
Description
When translating SQL Server aggregate string methods (string.Join, string.Concat), the maximum size for unicode/non-unicode strings is reversed, leading to an incorrect type mapping for the result
Customer impact
Reproducing an observable bug here isn't trivial (and may not be possible), since SqlServerStringTypeMapping has checks and doesn't take the incorrect size into account. However, the fix is trivial and ensures the correctness of the type mapping.
How found
Customer reported.
Regression
No, new feature (aggregate string function translation.
Testing
New testing added.
Risk
Very low; small self-evident fix in new code introduced for a new 7.0 feature only.