Allow relative assets in rust > 1.88 (#4658)

* Allow relative assets in rust > 1.88 and assets outside of the crate in
binary crates

* undo changes to assets outside of the crate

* don't use relative assets in examples

Cargo.lock

@@ -12744,9 +12744,9 @@ checksum = "dc375e1527247fe1a97d8b7156678dfe7c1af2fc075c9a4db3690ecd2a148068"
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.95"
+version = "1.0.101"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "02b3e5e68a3a1a02aad3ec490a98007cbc13c37cbe84a3cd7b8e406d76e7f778"
+checksum = "89ae43fd86e4158d6db51ad8e2b80f313af9cc74f5c0e03ccb87de09998732de"
 dependencies = [
  "unicode-ident",
 ]
@@ -13958,9 +13958,9 @@ dependencies = [
 
 [[package]]
 name = "rustversion"
-version = "1.0.21"
+version = "1.0.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8a0d197bd2c9dc6e53b84da9556a69ba4cdfab8619eb41a8bd1cc2027a0f6b1d"
+checksum = "b39cdef0fa800fc44525c84ccb54a029961a8215f9619753635a9c0d2538d46d"
 
 [[package]]
 name = "rustybuzz"

Cargo.toml

@@ -276,7 +276,7 @@ serde_json = "1.0.140"
 serde = "1.0.219"
 syn = "2.0"
 quote = "1.0"
-proc-macro2 = "1.0"
+proc-macro2 = "1.0.101"
 axum_session = "0.16.0"
 axum_session_auth = "0.16.0"
 axum_session_sqlx = "0.5.0"

examples/bevy/src/main.rs

@@ -12,7 +12,7 @@ mod bevy_scene_plugin;
 mod demo_renderer;
 
 // CSS Styles
-static STYLES: Asset = asset!("./src/styles.css");
+static STYLES: Asset = asset!("/src/styles.css");
 
 type Color = OpaqueColor<Srgb>;
 

examples/visible.rs

@@ -10,7 +10,7 @@ fn app() -> Element {
     let mut animated_classes = use_signal(|| ["animated-text", ""]);
 
     rsx! {
-        document::Link { rel: "stylesheet", href: asset!("./examples/assets/visible.css") }
+        document::Link { rel: "stylesheet", href: asset!("/examples/assets/visible.css") }
 
         div {
             class: "container",

examples/wgpu-texture/src/main.rs

@@ -11,7 +11,7 @@ use winit::window::WindowAttributes;
 mod demo_renderer;
 
 // CSS Styles
-static STYLES: Asset = asset!("./src/styles.css");
+static STYLES: Asset = asset!("/src/styles.css");
 
 // WGPU settings required by this example
 const FEATURES: Features = Features::PUSH_CONSTANTS;

packages/config-macro/Cargo.toml

@@ -13,7 +13,7 @@ keywords = ["web", "desktop", "mobile", "gui", "wasm"]
 proc-macro = true
 
 [dependencies]
-proc-macro2 = { version = "1.0" }
+proc-macro2 = { workspace = true }
 quote = { workspace = true }
 
 [features]

packages/manganis/manganis-macro/Cargo.toml

@@ -15,7 +15,7 @@ proc-macro = true
 # be careful with dependencies you add here - these need to get compiled for the proc macro and therefore
 # prevent the main code from compiling!
 [dependencies]
-proc-macro2 = { workspace = true }
+proc-macro2 = { workspace = true, features = ["span-locations"] }
 quote = { workspace = true }
 syn = { workspace = true, features = ["full", "extra-traits"] }
 manganis-core = { workspace = true }

packages/manganis/manganis-macro/src/asset.rs

@@ -45,7 +45,7 @@ impl Parse for AssetParser {
     fn parse(input: ParseStream) -> syn::Result<Self> {
         // And then parse the options
         let (MacroString(src), path_expr) = input.call(crate::parse_with_tokens)?;
-        let asset = resolve_path(&src);
+        let asset = resolve_path(&src, path_expr.span());
         let _comma = input.parse::<Token![,]>();
         let options = input.parse()?;
 

packages/manganis/manganis-macro/src/css_module.rs

@@ -4,6 +4,7 @@ use proc_macro2::{Span, TokenStream};
 use quote::{format_ident, quote, ToTokens, TokenStreamExt};
 use syn::{
     parse::{Parse, ParseStream},
+    spanned::Spanned,
     token::Comma,
     Ident, Token, Visibility,
 };
@@ -27,7 +28,7 @@ impl Parse for CssModuleParser {
 
         // Asset path "/path.css"
         let (MacroString(src), path_expr) = input.call(crate::parse_with_tokens)?;
-        let asset = resolve_path(&src);
+        let asset = resolve_path(&src, path_expr.span());
 
         let _comma = input.parse::<Comma>();
 

packages/manganis/manganis-macro/src/lib.rs

@@ -9,6 +9,7 @@ use std::{
 
 use css_module::CssModuleParser;
 use proc_macro::TokenStream;
+use proc_macro2::Span;
 use quote::{quote, ToTokens};
 use syn::{
     parse::{Parse, ParseStream},
@@ -169,7 +170,7 @@ pub fn css_module(input: TokenStream) -> TokenStream {
     quote! { #style }.into_token_stream().into()
 }
 
-fn resolve_path(raw: &str) -> Result<PathBuf, AssetParseError> {
+fn resolve_path(raw: &str, span: Span) -> Result<PathBuf, AssetParseError> {
     // Get the location of the root of the crate which is where all assets are relative to
     //
     // IE
@@ -186,8 +187,18 @@ fn resolve_path(raw: &str) -> Result<PathBuf, AssetParseError> {
     // 1. the input file should be a pathbuf
     let input = PathBuf::from(raw);
 
+    let path = if raw.starts_with('.') {
+        if let Some(local_folder) = span.local_file().as_ref().and_then(|f| f.parent()) {
+            local_folder.join(raw)
+        } else {
+            return Err(AssetParseError::RelativeAssetPath);
+        }
+    } else {
+        manifest_dir.join(raw.trim_start_matches('/'))
+    };
+
     // 2. absolute path to the asset
-    let Ok(path) = std::path::absolute(manifest_dir.join(raw.trim_start_matches('/'))) else {
+    let Ok(path) = std::path::absolute(path) else {
         return Err(AssetParseError::InvalidPath {
             path: input.clone(),
         });
@@ -275,6 +286,7 @@ enum AssetParseError {
     IoError { err: std::io::Error, path: PathBuf },
     InvalidPath { path: PathBuf },
     FailedToReadAsset(std::io::Error),
+    RelativeAssetPath,
 }
 
 impl std::fmt::Display for AssetParseError {
@@ -294,6 +306,7 @@ impl std::fmt::Display for AssetParseError {
                 )
             }
             AssetParseError::FailedToReadAsset(err) => write!(f, "Failed to read asset: {}", err),
+            AssetParseError::RelativeAssetPath => write!(f, "Failed to resolve relative asset path. Relative assets are only supported in rust 1.88+."),
         }
     }
 }