Minor: simplify code in datafusion-proto (#15752)

Author: alamb

datafusion/proto-common/src/common.rs

@@ -17,6 +17,7 @@
 
 use datafusion_common::{internal_datafusion_err, DataFusionError};
 
+/// Return a `DataFusionError::Internal` with the given message
 pub fn proto_error<S: Into<String>>(message: S) -> DataFusionError {
     internal_datafusion_err!("{}", message.into())
 }

datafusion/proto/src/logical_plan/mod.rs

@@ -355,10 +355,7 @@ impl AsLogicalPlan for LogicalPlanNode {
                     .as_ref()
                     .map(|expr| from_proto::parse_expr(expr, ctx, extension_codec))
                     .transpose()?
-                    .ok_or_else(|| {
-                        DataFusionError::Internal("expression required".to_string())
-                    })?;
-                // .try_into()?;
+                    .ok_or_else(|| proto_error("expression required"))?;
                 LogicalPlanBuilder::from(input).filter(expr)?.build()
             }
             LogicalPlanType::Window(window) => {
@@ -464,7 +461,7 @@ impl AsLogicalPlan for LogicalPlanNode {
                     .map(|col| {
                         let Some(arrow_type) = col.arrow_type.as_ref() else {
                             return Err(proto_error(
-                                "Missing Arrow type in partition columns".to_string(),
+                                "Missing Arrow type in partition columns",
                             ));
                         };
                         let arrow_type = DataType::try_from(arrow_type).map_err(|e| {