Extend support for Nix/NixOS/home-manager (#253)

README.md

@@ -22,6 +22,7 @@ package manager. Topgrade is tested on and knows the following platforms:
   * Red Hat based
   * Debian based
   * Gentoo
+  * NixOS
   * openSUSE
   * Void
 * DragonFly BSD
@@ -32,6 +33,12 @@ package manager. Topgrade is tested on and knows the following platforms:
 ## Installation
 Arch Linux users can use the [AUR](https://aur.archlinux.org/packages/topgrade/) package.
 
+On NixOS, use the `topgrade` package in `nixpkgs`:
+
+```sh
+nix-env -iA topgrade
+```
+
 macOS users can install topgrade via Homebrew.
 
 Other systems users can either use `cargo install` or use the compiled binaries from the release

src/main.rs

@@ -204,6 +204,12 @@ fn run() -> Result<(), Error> {
             )?;
 
             execute(&mut report, "nix", || unix::run_nix(run_type), config.no_retry())?;
+            execute(
+                &mut report,
+                "home-manager",
+                || unix::run_home_manager(run_type),
+                config.no_retry(),
+            )?;
         }
     }
 

src/steps/os/linux.rs

@@ -32,6 +32,7 @@ pub enum Distribution {
     Void,
     Solus,
     Exherbo,
+    NixOS,
 }
 
 impl Distribution {
@@ -61,6 +62,7 @@ impl Distribution {
             Some("solus") => Distribution::Solus,
             Some("gentoo") => Distribution::Gentoo,
             Some("exherbo") => Distribution::Exherbo,
+            Some("nixos") => Distribution::NixOS,
             _ => return Err(ErrorKind::UnknownLinuxDistribution.into()),
         })
     }
@@ -91,6 +93,7 @@ impl Distribution {
             Distribution::Void => upgrade_void(&sudo, run_type),
             Distribution::Solus => upgrade_solus(&sudo, run_type),
             Distribution::Exherbo => upgrade_exherbo(&sudo, cleanup, run_type),
+            Distribution::NixOS => upgrade_nixos(&sudo, cleanup, run_type),
         }
     }
 
@@ -331,6 +334,26 @@ fn upgrade_exherbo(sudo: &Option<PathBuf>, cleanup: bool, run_type: RunType) ->
     Ok(())
 }
 
+fn upgrade_nixos(sudo: &Option<PathBuf>, cleanup: bool, run_type: RunType) -> Result<(), Error> {
+    if let Some(sudo) = &sudo {
+        run_type
+            .execute(&sudo)
+            .args(&["/run/current-system/sw/bin/nixos-rebuild", "switch", "--upgrade"])
+            .check_run()?;
+
+        if cleanup {
+            run_type
+                .execute(&sudo)
+                .args(&["/run/current-system/sw/bin/nix-collect-garbage", "-d"])
+                .check_run()?;
+        }
+    } else {
+        print_warning("No sudo detected. Skipping system upgrade");
+    }
+
+    Ok(())
+}
+
 pub fn run_needrestart(sudo: Option<&PathBuf>, run_type: RunType) -> Result<(), Error> {
     let sudo = require_option(sudo)?;
     let needrestart = require("needrestart")?;
@@ -493,4 +516,9 @@ mod tests {
     fn test_exherbo() {
         test_template(&include_str!("os_release/exherbo"), Distribution::Exherbo);
     }
+
+    #[test]
+    fn test_nixos() {
+        test_template(&include_str!("os_release/nixos"), Distribution::NixOS);
+    }
 }

src/steps/os/os_release/nixos

@@ -0,0 +1,11 @@
+NAME=NixOS
+ID=nixos
+VERSION="20.03pre200231.7827d3f4497 (Markhor)"
+VERSION_CODENAME=markhor
+VERSION_ID="20.03pre200231.7827d3f4497"
+PRETTY_NAME="NixOS 20.03pre200231.7827d3f4497 (Markhor)"
+LOGO="nix-snowflake"
+HOME_URL="https://nixos.org/"
+DOCUMENTATION_URL="https://nixos.org/nixos/manual/index.html"
+SUPPORT_URL="https://nixos.org/nixos/support.html"
+BUG_REPORT_URL="https://github.com/NixOS/nixpkgs/issues"

src/steps/os/unix.rs

@@ -1,4 +1,4 @@
-use crate::error::Error;
+use crate::error::{Error, ErrorKind};
 use crate::executor::{CommandExt, RunType};
 use crate::terminal::print_separator;
 use crate::utils::{require, PathExt};
@@ -52,13 +52,33 @@ pub fn run_homebrew(cleanup: bool, run_type: RunType) -> Result<(), Error> {
 #[must_use]
 pub fn run_nix(run_type: RunType) -> Result<(), Error> {
     let nix = require("nix")?;
+    let nix_channel = require("nix-channel")?;
     let nix_env = require("nix-env")?;
-
     print_separator("Nix");
+
+    #[cfg(target_os = "linux")]
+    {
+        use super::linux::Distribution;
+        use log::debug;
+
+        if let Ok(Distribution::NixOS) = Distribution::detect() {
+            debug!("Nix on NixOS must be upgraded via 'nixos-rebuild switch', skipping.");
+            return Err(ErrorKind::SkipStep.into());
+        }
+    }
+
     run_type.execute(&nix).arg("upgrade-nix").check_run()?;
+    run_type.execute(&nix_channel).arg("--update").check_run()?;
     run_type.execute(&nix_env).arg("--upgrade").check_run()
 }
 
+pub fn run_home_manager(run_type: RunType) -> Result<(), Error> {
+    let home_manager = require("home-manager")?;
+
+    print_separator("home-manager");
+    run_type.execute(&home_manager).arg("switch").check_run()
+}
+
 pub fn run_pearl(run_type: RunType) -> Result<(), Error> {
     let pearl = require("pearl")?;
     print_separator("pearl");