Remove uses of #[allow(dead_code)] in favor of _identifier (#13328)

* Remove uses of #[allow(dead_code)] in favor of _identifier

* update comments

Author: ding-young

datafusion-examples/examples/advanced_parquet_index.rs

@@ -229,9 +229,9 @@ async fn main() -> Result<()> {
 /// `file1.parquet` contains values `0..1000`
 #[derive(Debug)]
 pub struct IndexTableProvider {
-    /// Where the file is stored (cleanup on drop)
-    #[allow(dead_code)]
-    tmpdir: TempDir,
+    /// Pointer to temporary file storage. Keeping it in scope to prevent temporary folder
+    /// to be deleted prematurely
+    _tmpdir: TempDir,
     /// The file that is being read.
     indexed_file: IndexedFile,
     /// The underlying object store
@@ -250,7 +250,7 @@ impl IndexTableProvider {
 
         Ok(Self {
             indexed_file,
-            tmpdir,
+            _tmpdir: tmpdir,
             object_store,
             use_row_selections: AtomicBool::new(false),
         })

datafusion/core/tests/parquet/external_access_plan.rs

@@ -313,7 +313,7 @@ impl TestFull {
         } = self;
 
         let TestData {
-            temp_file: _,
+            _temp_file: _,
             schema,
             file_name,
             file_size,
@@ -361,9 +361,9 @@ impl TestFull {
 
 // Holds necessary data for these tests to reuse the same parquet file
 struct TestData {
-    // field is present as on drop the file is deleted
-    #[allow(dead_code)]
-    temp_file: NamedTempFile,
+    /// Pointer to temporary file storage. Keeping it in scope to prevent temporary folder
+    /// to be deleted prematurely
+    _temp_file: NamedTempFile,
     schema: SchemaRef,
     file_name: String,
     file_size: u64,
@@ -402,7 +402,7 @@ fn get_test_data() -> &'static TestData {
         let file_size = temp_file.path().metadata().unwrap().len();
 
         TestData {
-            temp_file,
+            _temp_file: temp_file,
             schema,
             file_name,
             file_size,

datafusion/core/tests/parquet/mod.rs

@@ -100,10 +100,9 @@ enum Unit {
 /// table "t" registered, pointing at a parquet file made with
 /// `make_test_file`
 struct ContextWithParquet {
-    #[allow(dead_code)]
     /// temp file parquet data is written to. The file is cleaned up
     /// when dropped
-    file: NamedTempFile,
+    _file: NamedTempFile,
     provider: Arc<dyn TableProvider>,
     ctx: SessionContext,
 }
@@ -217,7 +216,7 @@ impl ContextWithParquet {
         ctx.register_table("t", provider.clone()).unwrap();
 
         Self {
-            file,
+            _file: file,
             provider,
             ctx,
         }

datafusion/execution/src/disk_manager.rs

@@ -139,7 +139,7 @@ impl DiskManager {
 
         let dir_index = thread_rng().gen_range(0..local_dirs.len());
         Ok(RefCountedTempFile {
-            parent_temp_dir: Arc::clone(&local_dirs[dir_index]),
+            _parent_temp_dir: Arc::clone(&local_dirs[dir_index]),
             tempfile: Builder::new()
                 .tempfile_in(local_dirs[dir_index].as_ref())
                 .map_err(DataFusionError::IoError)?,
@@ -153,8 +153,7 @@ impl DiskManager {
 pub struct RefCountedTempFile {
     /// The reference to the directory in which temporary files are created to ensure
     /// it is not cleaned up prior to the NamedTempFile
-    #[allow(dead_code)]
-    parent_temp_dir: Arc<TempDir>,
+    _parent_temp_dir: Arc<TempDir>,
     tempfile: NamedTempFile,
 }
 

datafusion/physical-plan/src/joins/cross_join.rs

@@ -53,8 +53,7 @@ struct JoinLeftData {
     merged_batch: RecordBatch,
     /// Track memory reservation for merged_batch. Relies on drop
     /// semantics to release reservation when JoinLeftData is dropped.
-    #[allow(dead_code)]
-    reservation: MemoryReservation,
+    _reservation: MemoryReservation,
 }
 
 #[allow(rustdoc::private_intra_doc_links)]
@@ -209,7 +208,7 @@ async fn load_left_input(
 
     Ok(JoinLeftData {
         merged_batch,
-        reservation,
+        _reservation: reservation,
     })
 }
 

datafusion/physical-plan/src/joins/hash_join.rs

@@ -92,8 +92,7 @@ struct JoinLeftData {
     probe_threads_counter: AtomicUsize,
     /// Memory reservation that tracks memory used by `hash_map` hash table
     /// `batch`. Cleared on drop.
-    #[allow(dead_code)]
-    reservation: MemoryReservation,
+    _reservation: MemoryReservation,
 }
 
 impl JoinLeftData {
@@ -110,7 +109,7 @@ impl JoinLeftData {
             batch,
             visited_indices_bitmap,
             probe_threads_counter,
-            reservation,
+            _reservation: reservation,
         }
     }
 

datafusion/physical-plan/src/joins/nested_loop_join.rs

@@ -69,22 +69,21 @@ struct JoinLeftData {
     probe_threads_counter: AtomicUsize,
     /// Memory reservation for tracking batch and bitmap
     /// Cleared on `JoinLeftData` drop
-    #[allow(dead_code)]
-    reservation: MemoryReservation,
+    _reservation: MemoryReservation,
 }
 
 impl JoinLeftData {
     fn new(
         batch: RecordBatch,
         bitmap: SharedBitmapBuilder,
         probe_threads_counter: AtomicUsize,
-        reservation: MemoryReservation,
+        _reservation: MemoryReservation,
     ) -> Self {
         Self {
             batch,
             bitmap,
             probe_threads_counter,
-            reservation,
+            _reservation,
         }
     }
 

datafusion/physical-plan/src/repartition/mod.rs

@@ -623,7 +623,7 @@ impl ExecutionPlan for RepartitionExec {
                         Box::pin(PerPartitionStream {
                             schema: Arc::clone(&schema_captured),
                             receiver,
-                            drop_helper: Arc::clone(&abort_helper),
+                            _drop_helper: Arc::clone(&abort_helper),
                             reservation: Arc::clone(&reservation),
                         }) as SendableRecordBatchStream
                     })
@@ -651,7 +651,7 @@ impl ExecutionPlan for RepartitionExec {
                     num_input_partitions_processed: 0,
                     schema: input.schema(),
                     input: rx.swap_remove(0),
-                    drop_helper: abort_helper,
+                    _drop_helper: abort_helper,
                     reservation,
                 }) as SendableRecordBatchStream)
             }
@@ -906,8 +906,7 @@ struct RepartitionStream {
     input: DistributionReceiver<MaybeBatch>,
 
     /// Handle to ensure background tasks are killed when no longer needed.
-    #[allow(dead_code)]
-    drop_helper: Arc<Vec<SpawnedTask<()>>>,
+    _drop_helper: Arc<Vec<SpawnedTask<()>>>,
 
     /// Memory reservation.
     reservation: SharedMemoryReservation,
@@ -970,8 +969,7 @@ struct PerPartitionStream {
     receiver: DistributionReceiver<MaybeBatch>,
 
     /// Handle to ensure background tasks are killed when no longer needed.
-    #[allow(dead_code)]
-    drop_helper: Arc<Vec<SpawnedTask<()>>>,
+    _drop_helper: Arc<Vec<SpawnedTask<()>>>,
 
     /// Memory reservation.
     reservation: SharedMemoryReservation,

datafusion/physical-plan/src/sorts/cursor.rs

@@ -156,8 +156,7 @@ pub struct RowValues {
 
     /// Tracks for the memory used by in the `Rows` of this
     /// cursor. Freed on drop
-    #[allow(dead_code)]
-    reservation: MemoryReservation,
+    _reservation: MemoryReservation,
 }
 
 impl RowValues {
@@ -173,7 +172,10 @@ impl RowValues {
             "memory reservation mismatch"
         );
         assert!(rows.num_rows() > 0);
-        Self { rows, reservation }
+        Self {
+            rows,
+            _reservation: reservation,
+        }
     }
 }