added check of metadata

Signed-off-by: JustinRush80 <[email protected]>

crates/core/src/operations/merge/mod.rs

@@ -56,7 +56,7 @@ use datafusion_expr::{
     UNNAMED_TABLE,
 };
 
-use delta_kernel::schema::StructType;
+use delta_kernel::schema::{ColumnMetadataKey, StructType};
 use filter::try_construct_early_filter;
 use futures::future::BoxFuture;
 use parquet::file::properties::WriterProperties;
@@ -1522,6 +1522,13 @@ fn modify_schema(
     {
         // This assume that all the columns in the MERGE operations of UPDATE and INSERT at least exists in the source table
         let source_field = source_schema.field_with_unqualified_name(columns.name())?;
+        if source_field
+            .metadata()
+            .contains_key(ColumnMetadataKey::GenerationExpression.as_ref())
+        {
+            let error = arrow::error::ArrowError::SchemaError("Schema evolved fields cannot have generated expressions. Recreate the table to achieve this.".to_string());
+            return Err(DeltaTableError::Arrow { source: error });
+        }
 
         if let Some(target_field) = target_schema.field_from_column(columns).ok() {
             // for nested data types we need to first merge then see if there a change then replace the pre-existing field