rustup-init: install proxy binaries

Formula/r/rustup-init.rb

@@ -16,6 +16,8 @@ class RustupInit < Formula
     sha256 cellar: :any_skip_relocation, x86_64_linux:   "5d9ff7b986a355cb60bff64754c0cb7213361a48e02991e246d8f7b242f38de9"
   end
 
+  keg_only "it conflicts with rust"
+
   depends_on "rust" => :build
 
   uses_from_macos "curl"
@@ -27,26 +29,45 @@ class RustupInit < Formula
   end
 
   def install
-    system "cargo", "install", "--features", "no-self-update", *std_cargo_args
+    system "cargo", "install", "--features=no-self-update", *std_cargo_args
+
+    %w[cargo cargo-clippy cargo-fmt cargo-miri clippy-driver rls rust-analyzer
+       rust-gdb rust-gdbgui rust-lldb rustc rustdoc rustfmt rustup].each do |name|
+      bin.install_symlink bin/"rustup-init" => name
+    end
+    generate_completions_from_executable(bin/"rustup", "completions", base_name: "rustup")
+  end
+
+  def post_install
+    (HOMEBREW_PREFIX/"bin").install_symlink bin/"rustup", bin/"rustup-init"
   end
 
   def caveats
     <<~EOS
-      Please run `rustup-init` to initialize `rustup` and install other Rust components.
+      To initialize `rustup`, set a default toolchain:
+        rustup default stable
     EOS
   end
 
   test do
     ENV["CARGO_HOME"] = testpath/".cargo"
-    ENV["RUSTUP_HOME"] = testpath/".multirust"
+    ENV["RUSTUP_HOME"] = testpath/".rustup"
+    ENV.prepend_path "PATH", bin
 
+    assert_match "no default is configured", shell_output("#{bin}/rustc --version 2>&1", 1)
+    system bin/"rustup", "default", "stable"
+
+    system bin/"cargo", "init", "--bin"
+    system bin/"cargo", "fmt"
+    system bin/"rustc", "src/main.rs"
+    assert_equal "Hello, world!", shell_output("./main").chomp
+    assert_empty shell_output("#{bin}/cargo clippy")
+
+    # Check for stale symlinks
     system bin/"rustup-init", "-y"
-    (testpath/"hello.rs").write <<~EOS
-      fn main() {
-        println!("Hello World!");
-      }
-    EOS
-    system testpath/".cargo/bin/rustc", "hello.rs"
-    assert_equal "Hello World!", shell_output("./hello").chomp
+    bins = bin.glob("*").to_set(&:basename).delete(Pathname("rustup-init"))
+    expected = testpath.glob(".cargo/bin/*").to_set(&:basename)
+    assert (extra = bins - expected).empty?, "Symlinks need to be removed: #{extra.join(",")}"
+    assert (missing = expected - bins).empty?, "Symlinks need to be added: #{missing.join(",")}"
   end
 end