Rewrite watch handling

Author: tuguzT

Cargo.lock

@@ -26,7 +26,7 @@ license = "MIT OR Apache-2.0"
 cargo-gpu-build = { path = "crates/cargo-gpu-build", default-features = false }
 cargo-gpu-test-utils = { path = "crates/cargo-gpu-test-utils", default-features = false }
 rustc_codegen_spirv-cache = { path = "crates/rustc_codegen_spirv-cache", default-features = false }
-spirv-builder = { git = "https://github.com/Rust-GPU/rust-gpu", rev = "3a897aa96c83b7caede692cbf8da7e58d7014ec8", default-features = false }
+spirv-builder = { git = "https://github.com/Rust-GPU/rust-gpu", rev = "ad2a34abb0576e1cf032237d191e8e63de1c3cea", default-features = false }
 anyhow = "1.0.98"
 thiserror = "2.0.12"
 clap = { version = "4.5.41", features = ["derive"] }

Cargo.toml

@@ -13,15 +13,6 @@
 //! Then is uses [`spirv-builder`](cache::spirv_builder) crate
 //! to pass the many additional parameters required to configure rustc and our codegen backend,
 //! but provide you with a toolchain-agnostic version that you may use from stable rustc.
-//!
-//! ## Building shader crates
-//!
-//! `cargo-gpu` takes a path to a shader crate to build, as well as a path to a directory
-//! to put the compiled `spv` source files. It also takes a path to an output manifest
-//! file where all shader entry points will be mapped to their `spv` source files. This
-//! manifest file can be used by build scripts (`build.rs` files) to generate linkage or
-//! conduct other post-processing, like converting the `spv` files into `wgsl` files,
-//! for example.
 
 pub use rustc_codegen_spirv_cache as cache;
 

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

@@ -3,13 +3,17 @@
 #![allow(clippy::shadow_reuse, reason = "let's not be silly")]
 #![allow(clippy::unwrap_used, reason = "this is basically a test")]
 
-use std::io::{self, Write as _};
-use std::path::PathBuf;
+use core::convert::Infallible;
+use std::{
+    io::{self, Write as _},
+    panic,
+    path::PathBuf,
+};
 
 use anyhow::Context as _;
 use cargo_gpu_build::lockfile::LockfileMismatchHandler;
 use rustc_codegen_spirv_cache::install::Install;
-use spirv_builder::{CompileResult, ModuleResult, SpirvBuilder};
+use spirv_builder::{CompileResult, ModuleResult, SpirvBuilder, Watch};
 
 use crate::{linkage::Linkage, user_consent::ask_for_user_consent};
 
@@ -103,7 +107,8 @@ impl Build {
         );
 
         if self.build.watch {
-            return self.watch();
+            let never = self.watch()?;
+            match never {}
         }
         self.build()
     }
@@ -119,21 +124,27 @@ impl Build {
         Ok(())
     }
 
-    /// Watches shader crate for changes using [`SpirvBuilder`]
-    /// or returns an error depending on presence of `watch` feature.
-    fn watch(&self) -> anyhow::Result<()> {
+    /// Watches shader crate for changes using [`SpirvBuilder`].
+    fn watch(&self) -> anyhow::Result<Infallible> {
         let this = self.clone();
-        self.build
-            .spirv_builder
-            .watch(move |result, accept| {
-                let parse_result = this.parse_compilation_result(&result);
-                if let Some(accept) = accept {
-                    accept.submit(parse_result);
-                }
-            })?
+        let Watch {
+            first_compile,
+            watch_thread,
+            ..
+        } = self.build.spirv_builder.watch(move |result, accept| {
+            let parse_result = this.parse_compilation_result(&result);
+            if let Some(accept) = accept {
+                accept.submit(parse_result);
+            }
+        })?;
+
+        first_compile
             .context("should always return the first compile result")
             .flatten()?;
-        anyhow::bail!("unexpected end of watch")
+        watch_thread.join().map_err(|payload| {
+            log::error!("watch thread panicked");
+            panic::resume_unwind(payload)
+        })
     }
 
     /// Parses compilation result from [`SpirvBuilder`] and writes it out to a file

crates/cargo-gpu/src/build.rs

@@ -3,7 +3,20 @@
 //! This program allows you to easily compile your rust-gpu shaders,
 //! without requiring you to fix your entire project to a specific toolchain.
 //!
-//! For additional information see the [`cargo-gpu-build`](cargo_gpu_build) crate documentation.
+//! ## Building shader crates
+//!
+//! It takes a path to a shader crate to build, as well as a path to a directory to put
+//! the compiled `spv` source files. It also takes a path to an output manifest file
+//! where all shader entry points will be mapped to their `spv` source files.
+//! This manifest file can be used by build scripts (`build.rs` files) to generate linkage
+//! or conduct other post-processing, like converting the `spv` files into `wgsl` files, for example.
+//!
+//! For additional information, see the [`cargo-gpu-build`](cargo_gpu_build) crate documentation.
+//!
+//! ## Where the binaries are
+//!
+//! Prebuilt binaries are stored in the [cache directory](rustc_codegen_spirv_cache::cache::cache_dir()),
+//! which path differs by OS you are using.
 
 #![expect(clippy::pub_use, reason = "part of public interface")]
 

crates/cargo-gpu/src/lib.rs

@@ -10,11 +10,6 @@
 //! Usually, this would require you to fix your entire project to that specific
 //! toolchain, but this project loosens that requirement by managing installations
 //! of `rustc_codegen_spirv` and their associated toolchains for you.
-//!
-//! ## Where the binaries are
-//!
-//! Prebuilt binaries are stored in the [cache directory](crate::cache::cache_dir()),
-//! which path differs by OS.
 
 #![expect(clippy::pub_use, reason = "reexport for convenience")]