refactor: Remove Compatible error

`Compatible` error is added in 0.9.41 to accept two types of error
returned from meta-service: `KVAppError` and `MetaAPIError`.

Such compatible layer can be removed since meta-client's min compatible
meta-service version has already increased to a newer version which does
not send `KVAppError` any more.

src/meta/api/src/lib.rs

@@ -22,7 +22,6 @@ mod background_api;
 mod background_api_impl;
 mod background_api_keys;
 mod background_api_test_suite;
-pub mod compat_errors;
 mod data_mask_api;
 mod data_mask_api_impl;
 mod data_mask_api_keys;

src/meta/api/src/reply.rs

@@ -15,63 +15,34 @@
 use databend_common_meta_types::protobuf::RaftReply;
 use databend_common_meta_types::InvalidReply;
 use databend_common_meta_types::MetaAPIError;
-use databend_common_meta_types::MetaError;
-use databend_common_meta_types::MetaNetworkError;
 use databend_common_meta_types::TxnOpResponse;
 use databend_common_meta_types::TxnReply;
 use serde::de::DeserializeOwned;
 
-use crate::compat_errors::Compatible;
-use crate::kv_app_error::KVAppError;
-
-/// Compatible layer:
-/// Convert either KVAppError or MetaAPIError to MetaAPIError
 pub fn reply_to_api_result<T>(msg: RaftReply) -> Result<T, MetaAPIError>
 where T: DeserializeOwned {
     if !msg.data.is_empty() {
         let res: T = serde_json::from_str(&msg.data)
             .map_err(|e| InvalidReply::new("can not decode RaftReply.data", &e))?;
         Ok(res)
     } else {
-        let err: Compatible<KVAppError, MetaAPIError> = serde_json::from_str(&msg.error)
+        let err: MetaAPIError = serde_json::from_str(&msg.error)
             .map_err(|e| InvalidReply::new("can not decode RaftReply.error", &e))?;
 
-        let err = err.into_inner();
         Err(err)
     }
 }
 
-/// Compatible layer:
-/// Convert either KVAppError or MetaError to MetaError
-pub fn reply_to_meta_result<T>(raft_reply: RaftReply) -> Result<T, MetaError>
-where T: DeserializeOwned {
-    if !raft_reply.data.is_empty() {
-        let res: T = serde_json::from_str(&raft_reply.data)
-            .map_err(|e| InvalidReply::new("can not decode RaftReply.data", &e))?;
-        Ok(res)
-    } else {
-        let err: Compatible<KVAppError, MetaError> = serde_json::from_str(&raft_reply.error)
-            .map_err(|e| InvalidReply::new("can not decode RaftReply.error", &e))?;
-
-        let err = err.into_inner();
-
-        Err(err)
-    }
-}
-
-/// Compatible layer:
 /// Convert txn response to `success` and a series of `TxnOpResponse`.
 pub fn txn_reply_to_api_result(
     txn_reply: TxnReply,
 ) -> Result<(bool, Vec<TxnOpResponse>), MetaAPIError> {
     if txn_reply.error.is_empty() {
         Ok((txn_reply.success, txn_reply.responses))
     } else {
-        let err: Compatible<KVAppError, MetaAPIError> = serde_json::from_str(&txn_reply.error)
-            .map_err(|e| {
-                MetaNetworkError::InvalidReply(InvalidReply::new("invalid TxnReply.error", &e))
-            })?;
-        let err = err.into_inner();
+        let err: MetaAPIError = serde_json::from_str(&txn_reply.error)
+            .map_err(|e| InvalidReply::new("invalid TxnReply.error", &e))?;
+
         Err(err)
     }
 }

src/meta/client/src/lib.rs

@@ -25,7 +25,6 @@ mod message;
 use std::sync::LazyLock;
 
 pub use databend_common_meta_api::reply::reply_to_api_result;
-pub use databend_common_meta_api::reply::reply_to_meta_result;
 pub use grpc_action::MetaGrpcReadReq;
 pub use grpc_action::MetaGrpcReq;
 pub use grpc_action::RequestFor;
@@ -83,6 +82,9 @@ pub static METACLI_COMMIT_SEMVER: LazyLock<Version> = LazyLock::new(|| {
 /// - 2023-12-16: since 1.2.258:
 ///   Meta service: add: ttl to TxnPutRequest and Upsert
 ///
+/// - 2024-01-02: since TODO: fill version when merged.
+///   Meta client: remove `Compatible` for KVAppError and MetaAPIError, added in `2023-02-16: since 0.9.41`
+///
 /// Server feature set:
 /// ```yaml
 /// server_features: