fix(dist): write lib/rustlib/components in sorted order

src/dist/component/components.rs

@@ -147,11 +147,18 @@ impl ComponentBuilder {
             utils::write_line("component", &mut file, &abs_path, &part.encode())?;
         }
 
-        // Add component to components file
+        // Add component to components file, sorting it to avoid depending
+        // on the order components were installed in.
+        let names = self.components.list()?;
+        let mut names: Vec<_> = names.into_iter().map(|c| c.name).collect();
+        names.push(self.name.clone());
+        names.sort();
+        let mut contents = names.join("\n");
+        contents.push('\n');
         let path = self.components.rel_components_file();
         let abs_path = self.components.prefix.abs_path(&path);
         self.tx.modify_file(path)?;
-        utils::append_file("components", &abs_path, &self.name)?;
+        utils::write_file("components", &abs_path, &contents)?;
 
         // Drop in the version file for future use
         self.components.write_version(&mut self.tx)?;

tests/suite/dist_install.rs

@@ -144,6 +144,32 @@ fn multiple_component_install() {
     assert!(components.find("mycomponent2").unwrap().is_some());
 }
 
+#[test]
+fn components_file_is_independent_of_install_order() {
+    // Deliberately not in sorted order.
+    let names = ["rustc", "cargo", "rust-std"];
+    let mock = MockInstallerBuilder {
+        components: names
+            .iter()
+            .map(|name| MockComponentBuilder {
+                name: name.to_string(),
+                files: vec![MockFile::new(format!("bin/{name}"), b"data")],
+            })
+            .collect(),
+    };
+
+    let cx = DistContext::new(Some(mock)).unwrap();
+    let (mut tx, components, pkg) = cx.start().unwrap();
+    for name in names {
+        tx = pkg.install(&components, name, None, tx).unwrap();
+    }
+    tx.commit();
+
+    let components_path = cx.prefix.manifest_file("components");
+    let contents = utils::read_file("components", &components_path).unwrap();
+    assert_eq!(contents, "cargo\nrust-std\nrustc\n");
+}
+
 #[test]
 fn uninstall() {
     let mock = MockInstallerBuilder {