Fix docs.rs (#3580)

* I think this will fix docs.rs but no idea how to test

* Generate to correct location

* Clippy

* Alphabetize

* Feature -> cfg

* New clippy is more demanding

datafusion/proto/Cargo.toml

@@ -28,6 +28,9 @@ keywords = ["arrow", "query", "sql"]
 edition = "2021"
 rust-version = "1.62"
 
+[package.metadata.docs.rs]
+rustc-args = ["--cfg", "docsrs"]
+
 [lib]
 name = "datafusion_proto"
 path = "src/lib.rs"

datafusion/proto/build.rs

@@ -28,12 +28,11 @@ fn main() -> Result<(), String> {
     Ok(())
 }
 
-#[cfg(feature = "json")]
 fn build() -> Result<(), String> {
     use std::io::Write;
 
     let out = std::path::PathBuf::from(
-        std::env::var("OUT_DIR").expect("Cannot find OUT_DIR environment vairable"),
+        std::env::var("OUT_DIR").expect("Cannot find OUT_DIR environment variable"),
     );
     let descriptor_path = out.join("proto_descriptor.bin");
 
@@ -44,9 +43,11 @@ fn build() -> Result<(), String> {
         .compile_protos(&["proto/datafusion.proto"], &["proto"])
         .map_err(|e| format!("protobuf compilation failed: {}", e))?;
 
+    #[cfg(feature = "json")]
     let descriptor_set = std::fs::read(&descriptor_path)
         .expect(&*format!("Cannot read {:?}", &descriptor_path));
 
+    #[cfg(feature = "json")]
     pbjson_build::Builder::new()
         .register_descriptors(&descriptor_set)
         .expect(&*format!(
@@ -58,22 +59,25 @@ fn build() -> Result<(), String> {
 
     // .serde.rs is not a valid package name, so append to datafusion.rs so we can treat it normally
     let proto = std::fs::read_to_string(out.join("datafusion.rs")).unwrap();
+
+    #[cfg(feature = "json")]
     let json = std::fs::read_to_string(out.join("datafusion.serde.rs")).unwrap();
+
+    #[cfg(feature = "docsrs")]
+    let path = out.join("datafusion.rs");
+    #[cfg(not(feature = "docsrs"))]
+    let path = "src/generated/datafusion.rs";
+
     let mut file = std::fs::OpenOptions::new()
         .write(true)
+        .truncate(true)
         .create(true)
-        .open("src/generated/datafusion_json.rs")
+        .open(path)
         .unwrap();
-    file.write(proto.as_str().as_ref()).unwrap();
-    file.write(json.as_str().as_ref()).unwrap();
+    file.write_all(proto.as_str().as_ref()).unwrap();
 
-    Ok(())
-}
+    #[cfg(feature = "json")]
+    file.write_all(json.as_str().as_ref()).unwrap();
 
-#[cfg(not(feature = "json"))]
-fn build() -> Result<(), String> {
-    prost_build::Config::new()
-        .out_dir("src/generated")
-        .compile_protos(&["proto/datafusion.proto"], &["proto"])
-        .map_err(|e| format!("protobuf compilation failed: {}", e))
+    Ok(())
 }

datafusion/proto/src/generated/mod.rs

@@ -15,13 +15,16 @@
 // specific language governing permissions and limitations
 // under the License.
 
-// include the generated protobuf source as a submodule
 #[allow(clippy::all)]
 #[rustfmt::skip]
-#[cfg(not(feature = "json"))]
+#[cfg(not(docsrs))]
 pub mod datafusion;
 
+#[cfg(docsrs)]
 #[allow(clippy::all)]
-#[rustfmt::skip]
-#[cfg(feature = "json")]
-pub mod datafusion_json;
+pub mod datafusion {
+    include!(concat!(env!("OUT_DIR"), "/datafusion.rs"));
+
+    #[cfg(feature = "json")]
+    include!(concat!(env!("OUT_DIR"), "/datafusion.serde.rs"));
+}

datafusion/proto/src/lib.rs

@@ -25,10 +25,7 @@ pub mod generated;
 pub mod logical_plan;
 pub mod to_proto;
 
-#[cfg(not(feature = "json"))]
 pub use generated::datafusion as protobuf;
-#[cfg(feature = "json")]
-pub use generated::datafusion_json as protobuf;
 
 #[cfg(doctest)]
 doc_comment::doctest!("../README.md", readme_example_test);