From 5ec5fbe61364a7d0ab72ec5bbd779786743aa0f8 Mon Sep 17 00:00:00 2001
From: Jiayu Liu <jiayu@hey.com>
Date: Mon, 19 Jul 2021 17:54:50 +0800
Subject: [PATCH] impl fmt::Display for PlanType

---
 datafusion/src/logical_plan/plan.rs     | 12 ++++++------
 datafusion/src/physical_plan/explain.rs |  2 +-
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/datafusion/src/logical_plan/plan.rs b/datafusion/src/logical_plan/plan.rs
index 4749840ed4c1..42eaf8e559c9 100644
--- a/datafusion/src/logical_plan/plan.rs
+++ b/datafusion/src/logical_plan/plan.rs
@@ -819,14 +819,14 @@ pub enum PlanType {
     PhysicalPlan,
 }
 
-impl From<&PlanType> for String {
-    fn from(t: &PlanType) -> Self {
-        match t {
-            PlanType::LogicalPlan => "logical_plan".into(),
+impl fmt::Display for PlanType {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            PlanType::LogicalPlan => write!(f, "logical_plan"),
             PlanType::OptimizedLogicalPlan { optimizer_name } => {
-                format!("logical_plan after {}", optimizer_name)
+                write!(f, "logical_plan after {}", optimizer_name)
             }
-            PlanType::PhysicalPlan => "physical_plan".into(),
+            PlanType::PhysicalPlan => write!(f, "physical_plan"),
         }
     }
 }
diff --git a/datafusion/src/physical_plan/explain.rs b/datafusion/src/physical_plan/explain.rs
index 3c5ef1af3236..c838ce4a94d4 100644
--- a/datafusion/src/physical_plan/explain.rs
+++ b/datafusion/src/physical_plan/explain.rs
@@ -104,7 +104,7 @@ impl ExecutionPlan for ExplainExec {
         let mut plan_builder = StringBuilder::new(self.stringified_plans.len());
 
         for p in &self.stringified_plans {
-            type_builder.append_value(&String::from(&p.plan_type))?;
+            type_builder.append_value(&p.plan_type.to_string())?;
             plan_builder.append_value(&*p.plan)?;
         }