Nix package manager

README.md

@@ -34,6 +34,7 @@ Just run `topgrade`. It will run the following steps:
   * *Debian/Ubuntu*: Run `apt update && apt dist-upgrade`
 * *Linux*: Run [etc-update](https://dev.gentoo.org/~zmedico/portage/doc/man/etc-update.1.html):
 * *Unix*: Run `brew update && brew upgrade`. This should handle both Homebrew and Linuxbrew
+* *Unix*: Run `nix upgrade-nix && nix --upgrade`.
 * *Windows*: Upgrade Powershell modules
 * *Windows*: Upgrade all [Chocolatey](https://chocolatey.org/) packages
 * *Windows*: Upgrade all [Scoop](https://scoop.sh) packages

src/main.rs

@@ -186,6 +186,11 @@ fn run() -> Result<(), Error> {
         |terminal| unix::run_homebrew(terminal, opt.dry_run),
         &mut execution_context,
     )?);
+    #[cfg(unix)]
+    report.push_result(execute(
+        |terminal| unix::run_nix(terminal, opt.dry_run),
+        &mut execution_context,
+    )?);
 
     if !opt.no_emacs {
         git_repos.insert(base_dirs.home_dir().join(".emacs.d"));

src/unix.rs

@@ -67,3 +67,30 @@ pub fn run_homebrew(terminal: &mut Terminal, dry_run: bool) -> Option<(&'static
 
     None
 }
+
+#[must_use]
+pub fn run_nix(terminal: &mut Terminal, dry_run: bool) -> Option<(&'static str, bool)> {
+    if let Some(nix) = which("nix") {
+        if let Some(nix_env) = which("nix-env") {
+            terminal.print_separator("Nix");
+
+            let inner = || -> Result<(), Error> {
+                Executor::new(&nix, dry_run)
+                    .arg("upgrade-nix")
+                    .spawn()?
+                    .wait()?
+                    .check()?;
+                Executor::new(&nix_env, dry_run)
+                    .arg("--upgrade")
+                    .spawn()?
+                    .wait()?
+                    .check()?;
+                Ok(())
+            };
+
+            return Some(("Nix", inner().is_ok()));
+        }
+    }
+
+    None
+}