docs: update placement visibility (#11)

Updates the requirements on [syn](https://github.com/dtolnay/syn) to permit the latest version.
- [Release notes](https://github.com/dtolnay/syn/releases)
- [Commits](https://github.com/dtolnay/syn/compare/1.0.0...2.0.10)

---
updated-dependencies:
- dependency-name: syn
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/dependabot.yml

@@ -0,0 +1,6 @@
+version: 2
+updates:
+  - package-ecosystem: cargo
+    directory: /
+    schedule:
+      interval: weekly

Cargo.toml

@@ -1,24 +1,23 @@
 [package]
 name = "serde-inline-default"
-version = "0.1.1"
-authors = ["ByteDream"]
+version = "0.2.3"
+authors = ["bytedream"]
 edition = "2021"
 description = "Serde default values via inline declaration"
 readme = "README.md"
-repository = "https://github.com/ByteDream/serde-inline-default"
+repository = "https://github.com/bytedream/serde-inline-default"
 license = "MIT OR Apache-2.0"
 keywords = ["serde", "serialization"]
 categories = ["encoding"]
 
 [lib]
 proc-macro = true
-
 doctest = false
 
 [dependencies]
 proc-macro2 = "1.0"
 quote = "1.0"
-syn = { version = "1.0", features = ["full"] }
+syn = { version = "2.0", features = ["full"] }
 
 [dev-dependencies]
 serde = { version = "1.0", features = ["derive"] }

README.md

@@ -1,4 +1,4 @@
-# serde-inline-default [![ci](https://github.com/ByteDream/serde-inline-default/actions/workflows/ci.yml/badge.svg)](https://github.com/ByteDream/serde-inline-default/actions/workflows/ci.yml) [![crates.io](https://img.shields.io/crates/v/serde-inline-default)](https://crates.io/crates/serde-inline-default) [![docs](https://img.shields.io/docsrs/serde-inline-default)](https://docs.rs/serde-inline-default/latest/serde_inline_default/)
+# serde-inline-default [![ci](https://github.com/ByteDream/serde-inline-default/actions/workflows/ci.yml/badge.svg)](https://github.com/ByteDream/serde-inline-default/actions/workflows/ci.yml) [![crates.io](https://img.shields.io/crates/v/serde-inline-default)](https://crates.io/crates/serde-inline-default) [![crates.io downloads](https://img.shields.io/crates/d/serde-inline-default)](https://crates.io/crates/serde-inline-default) [![docs](https://img.shields.io/docsrs/serde-inline-default)](https://docs.rs/serde-inline-default/latest/serde_inline_default/)
 
 Tiny crate to set default values for serde fields via inline attribute declaration.
 
@@ -19,7 +19,7 @@ fn value_default() -> u32 { 42 }
 
 That can get quiet messy if you have many fields with many (different) default values.
 This crate tries to solve this issue by providing the `#[serde_inline_default]` proc macro.
-With this macro set at the struct level (_before `#[derive(Deserialize)]`/`#[derive(Serialize)]`!_, otherwise it's not working correctly), you can set default values via `#[serde_inline_default(...)]` for your serde fields inline, without creating an extra function.
+With this macro set at the struct level, you can set default values via `#[serde_inline_default(...)]` for your serde fields inline, without creating an extra function.
 
 ```rust
 #[serde_inline_default]
@@ -30,9 +30,54 @@ struct Test {
 }
 ```
 
+> [!IMPORTANT]
+> **`#[serde_inline_default]` must be set before `#[derive(Deserialize)]`/`#[derive(Serialize)]`, otherwise it's not working correctly!**
+
 Internally, `#[serde_inline_default(...)]` gets expanded to a function which returns the set value and the attribute is replaced with `#[serde(default = "<function name>")]`.
 So this macro is just some syntax sugar for you, but can get quiet handy if you want to keep your code clean or write declarative macros / `macro_rules!`.
 
+## Alternatives
+
+This crate isn't perfect. Thus, you might be more satisfied with alternatives `serde` provides.
+
+With `#[serde(default)]` + `impl Default` on a struct, `serde` uses the default implementation of the struct to get default values for each field ([docs](https://serde.rs/container-attrs.html#default)):
+```rust
+#[derive(Deserialize)]
+#[serde(default)]
+struct Test {
+    value: u32
+}
+
+impl Default for Test {
+    fn default() -> Self {
+        Self {
+            value: 42
+        }
+    }
+}
+```
+
+If you still need/want `serde-inline-default` features, you also can combine them with `#[serde(default))` and `impl Default`:
+```rust
+#[serde_inline_default]
+#[derive(Deserialize)]
+#[serde(default)]
+struct Test {
+    value: u32,
+    #[serde_inline_default(0)]
+    other_value: u32,
+}
+
+impl Default for Test {
+    fn default() -> Self {
+        Self {
+            value: 42,
+            other_value: 42
+        }
+    }
+}
+```
+
 ## License
 
 This project is licensed under either of the following licenses, at your option:

examples/basic.rs

@@ -0,0 +1,29 @@
+use serde::Deserialize;
+use serde_inline_default::serde_inline_default;
+use serde_json::json;
+
+#[serde_inline_default]
+#[derive(Deserialize)]
+struct Basic {
+    // if using `String` you have to call `.to_string()`
+    #[serde_inline_default("0.0.0.0".to_string())]
+    host: String,
+    // works without specifying the integer type at the end of the value (8080u16)
+    #[serde_inline_default(8080)]
+    port: u16,
+    // expressions are working too
+    #[serde_inline_default(serde_json::json!({}))]
+    random_third_party_type: serde_json::Value,
+}
+
+fn main() -> Result<(), serde_json::Error> {
+    // creating a empty json object to use the default value of all fields
+    let json_object = json!({});
+    let basic: Basic = serde_json::from_value(json_object)?;
+
+    assert_eq!(basic.host, "0.0.0.0".to_string());
+    assert_eq!(basic.port, 8080);
+    assert_eq!(basic.random_third_party_type, json!({}));
+
+    Ok(())
+}

examples/macro_rules.rs

@@ -0,0 +1,39 @@
+use serde_json::json;
+macro_rules! simple_macro {
+    (struct $name:ident { $($field:ident: $type:ty $(= $default:expr)?),*$(,)? }) => {
+        #[serde_inline_default::serde_inline_default]
+        #[derive(serde::Deserialize)]
+        struct $name {
+            $(
+                $(
+                    #[serde_inline_default($default)]
+                )?
+                $field: $type
+            ),*
+        }
+    }
+}
+
+fn main() -> Result<(), serde_json::Error> {
+    // `username` and `password` must be set when deserializing as no default value is defined for
+    // them. `secret` not as we're defining a default value for it
+    simple_macro! {
+        struct Example {
+            username: String,
+            password: String,
+            secret: String = "verysecretsecret".to_string()
+        }
+    }
+
+    let json_object = json!({
+        "username": "testuser",
+        "password": "testpassword"
+    });
+
+    let example: Example = serde_json::from_value(json_object)?;
+    assert_eq!(example.username, "testuser");
+    assert_eq!(example.password, "testpassword");
+    assert_eq!(example.secret, "verysecretsecret");
+
+    Ok(())
+}

src/expand.rs

@@ -1,40 +1,34 @@
+use crate::utils::type_lifetimes_to_static;
 use proc_macro2::{Ident, Span, TokenStream};
 use quote::quote;
 use syn::{parse_quote, ItemStruct};
 
 pub(crate) fn expand_struct(mut item: ItemStruct) -> proc_macro::TokenStream {
-    let mut inline_fns: Vec<(String, TokenStream, TokenStream)> = vec![];
+    let mut inline_fns: Vec<TokenStream> = vec![];
 
     for (i, field) in item.fields.iter_mut().enumerate() {
         for (j, attr) in field.attrs.iter_mut().enumerate() {
-            if !attr.path.is_ident("serde_inline_default") {
+            if !attr.path().is_ident("serde_inline_default") {
                 continue;
             }
 
-            let _default_str = attr.tokens.to_string();
-            let default: TokenStream = _default_str[1.._default_str.len() - 1].parse().unwrap();
+            let default: TokenStream = attr.parse_args().unwrap();
 
-            // we check here if a function with the exact same return value already exists. if so,
-            // this function gets used.
-            let fn_name_lit = if let Some((fn_name_lit, _, _)) = inline_fns
-                .iter()
-                .find(|(_, def, _)| def.to_string() == default.to_string())
-            {
-                fn_name_lit.clone()
-            } else {
-                let fn_name_lit = format!("__serde_inline_default_{}_{}", item.ident, i);
-                let fn_name_ident = Ident::new(&fn_name_lit, Span::call_site());
-                let return_type = &field.ty;
+            let fn_name_lit = format!("__serde_inline_default_{}_{}", item.ident, i);
+            let fn_name_ident = Ident::new(&fn_name_lit, Span::call_site());
+            let mut return_type = field.ty.clone();
+
+            // replaces most lifetimes with 'static
+            type_lifetimes_to_static(&mut return_type);
+
+            inline_fns.push(quote! {
+                #[doc(hidden)]
+                #[allow(non_snake_case)]
+                fn #fn_name_ident () -> #return_type {
+                    #default
+                }
+            });
 
-                let inline_fn = quote! {
-                    #[doc(hidden)]
-                    fn #fn_name_ident () -> #return_type {
-                        #default
-                    }
-                };
-                inline_fns.push((fn_name_lit.clone(), default, inline_fn));
-                fn_name_lit
-            };
             field.attrs.remove(j);
             field
                 .attrs
@@ -43,10 +37,8 @@ pub(crate) fn expand_struct(mut item: ItemStruct) -> proc_macro::TokenStream {
         }
     }
 
-    let real_inline_fns: Vec<TokenStream> =
-        inline_fns.into_iter().map(|(_, _, func)| func).collect();
     let expanded = quote! {
-        #( #real_inline_fns )*
+        #( #inline_fns )*
 
         #item
     };

src/lib.rs

@@ -4,6 +4,7 @@ use proc_macro::TokenStream;
 use syn::{parse_macro_input, Item};
 
 mod expand;
+mod utils;
 
 /// The main macro of this crate.
 /// Use it to define default values of fields in structs you [`Serialize`] or [`Deserialize`].

src/utils.rs

@@ -0,0 +1,40 @@
+use syn::{parse_quote, GenericArgument, PathArguments, Type};
+
+pub(crate) fn type_lifetimes_to_static(ty: &mut Type) {
+    match ty {
+        Type::Array(array) => type_lifetimes_to_static(array.elem.as_mut()),
+        Type::Group(group) => type_lifetimes_to_static(&mut group.elem),
+        Type::Path(path) => {
+            for segment in &mut path.path.segments {
+                match &mut segment.arguments {
+                    PathArguments::None => (),
+                    PathArguments::AngleBracketed(angle_bracketed) => {
+                        for arg in &mut angle_bracketed.args {
+                            match arg {
+                                GenericArgument::Lifetime(lifetime) => {
+                                    *lifetime = parse_quote!('static);
+                                }
+                                GenericArgument::Type(ty) => type_lifetimes_to_static(ty),
+                                _ => (),
+                            }
+                        }
+                    }
+                    PathArguments::Parenthesized(parenthesized) => {
+                        for input in &mut parenthesized.inputs {
+                            type_lifetimes_to_static(input)
+                        }
+                    }
+                }
+            }
+        }
+        Type::Ptr(ptr) => type_lifetimes_to_static(&mut ptr.elem),
+        Type::Reference(reference) => reference.lifetime = Some(parse_quote!('static)),
+        Type::Slice(slice) => type_lifetimes_to_static(&mut slice.elem),
+        Type::Tuple(tuple) => {
+            for elem in &mut tuple.elems {
+                type_lifetimes_to_static(elem)
+            }
+        }
+        _ => (),
+    }
+}

tests/test_serde_inline_default.rs

@@ -1,6 +1,7 @@
 use serde::Deserialize;
 use serde_inline_default::serde_inline_default;
 use serde_json::json;
+use std::borrow::Cow;
 
 #[test]
 fn test_serde_inline_default() {
@@ -17,6 +18,8 @@ fn test_serde_inline_default() {
         inline: u32,
         #[serde_inline_default(-1337)]
         inline_negative: i32,
+        #[serde_inline_default("string".to_string())]
+        string: String,
     }
 
     let test: Test = serde_json::from_value(json!({})).unwrap();
@@ -24,4 +27,19 @@ fn test_serde_inline_default() {
     assert_eq!(test.native, 69);
     assert_eq!(test.inline, 420);
     assert_eq!(test.inline_negative, -1337);
+    assert_eq!(test.string, "string".to_string());
+}
+
+#[test]
+fn test_lifetime() {
+    #[serde_inline_default]
+    #[derive(Deserialize)]
+    struct LifetimeTest<'a> {
+        #[serde_inline_default("test".into())]
+        test_str: Cow<'a, str>,
+    }
+
+    let lifetime_test: LifetimeTest = serde_json::from_value(json!({})).unwrap();
+
+    assert_eq!(lifetime_test.test_str, "test");
 }