Option to disable skeleton formatting with rustfmt

libbpf-cargo/CHANGELOG.md

@@ -1,3 +1,10 @@
+Unreleased
+----------
+- Added ability to skip running `rustfmt` on the skeleton Rust source entirely
+  in `libbpf-cargo` by setting `rustfmt-path` to an empty string for the CLI or
+  passing an empty path to `SkeletonBuilder::rustfmt()`.
+
+
 0.27.2
 ------
 - Added `<arena-map>_data` skeleton members for accessing `__arena`

libbpf-cargo/src/gen/mod.rs

@@ -224,10 +224,14 @@ pub(crate) enum OutputDest<'a> {
 
 /// Try running `rustfmt` over `s` and return result.
 ///
-/// If no `rustfmt` binary could be found the content is left untouched, as
-/// it's only meant as a cosmetic brush up, without change of semantics.
+/// If no `rustfmt` binary could be found, or an empty path is supplied,
+/// the content is left untouched, as it's only meant as a cosmetic brush up,
+/// without change of semantics.
 fn try_rustfmt<'code>(s: &'code str, rustfmt_path: Option<&Path>) -> Result<Cow<'code, [u8]>> {
     let result = if let Some(r) = rustfmt_path {
+        if r.as_os_str().is_empty() {
+            return Ok(Cow::Borrowed(s.as_bytes()));
+        }
         Command::new(r)
     } else {
         Command::new("rustfmt")

libbpf-cargo/src/lib.rs

@@ -180,9 +180,10 @@ impl SkeletonBuilder {
         self
     }
 
-    /// Specify which `rustfmt` binary to use
+    /// Specify which `rustfmt` binary to use.
     ///
-    /// Default searches `$PATH` for `rustfmt`
+    /// Default searches `$PATH` for `rustfmt`.
+    /// To skip formatting, an empty path can be supplied.
     pub fn rustfmt<P: AsRef<Path>>(&mut self, rustfmt: P) -> &mut Self {
         self.rustfmt = rustfmt.as_ref().to_path_buf();
         self

libbpf-cargo/src/main.rs

@@ -78,7 +78,8 @@ enum Command {
         /// Path to top level Cargo.toml
         manifest_path: Option<PathBuf>,
         #[arg(long, value_parser)]
-        /// Path to rustfmt binary
+        /// Path to rustfmt binary.
+        /// If set to an empty path, formatting will be skipped.
         rustfmt_path: Option<PathBuf>,
         #[arg(long, value_parser)]
         /// Generate skeleton for the specified object file and print results to stdout