Improve error message when dx is called on a virtual or library packa…

…ge (#3505)

* Improve error message when dx is called on a virtual or library package

packages/cli/src/cli/bundle.rs

@@ -78,7 +78,8 @@ impl Bundle {
                     for src in bundle.bundle_paths {
                         let src = if let Some(outdir) = &self.outdir {
                             let dest = outdir.join(src.file_name().expect("Filename to exist"));
-                            crate::fastfs::copy_asset(&src, &dest)?;
+                            crate::fastfs::copy_asset(&src, &dest)
+                                .context("Failed to copy or compress optimized asset")?;
                             dest
                         } else {
                             src.clone()
@@ -141,13 +142,15 @@ impl Bundle {
         if cfg!(windows) {
             name.set_extension("exe");
         }
-        std::fs::create_dir_all(krate.bundle_dir(self.build_arguments.platform()))?;
+        std::fs::create_dir_all(krate.bundle_dir(self.build_arguments.platform()))
+            .context("Failed to create bundle directory")?;
         std::fs::copy(
             &bundle.app.exe,
             krate
                 .bundle_dir(self.build_arguments.platform())
                 .join(&name),
-        )?;
+        )
+        .with_context(|| "Failed to copy the output executable into the bundle directory")?;
 
         let binaries = vec![
             // We use the name of the exe but it has to be in the same directory
@@ -175,8 +178,14 @@ impl Bundle {
             bundle_settings.resources_map = Some(HashMap::new());
         }
 
-        for entry in std::fs::read_dir(bundle.build.asset_dir())?.flatten() {
-            let old = entry.path().canonicalize()?;
+        let asset_dir = bundle.build.asset_dir();
+        let asset_dir_entries = std::fs::read_dir(&asset_dir)
+            .with_context(|| format!("failed to read asset directory {:?}", asset_dir))?;
+        for entry in asset_dir_entries.flatten() {
+            let old = entry
+                .path()
+                .canonicalize()
+                .with_context(|| format!("Failed to canonicalize {entry:?}"))?;
             let new = PathBuf::from("assets").join(old.file_name().expect("Filename to exist"));
             tracing::debug!("Bundled asset: {old:?} -> {new:?}");
 
@@ -221,7 +230,9 @@ impl Bundle {
             settings = settings.target("aarch64-apple-ios".to_string());
         }
 
-        let settings = settings.build()?;
+        let settings = settings
+            .build()
+            .context("failed to bundle tauri bundle settings")?;
         tracing::debug!("Bundling project with settings: {:#?}", settings);
         if cfg!(target_os = "macos") {
             std::env::set_var("CI", "true");

packages/cli/src/dioxus_crate.rs

@@ -58,7 +58,27 @@ impl DioxusCrate {
             .find(|target| {
                 target_name == target.name.as_str() && target.kind.contains(&target_kind)
             })
-            .with_context(|| format!("Failed to find target {target_name}"))?
+            .with_context(|| {
+                let target_of_kind = |kind|-> String {
+                    let filtered_packages = main_package
+                .targets
+                .iter()
+                .filter_map(|target| {
+                    target.kind.contains(kind).then_some(target.name.as_str())
+                }).collect::<Vec<_>>();
+                filtered_packages.join(", ")};
+                if let Some(example) = &target.example {
+                    let examples = target_of_kind(&TargetKind::Example);
+                    format!("Failed to find example {example}. \nAvailable examples are:\n{}", examples)
+                } else if let Some(bin) = &target.bin {
+                    let binaries = target_of_kind(&TargetKind::Bin);
+                    format!("Failed to find binary {bin}. \nAvailable binaries are:\n{}", binaries)
+                } else {
+                    format!("Failed to find target {target_name}. \nIt looks like you are trying to build dioxus in a library crate. \
+                    You either need to run dx from inside a binary crate or build a specific example with the `--example` flag. \
+                    Available examples are:\n{}", target_of_kind(&TargetKind::Example))
+                }
+            })?
             .clone();
 
         let settings = CliSettings::load();
@@ -686,7 +706,15 @@ fn find_main_package(krates: &Krates, package: Option<String>) -> Result<NodeId>
 
     let kid = closest_parent
         .map(|(id, _)| id)
-        .context("Failed to find current package")?;
+        .with_context(|| {
+            let bin_targets = krates.workspace_members().filter_map(|krate|match krate {
+                krates::Node::Krate { krate, .. } if krate.targets.iter().any(|t| t.kind.contains(&krates::cm::TargetKind::Bin))=> {
+                    Some(format!("- {}", krate.name))
+                }
+                _ => None
+            }).collect::<Vec<_>>();
+            format!("Failed to find binary package to build.\nYou need to either run dx from inside a binary crate or specify a binary package to build with the `--package` flag. Try building again with one of the binary packages in the workspace:\n{}", bin_targets.join("\n"))
+        })?;
 
     let package = krates.nid_for_kid(kid).unwrap();
     Ok(package)