[serde-ser] Fix incorrect field count handling in skip_field

Apparently the specified expected length does not include skipped fields. Fixes #41
Marcono1234 · Jan 30, 2024 · 456c193 · 456c193
1 parent 4dec779
commit 456c193
Show file tree

Hide file tree

Showing 2 changed files with 39 additions and 26 deletions.
diff --git a/src/serde/ser.rs b/src/serde/ser.rs
@@ -796,18 +796,6 @@ impl<W: JsonWriter> serde::ser::SerializeStruct for SerializeStruct<'_, '_, W> {
         value.serialize(&mut *self.ser)
     }
 
-    fn skip_field(&mut self, _key: &'static str) -> Result<(), Self::Error> {
-        if self.len >= self.expected_len {
-            return Err(SerializerError::IncorrectElementsCount {
-                expected: self.expected_len,
-                // + 1 for currently added field
-                actual: self.len + 1,
-            });
-        }
-        self.len += 1;
-        Ok(())
-    }
-
     fn end(self) -> Result<Self::Ok, Self::Error> {
         if self.len < self.expected_len {
             return Err(SerializerError::IncorrectElementsCount {
@@ -850,18 +838,6 @@ impl<W: JsonWriter> serde::ser::SerializeStructVariant for SerializeStructVarian
         value.serialize(&mut *self.ser)
     }
 
-    fn skip_field(&mut self, _key: &'static str) -> Result<(), Self::Error> {
-        if self.len >= self.expected_len {
-            return Err(SerializerError::IncorrectElementsCount {
-                expected: self.expected_len,
-                // + 1 for currently added field
-                actual: self.len + 1,
-            });
-        }
-        self.len += 1;
-        Ok(())
-    }
-
     fn end(self) -> Result<Self::Ok, Self::Error> {
         if self.len < self.expected_len {
             return Err(SerializerError::IncorrectElementsCount {
@@ -1739,7 +1715,7 @@ mod tests {
 
         assert_serialized_cmp!(
             |s| {
-                let mut struc = s.serialize_struct("name", 3)?;
+                let mut struc = s.serialize_struct("name", 2)?;
                 struc.serialize_field("key1", &1)?;
                 struc.skip_field("skipped")?;
                 struc.serialize_field("key2", &2)?;
@@ -1781,7 +1757,7 @@ mod tests {
 
         assert_serialized_cmp!(
             |s| {
-                let mut struc = s.serialize_struct_variant("name", 1, "variant", 3)?;
+                let mut struc = s.serialize_struct_variant("name", 1, "variant", 2)?;
                 struc.serialize_field("key1", &1)?;
                 struc.skip_field("skipped")?;
                 struc.serialize_field("key2", &2)?;

diff --git a/tests/serde_serialize_test.rs b/tests/serde_serialize_test.rs
@@ -145,3 +145,40 @@ fn serialize_unit_variant() {
 
     assert_serialized(E::A, "\"A\"");
 }
+
+#[test]
+fn serialize_skipped_field() {
+    #[derive(Serialize)]
+    struct S {
+        a: u32,
+        #[allow(dead_code)]
+        #[serde(skip)]
+        b: u32,
+    }
+
+    assert_serialized(S { a: 1, b: 2 }, r#"{"a":1}"#);
+}
+
+#[test]
+fn serialize_conditional_skipped_field() {
+    #[derive(Serialize)]
+    struct S {
+        a: u32,
+        #[serde(skip_serializing_if = "Option::is_none")]
+        b: Option<u32>,
+    }
+
+    assert_serialized(S { a: 1, b: Some(2) }, r#"{"a":1,"b":2}"#);
+    assert_serialized(S { a: 1, b: None }, r#"{"a":1}"#);
+
+    #[derive(Serialize)]
+    enum E {
+        S {
+            a: u32,
+            #[serde(skip_serializing_if = "Option::is_none")]
+            b: Option<u32>,
+        },
+    }
+    assert_serialized(E::S { a: 1, b: Some(2) }, r#"{"S":{"a":1,"b":2}}"#);
+    assert_serialized(E::S { a: 1, b: None }, r#"{"S":{"a":1}}"#);
+}