From 0139d63f6dae7128af4a3f25c347b4568096e5d2 Mon Sep 17 00:00:00 2001
From: olvyko <olvyko@gmail.com>
Date: Thu, 29 Apr 2021 21:39:47 +0600
Subject: [PATCH 1/2] Alter yaserde_derive crate to support skip_serialize_if
 for attributes

---
 yaserde_derive/src/common/field.rs | 9 +++++++--
 yaserde_derive/src/lib.rs          | 4 ++--
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/yaserde_derive/src/common/field.rs b/yaserde_derive/src/common/field.rs
index 9cdb65e..35a8850 100644
--- a/yaserde_derive/src/common/field.rs
+++ b/yaserde_derive/src/common/field.rs
@@ -145,13 +145,18 @@ impl YaSerdeField {
       .map(|builder| quote!(let yaserde_inner = #builder;))
       .unwrap_or_default();
 
+    let skip_if = self
+      .get_skip_serializing_if_function()
+      .map(|skip_if_function| quote!(!self.#skip_if_function(&self.#label)))
+      .unwrap_or(quote!(true));
+
     self
       .get_default_function()
       .map(|default_function| {
         quote! {
           #yaserde_inner_definition
           let struct_start_event =
-            if self.#label != #default_function() {
+            if #skip_if && self.#label != #default_function() {
               #setter
             } else {
               struct_start_event
@@ -160,7 +165,7 @@ impl YaSerdeField {
       })
       .unwrap_or(quote! {
         #yaserde_inner_definition
-        let struct_start_event = #setter;
+        let struct_start_event = if #skip_if { #setter } else { struct_start_event };
       })
   }
 }
diff --git a/yaserde_derive/src/lib.rs b/yaserde_derive/src/lib.rs
index f09ab20..9d881a1 100644
--- a/yaserde_derive/src/lib.rs
+++ b/yaserde_derive/src/lib.rs
@@ -14,7 +14,7 @@ pub fn derive_deserialize(input: TokenStream) -> TokenStream {
   let ast = syn::parse(input).unwrap();
   match de::expand_derive_deserialize(&ast) {
     Ok(expanded) => expanded.into(),
-    Err(msg) => panic!(msg),
+    Err(msg) => panic!("{}", msg),
   }
 }
 
@@ -23,6 +23,6 @@ pub fn derive_serialize(input: TokenStream) -> TokenStream {
   let ast = syn::parse(input).unwrap();
   match ser::expand_derive_serialize(&ast) {
     Ok(expanded) => expanded.into(),
-    Err(msg) => panic!(msg),
+    Err(msg) => panic!("{}", msg),
   }
 }

From cb25872cde2af5645c79e61b28b9f90d4bbab6fb Mon Sep 17 00:00:00 2001
From: olvyko <olvyko@gmail.com>
Date: Thu, 29 Apr 2021 22:10:52 +0600
Subject: [PATCH 2/2] Add test for attribute with skip_serialize_if

---
 yaserde/tests/skip_if.rs | 57 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/yaserde/tests/skip_if.rs b/yaserde/tests/skip_if.rs
index a485a8f..6bb7910 100644
--- a/yaserde/tests/skip_if.rs
+++ b/yaserde/tests/skip_if.rs
@@ -62,3 +62,60 @@ fn skip_serializing_if_for_struct() {
   let content = "<base />";
   serialize_and_validate!(model, content);
 }
+
+#[test]
+fn skip_serializing_if_for_struct_attributes() {
+  init();
+
+  fn default_string_function() -> String {
+    "mask_default".to_string()
+  }
+
+  #[derive(YaSerialize, PartialEq, Debug)]
+  #[yaserde(rename = "base")]
+  pub struct XmlStruct {
+    #[yaserde(
+      attribute,
+      skip_serializing_if = "check_string_function",
+      default = "default_string_function"
+    )]
+    string_with_default_item: String,
+    #[yaserde(attribute, skip_serializing_if = "check_string_function")]
+    string_item: String,
+    #[yaserde(attribute, skip_serializing_if = "check_bool_function")]
+    bool_item: bool,
+    #[yaserde(attribute, skip_serializing_if = "check_f32_function")]
+    f32_item: f32,
+    #[yaserde(attribute, skip_serializing_if = "check_option_string_function")]
+    option_string_item: Option<String>,
+  }
+
+  impl XmlStruct {
+    fn check_string_function(&self, value: &str) -> bool {
+      value == "something"
+    }
+
+    fn check_option_string_function(&self, value: &Option<String>) -> bool {
+      value == &Some("something".to_string())
+    }
+
+    fn check_bool_function(&self, value: &bool) -> bool {
+      value == &true
+    }
+
+    fn check_f32_function(&self, value: &f32) -> bool {
+      (value - 0.0).abs() < std::f32::EPSILON
+    }
+  }
+
+  let model = XmlStruct {
+    string_with_default_item: "mask_default".to_string(),
+    string_item: "something".to_string(),
+    bool_item: true,
+    f32_item: 0.0,
+    option_string_item: Some("something".to_string()),
+  };
+
+  let content = "<base />";
+  serialize_and_validate!(model, content);
+}