feat(build): use prettyplease to format output (#890) (#904)

tonic-build/src/prost.rs

@@ -22,8 +22,6 @@ pub fn configure() -> Builder {
         client_attributes: Attributes::default(),
         proto_path: "super".to_string(),
         compile_well_known_types: false,
-        #[cfg(feature = "rustfmt")]
-        format: true,
         emit_package: true,
         protoc_args: Vec::new(),
         include_file: None,
@@ -184,7 +182,8 @@ impl prost_build::ServiceGenerator for ServiceGenerator {
                 #clients
             };
 
-            let code = format!("{}", client_service);
+            let ast: syn::File = syn::parse2(client_service).expect("not a valid tokenstream");
+            let code = prettyplease::unparse(&ast);
             buf.push_str(&code);
 
             self.clients = TokenStream::default();
@@ -197,7 +196,8 @@ impl prost_build::ServiceGenerator for ServiceGenerator {
                 #servers
             };
 
-            let code = format!("{}", server_service);
+            let ast: syn::File = syn::parse2(server_service).expect("not a valid tokenstream");
+            let code = prettyplease::unparse(&ast);
             buf.push_str(&code);
 
             self.servers = TokenStream::default();
@@ -223,8 +223,6 @@ pub struct Builder {
     pub(crate) include_file: Option<PathBuf>,
 
     out_dir: Option<PathBuf>,
-    #[cfg(feature = "rustfmt")]
-    format: bool,
 }
 
 impl Builder {
@@ -247,13 +245,6 @@ impl Builder {
         self
     }
 
-    /// Enable the output to be formated by rustfmt.
-    #[cfg(feature = "rustfmt")]
-    pub fn format(mut self, run: bool) -> Self {
-        self.format = run;
-        self
-    }
-
     /// Set the output directory to generate code to.
     ///
     /// Defaults to the `OUT_DIR` environment variable.
@@ -397,9 +388,6 @@ impl Builder {
             PathBuf::from(std::env::var("OUT_DIR").unwrap())
         };
 
-        #[cfg(feature = "rustfmt")]
-        let format = self.format;
-
         config.out_dir(out_dir.clone());
         if let Some(path) = self.file_descriptor_set_path.as_ref() {
             config.file_descriptor_set_path(path);
@@ -428,13 +416,6 @@ impl Builder {
 
         config.compile_protos(protos, includes)?;
 
-        #[cfg(feature = "rustfmt")]
-        {
-            if format {
-                super::fmt(out_dir.to_str().expect("Expected utf8 out_dir"));
-            }
-        }
-
         Ok(())
     }
 }