{nixos,home,darwin}: add edit subcommand

CHANGELOG.md

@@ -46,6 +46,7 @@ functionality, under the "Removed" section.
   - It's roughly %4 faster according to testing, but IO is still a limiting
     factor and results may differ.
 - Added more context to some minor debug messages across platform commands.
+- Added `nh {os,home,darwin} edit` subcommand.
 
 ### Fixed
 

src/darwin.rs

@@ -8,7 +8,9 @@ use crate::Result;
 use crate::commands;
 use crate::commands::Command;
 use crate::installable::Installable;
-use crate::interface::{DarwinArgs, DarwinRebuildArgs, DarwinReplArgs, DarwinSubcommand, DiffType};
+use crate::interface::{
+    DarwinArgs, DarwinEditArgs, DarwinRebuildArgs, DarwinReplArgs, DarwinSubcommand, DiffType,
+};
 use crate::nixos::toplevel_for;
 use crate::update::update;
 use crate::util::{get_hostname, print_dix_diff};
@@ -33,6 +35,7 @@ impl DarwinArgs {
                 args.rebuild(&Build)
             }
             DarwinSubcommand::Repl(args) => args.run(),
+            DarwinSubcommand::Edit(args) => args.run(),
         }
     }
 }
@@ -231,3 +234,86 @@ impl DarwinReplArgs {
         Ok(())
     }
 }
+
+impl DarwinEditArgs {
+    fn run(self) -> Result<()> {
+        let editor = if let Ok(var) = env::var("EDITOR") {
+            var
+        } else {
+            bail!("Unset environment variable `EDITOR`.")
+        };
+
+        // Use NH_DARWIN_FLAKE if available, otherwise use the provided installable
+        let target_installable = if let Ok(darwin_flake) = env::var("NH_DARWIN_FLAKE") {
+            debug!("Using NH_DARWIN_FLAKE: {}", darwin_flake);
+
+            let mut elems = darwin_flake.splitn(2, '#');
+            let reference = match elems.next() {
+                Some(r) => r.to_owned(),
+                None => return Err(eyre!("NH_DARWIN_FLAKE missing reference part")),
+            };
+            let attribute = elems
+                .next()
+                .map(crate::installable::parse_attribute)
+                .unwrap_or_default();
+
+            Installable::Flake {
+                reference,
+                attribute,
+            }
+        } else {
+            self.installable
+        };
+
+        match target_installable {
+            Installable::File { path, .. } => {
+                let str_path = path
+                    .to_str()
+                    .ok_or_else(|| eyre!("Edit path is not valid UTF-8"))?;
+
+                Command::new(editor)
+                    .arg(str_path)
+                    .with_required_env()
+                    .show_output(true)
+                    .run()?
+            }
+            Installable::Flake { reference, .. } => {
+                match &reference[0..5] {
+                    "path:" => {
+                        // Removes `path:` prefix
+                        let path = &reference[5..];
+
+                        Command::new(editor)
+                            .arg(path)
+                            .with_required_env()
+                            .show_output(true)
+                            .run()?
+                    }
+                    _ => {
+                        Command::new("nix")
+                            .arg("flake")
+                            .arg("prefetch")
+                            .arg("-o")
+                            .arg("result")
+                            .arg(reference)
+                            .with_required_env()
+                            .show_output(true)
+                            .run()?;
+
+                        Command::new(editor)
+                            .arg("result")
+                            .with_required_env()
+                            .show_output(true)
+                            .run()?;
+
+                        std::fs::remove_file("result")?
+                    }
+                };
+            }
+            Installable::Store { .. } => bail!("Nix doesn't support nix store installables."),
+            Installable::Expression { .. } => bail!("Nix doesn't support nix expression."),
+        };
+
+        Ok(())
+    }
+}

src/home.rs

@@ -9,7 +9,9 @@ use tracing::{debug, info, warn};
 use crate::commands;
 use crate::commands::Command;
 use crate::installable::Installable;
-use crate::interface::{self, DiffType, HomeRebuildArgs, HomeReplArgs, HomeSubcommand};
+use crate::interface::{
+    self, DiffType, HomeEditArgs, HomeRebuildArgs, HomeReplArgs, HomeSubcommand,
+};
 use crate::update::update;
 use crate::util::{get_hostname, print_dix_diff};
 
@@ -30,6 +32,7 @@ impl interface::HomeArgs {
                 args.rebuild(&Build)
             }
             HomeSubcommand::Repl(args) => args.run(),
+            HomeSubcommand::Edit(args) => args.run(),
         }
     }
 }
@@ -398,3 +401,93 @@ impl HomeReplArgs {
         Ok(())
     }
 }
+
+impl HomeEditArgs {
+    fn run(self) -> Result<()> {
+        let editor = if let Ok(var) = env::var("EDITOR") {
+            var
+        } else {
+            bail!("Unset environment variable `EDITOR`.")
+        };
+
+        // Use NH_HOME_FLAKE if available, otherwise use the provided installable
+        let installable = if let Ok(home_flake) = env::var("NH_HOME_FLAKE") {
+            debug!("Using NH_HOME_FLAKE: {home_flake}");
+
+            let mut elems = home_flake.splitn(2, '#');
+            let reference = match elems.next() {
+                Some(r) => r.to_owned(),
+                None => return Err(eyre!("NH_HOME_FLAKE missing reference part")),
+            };
+            let attribute = elems
+                .next()
+                .map(crate::installable::parse_attribute)
+                .unwrap_or_default();
+
+            Installable::Flake {
+                reference,
+                attribute,
+            }
+        } else {
+            self.installable
+        };
+
+        let toplevel = toplevel_for(
+            installable,
+            false,
+            &self.extra_args,
+            self.configuration.clone(),
+        )?;
+
+        match toplevel {
+            Installable::File { path, .. } => {
+                let str_path = path
+                    .to_str()
+                    .ok_or_else(|| eyre!("Edit path is not valid UTF-8"))?;
+
+                Command::new(editor)
+                    .arg(str_path)
+                    .with_required_env()
+                    .show_output(true)
+                    .run()?
+            }
+            Installable::Flake { reference, .. } => {
+                match &reference[0..5] {
+                    "path:" => {
+                        // Removes `path:` prefix
+                        let path = &reference[5..];
+
+                        Command::new(editor)
+                            .arg(path)
+                            .with_required_env()
+                            .show_output(true)
+                            .run()?
+                    }
+                    _ => {
+                        Command::new("nix")
+                            .arg("flake")
+                            .arg("prefetch")
+                            .arg("-o")
+                            .arg("result")
+                            .arg(reference)
+                            .with_required_env()
+                            .show_output(true)
+                            .run()?;
+
+                        Command::new(editor)
+                            .arg("result")
+                            .with_required_env()
+                            .show_output(true)
+                            .run()?;
+
+                        std::fs::remove_file("result")?
+                    }
+                };
+            }
+            Installable::Store { .. } => bail!("Nix doesn't support nix store installables."),
+            Installable::Expression { .. } => bail!("Nix doesn't support nix expression."),
+        };
+
+        Ok(())
+    }
+}

src/interface.rs

@@ -121,6 +121,13 @@ impl OsArgs {
                 let is_flake = args.uses_flakes();
                 Box::new(OsReplFeatures { is_flake })
             }
+            OsSubcommand::Edit(args) => {
+                if args.uses_flakes() {
+                    Box::new(FlakeFeatures)
+                } else {
+                    Box::new(LegacyFeatures)
+                }
+            }
             OsSubcommand::Switch(args)
             | OsSubcommand::Boot(args)
             | OsSubcommand::Test(args)
@@ -160,6 +167,9 @@ pub enum OsSubcommand {
     /// Load system in a repl
     Repl(OsReplArgs),
 
+    /// Edit a NixOS configuration
+    Edit(OsEditArgs),
+
     /// List available generations from profile path
     Info(OsGenerationsArgs),
 
@@ -316,7 +326,29 @@ impl OsReplArgs {
     #[must_use]
     pub fn uses_flakes(&self) -> bool {
         // Check environment variables first
-        if env::var("NH_OS_FLAKE").is_ok() {
+        if env::var("NH_OS_FLAKE").is_ok_and(|v| !v.is_empty()) {
+            return true;
+        }
+
+        // Check installable type
+        matches!(self.installable, Installable::Flake { .. })
+    }
+}
+
+#[derive(Debug, Args)]
+pub struct OsEditArgs {
+    #[command(flatten)]
+    pub installable: Installable,
+
+    /// When using a flake installable, select this hostname from nixosConfigurations
+    #[arg(long, short = 'H', global = true)]
+    pub hostname: Option<String>,
+}
+
+impl OsEditArgs {
+    pub fn uses_flakes(&self) -> bool {
+        // Check environment variables first
+        if env::var("NH_OS_FLAKE").is_ok_and(|v| !v.is_empty()) {
             return true;
         }
 
@@ -447,6 +479,13 @@ impl HomeArgs {
                 let is_flake = args.uses_flakes();
                 Box::new(HomeReplFeatures { is_flake })
             }
+            HomeSubcommand::Edit(args) => {
+                if args.uses_flakes() {
+                    Box::new(FlakeFeatures)
+                } else {
+                    Box::new(LegacyFeatures)
+                }
+            }
             HomeSubcommand::Switch(args) | HomeSubcommand::Build(args) => {
                 if args.uses_flakes() {
                     Box::new(FlakeFeatures)
@@ -468,6 +507,9 @@ pub enum HomeSubcommand {
 
     /// Load a home-manager configuration in a Nix REPL
     Repl(HomeReplArgs),
+
+    /// Edit a home-manager configuration
+    Edit(HomeEditArgs),
 }
 
 #[derive(Debug, Args)]
@@ -543,6 +585,34 @@ impl HomeReplArgs {
     }
 }
 
+#[derive(Debug, Args)]
+pub struct HomeEditArgs {
+    #[command(flatten)]
+    pub installable: Installable,
+
+    /// Name of the flake homeConfigurations attribute, like username@hostname
+    ///
+    /// If unspecified, will try <username>@<hostname> and <username>
+    #[arg(long, short)]
+    pub configuration: Option<String>,
+
+    /// Extra arguments passed to nix repl
+    #[arg(last = true)]
+    pub extra_args: Vec<String>,
+}
+
+impl HomeEditArgs {
+    pub fn uses_flakes(&self) -> bool {
+        // Check environment variables first
+        if env::var("NH_HOME_FLAKE").is_ok_and(|v| !v.is_empty()) {
+            return true;
+        }
+
+        // Check installable type
+        matches!(self.installable, Installable::Flake { .. })
+    }
+}
+
 #[derive(Debug, Parser)]
 /// Generate shell completion files into stdout
 pub struct CompletionArgs {
@@ -567,6 +637,13 @@ impl DarwinArgs {
                 let is_flake = args.uses_flakes();
                 Box::new(DarwinReplFeatures { is_flake })
             }
+            DarwinSubcommand::Edit(args) => {
+                if args.uses_flakes() {
+                    Box::new(FlakeFeatures)
+                } else {
+                    Box::new(LegacyFeatures)
+                }
+            }
             DarwinSubcommand::Switch(args) | DarwinSubcommand::Build(args) => {
                 if args.uses_flakes() {
                     Box::new(FlakeFeatures)
@@ -586,6 +663,8 @@ pub enum DarwinSubcommand {
     Build(DarwinRebuildArgs),
     /// Load a nix-darwin configuration in a Nix REPL
     Repl(DarwinReplArgs),
+    /// Edit a nix-darwin configuration
+    Edit(DarwinEditArgs),
 }
 
 #[derive(Debug, Args)]
@@ -645,6 +724,28 @@ impl DarwinReplArgs {
     }
 }
 
+#[derive(Debug, Args)]
+pub struct DarwinEditArgs {
+    #[command(flatten)]
+    pub installable: Installable,
+
+    /// When using a flake installable, select this hostname from darwinConfigurations
+    #[arg(long, short = 'H', global = true)]
+    pub hostname: Option<String>,
+}
+
+impl DarwinEditArgs {
+    pub fn uses_flakes(&self) -> bool {
+        // Check environment variables first
+        if env::var("NH_DARWIN_FLAKE").is_ok_and(|v| !v.is_empty()) {
+            return true;
+        }
+
+        // Check installable type
+        matches!(self.installable, Installable::Flake { .. })
+    }
+}
+
 #[derive(Debug, Args)]
 pub struct UpdateArgs {
     #[arg(short = 'u', long = "update", conflicts_with = "update_input")]