From d57437aacea339e3067b3b6c577f178d1dbb5755 Mon Sep 17 00:00:00 2001
From: irenjj <renj.jiang@gmail.com>
Date: Thu, 13 Mar 2025 21:09:24 +0800
Subject: [PATCH] Implement `tree` explain for `CsvSink`

---
 datafusion/datasource-csv/src/file_format.rs     |  6 ++++--
 .../sqllogictest/test_files/explain_tree.slt     | 16 ++++++++++++++++
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/datafusion/datasource-csv/src/file_format.rs b/datafusion/datasource-csv/src/file_format.rs
index cab561d163b3..cc1b63cfc9b4 100644
--- a/datafusion/datasource-csv/src/file_format.rs
+++ b/datafusion/datasource-csv/src/file_format.rs
@@ -666,8 +666,10 @@ impl DisplayAs for CsvSink {
                 write!(f, ")")
             }
             DisplayFormatType::TreeRender => {
-                // TODO: collect info
-                write!(f, "")
+                if !self.config.file_groups.is_empty() {
+                    FileGroupDisplay(&self.config.file_groups).fmt_as(t, f)?;
+                }
+                Ok(())
             }
         }
     }
diff --git a/datafusion/sqllogictest/test_files/explain_tree.slt b/datafusion/sqllogictest/test_files/explain_tree.slt
index fbadc3a4f52f..9e047133fcfc 100644
--- a/datafusion/sqllogictest/test_files/explain_tree.slt
+++ b/datafusion/sqllogictest/test_files/explain_tree.slt
@@ -1725,6 +1725,22 @@ physical_plan
 09)│          rows: 1          │
 10)└───────────────────────────┘
 
+query TT
+explain COPY (VALUES (1, 'foo', 1, '2023-01-01'), (2, 'bar', 2, '2023-01-02'), (3, 'baz', 3, '2023-01-03'))
+TO 'test_files/scratch/explain_tree/2.csv';
+----
+physical_plan
+01)┌───────────────────────────┐
+02)│        DataSinkExec       │
+03)└─────────────┬─────────────┘
+04)┌─────────────┴─────────────┐
+05)│       DataSourceExec      │
+06)│    --------------------   │
+07)│        bytes: 2672        │
+08)│       format: memory      │
+09)│          rows: 1          │
+10)└───────────────────────────┘
+
 # Test explain tree rendering for CoalesceBatchesExec with limit
 statement ok
 CREATE TABLE IF NOT EXISTS t1 (a INT) AS VALUES(1),(2),(3),(4),(5),(6),(7),(8),(9),(10);