Revert "Support cast varchar to bitmap (#1941)" (#1960)

This reverts commit 8813710.

be/src/exprs/vectorized/cast_expr.cpp

@@ -15,7 +15,6 @@
 #include "gutil/strings/substitute.h"
 #include "runtime/runtime_state.h"
 #include "storage/hll.h"
-#include "util/bitmap_value.h"
 #include "util/date_func.h"
 
 namespace starrocks {
@@ -158,30 +157,6 @@ ColumnPtr cast_fn<TYPE_VARCHAR, TYPE_HLL>(ColumnPtr& column) {
 
     return builder.build(column->is_constant());
 }
-
-template <>
-ColumnPtr cast_fn<TYPE_VARCHAR, TYPE_OBJECT>(ColumnPtr& column) {
-    ColumnBuilder<TYPE_OBJECT> builder;
-    ColumnViewer<TYPE_VARCHAR> viewer(column);
-    for (int row = 0; row < viewer.size(); ++row) {
-        if (viewer.is_null(row)) {
-            builder.append_null();
-            continue;
-        }
-
-        auto value = viewer.value(row);
-        BitmapValue bitmap;
-        // TODO(kks): check value.data is valid bitmap firstly
-        if (bitmap.deserialize(value.data)) {
-            builder.append(&bitmap);
-        } else {
-            builder.append_null();
-        }
-    }
-
-    return builder.build(column->is_constant());
-}
-
 // all int(tinyint, smallint, int, bigint, largeint) cast implements
 DEFINE_UNARY_FN_WITH_IMPL(ImplicitToNumber, value) {
     return value;
@@ -1058,10 +1033,6 @@ Expr* VectorizedCastExprFactory::from_thrift(const TExprNode& node) {
         return new VectorizedCastExpr<TYPE_VARCHAR, TYPE_HLL>(node);
     }
 
-    if (from_type == TYPE_VARCHAR && to_type == TYPE_OBJECT) {
-        return new VectorizedCastExpr<TYPE_VARCHAR, TYPE_OBJECT>(node);
-    }
-
     if (to_type == TYPE_VARCHAR) {
         switch (from_type) {
             CASE_TO_STRING_FROM(TYPE_BOOLEAN);