Retry command invocation with argfile

.github/workflows/main.yml

@@ -68,6 +68,13 @@ jobs:
 
     # Deny warnings on CI to avoid warnings getting into the codebase.
     - run: cargo test --features 'deny-warnings'
+    - name: Check operability of rustc invocation with argfile
+      env:
+        __CARGO_TEST_FORCE_ARGFILE: 1
+      run: |
+        # This only tests `cargo fix` because fix-proxy-mode is one of the most
+        # complicated subprocess management in Cargo.
+        cargo test --test testsuite --features 'deny-warnings' -- fix::
     - run: cargo test --features 'deny-warnings' --manifest-path crates/cargo-test-support/Cargo.toml
       env:
         CARGO_TARGET_DIR: target

Cargo.toml

@@ -19,7 +19,7 @@ path = "src/cargo/lib.rs"
 atty = "0.2"
 bytesize = "1.0"
 cargo-platform = { path = "crates/cargo-platform", version = "0.1.2" }
-cargo-util = { path = "crates/cargo-util", version = "0.1.2" }
+cargo-util = { path = "crates/cargo-util", version = "0.1.3" }
 crates-io = { path = "crates/crates-io", version = "0.34.0" }
 crossbeam-utils = "0.8"
 curl = { version = "0.4.41", features = ["http2"] }

crates/cargo-test-support/src/tools.rs

@@ -24,8 +24,17 @@ pub fn echo_wrapper() -> PathBuf {
         .file(
             "src/main.rs",
             r#"
+            use std::fs::read_to_string;
+            use std::path::PathBuf;
             fn main() {
-                let args = std::env::args().collect::<Vec<_>>();
+                // Handle args from `@path` argfile for rustc
+                let args = std::env::args()
+                    .flat_map(|p| if let Some(p) = p.strip_prefix("@") {
+                        read_to_string(p).unwrap().lines().map(String::from).collect()
+                    } else {
+                        vec![p]
+                    })
+                    .collect::<Vec<_>>();
                 eprintln!("WRAPPER CALLED: {}", args[1..].join(" "));
                 let status = std::process::Command::new(&args[1])
                     .args(&args[2..]).status().unwrap();

crates/cargo-util/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cargo-util"
-version = "0.1.2"
+version = "0.1.3"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 homepage = "https://github.com/rust-lang/cargo"