Fix extremely slow dev builds caused by embedding + compressing assets at compile time (#1395)

core/tauri-codegen/src/context.rs

@@ -24,6 +24,7 @@ pub fn context_codegen(data: ContextData) -> Result<TokenStream, EmbeddedAssetsE
   let assets = EmbeddedAssets::new(&dist_dir)?;
 
   // handle default window icons for Windows targets
+  #[cfg(not(debug_assertions))]
   let default_window_icon = if cfg!(windows) {
     let icon_path = config_parent.join("icons/icon.ico").display().to_string();
     quote!(Some(include_bytes!(#icon_path)))
@@ -31,6 +32,10 @@ pub fn context_codegen(data: ContextData) -> Result<TokenStream, EmbeddedAssetsE
     quote!(None)
   };
 
+  // in development builds, don't use an icon as it slows down cargo check
+  #[cfg(debug_assertions)]
+  let default_window_icon = quote!(None);
+
   // double braces are purposeful to force the code into a block expression
   Ok(quote! {{
     use ::tauri::api::private::{OnceCell, AsTauriContext};

core/tauri-codegen/src/embedded_assets.rs

@@ -51,6 +51,7 @@ pub enum EmbeddedAssetsError {
 pub struct EmbeddedAssets(HashMap<AssetKey, (String, Vec<u8>)>);
 
 impl EmbeddedAssets {
+  #[cfg(not(debug_assertions))]
   /// Compress a directory of assets, ready to be generated into a [`tauri_api::assets::Assets`].
   pub fn new(path: &Path) -> Result<Self, EmbeddedAssetsError> {
     WalkDir::new(&path)
@@ -73,6 +74,14 @@ impl EmbeddedAssets {
       .map(Self)
   }
 
+  #[cfg(debug_assertions)]
+  /// A dummy EmbeddedAssets for use during development builds.
+  /// Compressing + including the bytes of assets during development takes a long time.
+  /// On development builds, assets will simply be resolved & fetched from the configured dist folder.
+  pub fn new(_: &Path) -> Result<Self, EmbeddedAssetsError> {
+    Ok(EmbeddedAssets(HashMap::new()))
+  }
+
   /// Use highest compression level for release, the fastest one for everything else
   fn compression_level() -> i32 {
     match var("PROFILE").as_ref().map(String::as_str) {