errors: lower enum size from 120 bytes to 80 (#561)

baloo · web-flow · commit 490fc229382b · 2025-05-27T17:38:58.000+02:00
This lowers the size of the Error enum from 120 bytes to 80 bytes to steer away from the limit checked by clippy (128 bytes): <https://rust-lang.github.io/rust-clippy/master/index.html#result_large_err> Fixes #558
diff --git a/src/errors.rs b/src/errors.rs
@@ -36,7 +36,8 @@ pub enum Error {
     PacketTooLarge { size: u64 },
     #[snafu(transparent)]
     RSAError {
-        source: rsa::errors::Error,
+        #[snafu(source(from(rsa::errors::Error, Box::new)))]
+        source: Box<rsa::errors::Error>,
         backtrace: Option<Backtrace>,
     },
     #[snafu(transparent)]
@@ -118,13 +119,13 @@ pub enum Error {
     AesKek { source: aes_kw::Error },
     #[snafu(transparent)]
     PacketParsing {
-        #[snafu(backtrace)]
-        source: ParsingError,
+        #[snafu(backtrace, source(from(ParsingError, Box::new)))]
+        source: Box<ParsingError>,
     },
     #[snafu(display("packet is incomplete"))]
     PacketIncomplete {
         #[snafu(backtrace)]
-        source: ParsingError,
+        source: Box<ParsingError>,
     },
     #[snafu(transparent)]
     Argon2 {
@@ -293,3 +294,21 @@ pub(crate) use err_opt;
 pub(crate) use format_err;
 pub(crate) use unimplemented_err;
 pub(crate) use unsupported_err;
+
+#[cfg(test)]
+mod tests {
+    /// Check the size of the error enum
+    ///
+    /// Because clippy will start throwing warning if an enum gets above 128, we'd like to keep the
+    /// size of the `Error` enum lower than that limit with some headroom to be wrapped by a
+    /// downstream crate.
+    ///
+    /// If this test triggers, you should consider Box'ing the offending member.
+    ///
+    /// See: <https://rust-lang.github.io/rust-clippy/master/index.html#result_large_err>
+    #[cfg(target_pointer_width = "64")]
+    #[test]
+    fn size_of_error() {
+        assert_eq!(core::mem::size_of::<super::Error>(), 80);
+    }
+}
diff --git a/src/packet/single.rs b/src/packet/single.rs
@@ -111,7 +111,7 @@ impl Packet {
                 if source.kind() == std::io::ErrorKind::UnexpectedEof =>
             {
                 Err(Error::PacketIncomplete {
-                    source: crate::parsing::Error::UnexpectedEof { source, backtrace },
+                    source: Box::new(crate::parsing::Error::UnexpectedEof { source, backtrace }),
                 })
             }
             Err(err) => {

Original file line number	Diff line number	Diff line change
`@@ -111,7 +111,7 @@ impl Packet {`
`111`	`111`	`if source.kind() == std::io::ErrorKind::UnexpectedEof =>`
`112`	`112`	`{`
`113`	`113`	`Err(Error::PacketIncomplete {`
`114`		`- source: crate::parsing::Error::UnexpectedEof { source, backtrace },`
	`114`	`+ source: Box::new(crate::parsing::Error::UnexpectedEof { source, backtrace }),`
`115`	`115`	`})`
`116`	`116`	`}`
`117`	`117`	`Err(err) => {`