Remove CastColumnExpr and custom_file_casts example; unify on field-aware CastExpr

datafusion-examples/README.md

@@ -77,7 +77,6 @@ cargo run --example dataframe -- dataframe
 | csv_json_opener       | [`custom_data_source/csv_json_opener.rs`](examples/custom_data_source/csv_json_opener.rs)             | Use low-level FileOpener APIs for CSV/JSON                                                                          |
 | csv_sql_streaming     | [`custom_data_source/csv_sql_streaming.rs`](examples/custom_data_source/csv_sql_streaming.rs)         | Run a streaming SQL query against CSV data                                                                          |
 | custom_datasource     | [`custom_data_source/custom_datasource.rs`](examples/custom_data_source/custom_datasource.rs)         | Query a custom TableProvider                                                                                        |
-| custom_file_casts     | [`custom_data_source/custom_file_casts.rs`](examples/custom_data_source/custom_file_casts.rs)         | Implement custom casting rules                                                                                      |
 | custom_file_format    | [`custom_data_source/custom_file_format.rs`](examples/custom_data_source/custom_file_format.rs)       | Write to a custom file format                                                                                       |
 | default_column_values | [`custom_data_source/default_column_values.rs`](examples/custom_data_source/default_column_values.rs) | Custom default values using metadata                                                                                |
 | file_stream_provider  | [`custom_data_source/file_stream_provider.rs`](examples/custom_data_source/file_stream_provider.rs)   | Read/write via FileStreamProvider for streams                                                                       |

datafusion-examples/examples/custom_data_source/main.rs

@@ -21,7 +21,7 @@
 //!
 //! ## Usage
 //! ```bash
-//! cargo run --example custom_data_source -- [all|csv_json_opener|csv_sql_streaming|custom_datasource|custom_file_casts|custom_file_format|default_column_values|file_stream_provider]
+//! cargo run --example custom_data_source -- [all|adapter_serialization|csv_json_opener|csv_sql_streaming|custom_datasource|custom_file_format|default_column_values|file_stream_provider]
 //! ```
 //!
 //! Each subcommand runs a corresponding example:
@@ -39,9 +39,6 @@
 //! - `custom_datasource`  
 //!   (file: custom_datasource.rs, desc: Query a custom TableProvider)
 //!
-//! - `custom_file_casts`
-//!   (file: custom_file_casts.rs, desc: Implement custom casting rules)
-//!
 //! - `custom_file_format`
 //!   (file: custom_file_format.rs, desc: Write to a custom file format)
 //!
@@ -55,7 +52,6 @@ mod adapter_serialization;
 mod csv_json_opener;
 mod csv_sql_streaming;
 mod custom_datasource;
-mod custom_file_casts;
 mod custom_file_format;
 mod default_column_values;
 mod file_stream_provider;
@@ -72,7 +68,6 @@ enum ExampleKind {
     CsvJsonOpener,
     CsvSqlStreaming,
     CustomDatasource,
-    CustomFileCasts,
     CustomFileFormat,
     DefaultColumnValues,
     FileStreamProvider,
@@ -103,9 +98,6 @@ impl ExampleKind {
             ExampleKind::CustomDatasource => {
                 custom_datasource::custom_datasource().await?
             }
-            ExampleKind::CustomFileCasts => {
-                custom_file_casts::custom_file_casts().await?
-            }
             ExampleKind::CustomFileFormat => {
                 custom_file_format::custom_file_format().await?
             }

datafusion/physical-expr-adapter/src/schema_rewriter.rs

@@ -644,7 +644,7 @@ mod tests {
             .expect("Expected CastExpr")
     }
 
-    fn assert_cast_column(cast_expr: &CastExpr, name: &str, index: usize) {
+    fn assert_cast_input_column(cast_expr: &CastExpr, name: &str, index: usize) {
         let inner_col = cast_expr
             .expr()
             .as_any()
@@ -771,7 +771,7 @@ mod tests {
 
         let left_cast = assert_cast_expr(left.left());
         assert_eq!(left_cast.target_field().data_type(), &DataType::Int64);
-        assert_cast_column(left_cast, "a", 0);
+        assert_cast_input_column(left_cast, "a", 0);
 
         let right = outer
             .right()
@@ -1672,7 +1672,7 @@ mod tests {
         let cast_expr = assert_cast_expr(&result);
 
         // Verify the inner column points to the correct physical index (1)
-        assert_cast_column(cast_expr, "a", 1);
+        assert_cast_input_column(cast_expr, "a", 1);
 
         // Verify cast types
         assert_eq!(
@@ -1692,7 +1692,7 @@ mod tests {
         // Regression: this must still resolve against physical field `a` by name.
         let rewritten = adapter.rewrite(Arc::new(Column::new("a", 0))).unwrap();
         let cast_expr = assert_cast_expr(&rewritten);
-        assert_cast_column(cast_expr, "a", 1);
+        assert_cast_input_column(cast_expr, "a", 1);
         assert_eq!(cast_expr.target_field().data_type(), &DataType::Int64);
     }
 }