fix(quick-xml): Fixed sequence-based text values (enums) not being supported in attributes. (#114)

* Add inline attribute declaration tests.

* Identified issue with enum values of attributes for xmlity-quick-xml.

* Fixed.

* `cargo clippy`

Author: lukasfri

xmlity-quick-xml/src/de.rs

@@ -355,13 +355,15 @@ impl<'de> de::AttributeAccess<'de> for AttributeAccess<'_, 'de> {
         T::deserialize(TextDeserializer {
             value: self.value,
             deserializer: self.deserializer,
+            used_up: false,
         })
     }
 }
 
 struct TextDeserializer<'a, 'v> {
     value: Cow<'v, [u8]>,
     deserializer: &'a Deserializer<'a>,
+    used_up: bool,
 }
 
 impl<'de> de::XmlText<'de> for TextDeserializer<'_, 'de> {
@@ -394,6 +396,61 @@ impl<'de> de::XmlText<'de> for TextDeserializer<'_, 'de> {
     }
 }
 
+impl<'de> de::SeqAccess<'de> for TextDeserializer<'_, 'de> {
+    type Error = Error;
+
+    type SubAccess<'g>
+        = TextDeserializer<'g, 'de>
+    where
+        Self: 'g;
+
+    fn next_element<T>(&mut self) -> Result<Option<T>, Self::Error>
+    where
+        T: Deserialize<'de>,
+    {
+        if self.used_up {
+            return Ok(None);
+        }
+
+        T::deserialize(TextDeserializer {
+            value: self.value.clone(),
+            deserializer: self.deserializer,
+            used_up: false,
+        })
+        .map(|value| {
+            self.used_up = true;
+            Some(value)
+        })
+    }
+
+    fn next_element_seq<T>(&mut self) -> Result<Option<T>, Self::Error>
+    where
+        T: Deserialize<'de>,
+    {
+        if self.used_up {
+            return Ok(None);
+        }
+
+        T::deserialize_seq(TextDeserializer {
+            value: self.value.clone(),
+            deserializer: self.deserializer,
+            used_up: false,
+        })
+        .map(|value| {
+            self.used_up = true;
+            Some(value)
+        })
+    }
+
+    fn sub_access(&mut self) -> Result<Self::SubAccess<'_>, Self::Error> {
+        Ok(TextDeserializer {
+            value: self.value.clone(),
+            deserializer: self.deserializer,
+            used_up: self.used_up,
+        })
+    }
+}
+
 impl<'de> de::Deserializer<'de> for TextDeserializer<'_, 'de> {
     type Error = Error;
 
@@ -408,7 +465,7 @@ impl<'de> de::Deserializer<'de> for TextDeserializer<'_, 'de> {
     where
         V: Visitor<'de>,
     {
-        visitor.visit_text(self)
+        visitor.visit_seq(self)
     }
 }
 

xmlity-quick-xml/src/ser.rs

@@ -348,19 +348,49 @@ pub struct AttributeSerializer<'t, W: Write> {
 
 /// The text serializer for the `quick-xml` crate. Used when serializing to an attribute value.
 pub struct TextSerializer {
-    value: Vec<u8>,
+    value: Option<String>,
 }
 
-impl ser::Serializer for &mut TextSerializer {
+impl ser::SerializeSeq for &mut TextSerializer {
+    type Ok = ();
+    type Error = Error;
+
+    fn serialize_element<V: Serialize>(&mut self, value: &V) -> Result<Self::Ok, Self::Error> {
+        if self.value.is_some() {
+            return Err(Error::unexpected_serialize(Unexpected::Text));
+        }
+
+        let mut text_ser = TextSerializer { value: None };
+        value.serialize(&mut text_ser)?;
+
+        if let Some(value) = text_ser.value {
+            self.value = Some(value);
+        } else {
+            return Err(Error::unexpected_serialize(Unexpected::None));
+        }
+
+        Ok(())
+    }
+
+    fn end(self) -> Result<Self::Ok, Self::Error> {
+        Ok(())
+    }
+}
+
+impl<'a> ser::Serializer for &'a mut TextSerializer {
     type Ok = ();
     type Error = Error;
 
     type SerializeElement = NoopDeSerializer<Self::Ok, Self::Error>;
 
-    type SerializeSeq = NoopDeSerializer<Self::Ok, Self::Error>;
+    type SerializeSeq = &'a mut TextSerializer;
 
     fn serialize_text<S: AsRef<str>>(self, text: S) -> Result<Self::Ok, Self::Error> {
-        self.value.extend_from_slice(text.as_ref().as_bytes());
+        if self.value.is_some() {
+            return Err(Error::unexpected_serialize(Unexpected::Text));
+        }
+
+        self.value = Some(text.as_ref().to_string());
 
         Ok(())
     }
@@ -381,7 +411,7 @@ impl ser::Serializer for &mut TextSerializer {
     }
 
     fn serialize_seq(self) -> Result<Self::SerializeSeq, Self::Error> {
-        Err(Error::unexpected_serialize(Unexpected::Seq))
+        Ok(self)
     }
 
     fn serialize_decl<S: AsRef<str>>(
@@ -447,11 +477,17 @@ impl<W: Write> ser::SerializeAttributeAccess for AttributeSerializer<'_, W> {
             self.serializer.push_decl_attr(decl);
         }
 
-        let mut text_ser = TextSerializer { value: Vec::new() };
+        let mut text_ser = TextSerializer { value: None };
 
         value.serialize(&mut text_ser)?;
 
-        self.serializer.push_attr(qname, text_ser.value);
+        self.serializer.push_attr(
+            qname,
+            text_ser
+                .value
+                .expect("TextSerializer should have a value")
+                .into_bytes(),
+        );
 
         Ok(())
     }

xmlity-quick-xml/tests/elements/inline_attribute_declarations.rs

@@ -2,21 +2,39 @@ use crate::define_test;
 
 use xmlity::{Deserialize, Serialize};
 
+fn f_serialize<T: xmlity::Serializer>(f: &F, serializer: T) -> Result<T::Ok, T::Error> {
+    serializer.serialize_text(&f.0)
+}
+
+fn f_deserialize<'de, T: xmlity::Deserializer<'de>>(deserializer: T) -> Result<F, T::Error> {
+    let s = String::deserialize(deserializer)?;
+    Ok(F(s))
+}
+
+#[derive(Debug, PartialEq, Serialize, Deserialize)]
+#[xvalue(serialize_with = "f_serialize", deserialize_with = "f_deserialize")]
+struct F(pub String);
+
 #[derive(Debug, PartialEq, Serialize, Deserialize)]
 #[xelement(name = "c")]
-pub struct C {
+struct C {
     #[xattribute(name = "b")]
-    pub c: String,
+    pub c: F,
 }
 
 define_test!(
     element_with_single_child,
-    [(C { c: "A".to_string() }, r#"<c b="A"/>"#)]
+    [(
+        C {
+            c: F("A".to_string())
+        },
+        r#"<c b="A"/>"#
+    )]
 );
 
 #[derive(Debug, PartialEq, Serialize, Deserialize)]
 #[xelement(name = "d")]
-pub struct D {
+struct D {
     #[xattribute(name = "b")]
     pub b: String,
     pub c: C,
@@ -27,15 +45,17 @@ define_test!(
     [(
         D {
             b: "A".to_string(),
-            c: C { c: "B".to_string() }
+            c: C {
+                c: F("B".to_string())
+            }
         },
         r#"<d b="A"><c b="B"/></d>"#
     )]
 );
 
 #[derive(Debug, PartialEq, Serialize, Deserialize)]
 #[xelement(name = "e")]
-pub struct E {
+struct E {
     pub d: Vec<D>,
 }
 
@@ -46,14 +66,43 @@ define_test!(
             d: vec![
                 D {
                     b: "A".to_string(),
-                    c: C { c: "B".to_string() }
+                    c: C {
+                        c: F("B".to_string())
+                    }
                 },
                 D {
                     b: "C".to_string(),
-                    c: C { c: "D".to_string() }
+                    c: C {
+                        c: F("D".to_string())
+                    }
                 }
             ]
         },
         r#"<e><d b="A"><c b="B"/></d><d b="C"><c b="D"/></d></e>"#
     )]
 );
+
+#[derive(Debug, PartialEq, Serialize, Deserialize)]
+enum H {
+    F(F),
+}
+
+#[derive(Debug, PartialEq, Serialize, Deserialize)]
+#[xelement(name = "g")]
+struct G {
+    #[xattribute(name = "f", optional, default)]
+    pub f: Option<H>,
+}
+
+define_test!(
+    element_with_optional_attribute_of_enum,
+    [
+        (
+            G {
+                f: Some(H::F(F("A".to_string())))
+            },
+            r#"<g f="A"/>"#
+        ),
+        (G { f: None }, r#"<g/>"#)
+    ]
+);