fix: resolve case where unsigned integers were cast to signed integer…

…s in native (delta) storage (#2640)

crates/datasources/src/native/access.rs

@@ -120,6 +120,17 @@ fn arrow_to_delta_safe(arrow_type: &DataType) -> DeltaResult<DeltaField> {
                 metadata: Some(metadata),
             })
         }
+        dtype @ (DataType::UInt8 | DataType::UInt16 | DataType::UInt32 | DataType::UInt64) => {
+            let mut metadata = HashMap::new();
+            metadata.insert("arrow_type".to_string(), json!(dtype));
+
+            let delta_type = dtype.try_into()?;
+
+            Ok(DeltaField {
+                data_type: delta_type,
+                metadata: Some(metadata),
+            })
+        }
         other => {
             let delta_type = other.try_into()?;
             Ok(DeltaField {
@@ -130,7 +141,6 @@ fn arrow_to_delta_safe(arrow_type: &DataType) -> DeltaResult<DeltaField> {
     }
 }
 
-
 impl NativeTableStorage {
     /// Create a native table storage provider from a URL and an object store instance
     /// rooted at that location.
@@ -194,7 +204,6 @@ impl NativeTableStorage {
                 .with_table_name(&table.meta.name)
                 .with_log_store(delta_store);
 
-
             for col in &opts.columns {
                 let delta_col = arrow_to_delta_safe(&col.arrow_type)?;
 
@@ -371,7 +380,6 @@ impl TableProvider for NativeTable {
             if let Some(arrow_type) = metadata.get("arrow_type") {
                 // this is dumb AF, delta-lake is returning a string of a json object instead of a json object
 
-
                 // any panics here are bugs in writing the metadata in the first place
                 let s: String =
                     serde_json::from_str(arrow_type).expect("metadata was not correctly written");

testdata/sqllogictests/datatypes.slt

@@ -33,4 +33,20 @@ statement error
 select array_element(1, f) from test;
 
 statement error 
-select array_append(f, 3) from test;
+select array_append(f, 3) from test;
+
+
+
+# 2588 Unsigned integers downgraded to integers in delta-lake 
+statement ok
+create table datatypes (u8 tinyint unsigned, u16 smallint unsigned, u32 int unsigned, u64 bigint unsigned);
+
+
+# Inserting negative values to test validity of unsigned integers
+statement error 
+insert into datatypes (u8, u16, u32, u64) values (-1, -1, -1, -1); 
+
+
+# Inserting positive values 
+statement ok 
+insert into datatypes (u8, u16, u32, u64) values (1, 1, 1, 1);