From 4643b0a0d5fc921d1892914c0b5f7dc1e5fd7202 Mon Sep 17 00:00:00 2001
From: Keith Lee <leekeiabstraction@gmail.com>
Date: Mon, 29 Dec 2025 11:50:47 +0000
Subject: [PATCH] Error when using currently unimplemented non default ZSTD
 compression level

---
 .../src/compression/arrow_compression.rs      | 31 ++++++++++++++-----
 1 file changed, 24 insertions(+), 7 deletions(-)

diff --git a/crates/fluss/src/compression/arrow_compression.rs b/crates/fluss/src/compression/arrow_compression.rs
index 32dfadb..776a4c2 100644
--- a/crates/fluss/src/compression/arrow_compression.rs
+++ b/crates/fluss/src/compression/arrow_compression.rs
@@ -81,11 +81,20 @@ impl ArrowCompressionInfo {
                     e
                 ),
             }),
-
-            Some(Ok(level)) => Ok(Self {
-                compression_type,
-                compression_level: level,
-            }),
+            Some(Ok(level)) => {
+                // TODO Remove once non-default ZSTD compression level is implemented https://github.com/apache/fluss-rust/issues/109
+                if level != DEFAULT_ZSTD_COMPRESSION_LEVEL {
+                    return Err(Error::IoUnsupported {
+                        message: format!(
+                            "Rust client currently only implements default ZSTD compression level {DEFAULT_ZSTD_COMPRESSION_LEVEL}. Got: {level}"
+                        ),
+                    });
+                }
+                Ok(Self {
+                    compression_type,
+                    compression_level: level,
+                })
+            }
             None => Ok(Self {
                 compression_type,
                 compression_level: DEFAULT_ZSTD_COMPRESSION_LEVEL,
@@ -171,11 +180,19 @@ mod tests {
             "ZSTD",
         )]));
         assert_eq!(compression_info.unwrap().compression_level, 3);
-        let compression_info = ArrowCompressionInfo::from_conf(&mk_map(&[
+    }
+
+    // TODO Remove once non-default ZSTD compression level is implemented https://github.com/apache/fluss-rust/issues/109
+    #[test]
+    fn test_from_conf_zstd_compression_level_error_when_non_default() {
+        let result = ArrowCompressionInfo::from_conf(&mk_map(&[
             ("table.log.arrow.compression.type", "ZSTD"),
             ("table.log.arrow.compression.zstd.level", "1"),
         ]));
-        assert_eq!(compression_info.unwrap().compression_level, 1);
+        assert!(result.is_err());
+        assert!(result.unwrap_err().to_string().contains(
+            "Rust client currently only implements default ZSTD compression level 3. Got: 1."
+        ));
     }
 
     #[test]