Get a half working example working

Signed-off-by: Marcel Müller <neikos@neikos.email>

lib/cargo-dylint-driver.nix

@@ -0,0 +1,27 @@
+{
+  craneLib,
+}:
+
+let
+  pname = "cargo-dylint-driver";
+  version = "4.0.0";
+
+  src = ../dylint_driver;
+
+  commonArgs = {
+    inherit pname version src;
+
+    strictDeps = true;
+
+    RUSTUP_TOOLCHAIN = "nightly-nix";
+  };
+in
+
+craneLib.buildPackage (
+  commonArgs
+  // {
+    cargoArtifacts = craneLib.buildDepsOnly commonArgs;
+
+    doNotRemoveReferencesToRustToolchain = true;
+  }
+)

lib/cargo-dylint-patch-rustup.patch

@@ -0,0 +1,82 @@
+diff --git a/dylint/build.rs b/dylint/build.rs
+index f96b676f..297d2dcf 100644
+--- a/dylint/build.rs
++++ b/dylint/build.rs
+@@ -31,7 +31,7 @@ fn write_dylint_driver_manifest_dir() {
+     {
+         "None".to_owned()
+     } else {
+-        let path_buf = dylint_manifest_dir.join("../driver");
++        let path_buf = Path::new("@DRIVER_DIR@");
+ 
+         // smoelius: Ensure the path exists at build time.
+         assert!(path_buf.is_dir(), "{path_buf:?} is not a directory");
+diff --git a/internal/src/cargo.rs b/internal/src/cargo.rs
+index 8532d68c..4e7f715c 100644
+--- a/internal/src/cargo.rs
++++ b/internal/src/cargo.rs
+@@ -14,16 +14,7 @@ use std::{
+ pub use home::cargo_home;
+ 
+ static STABLE_CARGO: Lazy<PathBuf> = Lazy::new(|| {
+-    let mut command = Command::new("rustup");
+-    // smoelius: Rustup 1.27.1 doesn't properly handle the case where the toolchain is specified via
+-    // both the `RUSTUP_TOOLCHAIN` environment variable and the command line (e.g., `+stable`). This
+-    // bug is fixed in Rustup's `master` branch, though.
+-    command.env_remove("RUSTUP_TOOLCHAIN");
+-    command.args(["+stable", "which", "cargo"]);
+-    let output = command.logged_output(true).unwrap();
+-    assert!(output.status.success());
+-    let stdout = String::from_utf8(output.stdout).unwrap();
+-    PathBuf::from(stdout.trim_end())
++    PathBuf::from("@STABLE_CARGO@")
+ });
+ 
+ bitflags! {
+diff --git a/internal/src/rustup.rs b/internal/src/rustup.rs
+index fb72a3fa..9b320670 100644
+--- a/internal/src/rustup.rs
++++ b/internal/src/rustup.rs
+@@ -15,7 +15,7 @@ impl SanitizeEnvironment for Command {
+     fn sanitize_environment(&mut self) -> &mut Self {
+         self.env_remove(env::CARGO);
+         self.env_remove(env::RUSTC);
+-        self.env_remove(env::RUSTUP_TOOLCHAIN);
++        // self.env_remove(env::RUSTUP_TOOLCHAIN);
+         self
+     }
+ }
+@@ -23,31 +23,11 @@ impl SanitizeEnvironment for Command {
+ // smoelius: Consider carefully whether you need to call this function! In most cases, the toolchain
+ // you want is not the one returned by rustup.
+ pub fn active_toolchain(path: &Path) -> Result<String> {
+-    let output = Command::new("rustup")
+-        .sanitize_environment()
+-        .current_dir(path)
+-        .args(["show", "active-toolchain"])
+-        .logged_output(true)?;
+-    let stdout = std::str::from_utf8(&output.stdout)?;
+-    stdout
+-        .split_once(' ')
+-        .map(|(s, _)| s.to_owned())
+-        .ok_or_else(|| anyhow!("Could not determine active toolchain"))
++    Ok(String::from("@RUST_TOOLCHAIN@"))
+ }
+ 
+ pub fn toolchain_path(path: &Path) -> Result<PathBuf> {
+-    let output = Command::new("rustup")
+-        .sanitize_environment()
+-        .current_dir(path)
+-        .args(["which", "rustc"])
+-        .logged_output(true)?;
+-    let stdout = std::str::from_utf8(&output.stdout)?;
+-    let path = PathBuf::from(stdout);
+-    // smoelius: `path` should end with `/bin/rustc`.
+-    path.ancestors()
+-        .nth(2)
+-        .map(Into::into)
+-        .ok_or_else(|| anyhow!("Could not get ancestor"))
++    Ok(PathBuf::from("@RUST_TOOLCHAIN_PATH@"))
+ }
+ 
+ pub fn is_rustc<T: AsRef<OsStr> + ?Sized>(arg: &T) -> bool {

lib/cargo-dylint.nix

@@ -4,6 +4,8 @@
 
   pkg-config,
   openssl,
+
+  cargo-dylint-driver,
 }:
 
 let
@@ -16,24 +18,44 @@ let
     tag = "v${version}";
     sha256 = "sha256-Z8uuewp7Buoadayc0oTafmfvwNT36KukWKiHxL/mQfI=";
   };
+
+  commonArgs = {
+    inherit pname version src;
+
+    buildInputs = [
+      openssl
+    ];
+
+    nativeBuildInputs = [
+      pkg-config
+    ];
+
+    RUSTUP_TOOLCHAIN = "nightly-nix";
+
+    doCheck = false;
+  };
+  cargoArtifacts = craneLib.buildDepsOnly commonArgs;
 in
 
-craneLib.buildPackage {
-  inherit
-    pname
-    version
-    src
-    ;
+craneLib.buildPackage (
+  commonArgs
+  // {
+    inherit cargoArtifacts;
 
-  buildInputs = [
-    openssl
-  ];
+    patches = [ ./cargo-dylint-patch-rustup.patch ];
 
-  nativeBuildInputs = [
-    pkg-config
-  ];
+    postPatch = ''
+      substituteInPlace dylint/build.rs \
+        --replace-fail @DRIVER_DIR@ ${src}/driver
 
-  RUSTUP_TOOLCHAIN = craneLib.rustc.version;
+      substituteInPlace internal/src/cargo.rs \
+        --replace-fail @STABLE_CARGO@ ${craneLib.cargo}/bin/cargo
 
-  doCheck = false;
-}
+      substituteInPlace internal/src/rustup.rs \
+        --replace-fail @RUST_TOOLCHAIN@ "nightly-nix" \
+        --replace-fail @RUST_TOOLCHAIN_PATH@ ${craneLib.rustc}
+    '';
+
+    doNotRemoveReferencesToRustToolchain = true;
+  }
+)

lib/default.nix

@@ -9,6 +9,7 @@ let
   callPackage = pkgs.lib.callPackageWith (pkgs // packages // { inherit inputs craneLib; });
   packages = {
     cargo-dylint = callPackage ./cargo-dylint.nix { };
+    cargo-dylint-driver = callPackage ./cargo-dylint-driver.nix { };
   };
 
 in