Fix bug in SerdeDerive macro implementation

serde-diff-derive/src/serde_diff/mod.rs

@@ -332,6 +332,9 @@ fn generate(
  match (self, other) {
  #(#diff_match_arms)*
  }
+ if (__changed__) {
+ ctx.save_exit()?;
+ }
  Ok(__changed__)
  }
  }

src/difference.rs

@@ -148,6 +148,11 @@ impl<'a, S: SerializeSeq> DiffContext<'a, S> {
  self.save_command(&DiffCommandRef::Value(value), true, true)
  }
 
+ /// Write exit command
+ pub fn save_exit(&mut self) -> Result<(), S::Error> {
+ self.save_command::<()>(&DiffCommandRef::Exit, true, false)
+ }
+
  /// Stores an arbitrary DiffCommand to be handled by the type.
  /// Any custom sequence of DiffCommands must be followed by Exit.
  pub fn save_command<'b, T: Serialize>(

src/tests.rs

@@ -1,7 +1,9 @@
 use crate as serde_diff;
 use crate::{Apply, Diff, SerdeDiff};
 use serde::{Deserialize, Serialize};
+use std::collections::HashMap;
 use std::fmt::Debug;
+use std::iter::FromIterator;
 
 #[derive(SerdeDiff, Serialize, Deserialize, PartialEq, Debug, Copy, Clone)]
 struct TestStruct {
@@ -15,6 +17,9 @@ fn roundtrip<T: SerdeDiff + Serialize + for<'a> Deserialize<'a> + PartialEq + De
 ) {
  let diff = Diff::serializable(&old, &new);
  let json_diff = serde_json::to_string(&diff).unwrap();
+
+ println!("{}", json_diff);
+
  let mut deserializer = serde_json::Deserializer::from_str(&json_diff);
  let mut target = old.clone();
  Apply::apply(&mut deserializer, &mut target).unwrap();
@@ -59,6 +64,18 @@ fn test_option() {
  Some(TestStruct { a: 52, b: 32. }),
  Some(TestStruct { a: 42, b: 12. }),
  );
+ roundtrip(
+ HashMap::from_iter([
+ (1, TestStruct { a: 1, b: 1. }),
+ (2, TestStruct { a: 2, b: 2. }),
+ (3, TestStruct { a: 3, b: 3. }),
+ ]),
+ HashMap::from_iter([
+ (1, TestStruct { a: 1, b: 1. }),
+ (3, TestStruct { a: 4, b: 4. }),
+ (4, TestStruct { a: 1, b: 1. }),
+ ]),
+ );
 
  partial(
  Some(TestStruct { a: 5, b: 2. }),