make list layout the default

Signed-off-by: Matt Katz <mhkatz97@gmail.com>

Author: mhk197

vortex-file/src/strategy.rs

@@ -50,7 +50,6 @@ use vortex_layout::layouts::compressed::CompressingStrategy;
 use vortex_layout::layouts::compressed::CompressorPlugin;
 use vortex_layout::layouts::dict::writer::DictStrategy;
 use vortex_layout::layouts::flat::writer::FlatLayoutStrategy;
-#[cfg(feature = "unstable_encodings")]
 use vortex_layout::layouts::list::writer::ListLayoutStrategy;
 use vortex_layout::layouts::repartition::RepartitionStrategy;
 use vortex_layout::layouts::repartition::RepartitionWriterOptions;
@@ -244,11 +243,9 @@ impl WriteStrategyBuilder {
             Arc::new(FlatLayoutStrategy::default())
         };
 
-        // 7. for each chunk create a layout. Under the `unstable_encodings` feature, list-typed
-        // chunks route through `ListLayoutStrategy` (separately-addressable elements/offsets/
-        // validity sub-layouts; non-list chunks fall through its built-in fallback to `flat`).
-        // Otherwise everything goes through the flat strategy.
-        #[cfg(feature = "unstable_encodings")]
+        // 7. for each chunk create a layout. List-typed chunks route through
+        // `ListLayoutStrategy` (separately-addressable elements/offsets/validity sub-layouts;
+        // non-list chunks fall through its built-in fallback to `flat`).
         let leaf: Arc<dyn LayoutStrategy> = Arc::new(
             // Thread the configured `flat` (which carries `allow_encodings` / any custom flat
             // override) through every child.
@@ -258,8 +255,6 @@ impl WriteStrategyBuilder {
                 .with_validity(Arc::clone(&flat))
                 .with_fallback(Arc::clone(&flat)),
         );
-        #[cfg(not(feature = "unstable_encodings"))]
-        let leaf: Arc<dyn LayoutStrategy> = Arc::clone(&flat);
 
         let chunked = ChunkedLayoutStrategy::new(leaf);
         // 6. buffer chunks so they end up with closer segment ids physically