Auto merge of #4513 - matthiaskrgr:dogdood_incrcomp, r=llogiq

tests: disable incremental compilation in dogfood to reduce target dir size

tests: execute dogfood tests with incremental compilation disabled reduces target/ dir size of when "cargo test"ing by around 2 gigs.

changelog: none

tests/dogfood.rs

@@ -1,24 +1,27 @@
 #[test]
-fn dogfood() {
+fn dogfood_clippy() {
+    // run clippy on itself and fail the test if lint warnings are reported
     if option_env!("RUSTC_TEST_SUITE").is_some() || cfg!(windows) {
         return;
     }
     let root_dir = std::path::PathBuf::from(env!("CARGO_MANIFEST_DIR"));
-    let clippy_cmd = std::path::Path::new(&root_dir)
+    let clippy_binary = std::path::Path::new(&root_dir)
         .join("target")
         .join(env!("PROFILE"))
         .join("cargo-clippy");
 
-    let output = std::process::Command::new(clippy_cmd)
+    let output = std::process::Command::new(clippy_binary)
         .current_dir(root_dir)
         .env("CLIPPY_DOGFOOD", "1")
+        .env("CARGO_INCREMENTAL", "0")
         .arg("clippy-preview")
         .arg("--all-targets")
         .arg("--all-features")
         .arg("--")
         .args(&["-D", "clippy::all"])
         .args(&["-D", "clippy::internal"])
         .args(&["-D", "clippy::pedantic"])
+        .arg("-Cdebuginfo=0") // disable debuginfo to generate less data in the target dir
         .output()
         .unwrap();
     println!("status: {}", output.status);
@@ -29,12 +32,13 @@ fn dogfood() {
 }
 
 #[test]
-fn dogfood_tests() {
+fn dogfood_subprojects() {
+    // run clippy on remaining subprojects and fail the test if lint warnings are reported
     if option_env!("RUSTC_TEST_SUITE").is_some() || cfg!(windows) {
         return;
     }
     let root_dir = std::path::PathBuf::from(env!("CARGO_MANIFEST_DIR"));
-    let clippy_cmd = std::path::Path::new(&root_dir)
+    let clippy_binary = std::path::Path::new(&root_dir)
         .join("target")
         .join(env!("PROFILE"))
         .join("cargo-clippy");
@@ -47,13 +51,15 @@ fn dogfood_tests() {
         "clippy_dev",
         "rustc_tools_util",
     ] {
-        let output = std::process::Command::new(&clippy_cmd)
+        let output = std::process::Command::new(&clippy_binary)
             .current_dir(root_dir.join(d))
             .env("CLIPPY_DOGFOOD", "1")
+            .env("CARGO_INCREMENTAL", "0")
             .arg("clippy")
             .arg("--")
             .args(&["-D", "clippy::all"])
             .args(&["-D", "clippy::pedantic"])
+            .arg("-Cdebuginfo=0") // disable debuginfo to generate less data in the target dir
             .output()
             .unwrap();
         println!("status: {}", output.status);