feat: added PartialEq to Cors (#486)

* added PartialEq to Cors

* added a changelog entry

* re-ran rustfmt

* removed a subtle bug in the new testcase

* removed a not so subtle bug in the new testcase

* ci: rm public-api-diff job

---------

Co-authored-by: Rob Ede <robjtede@icloud.com>

actix-cors/src/builder.rs

@@ -608,6 +608,19 @@ where
         .unwrap()
 }
 
+impl PartialEq for Cors {
+    fn eq(&self, other: &Self) -> bool {
+        self.inner == other.inner
+        // Because of the cors-function, checking if the content is equal implies that the errors are equal
+        //
+        // Proof by contradiction:
+        // Lets assume that the inner values are equal, but the error values are not.
+        // This means there had been an error, which has been fixed.
+        // This cannot happen as the first call to set the invalid value means that further usages of the cors-function will reject other input.
+        // => inner has to be in a different state
+    }
+}
+
 #[cfg(test)]
 mod test {
     use std::convert::Infallible;
@@ -679,4 +692,11 @@ mod test {
 
         Cors::default().new_transform(srv).await.unwrap();
     }
+
+    #[test]
+    fn impl_eq() {
+        assert_eq!(Cors::default(), Cors::default());
+        assert_ne!(Cors::default().send_wildcard(), Cors::default());
+        assert_ne!(Cors::default(), Cors::permissive());
+    }
 }

actix-cors/src/inner.rs

@@ -27,6 +27,12 @@ impl Default for OriginFn {
     }
 }
 
+impl PartialEq for OriginFn {
+    fn eq(&self, other: &Self) -> bool {
+        Rc::ptr_eq(&self.boxed_fn, &other.boxed_fn)
+    }
+}
+
 impl fmt::Debug for OriginFn {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.write_str("origin_fn")
@@ -40,7 +46,7 @@ pub(crate) fn header_value_try_into_method(hdr: &HeaderValue) -> Option<Method>
         .and_then(|meth| Method::try_from(meth).ok())
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
 pub(crate) struct Inner {
     pub(crate) allowed_origins: AllOrSome<HashSet<HeaderValue>>,
     pub(crate) allowed_origins_fns: SmallVec<[OriginFn; 4]>,