Removed serde_derive dependency.

Cargo.toml

@@ -85,7 +85,7 @@ default = [
 ]
 merge_sort = ["itertools"]
 io_csv = ["csv", "lazy_static", "regex"]
-io_json = ["serde", "serde_derive", "serde_json", "indexmap"]
+io_json = ["serde", "serde_json", "indexmap"]
 io_ipc = ["flatbuffers"]
 io_ipc_compression = ["lz4", "zstd"]
 io_parquet_compression = [
@@ -95,7 +95,9 @@ io_parquet_compression = [
     "parquet2/lz4",
     "parquet2/brotli",
 ]
-io_json_integration = ["io_json", "hex"]
+# io_json: its dependencies + error handling
+# serde_derive: there is some derive around
+io_json_integration = ["io_json", "serde_derive", "hex"]
 io_print = ["comfy-table"]
 # the compute kernels. Disabling this significantly reduces compile time.
 compute = []

src/io/json/mod.rs

@@ -18,11 +18,9 @@
 //! Convert data between the Arrow memory format and JSON line-delimited records.
 
 mod read;
-mod schema;
 mod write;
 
 pub use read::*;
-pub use schema::*;
 pub use write::*;
 
 use crate::error::ArrowError;

src/io/json_integration/mod.rs

@@ -23,8 +23,9 @@ use serde_derive::{Deserialize, Serialize};
 use serde_json::{Map, Value};
 
 use crate::datatypes::*;
-use crate::io::json::ToJson;
 
+mod schema;
+use schema::ToJson;
 mod read;
 mod write;
 pub use read::to_record_batch;