[BUG] MERGE operation fails due to AnalysisException when target table contains CHAR(N) columns

[clee704]

Bug

Which Delta project/connector is this regarding?

• Spark
• Standalone
• Flink
• Kernel
• Other (fill in here)

Describe the problem

Steps to reproduce

create table target (id char(10), value char(10)) using delta;
create table source (id char(10), value char(10)) using parquet;
merge into target
using source on target.id = source.id
when matched then update set target.value = source.value;

Observed results

org.apache.spark.sql.delta.DeltaAnalysisException: [DELTA_MERGE_RESOLVED_ATTRIBUTE_MISSING_FROM_INPUT] Resolved attribute(s) id#878,id#880,value#887,id#892,value#893 missing from id#872,value#873,id#874,value#875 in operator !DeltaMergeInto (id#878 = id#880), [Update [actions: [`value` = value#887]]], [Insert [actions: [`id` = id#892, `value` = value#893]]], false, StructType(StructField(id,StringType,true),StructField(value,StringType,true)); line 2 pos 0
at org.apache.spark.sql.delta.ResolveDeltaMergeInto$.resolveReferencesAndSchema(ResolveDeltaMergeInto.scala:335)                                                                                                                                                                          at org.apache.spark.sql.delta.DeltaAnalysis$$anonfun$apply$1.applyOrElse(DeltaAnalysis.scala:547)                                                                                                                                                                                         at org.apache.spark.sql.delta.DeltaAnalysis$$anonfun$apply$1.applyOrElse(DeltaAnalysis.scala:81)
at org.apache.spark.sql.catalyst.plans.logical.AnalysisHelper.$anonfun$resolveOperatorsDownWithPruning$2(AnalysisHelper.scala:170)
...

Expected results

MERGE should be performed.

Environment information

• Delta Lake version: latest (860438f)
• Spark version: 3.5.3
• Scala version: 2.12.18

Willingness to contribute

The Delta Lake Community encourages bug fix contributions. Would you or another member of your organization be willing to contribute a fix for this bug to the Delta Lake code base?

• Yes. I can contribute a fix for this bug independently.
• Yes. I would be willing to contribute a fix for this bug with guidance from the Delta Lake community.
• No. I cannot contribute a bug fix at this time.