Fallback to Utf8View for Dict(_, Utf8View) in `type_union_resolutio…

…n_coercion` (#14602) * utf8view fix * fmt * add more view type * fmt * add test and remove coercion that has no test * fix
apache · Feb 13, 2025 · 28856e1 · 28856e1
1 parent 3e6d70e
commit 28856e1
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Showing 2 changed files with 16 additions and 2 deletions.
diff --git a/datafusion/expr-common/src/type_coercion/binary.rs b/datafusion/expr-common/src/type_coercion/binary.rs
@@ -537,8 +537,16 @@ fn type_union_resolution_coercion(
         }
         (DataType::Dictionary(index_type, value_type), other_type)
         | (other_type, DataType::Dictionary(index_type, value_type)) => {
-            let new_value_type = type_union_resolution_coercion(value_type, other_type);
-            new_value_type.map(|t| DataType::Dictionary(index_type.clone(), Box::new(t)))
+            match type_union_resolution_coercion(value_type, other_type) {
+                // Dict with View type is redundant, use value type instead
+                // TODO: Add binary view, list view with tests
+                Some(DataType::Utf8View) => Some(DataType::Utf8View),
+                Some(new_value_type) => Some(DataType::Dictionary(
+                    index_type.clone(),
+                    Box::new(new_value_type),
+                )),
+                None => None,
+            }
         }
         (DataType::Struct(lhs), DataType::Struct(rhs)) => {
             if lhs.len() != rhs.len() {
@@ -589,6 +597,7 @@ fn type_union_resolution_coercion(
                 .or_else(|| temporal_coercion_nonstrict_timezone(lhs_type, rhs_type))
                 .or_else(|| string_coercion(lhs_type, rhs_type))
                 .or_else(|| numeric_string_coercion(lhs_type, rhs_type))
+                .or_else(|| binary_coercion(lhs_type, rhs_type))
         }
     }
 }

diff --git a/datafusion/sqllogictest/test_files/coalesce.slt b/datafusion/sqllogictest/test_files/coalesce.slt
@@ -438,3 +438,8 @@ Date32
 
 statement ok
 drop table test
+
+query T
+select coalesce(arrow_cast('', 'Utf8View'), arrow_cast('', 'Dictionary(UInt32, Utf8)'));
+----
+(empty)