Decouple target specs handling, add error types for it

Author: tuguzT

Cargo.lock

@@ -12,7 +12,6 @@ rustc_codegen_spirv-cache = { path = "../rustc_codegen_spirv-cache", default-fea
 cargo_metadata.workspace = true
 anyhow.workspace = true
 spirv-builder.workspace = true
-legacy_target_specs.workspace = true
 clap = { workspace = true, optional = true }
 log.workspace = true
 relative-path.workspace = true

crates/cargo-gpu-cache/Cargo.toml

@@ -6,12 +6,11 @@ use anyhow::Context as _;
 use rustc_codegen_spirv_cache::{
     cache::cache_dir,
     metadata::{query_metadata, MetadataExt as _},
-    spirv_source::{get_channel_from_rustc_codegen_spirv_build_script, SpirvSource},
+    spirv_source::{rust_gpu_toolchain_channel, SpirvSource},
+    target_specs::update_target_specs_files,
 };
 use spirv_builder::SpirvBuilder;
 
-use crate::target_specs::update_target_specs_files;
-
 /// Represents a functional backend installation, whether it was cached or just installed.
 #[derive(Clone, Debug, Default)]
 #[non_exhaustive]
@@ -262,10 +261,9 @@ package = "rustc_codegen_spirv"
         let rustc_codegen_spirv = dummy_metadata.find_package("rustc_codegen_spirv").context(
             "resolving toolchain version: expected a dependency on `rustc_codegen_spirv`",
         )?;
-        let toolchain_channel =
-            get_channel_from_rustc_codegen_spirv_build_script(rustc_codegen_spirv).context(
-                "resolving toolchain version: read toolchain from `rustc_codegen_spirv`'s build.rs",
-            )?;
+        let toolchain_channel = rust_gpu_toolchain_channel(rustc_codegen_spirv).context(
+            "resolving toolchain version: read toolchain from `rustc_codegen_spirv`'s build.rs",
+        )?;
         log::info!("selected toolchain channel `{toolchain_channel:?}`");
 
         log::debug!("update_spec_files");

crates/cargo-gpu-cache/src/install.rs

@@ -52,7 +52,6 @@ mod linkage;
 mod lockfile;
 mod metadata;
 mod show;
-mod target_specs;
 
 pub use install::*;
 pub use spirv_builder;

crates/cargo-gpu-cache/src/lib.rs

@@ -5,10 +5,9 @@ use std::{fs, path::Path};
 use anyhow::bail;
 use rustc_codegen_spirv_cache::{
     cache::cache_dir, metadata::query_metadata, spirv_source::SpirvSource,
+    target_specs::update_target_specs_files,
 };
 
-use crate::target_specs::update_target_specs_files;
-
 /// Show the computed source of the spirv-std dependency.
 #[derive(Clone, Debug)]
 #[cfg_attr(feature = "clap", derive(clap::Parser))]

crates/cargo-gpu-cache/src/show.rs

@@ -8,6 +8,7 @@ keywords.workspace = true
 license.workspace = true
 
 [dependencies]
+legacy_target_specs.workspace = true
 thiserror.workspace = true
 directories.workspace = true
 cargo_metadata.workspace = true

crates/cargo-gpu-cache/src/target_specs.rs

@@ -23,3 +23,4 @@ pub use cargo_metadata;
 pub mod cache;
 pub mod metadata;
 pub mod spirv_source;
+pub mod target_specs;

crates/rustc_codegen_spirv-cache/Cargo.toml

@@ -251,75 +251,27 @@ pub enum ParseSourceVersionError {
     InvalidManifestPath(Utf8PathBuf),
 }
 
-/// An error indicating that getting the channel of a Rust toolchain from the package failed.
-#[derive(Debug, thiserror::Error)]
-#[non_exhaustive]
-pub enum GetChannelError {
-    /// Package is located at the root of the file system
-    /// and cannot have a parent.
-    #[error("package located at root")]
-    PackageAtRoot,
-    /// Build script file is not valid or does not exist.
-    #[error("invalid build script {build_script}: {source}")]
-    InvalidBuildScript {
-        /// Source of the error.
-        source: io::Error,
-        /// Path to the build script file.
-        build_script: Utf8PathBuf,
-    },
-    /// There is no line starting with `channel_start`
-    /// in the build script file contents.
-    #[error("`{channel_start}` line in {build_script:?} not found")]
-    ChannelStartNotFound {
-        /// Start of the channel line.
-        channel_start: &'static str,
-        /// Path to the build script file.
-        build_script: Utf8PathBuf,
-    },
-    /// Channel line does not contain `channel_end`
-    /// in the build script file contents.
-    #[error("ending `{channel_end}` of line \"{channel_line}\" in {build_script:?} not found")]
-    ChannelEndNotFound {
-        /// End of the channel line.
-        channel_end: &'static str,
-        /// The line containing the channel information.
-        channel_line: String,
-        /// Path to the build script file.
-        build_script: Utf8PathBuf,
-    },
-    /// The range to slice the channel line is not valid.
-    #[error("cannot slice line \"{channel_line}\" of {build_script:?} by range {range:?}")]
-    InvalidRange {
-        /// The invalid range.
-        range: Range<usize>,
-        /// The line containing the channel information.
-        channel_line: String,
-        /// Path to the build script file.
-        build_script: Utf8PathBuf,
-    },
-}
-
 /// Parse the `rust-toolchain.toml` in the working tree of the checked-out version of the `rust-gpu` repo.
 ///
 /// # Errors
 ///
 /// Returns an error if the package is at the root of the filesystem,
 /// build script does not exist, or there is no definition of `channel` in it.
 #[inline]
-pub fn get_channel_from_rustc_codegen_spirv_build_script(
-    rustc_codegen_spirv_package: &Package,
-) -> Result<String, GetChannelError> {
-    let path = rustc_codegen_spirv_package
+pub fn rust_gpu_toolchain_channel(
+    rustc_codegen_spirv: &Package,
+) -> Result<String, RustGpuToolchainChannelError> {
+    let path = rustc_codegen_spirv
         .manifest_path
         .parent()
-        .ok_or(GetChannelError::PackageAtRoot)?;
+        .ok_or(RustGpuToolchainChannelError::PackageAtRoot)?;
     let build_script = path.join("build.rs");
 
     log::debug!("Parsing `build.rs` at {build_script:?} for the used toolchain");
     let contents = match fs::read_to_string(&build_script) {
         Ok(contents) => contents,
         Err(source) => {
-            let err = GetChannelError::InvalidBuildScript {
+            let err = RustGpuToolchainChannelError::InvalidBuildScript {
                 source,
                 build_script,
             };
@@ -332,8 +284,8 @@ pub fn get_channel_from_rustc_codegen_spirv_build_script(
         .lines()
         .find(|line| line.starts_with(channel_start))
     else {
-        let err = GetChannelError::ChannelStartNotFound {
-            channel_start,
+        let err = RustGpuToolchainChannelError::ChannelStartNotFound {
+            channel_start: channel_start.to_owned(),
             build_script,
         };
         return Err(err);
@@ -346,8 +298,8 @@ pub fn get_channel_from_rustc_codegen_spirv_build_script(
         .find(channel_end)
         .map(|end| end + start)
     else {
-        let err = GetChannelError::ChannelEndNotFound {
-            channel_end,
+        let err = RustGpuToolchainChannelError::ChannelEndNotFound {
+            channel_end: channel_end.to_owned(),
             channel_line: channel_line.to_owned(),
             build_script,
         };
@@ -356,7 +308,7 @@ pub fn get_channel_from_rustc_codegen_spirv_build_script(
 
     let range = start..end;
     let Some(channel) = channel_line.get(range.clone()) else {
-        let err = GetChannelError::InvalidRange {
+        let err = RustGpuToolchainChannelError::InvalidRange {
             range,
             channel_line: channel_line.to_owned(),
             build_script,
@@ -366,6 +318,54 @@ pub fn get_channel_from_rustc_codegen_spirv_build_script(
     Ok(channel.to_owned())
 }
 
+/// An error indicating that getting the channel of a Rust toolchain from the package failed.
+#[derive(Debug, thiserror::Error)]
+#[non_exhaustive]
+pub enum RustGpuToolchainChannelError {
+    /// Package is located at the root of the file system
+    /// and cannot have a parent.
+    #[error("package located at root")]
+    PackageAtRoot,
+    /// Build script file is not valid or does not exist.
+    #[error("invalid build script {build_script}: {source}")]
+    InvalidBuildScript {
+        /// Source of the error.
+        source: io::Error,
+        /// Path to the build script file.
+        build_script: Utf8PathBuf,
+    },
+    /// There is no line starting with `channel_start`
+    /// in the build script file contents.
+    #[error("`{channel_start}` line in {build_script:?} not found")]
+    ChannelStartNotFound {
+        /// Start of the channel line.
+        channel_start: String,
+        /// Path to the build script file.
+        build_script: Utf8PathBuf,
+    },
+    /// Channel line does not contain `channel_end`
+    /// in the build script file contents.
+    #[error("ending `{channel_end}` of line \"{channel_line}\" in {build_script:?} not found")]
+    ChannelEndNotFound {
+        /// End of the channel line.
+        channel_end: String,
+        /// The line containing the channel information.
+        channel_line: String,
+        /// Path to the build script file.
+        build_script: Utf8PathBuf,
+    },
+    /// The range to slice the channel line is not valid.
+    #[error("cannot slice line \"{channel_line}\" of {build_script:?} by range {range:?}")]
+    InvalidRange {
+        /// The invalid range.
+        range: Range<usize>,
+        /// The line containing the channel information.
+        channel_line: String,
+        /// Path to the build script file.
+        build_script: Utf8PathBuf,
+    },
+}
+
 /// Returns a string suitable to use as a directory.
 ///
 /// Created from the spirv-builder source dep and the rustc channel.