fix: cargo build/install -p resolves target to shader crate

crates/cargo-gpu/src/build.rs

@@ -60,6 +60,11 @@ impl Build {
     pub fn run(&mut self) -> anyhow::Result<()> {
         let installed_backend = self.install.run()?;
 
+        if let Some(package) = self.install.package.as_ref() {
+            self.install.shader_crate =
+                crate::metadata::Metadata::resolve_package_to_shader_crate(package)?;
+        }
+
         let _lockfile_mismatch_handler = LockfileMismatchHandler::new(
             &self.install.shader_crate,
             &installed_backend.toolchain_channel,

crates/cargo-gpu/src/install.rs

@@ -64,9 +64,16 @@ impl InstalledBackend {
 #[derive(clap::Parser, Debug, Clone, serde::Deserialize, serde::Serialize)]
 #[non_exhaustive]
 pub struct Install {
+    /// Cargo target to compile.
+    ///
+    /// Conflicts with `--shader-crate`.
+    #[clap(short, long, conflicts_with("shader_crate"))]
+    pub package: Option<String>,
+
     /// Directory containing the shader crate to compile.
-    #[clap(long, alias("package"), short_alias('p'), default_value = "./")]
-    #[serde(alias = "package")]
+    ///
+    /// Conflicts with `--package` or `-p`.
+    #[clap(long, default_value = "./", conflicts_with("package"))]
     pub shader_crate: PathBuf,
 
     #[expect(
@@ -132,6 +139,7 @@ impl Install {
     #[must_use]
     pub const fn from_shader_crate(shader_crate: PathBuf) -> Self {
         Self {
+            package: None,
             shader_crate,
             spirv_builder_source: None,
             spirv_builder_version: None,

crates/cargo-gpu/src/metadata.rs

@@ -1,5 +1,6 @@
 //! Get config from the shader crate's `Cargo.toml` `[*.metadata.rust-gpu.*]`
 
+use anyhow::Context as _;
 use cargo_metadata::MetadataCommand;
 use serde_json::Value;
 
@@ -9,6 +10,28 @@ use serde_json::Value;
 pub struct Metadata;
 
 impl Metadata {
+    /// Resolve a package name to a crate directory.
+    pub fn resolve_package_to_shader_crate(package: &str) -> anyhow::Result<std::path::PathBuf> {
+        log::debug!("resolving package '{package}' to shader crate");
+        let metadata = MetadataCommand::new().exec()?;
+        let meta_package = metadata
+            .packages
+            .iter()
+            .find(|pkg| pkg.name.as_str() == package)
+            .context("Package not found in metadata")?;
+        let shader_crate_path: std::path::PathBuf = meta_package
+            .manifest_path
+            .parent()
+            .context("manifest is missing a parent directory")?
+            .to_path_buf()
+            .into();
+        log::debug!(
+            "  determined shader crate path to be '{}'",
+            shader_crate_path.display()
+        );
+        Ok(shader_crate_path)
+    }
+
     /// Convert `rust-gpu`-specific sections in `Cargo.toml` to `clap`-compatible arguments.
     /// The section in question is: `[package.metadata.rust-gpu.*]`. See the `shader-crate-template`
     /// for an example.
@@ -17,6 +40,7 @@ impl Metadata {
     /// from the workspace `Cargo.toml`, then on top of those we merge any config from the shader
     /// crate's `Cargo.toml`.
     pub fn as_json(path: &std::path::PathBuf) -> anyhow::Result<Value> {
+        log::debug!("reading package metadata from {}", path.display());
         let cargo_json = Self::get_cargo_toml_as_json(path)?;
         let config = Self::merge_configs(&cargo_json, path)?;
         Ok(config)
@@ -27,6 +51,7 @@ impl Metadata {
         cargo_json: &cargo_metadata::Metadata,
         path: &std::path::Path,
     ) -> anyhow::Result<Value> {
+        log::debug!("merging cargo metadata from {}", path.display());
         let mut metadata = crate::config::Config::defaults_as_json()?;
         crate::config::Config::json_merge(
             &mut metadata,