Place Config::format behind the format feature flag.

prost-build/Cargo.toml

@@ -33,6 +33,7 @@ tempfile = "3"
 once_cell = "1.17.1"
 regex = { version = "1.8.1", default-features = false, features = ["std", "unicode-bool"] }
 
+# feature: format
 prettyplease = { version = "0.2", optional = true }
 syn = { version = "2", features = ["full"], optional = true }
 

prost-build/src/config.rs

@@ -49,6 +49,7 @@ pub struct Config {
     pub(crate) skip_protoc_run: bool,
     pub(crate) include_file: Option<PathBuf>,
     pub(crate) prost_path: Option<String>,
+    #[cfg(feature = "format")]
     pub(crate) fmt: bool,
 }
 
@@ -735,10 +736,12 @@ impl Config {
         self
     }
 
+    // IMPROVEMENT: https://github.com/tokio-rs/prost/pull/1022/files#r1563818651
     /// Configures the code generator to format the output code via `prettyplease`.
     ///
     /// By default, this is enabled but if the `format` feature is not enabled this does
     /// nothing.
+    #[cfg(feature = "format")]
     pub fn format(&mut self, enabled: bool) -> &mut Self {
         self.fmt = enabled;
         self
@@ -1056,8 +1059,13 @@ impl Config {
             }
         }
 
+        #[cfg(feature = "format")]
         if self.fmt {
-            self.fmt_modules(&mut modules);
+            for buf in modules.values_mut() {
+                let file = syn::parse_file(buf).unwrap();
+                let formatted = prettyplease::unparse(&file);
+                *buf = formatted;
+            }
         }
 
         self.add_generated_modules(&mut modules);
@@ -1071,18 +1079,6 @@ impl Config {
             *buf = with_generated;
         }
     }
-
-    #[cfg(feature = "format")]
-    fn fmt_modules(&mut self, modules: &mut HashMap<Module, String>) {
-        for buf in modules.values_mut() {
-            let file = syn::parse_file(buf).unwrap();
-            let formatted = prettyplease::unparse(&file);
-            *buf = formatted;
-        }
-    }
-
-    #[cfg(not(feature = "format"))]
-    fn fmt_modules(&mut self, _: &mut HashMap<Module, String>) {}
 }
 
 impl default::Default for Config {
@@ -1110,6 +1106,7 @@ impl default::Default for Config {
             skip_protoc_run: false,
             include_file: None,
             prost_path: None,
+            #[cfg(feature = "format")]
             fmt: true,
         }
     }