Backend trait refactors

- Refactor the confusing/bodgy consts backend macro to use a single
  `BackendInfo` struct
- Combine `supports_as_dependency()` and the `switches_dependency` into a single `Option` type as that is a better representation as it is an optional backend feature.
- Add more types like `Packages`, `Sections` for uniformity.
- Added a crate-private prelude and switches all imports to use a
  prelude glob import (excluding functions because it's nice to only be
  importing types)
- Refactored Backend section name in logging by implementing Display for
  `AnyBackend` that just prints the `section`

crates/pacdef/src/backend/actual/arch.rs

@@ -5,52 +5,37 @@ use alpm::Alpm;
 use alpm::PackageReason::Explicit;
 use anyhow::{Context, Result};
 
-use crate::backend::backend_trait::{Backend, Switches, Text};
-use crate::backend::macros::impl_backend_constants;
 use crate::cmd::run_external_command;
-use crate::Package;
+use crate::prelude::*;
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
 pub struct Arch {
     pub binary: String,
     pub aur_rm_args: Vec<String>,
-    pub packages: HashSet<Package>,
 }
 impl Arch {
-    pub fn new() -> Self {
+    pub fn new(config: &Config) -> Self {
         Self {
-            binary: BINARY.to_string(),
+            binary: config.aur_helper.clone(),
-            aur_rm_args: vec![],
+            aur_rm_args: config.aur_rm_args.clone(),
-            packages: HashSet::new(),
         }
     }
 }
-impl Default for Arch {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
-const BINARY: Text = "pacman";
-const SECTION: Text = "arch";
-
-const SWITCHES_INFO: Switches = &["--query", "--info"];
-const SWITCHES_INSTALL: Switches = &["--sync"];
-const SWITCHES_MAKE_DEPENDENCY: Switches = &["--database", "--asdeps"];
-const SWITCHES_NOCONFIRM: Switches = &["--noconfirm"];
-const SWITCHES_REMOVE: Switches = &["--remove", "--recursive"];
-
-const SUPPORTS_AS_DEPENDENCY: bool = true;
 
 impl Backend for Arch {
-    impl_backend_constants!();
+    fn backend_info(&self) -> BackendInfo {
-
+        BackendInfo {
-    fn get_binary(&self) -> Text {
+            binary: self.binary.clone(),
-        let r#box = self.binary.clone().into_boxed_str();
+            section: "arch",
-        Box::leak(r#box)
+            switches_info: &["--query", "--info"],
+            switches_install: &["--sync"],
+            switches_noconfirm: &["--noconfirm"],
+            switches_remove: &["--remove", "--recursive"],
+            switches_make_dependency: Some(&["--database", "--asdeps"]),
+        }
     }
 
-    fn get_all_installed_packages(&self) -> Result<HashSet<Package>> {
+    fn get_all_installed_packages(&self) -> Result<Packages> {
         let alpm_packages = get_all_installed_packages_from_alpm()
             .context("getting all installed packages from alpm")?;
 
@@ -58,7 +43,7 @@ impl Backend for Arch {
         Ok(result)
     }
 
-    fn get_explicitly_installed_packages(&self) -> Result<HashSet<Package>> {
+    fn get_explicitly_installed_packages(&self) -> Result<Packages> {
         let alpm_packages = get_explicitly_installed_packages_from_alpm()
             .context("getting all installed packages from alpm")?;
         let result = convert_to_pacdef_packages(alpm_packages);
@@ -67,12 +52,14 @@ impl Backend for Arch {
 
     /// Install the specified packages.
     fn install_packages(&self, packages: &[Package], noconfirm: bool) -> Result<()> {
+        let backend_info = self.backend_info();
+
         let mut cmd = Command::new(&self.binary);
 
-        cmd.args(self.get_switches_install());
+        cmd.args(backend_info.switches_install);
 
         if noconfirm {
-            cmd.args(self.get_switches_noconfirm());
+            cmd.args(backend_info.switches_noconfirm);
         }
 
         for p in packages {
@@ -84,13 +71,15 @@ impl Backend for Arch {
 
     /// Remove the specified packages.
     fn remove_packages(&self, packages: &[Package], noconfirm: bool) -> Result<()> {
+        let backend_info = self.backend_info();
+
         let mut cmd = Command::new(&self.binary);
 
-        cmd.args(self.get_switches_remove());
+        cmd.args(backend_info.switches_remove);
         cmd.args(&self.aur_rm_args);
 
         if noconfirm {
-            cmd.args(self.get_switches_noconfirm());
+            cmd.args(backend_info.switches_noconfirm);
         }
 
         for p in packages {
@@ -124,7 +113,7 @@ fn get_explicitly_installed_packages_from_alpm() -> Result<HashSet<String>> {
     Ok(result)
 }
 
-fn convert_to_pacdef_packages(packages: HashSet<String>) -> HashSet<Package> {
+fn convert_to_pacdef_packages(packages: HashSet<String>) -> Packages {
     packages.into_iter().map(Package::from).collect()
 }
 

crates/pacdef/src/backend/actual/debian.rs

@@ -1,24 +1,16 @@
-use std::collections::HashSet;
-
 use anyhow::Result;
 use rust_apt::cache::PackageSort;
 use rust_apt::new_cache;
 
-use crate::backend::backend_trait::{Backend, Switches, Text};
-use crate::backend::macros::impl_backend_constants;
 use crate::backend::root::build_base_command_with_privileges;
 use crate::cmd::run_external_command;
-use crate::Package;
+use crate::prelude::*;
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
-pub struct Debian {
+pub struct Debian {}
-    pub packages: HashSet<Package>,
-}
 impl Debian {
     pub fn new() -> Self {
-        Self {
+        Self {}
-            packages: HashSet::new(),
-        }
     }
 }
 impl Default for Debian {
@@ -27,36 +19,35 @@ impl Default for Debian {
     }
 }
 
-const BINARY: Text = "apt";
-const SECTION: Text = "debian";
-
-const SWITCHES_INFO: Switches = &["show"];
-const SWITCHES_INSTALL: Switches = &["install"];
-const SWITCHES_MAKE_DEPENDENCY: Switches = &[]; // not needed
-const SWITCHES_NOCONFIRM: Switches = &["--yes"];
-const SWITCHES_REMOVE: Switches = &["remove"];
-
-const SUPPORTS_AS_DEPENDENCY: bool = true;
-
 impl Backend for Debian {
-    impl_backend_constants!();
+    fn backend_info(&self) -> BackendInfo {
+        BackendInfo {
+            binary: "apt".to_string(),
+            section: "debian",
+            switches_info: &["show"],
+            switches_install: &["install"],
+            switches_noconfirm: &["--yes"],
+            switches_remove: &["remove"],
+            switches_make_dependency: Some(&[]),
+        }
+    }
 
-    fn get_all_installed_packages(&self) -> Result<HashSet<Package>> {
+    fn get_all_installed_packages(&self) -> Result<Packages> {
         let cache = new_cache!()?;
         let sort = PackageSort::default().installed();
 
-        let mut result = HashSet::new();
+        let mut result = Packages::new();
         for pkg in cache.packages(&sort)? {
             result.insert(Package::from(pkg.name().to_string()));
         }
         Ok(result)
     }
 
-    fn get_explicitly_installed_packages(&self) -> Result<HashSet<Package>> {
+    fn get_explicitly_installed_packages(&self) -> Result<Packages> {
         let cache = new_cache!()?;
         let sort = PackageSort::default().installed().manually_installed();
 
-        let mut result = HashSet::new();
+        let mut result = Packages::new();
         for pkg in cache.packages(&sort)? {
             result.insert(Package::from(pkg.name().to_string()));
         }
@@ -75,12 +66,14 @@ impl Backend for Debian {
 
     /// Install the specified packages.
     fn install_packages(&self, packages: &[Package], noconfirm: bool) -> Result<()> {
-        let mut cmd = build_base_command_with_privileges(self.get_binary());
+        let backend_info = self.backend_info();
 
-        cmd.args(self.get_switches_install());
+        let mut cmd = build_base_command_with_privileges(&backend_info.binary);
+
+        cmd.args(backend_info.switches_install);
 
         if noconfirm {
-            cmd.args(self.get_switches_noconfirm());
+            cmd.args(backend_info.switches_noconfirm);
         }
 
         for p in packages {
@@ -92,11 +85,13 @@ impl Backend for Debian {
 
     /// Remove the specified packages.
     fn remove_packages(&self, packages: &[Package], noconfirm: bool) -> Result<()> {
-        let mut cmd = build_base_command_with_privileges(self.get_binary());
+        let backend_info = self.backend_info();
-        cmd.args(self.get_switches_remove());
+
+        let mut cmd = build_base_command_with_privileges(&backend_info.binary);
+        cmd.args(backend_info.switches_remove);
 
         if noconfirm {
-            cmd.args(self.get_switches_noconfirm());
+            cmd.args(backend_info.switches_noconfirm);
         }
 
         for p in packages {

crates/pacdef/src/backend/actual/fedora.rs

@@ -1,22 +1,15 @@
-use std::collections::HashSet;
 use std::process::Command;
 
 use anyhow::Result;
 
-use crate::backend::backend_trait::{Backend, Switches, Text};
-use crate::backend::macros::impl_backend_constants;
 use crate::cmd::run_external_command;
-use crate::Package;
+use crate::prelude::*;
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
-pub struct Fedora {
+pub struct Fedora {}
-    pub packages: HashSet<Package>,
-}
 impl Fedora {
     pub fn new() -> Self {
-        Self {
+        Self {}
-            packages: HashSet::new(),
-        }
     }
 }
 impl Default for Fedora {
@@ -25,16 +18,9 @@ impl Default for Fedora {
     }
 }
 
-const BINARY: Text = "dnf";
+/// These repositories are ignored when storing the packages
-const SECTION: Text = "fedora";
+/// as these are present by default on any sane fedora system
-
+const DEFAULT_REPOS: [&str; 5] = ["koji", "fedora", "updates", "anaconda", "@"];
-const SWITCHES_INFO: Switches = &["info"];
-const SWITCHES_INSTALL: Switches = &["install"];
-const SWITCHES_MAKE_DEPENDENCY: Switches = &[];
-const SWITCHES_NOCONFIRM: Switches = &["--assumeyes"];
-const SWITCHES_REMOVE: Switches = &["remove"];
-
-const SUPPORTS_AS_DEPENDENCY: bool = false;
 
 /// These switches are responsible for
 /// getting the packages explicitly installed by the user
@@ -54,15 +40,21 @@ const SWITCHES_FETCH_GLOBAL: Switches = &[
     "%{from_repo}/%{name}",
 ];
 
-/// These repositories are ignored when storing the packages
-/// as these are present by default on any sane fedora system
-const DEFAULT_REPOS: [&str; 5] = ["koji", "fedora", "updates", "anaconda", "@"];
-
 impl Backend for Fedora {
-    impl_backend_constants!();
+    fn backend_info(&self) -> BackendInfo {
+        BackendInfo {
+            binary: "dnf".to_string(),
+            section: "fedora",
+            switches_info: &["info"],
+            switches_install: &["install"],
+            switches_noconfirm: &["--assumeyes"],
+            switches_remove: &["remove"],
+            switches_make_dependency: None,
+        }
+    }
 
-    fn get_all_installed_packages(&self) -> Result<HashSet<Package>> {
+    fn get_all_installed_packages(&self) -> Result<Packages> {
-        let mut cmd = Command::new(self.get_binary());
+        let mut cmd = Command::new(self.backend_info().binary);
         cmd.args(SWITCHES_FETCH_GLOBAL);
 
         let output = String::from_utf8(cmd.output()?.stdout)?;
@@ -71,8 +63,8 @@ impl Backend for Fedora {
         Ok(packages)
     }
 
-    fn get_explicitly_installed_packages(&self) -> Result<HashSet<Package>> {
+    fn get_explicitly_installed_packages(&self) -> Result<Packages> {
-        let mut cmd = Command::new(self.get_binary());
+        let mut cmd = Command::new(self.backend_info().binary);
         cmd.args(SWITCHES_FETCH_USER);
 
         let output = String::from_utf8(cmd.output()?.stdout)?;
@@ -83,12 +75,14 @@ impl Backend for Fedora {
 
     /// Install the specified packages.
     fn install_packages(&self, packages: &[Package], noconfirm: bool) -> Result<()> {
+        let backend_info = self.backend_info();
+
         let mut cmd = Command::new("sudo");
-        cmd.arg(self.get_binary());
+        cmd.arg(backend_info.binary);
-        cmd.args(self.get_switches_install());
+        cmd.args(backend_info.switches_install);
 
         if noconfirm {
-            cmd.args(self.get_switches_noconfirm());
+            cmd.args(backend_info.switches_noconfirm);
         }
 
         for p in packages {
@@ -107,12 +101,14 @@ impl Backend for Fedora {
 
     /// Show information from package manager for package.
     fn remove_packages(&self, packages: &[Package], noconfirm: bool) -> Result<()> {
+        let backend_info = self.backend_info();
+
         let mut cmd = Command::new("sudo");
-        cmd.arg(self.get_binary());
+        cmd.arg(backend_info.binary);
-        cmd.args(self.get_switches_remove());
+        cmd.args(backend_info.switches_remove);
 
         if noconfirm {
-            cmd.args(self.get_switches_noconfirm());
+            cmd.args(backend_info.switches_noconfirm);
         }
 
         for p in packages {
@@ -123,8 +119,10 @@ impl Backend for Fedora {
     }
 
     fn show_package_info(&self, package: &Package) -> Result<()> {
-        let mut cmd = Command::new(self.get_binary());
+        let backend_info = self.backend_info();
-        cmd.args(self.get_switches_info());
+
+        let mut cmd = Command::new(backend_info.binary);
+        cmd.args(backend_info.switches_info);
         cmd.arg(&package.name);
 
         run_external_command(cmd)

crates/pacdef/src/backend/actual/flatpak.rs

@@ -1,23 +1,18 @@
-use std::collections::HashSet;
 use std::process::Command;
 
 use anyhow::Result;
 
-use crate::backend::backend_trait::{Backend, Switches, Text};
-use crate::backend::macros::impl_backend_constants;
 use crate::cmd::run_external_command;
-use crate::Package;
+use crate::prelude::*;
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
 pub struct Flatpak {
-    pub packages: HashSet<Package>,
     pub systemwide: bool,
 }
 impl Flatpak {
-    pub fn new() -> Self {
+    pub fn new(config: &Config) -> Self {
         Self {
-            packages: HashSet::new(),
+            systemwide: config.flatpak_systemwide,
-            systemwide: true,
         }
     }
 
@@ -29,8 +24,8 @@ impl Flatpak {
         }
     }
 
-    fn get_installed_packages(&self, include_implicit: bool) -> Result<HashSet<Package>> {
+    fn get_installed_packages(&self, include_implicit: bool) -> Result<Packages> {
-        let mut cmd = Command::new(BINARY);
+        let mut cmd = Command::new(self.backend_info().binary);
         cmd.args(["list", "--columns=application"]);
         if !include_implicit {
             cmd.arg("--app");
@@ -40,48 +35,41 @@ impl Flatpak {
         }
 
         let output = String::from_utf8(cmd.output()?.stdout)?;
-        Ok(output
+        Ok(output.lines().map(Package::from).collect::<Packages>())
-            .lines()
-            .map(Package::from)
-            .collect::<HashSet<Package>>())
     }
 }
-impl Default for Flatpak {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
-const BINARY: Text = "flatpak";
-const SECTION: Text = "flatpak";
-
-const SWITCHES_INSTALL: Switches = &["install"];
-const SWITCHES_INFO: Switches = &["info"];
-const SWITCHES_MAKE_DEPENDENCY: Switches = &[];
-const SWITCHES_NOCONFIRM: Switches = &["--assumeyes"];
-const SWITCHES_REMOVE: Switches = &["uninstall"];
-
-const SUPPORTS_AS_DEPENDENCY: bool = false;
 
 impl Backend for Flatpak {
-    impl_backend_constants!();
+    fn backend_info(&self) -> BackendInfo {
+        BackendInfo {
+            binary: "flatpak".to_string(),
+            section: "flatpak",
+            switches_info: &["info"],
+            switches_install: &["install"],
+            switches_noconfirm: &["--assumeyes"],
+            switches_remove: &["uninstall"],
+            switches_make_dependency: None,
+        }
+    }
 
-    fn get_all_installed_packages(&self) -> Result<HashSet<Package>> {
+    fn get_all_installed_packages(&self) -> Result<Packages> {
         self.get_installed_packages(true)
     }
 
-    fn get_explicitly_installed_packages(&self) -> Result<HashSet<Package>> {
+    fn get_explicitly_installed_packages(&self) -> Result<Packages> {
         self.get_installed_packages(false)
     }
 
     /// Install the specified packages.
     fn install_packages(&self, packages: &[Package], noconfirm: bool) -> Result<()> {
-        let mut cmd = Command::new(self.get_binary());
+        let backend_info = self.backend_info();
-        cmd.args(self.get_switches_install());
+
+        let mut cmd = Command::new(backend_info.binary);
+        cmd.args(backend_info.switches_install);
         cmd.args(self.get_switches_runtime());
 
         if noconfirm {
-            cmd.args(self.get_switches_noconfirm());
+            cmd.args(backend_info.switches_noconfirm);
         }
 
         for p in packages {
@@ -92,17 +80,19 @@ impl Backend for Flatpak {
     }
 
     fn make_dependency(&self, _: &[Package]) -> Result<()> {
-        panic!("not supported by {}", BINARY)
+        panic!("not supported by {}", self.backend_info().binary)
     }
 
     /// Remove the specified packages.
     fn remove_packages(&self, packages: &[Package], noconfirm: bool) -> Result<()> {
-        let mut cmd = Command::new(self.get_binary());
+        let backend_info = self.backend_info();
-        cmd.args(self.get_switches_remove());
+
+        let mut cmd = Command::new(backend_info.binary);
+        cmd.args(backend_info.switches_remove);
         cmd.args(self.get_switches_runtime());
 
         if noconfirm {
-            cmd.args(self.get_switches_noconfirm());
+            cmd.args(backend_info.switches_noconfirm);
         }
 
         for p in packages {
@@ -114,8 +104,10 @@ impl Backend for Flatpak {
 
     /// Show information from package manager for package.
     fn show_package_info(&self, package: &Package) -> Result<()> {
-        let mut cmd = Command::new(self.get_binary());
+        let backend_info = self.backend_info();
-        cmd.args(self.get_switches_info());
+
+        let mut cmd = Command::new(backend_info.binary);
+        cmd.args(backend_info.switches_info);
         cmd.args(self.get_switches_runtime());
         cmd.arg(format!("{package}"));
 

crates/pacdef/src/backend/actual/python.rs

@@ -1,13 +1,10 @@
-use std::collections::HashSet;
 use std::process::Command;
 
 use anyhow::Context;
 use anyhow::Result;
 use serde_json::Value;
 
-use crate::backend::backend_trait::{Backend, Switches, Text};
+use crate::prelude::*;
-use crate::backend::macros::impl_backend_constants;
-use crate::Package;
 
 macro_rules! ERROR{
     ($bin:expr) => {
@@ -15,81 +12,68 @@ macro_rules! ERROR{
     };
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
 pub struct Python {
     pub binary: String,
-    pub packages: HashSet<Package>,
 }
 impl Python {
-    pub fn new() -> Self {
+    pub fn new(config: &Config) -> Self {
         Self {
-            binary: BINARY.to_string(),
+            binary: config.pip_binary.to_string(),
-            packages: HashSet::new(),
         }
     }
 
     fn get_switches_runtime(&self) -> Switches {
-        match self.get_binary() {
+        match self.backend_info().binary.as_str() {
             "pip" => &["list", "--format", "json", "--not-required", "--user"],
             "pipx" => &["list", "--json"],
-            _ => ERROR!(self.get_binary()),
+            _ => ERROR!(self.backend_info().binary),
         }
     }
     fn get_switches_explicit(&self) -> Switches {
-        match self.get_binary() {
+        match self.backend_info().binary.as_str() {
             "pip" => &["list", "--format", "json", "--user"],
             "pipx" => &["list", "--json"],
-            _ => ERROR!(self.get_binary()),
+            _ => ERROR!(self.backend_info().binary),
         }
     }
 
-    fn extract_packages(&self, output: Value) -> Result<HashSet<Package>> {
+    fn extract_packages(&self, output: Value) -> Result<Packages> {
-        match self.get_binary() {
+        match self.backend_info().binary.as_str() {
             "pip" => extract_pacdef_packages(output),
             "pipx" => extract_pacdef_packages_pipx(output),
-            _ => ERROR!(self.get_binary()),
+            _ => ERROR!(self.backend_info().binary),
         }
     }
 }
-impl Default for Python {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
-const BINARY: Text = "pip";
-const SECTION: Text = "python";
-
-const SWITCHES_INFO: Switches = &["show"];
-const SWITCHES_INSTALL: Switches = &["install"];
-const SWITCHES_MAKE_DEPENDENCY: Switches = &[]; // not needed
-const SWITCHES_NOCONFIRM: Switches = &[]; // not needed
-const SWITCHES_REMOVE: Switches = &["uninstall"];
-
-const SUPPORTS_AS_DEPENDENCY: bool = false;
 
 impl Backend for Python {
-    impl_backend_constants!();
+    fn backend_info(&self) -> BackendInfo {
-
+        BackendInfo {
-    fn get_binary(&self) -> Text {
+            binary: self.binary.clone(),
-        let r#box = self.binary.clone().into_boxed_str();
+            section: "python",
-        Box::leak(r#box)
+            switches_info: &["show"],
+            switches_install: &["install"],
+            switches_noconfirm: &[],
+            switches_remove: &["uninstall"],
+            switches_make_dependency: None,
+        }
     }
 
-    fn get_all_installed_packages(&self) -> Result<HashSet<Package>> {
+    fn get_all_installed_packages(&self) -> Result<Packages> {
-        let mut cmd = Command::new(self.get_binary());
+        let mut cmd = Command::new(self.backend_info().binary);
         let output = run_pip_command(&mut cmd, self.get_switches_runtime())?;
         self.extract_packages(output)
     }
 
-    fn get_explicitly_installed_packages(&self) -> Result<HashSet<Package>> {
+    fn get_explicitly_installed_packages(&self) -> Result<Packages> {
-        let mut cmd = Command::new(self.get_binary());
+        let mut cmd = Command::new(self.backend_info().binary);
         let output = run_pip_command(&mut cmd, self.get_switches_explicit())?;
         self.extract_packages(output)
     }
 
     fn make_dependency(&self, _packages: &[Package]) -> Result<()> {
-        panic!("not supported by {}", BINARY)
+        panic!("not supported by {}", self.binary)
     }
 }
 
@@ -100,7 +84,7 @@ fn run_pip_command(cmd: &mut Command, args: &[&str]) -> Result<Value> {
     Ok(val)
 }
 
-fn extract_pacdef_packages(value: Value) -> Result<HashSet<Package>> {
+fn extract_pacdef_packages(value: Value) -> Result<Packages> {
     let result = value
         .as_array()
         .context("getting inner json array")?
@@ -111,7 +95,7 @@ fn extract_pacdef_packages(value: Value) -> Result<HashSet<Package>> {
     Ok(result)
 }
 
-fn extract_pacdef_packages_pipx(value: Value) -> Result<HashSet<Package>> {
+fn extract_pacdef_packages_pipx(value: Value) -> Result<Packages> {
     let result = value["venvs"]
         .as_object()
         .context("getting inner json object")?

crates/pacdef/src/backend/actual/rust.rs

@@ -1,4 +1,3 @@
-use std::collections::HashSet;
 use std::fs::read_to_string;
 use std::io::ErrorKind::NotFound;
 use std::path::PathBuf;
@@ -6,19 +5,13 @@ use std::path::PathBuf;
 use anyhow::{bail, Context, Result};
 use serde_json::Value;
 
-use crate::backend::backend_trait::{Backend, Switches, Text};
+use crate::prelude::*;
-use crate::backend::macros::impl_backend_constants;
-use crate::Package;
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
-pub struct Rust {
+pub struct Rust {}
-    pub packages: HashSet<Package>,
-}
 impl Rust {
     pub fn new() -> Self {
-        Self {
+        Self {}
-            packages: HashSet::new(),
-        }
     }
 }
 impl Default for Rust {
@@ -27,28 +20,27 @@ impl Default for Rust {
     }
 }
 
-const BINARY: Text = "cargo";
-const SECTION: Text = "rust";
-
-const SWITCHES_INSTALL: Switches = &["install"];
-const SWITCHES_INFO: Switches = &["search", "--limit", "1"];
-const SWITCHES_MAKE_DEPENDENCY: Switches = &[];
-const SWITCHES_NOCONFIRM: Switches = &[]; // not needed
-const SWITCHES_REMOVE: Switches = &["uninstall"];
-
-const SUPPORTS_AS_DEPENDENCY: bool = false;
-
 impl Backend for Rust {
-    impl_backend_constants!();
+    fn backend_info(&self) -> BackendInfo {
+        BackendInfo {
+            binary: "cargo".to_string(),
+            section: "rust",
+            switches_info: &["search", "--limit", "1"],
+            switches_install: &["install"],
+            switches_noconfirm: &[],
+            switches_remove: &["uninstall"],
+            switches_make_dependency: None,
+        }
+    }
 
-    fn get_all_installed_packages(&self) -> Result<HashSet<Package>> {
+    fn get_all_installed_packages(&self) -> Result<Packages> {
         let file = get_crates_file().context("getting path to crates file")?;
 
         let content = match read_to_string(file) {
             Ok(string) => string,
             Err(err) if err.kind() == NotFound => {
                 log::warn!("no crates file found for cargo. Assuming no crates installed yet.");
-                return Ok(HashSet::new());
+                return Ok(Packages::new());
             }
             Err(err) => bail!(err),
         };
@@ -58,18 +50,18 @@ impl Backend for Rust {
         extract_packages(&json).context("extracting packages from crates file")
     }
 
-    fn get_explicitly_installed_packages(&self) -> Result<HashSet<Package>> {
+    fn get_explicitly_installed_packages(&self) -> Result<Packages> {
         self.get_all_installed_packages()
             .context("getting all installed packages")
     }
 
     fn make_dependency(&self, _: &[Package]) -> Result<()> {
-        panic!("not supported by {}", BINARY)
+        panic!("not supported by {}", self.backend_info().binary)
     }
 }
 
-fn extract_packages(json: &Value) -> Result<HashSet<Package>> {
+fn extract_packages(json: &Value) -> Result<Packages> {
-    let result: HashSet<_> = json
+    let result: Packages = json
         .get("installs")
         .context("get 'installs' field from json")?
         .as_object()
@@ -83,6 +75,7 @@ fn extract_packages(json: &Value) -> Result<HashSet<Package>> {
         })
         .map(|name| Package::try_from(name).expect("name is valid"))
         .collect();
+
     Ok(result)
 }
 

crates/pacdef/src/backend/actual/rustup/mod.rs

@@ -1,12 +1,9 @@
 mod helpers;
 mod types;
 
-use crate::backend::backend_trait::{Backend, Switches, Text};
-use crate::backend::macros::impl_backend_constants;
 use crate::cmd::run_external_command;
-use crate::Package;
+use crate::prelude::*;
 use anyhow::{bail, Context, Result};
-use std::collections::HashSet;
 use std::process::Command;
 
 use self::helpers::{
@@ -14,15 +11,11 @@ use self::helpers::{
 };
 use self::types::{Repotype, RustupPackage};
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
-pub struct Rustup {
+pub struct Rustup {}
-    pub packages: HashSet<Package>,
-}
 impl Rustup {
     pub fn new() -> Self {
-        Self {
+        Self {}
-            packages: HashSet::new(),
-        }
     }
 }
 impl Default for Rustup {
@@ -31,38 +24,37 @@ impl Default for Rustup {
     }
 }
 
-const BINARY: Text = "rustup";
-const SECTION: Text = "rustup";
-
-const SWITCHES_INSTALL: Switches = &["component", "add"];
-const SWITCHES_INFO: Switches = &["component", "list", "--installed"];
-const SWITCHES_MAKE_DEPENDENCY: Switches = &[];
-const SWITCHES_NOCONFIRM: Switches = &[];
-const SWITCHES_REMOVE: Switches = &["component", "remove"];
-
-const SUPPORTS_AS_DEPENDENCY: bool = false;
-
 impl Backend for Rustup {
-    impl_backend_constants!();
+    fn backend_info(&self) -> BackendInfo {
+        BackendInfo {
+            binary: "rustup".to_string(),
+            section: "rustup",
+            switches_install: &["component", "add"],
+            switches_info: &["component", "list", "--installed"],
+            switches_noconfirm: &[],
+            switches_remove: &["component", "remove"],
+            switches_make_dependency: None,
+        }
+    }
 
-    fn get_all_installed_packages(&self) -> Result<HashSet<Package>> {
+    fn get_all_installed_packages(&self) -> Result<Packages> {
         let toolchains_vec = self
             .run_toolchain_command(Repotype::Toolchain.get_info_switches())
             .context("Getting installed toolchains")?;
 
-        let toolchains: HashSet<Package> = toolchains_vec
+        let toolchains: Packages = toolchains_vec
             .iter()
             .map(|name| ["toolchain", name].join("/").into())
             .collect();
 
-        let components: HashSet<Package> = self
+        let components: Packages = self
             .run_component_command(Repotype::Component.get_info_switches(), &toolchains_vec)
             .context("Getting installed components")?
             .iter()
             .map(|name| ["component", name].join("/").into())
             .collect();
 
-        let mut packages = HashSet::new();
+        let mut packages = Packages::new();
 
         packages.extend(toolchains);
         packages.extend(components);
@@ -70,13 +62,13 @@ impl Backend for Rustup {
         Ok(packages)
     }
 
-    fn get_explicitly_installed_packages(&self) -> Result<HashSet<Package>> {
+    fn get_explicitly_installed_packages(&self) -> Result<Packages> {
         self.get_all_installed_packages()
             .context("Getting all installed packages")
     }
 
     fn make_dependency(&self, _: &[Package]) -> Result<()> {
-        panic!("Not supported by {}", self.get_binary())
+        panic!("Not supported by {}", self.backend_info().binary)
     }
 
     fn install_packages(&self, packages: &[Package], _: bool) -> Result<()> {
@@ -110,7 +102,7 @@ impl Rustup {
         let mut val = Vec::new();
 
         for toolchain in toolchains {
-            let mut cmd = Command::new(self.get_binary());
+            let mut cmd = Command::new(self.backend_info().binary);
             cmd.args(args).arg(toolchain);
 
             let output = String::from_utf8(cmd.output()?.stdout)?;
@@ -124,7 +116,7 @@ impl Rustup {
     }
 
     fn run_toolchain_command(&self, args: &[&str]) -> Result<Vec<String>> {
-        let mut cmd = Command::new(self.get_binary());
+        let mut cmd = Command::new(self.backend_info().binary);
         cmd.args(args);
 
         let output = String::from_utf8(cmd.output()?.stdout)?;
@@ -146,7 +138,7 @@ impl Rustup {
         if toolchains.is_empty() {
             return Ok(());
         }
-        let mut cmd = Command::new(self.get_binary());
+        let mut cmd = Command::new(self.backend_info().binary);
         cmd.args(Repotype::Toolchain.get_install_switches());
 
         for toolchain in toolchains {
@@ -166,7 +158,7 @@ impl Rustup {
         let components_by_toolchain = group_components_by_toolchains(components);
 
         for components_for_one_toolchain in components_by_toolchain {
-            let mut cmd = Command::new(self.get_binary());
+            let mut cmd = Command::new(self.backend_info().binary);
             cmd.args(Repotype::Component.get_install_switches());
 
             let the_toolchain = &components_for_one_toolchain
@@ -195,7 +187,7 @@ impl Rustup {
     fn remove_toolchains(&self, toolchains: Vec<RustupPackage>) -> Result<Vec<String>> {
         let mut removed_toolchains = vec![];
         if !toolchains.is_empty() {
-            let mut cmd = Command::new(self.get_binary());
+            let mut cmd = Command::new(self.backend_info().binary);
             cmd.args(Repotype::Toolchain.get_remove_switches());
 
             for toolchain_package in &toolchains {
@@ -216,7 +208,7 @@ impl Rustup {
         removed_toolchains: Vec<String>,
     ) -> Result<()> {
         for component_package in components {
-            let mut cmd = Command::new(self.get_binary());
+            let mut cmd = Command::new(self.backend_info().binary);
             cmd.args(Repotype::Component.get_remove_switches());
 
             if toolchain_of_component_was_already_removed(&removed_toolchains, &component_package) {

crates/pacdef/src/backend/actual/rustup/types.rs

@@ -1,6 +1,6 @@
 use anyhow::{bail, Context, Result};
 
-use crate::{backend::backend_trait::Switches, Package};
+use crate::prelude::*;
 
 #[derive(Debug)]
 pub enum Repotype {

crates/pacdef/src/backend/actual/void.rs

@@ -1,24 +1,17 @@
-use std::collections::HashSet;
 use std::process::Command;
 
 use anyhow::Result;
 use regex::Regex;
 
-use crate::backend::backend_trait::{Backend, Switches, Text};
-use crate::backend::macros::impl_backend_constants;
 use crate::backend::root::build_base_command_with_privileges;
 use crate::cmd::run_external_command;
-use crate::Package;
+use crate::prelude::*;
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
-pub struct Void {
+pub struct Void {}
-    pub packages: HashSet<Package>,
-}
 impl Void {
     pub fn new() -> Self {
-        Self {
+        Self {}
-            packages: HashSet::new(),
-        }
     }
 }
 impl Default for Void {
@@ -27,25 +20,25 @@ impl Default for Void {
     }
 }
 
-const BINARY: Text = "xbps-install";
 const INSTALL_BINARY: Text = "xbps-install";
 const REMOVE_BINARY: Text = "xbps-remove";
 const QUERY_BINARY: Text = "xbps-query";
 const PKGDB_BINARY: Text = "xbps-pkgdb";
-const SECTION: Text = "void";
-
-const SWITCHES_INFO: Switches = &[];
-const SWITCHES_INSTALL: Switches = &["-S"];
-const SWITCHES_MAKE_DEPENDENCY: Switches = &["-m", "auto"];
-const SWITCHES_NOCONFIRM: Switches = &["-y"];
-const SWITCHES_REMOVE: Switches = &["-R"];
-
-const SUPPORTS_AS_DEPENDENCY: bool = true;
 
 impl Backend for Void {
-    impl_backend_constants!();
+    fn backend_info(&self) -> BackendInfo {
+        BackendInfo {
+            binary: "xbps-install".to_string(),
+            section: "void",
+            switches_info: &[],
+            switches_install: &["-S"],
+            switches_noconfirm: &["-y"],
+            switches_remove: &["-R"],
+            switches_make_dependency: Some(&["-m", "auto"]),
+        }
+    }
 
-    fn get_all_installed_packages(&self) -> Result<HashSet<Package>> {
+    fn get_all_installed_packages(&self) -> Result<Packages> {
         // Removes the package status and description from output
         let re_str_1 = r"^ii |^uu |^hr |^\?\? | .*";
         // Removes the package version from output
@@ -67,7 +60,7 @@ impl Backend for Void {
         Ok(packages)
     }
 
-    fn get_explicitly_installed_packages(&self) -> Result<HashSet<Package>> {
+    fn get_explicitly_installed_packages(&self) -> Result<Packages> {
         // Removes the package version from output
         let re_str = r"-[^-]*$";
         let re = Regex::new(re_str)?;
@@ -87,11 +80,13 @@ impl Backend for Void {
 
     /// Install the specified packages.
     fn install_packages(&self, packages: &[Package], noconfirm: bool) -> Result<()> {
+        let backend_info = self.backend_info();
+
         let mut cmd = build_base_command_with_privileges(INSTALL_BINARY);
-        cmd.args(self.get_switches_install());
+        cmd.args(backend_info.switches_install);
 
         if noconfirm {
-            cmd.args(self.get_switches_noconfirm());
+            cmd.args(backend_info.switches_noconfirm);
         }
 
         for p in packages {
@@ -102,11 +97,13 @@ impl Backend for Void {
     }
 
     fn remove_packages(&self, packages: &[Package], noconfirm: bool) -> Result<()> {
+        let backend_info = self.backend_info();
+
         let mut cmd = build_base_command_with_privileges(REMOVE_BINARY);
-        cmd.args(self.get_switches_remove());
+        cmd.args(backend_info.switches_remove);
 
         if noconfirm {
-            cmd.args(self.get_switches_noconfirm());
+            cmd.args(backend_info.switches_noconfirm);
         }
 
         for p in packages {
@@ -117,8 +114,14 @@ impl Backend for Void {
     }
 
     fn make_dependency(&self, packages: &[Package]) -> Result<()> {
+        let backend_info = self.backend_info();
+
         let mut cmd = build_base_command_with_privileges(PKGDB_BINARY);
-        cmd.args(self.get_switches_make_dependency());
+        cmd.args(
+            backend_info
+                .switches_make_dependency
+                .expect("void should support make make dependency"),
+        );
 
         for p in packages {
             cmd.arg(format!("{p}"));
@@ -129,8 +132,10 @@ impl Backend for Void {
 
     /// Show information from package manager for package.
     fn show_package_info(&self, package: &Package) -> Result<()> {
+        let backend_info = self.backend_info();
+
         let mut cmd = Command::new(QUERY_BINARY);
-        cmd.args(self.get_switches_info());
+        cmd.args(backend_info.switches_info);
         cmd.arg(format!("{package}"));
 
         run_external_command(cmd)

crates/pacdef/src/backend/backend_trait.rs

@@ -1,68 +1,54 @@
 use std::cmp::{Eq, Ord};
-use std::collections::{HashMap, HashSet};
+use std::collections::HashMap;
 use std::hash::Hash;
 use std::process::Command;
 
-use anyhow::{Context, Result};
+use anyhow::Result;
 
 use crate::cmd::run_external_command;
-use crate::{Group, Groups, Package};
+use crate::prelude::*;
 
 pub type Switches = &'static [&'static str];
 pub type Text = &'static str;
 
+// A bundle of small of bits of info associated with a backend.
+pub struct BackendInfo {
+    /// The binary name when calling the backend.
+    pub binary: String,
+    /// The name of the section in the group files.
+    pub section: Text,
+    /// CLI switches for the package manager to show information for
+    /// packages.
+    pub switches_info: Switches,
+    /// CLI switches for the package manager to install packages.
+    pub switches_install: Switches,
+    /// CLI switches for the package manager to perform `sync` and `clean` without
+    /// confirmation.
+    pub switches_noconfirm: Switches,
+    /// CLI switches for the package manager to remove packages.
+    pub switches_remove: Switches,
+    /// CLI switches for the package manager to mark packages as
+    /// dependency. This is not supported by all package managers.
+    pub switches_make_dependency: Option<Switches>,
+}
+
 /// The trait of a struct that is used as a backend.
 #[enum_dispatch::enum_dispatch]
 pub trait Backend {
-    /// Return the actual binary. Iff the backend supports different
+    /// Return the [`BackendInfo`] associated with this backend.
-    /// binaries, you will need to overwrite this implementation to return
+    fn backend_info(&self) -> BackendInfo;
-    /// the binary that was loaded at runtime. See
+
-    /// [`Backend::get_binary_default()`].
+    fn supports_as_dependency(&self) -> bool {
-    fn get_binary(&self) -> Text {
+        self.backend_info().switches_make_dependency.is_some()
-        self.get_binary_default()
     }
 
-    /// Return the default binary as defined in the constant of the module.
-    /// See [`Backend::get_binary()`].
-    fn get_binary_default(&self) -> Text;
-
-    /// Get the name of the section in the group files.
-    fn get_section(&self) -> Text;
-
-    /// Get CLI switches for the package manager to show information for
-    /// packages.
-    fn get_switches_info(&self) -> Switches;
-
-    /// Get CLI switches for the package manager to install packages.
-    fn get_switches_install(&self) -> Switches;
-
-    /// Get CLI switches for the package manager to perform `sync` and `clean` without
-    /// confirmation.
-    fn get_switches_noconfirm(&self) -> Switches;
-
-    /// Get CLI switches for the package manager to remove packages.
-    fn get_switches_remove(&self) -> Switches;
-
-    /// Get CLI switches for the package manager to mark packages as
-    /// dependency. This is not supported by all package managers. See
-    /// [`Backend::supports_as_dependency()`].
-    fn get_switches_make_dependency(&self) -> Switches;
-
-    /// Load all packages from a set of groups. The backend will visit all groups,
-    /// find its own section, and clone all packages into its own struct.
-    fn load(&mut self, groups: &Groups);
-
-    /// Get all managed packages for this backend, i.e. all packages
-    /// under the corresponding section in all group files.
-    fn get_managed_packages(&self) -> &HashSet<Package>;
-
     /// Get all packages that are installed in the system.
     ///
     /// # Errors
     ///
     /// This function shall return an error if the installed packages cannot be
     /// determined.
-    fn get_all_installed_packages(&self) -> Result<HashSet<Package>>;
+    fn get_all_installed_packages(&self) -> Result<Packages>;
 
     /// Get all packages that were installed in the system explicitly.
     ///
@@ -70,13 +56,17 @@ pub trait Backend {
     ///
     /// This function shall return an error if the explicitly installed packages
     /// cannot be determined.
-    fn get_explicitly_installed_packages(&self) -> Result<HashSet<Package>>;
+    fn get_explicitly_installed_packages(&self) -> Result<Packages>;
 
     /// Assign each of the packages to an individual group by editing the
     /// group files.
+    ///
+    /// # Errors
+    ///
+    /// Returns an Error if any of the groups fails to save their given packages.
     fn assign_group(&self, to_assign: Vec<(Package, Group)>) -> Result<()> {
         let group_package_map = to_hashmap(to_assign);
-        let section_header = format!("[{}]", self.get_section());
+        let section_header = format!("[{}]", self.backend_info().section);
 
         for (group, packages) in group_package_map {
             group.save_packages(&section_header, &packages)?;
@@ -93,11 +83,13 @@ pub trait Backend {
     /// This function will return an error if the package manager cannot be run or it
     /// returns an error.
     fn install_packages(&self, packages: &[Package], noconfirm: bool) -> Result<()> {
-        let mut cmd = Command::new(self.get_binary());
+        let backend_info = self.backend_info();
-        cmd.args(self.get_switches_install());
+
+        let mut cmd = Command::new(self.backend_info().binary);
+        cmd.args(backend_info.switches_install);
 
         if noconfirm {
-            cmd.args(self.get_switches_noconfirm());
+            cmd.args(backend_info.switches_noconfirm);
         }
 
         for p in packages {
@@ -113,9 +105,18 @@ pub trait Backend {
     /// # Panics
     ///
     /// This method shall panic when the backend does not support dependent packages.
+    ///
+    /// # Errors
+    ///
+    /// Returns an error if the external command fails.
     fn make_dependency(&self, packages: &[Package]) -> Result<()> {
-        let mut cmd = Command::new(self.get_binary());
+        let backend_info = self.backend_info();
-        cmd.args(self.get_switches_make_dependency());
+
+        let mut cmd = Command::new(backend_info.binary);
+
+        if let Some(switches_make_dependency) = backend_info.switches_make_dependency {
+            cmd.args(switches_make_dependency);
+        }
 
         for p in packages {
             cmd.arg(format!("{p}"));
@@ -126,12 +127,17 @@ pub trait Backend {
 
     /// Remove the specified packages.
     ///
+    /// # Errors
+    ///
+    /// Returns an error if the external command fails.
     fn remove_packages(&self, packages: &[Package], noconfirm: bool) -> Result<()> {
-        let mut cmd = Command::new(self.get_binary());
+        let backend_info = self.backend_info();
-        cmd.args(self.get_switches_remove());
+
+        let mut cmd = Command::new(backend_info.binary);
+        cmd.args(backend_info.switches_remove);
 
         if noconfirm {
-            cmd.args(self.get_switches_noconfirm());
+            cmd.args(backend_info.switches_noconfirm);
         }
 
         for p in packages {
@@ -141,39 +147,20 @@ pub trait Backend {
         run_external_command(cmd)
     }
 
-    /// Get missing packages, sorted alphabetically.
-    fn get_missing_packages_sorted(&self) -> Result<Vec<Package>> {
-        let installed = self
-            .get_all_installed_packages()
-            .context("could not get installed packages")?;
-        let managed = self.get_managed_packages();
-        let mut diff: Vec<_> = managed.difference(&installed).cloned().collect();
-        diff.sort_unstable();
-        Ok(diff)
-    }
-
     /// Show information from package manager for package.
+    ///
+    /// # Errors
+    ///
+    /// Returns an error if the external command fails.
     fn show_package_info(&self, package: &Package) -> Result<()> {
-        let mut cmd = Command::new(self.get_binary());
+        let backend_info = self.backend_info();
-        cmd.args(self.get_switches_info());
+
+        let mut cmd = Command::new(backend_info.binary);
+        cmd.args(backend_info.switches_info);
         cmd.arg(format!("{package}"));
 
         run_external_command(cmd)
     }
-
-    /// Get unmanaged packages, sorted alphabetically.
-    fn get_unmanaged_packages_sorted(&self) -> Result<Vec<Package>> {
-        let installed = self
-            .get_explicitly_installed_packages()
-            .context("could not get explicitly installed packages")?;
-        let required = self.get_managed_packages();
-        let mut diff: Vec<_> = installed.difference(required).cloned().collect();
-        diff.sort_unstable();
-        Ok(diff)
-    }
-
-    /// Whether the underlying package manager supports dependency packages.
-    fn supports_as_dependency(&self) -> bool;
 }
 
 /// For a vector of tuples containing a `V` and `K`, where a `K` may occur more than

crates/pacdef/src/backend/macros.rs

@@ -1,56 +0,0 @@
-/// Used to implement parts of the `Backend` trait that should not change between the actual
-/// backends (boilerplate).
-macro_rules! impl_backend_constants {
-    () => {
-        fn get_binary_default(&self) -> Text {
-            BINARY
-        }
-
-        fn get_section(&self) -> Text {
-            SECTION
-        }
-
-        fn get_switches_info(&self) -> Switches {
-            SWITCHES_INFO
-        }
-
-        fn get_switches_install(&self) -> Switches {
-            SWITCHES_INSTALL
-        }
-
-        fn get_switches_noconfirm(&self) -> Switches {
-            SWITCHES_NOCONFIRM
-        }
-
-        fn get_switches_remove(&self) -> Switches {
-            SWITCHES_REMOVE
-        }
-
-        fn get_switches_make_dependency(&self) -> Switches {
-            SWITCHES_MAKE_DEPENDENCY
-        }
-
-        fn get_managed_packages(&self) -> &HashSet<Package> {
-            &self.packages
-        }
-
-        fn load(&mut self, groups: &crate::Groups) {
-            let own_section_name = self.get_section();
-
-            groups
-                .iter()
-                .flat_map(|g| &g.sections)
-                .filter(|section| section.name == own_section_name)
-                .flat_map(|section| &section.packages)
-                .for_each(|package| {
-                    self.packages.insert(package.clone());
-                })
-        }
-
-        fn supports_as_dependency(&self) -> bool {
-            SUPPORTS_AS_DEPENDENCY
-        }
-    };
-}
-
-pub(crate) use impl_backend_constants;

crates/pacdef/src/backend/mod.rs

@@ -1,23 +1,53 @@
 pub mod actual;
 pub mod backend_trait;
-pub mod macros;
 mod root;
 pub mod todo_per_backend;
 
-use crate::backend::backend_trait::Switches;
+use std::fmt::Display;
-use crate::backend::backend_trait::Text;
-use crate::Group;
-use crate::Groups;
-use crate::Package;
-use anyhow::Result;
-use backend_trait::Backend;
-use std::collections::HashSet;
 
-use self::actual::{
+use crate::prelude::*;
-    fedora::Fedora, flatpak::Flatpak, python::Python, rust::Rust, rustup::Rustup, void::Void,
+use anyhow::{Context, Result};
-};
 
-#[derive(Debug)]
+// A backend with its associated managed packages
+pub struct ManagedBackend {
+    /// All managed packages for this backend, i.e. all packages
+    /// under the corresponding section in all group files.
+    pub packages: Packages,
+    pub any_backend: AnyBackend,
+}
+impl ManagedBackend {
+    /// Get unmanaged packages, sorted alphabetically.
+    ///
+    /// # Errors
+    ///
+    /// Returns an error if the backend fails to get the explicitly installed packages.
+    pub fn get_unmanaged_packages_sorted(&self) -> Result<Vec<Package>> {
+        let installed = self
+            .any_backend
+            .get_explicitly_installed_packages()
+            .context("could not get explicitly installed packages")?;
+        let mut diff: Vec<_> = installed.difference(&self.packages).cloned().collect();
+        diff.sort_unstable();
+        Ok(diff)
+    }
+
+    /// Get missing packages, sorted alphabetically.
+    ///
+    /// # Errors
+    ///
+    /// Returns an error if the backend fails to get the installed packages.
+    pub fn get_missing_packages_sorted(&self) -> Result<Vec<Package>> {
+        let installed = self
+            .any_backend
+            .get_all_installed_packages()
+            .context("could not get installed packages")?;
+        let mut diff: Vec<_> = self.packages.difference(&installed).cloned().collect();
+        diff.sort_unstable();
+        Ok(diff)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
 #[enum_dispatch::enum_dispatch(Backend)]
 pub enum AnyBackend {
     #[cfg(feature = "arch")]
@@ -31,22 +61,44 @@ pub enum AnyBackend {
     Rustup(Rustup),
     Void(Void),
 }
-
 impl AnyBackend {
     /// Returns an iterator of every variant of backend.
-    pub fn iter() -> impl Iterator<Item = Self> {
+    pub fn all(config: &Config) -> impl Iterator<Item = Self> {
         vec![
             #[cfg(feature = "arch")]
-            Self::Arch(actual::arch::Arch::new()),
+            Self::Arch(actual::arch::Arch::new(config)),
             #[cfg(feature = "debian")]
             Self::Debian(actual::debian::Debian::new()),
-            Self::Flatpak(Flatpak::new()),
+            Self::Flatpak(Flatpak::new(config)),
             Self::Fedora(Fedora::new()),
-            Self::Python(Python::new()),
+            Self::Python(Python::new(config)),
             Self::Rust(Rust::new()),
             Self::Rustup(Rustup::new()),
             Self::Void(Void::new()),
         ]
         .into_iter()
     }
+
+    pub fn from_section(section: &str, config: &Config) -> Result<Self> {
+        match section {
+            #[cfg(feature = "arch")]
+            "arch" => Ok(Self::Arch(actual::arch::Arch::new(config))),
+            #[cfg(feature = "debian")]
+            "debian" => Ok(Self::Debian(actual::debian::Debian::new())),
+            "flatpak" => Ok(Self::Flatpak(Flatpak::new(config))),
+            "fedora" => Ok(Self::Fedora(Fedora::new())),
+            "python" => Ok(Self::Python(Python::new(config))),
+            "rust" => Ok(Self::Rust(Rust::new())),
+            "rustup" => Ok(Self::Rustup(Rustup::new())),
+            "void" => Ok(Self::Void(Void::new())),
+            _ => Err(anyhow::anyhow!(
+                "no matching backend for the section: {section}"
+            )),
+        }
+    }
+}
+impl Display for AnyBackend {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.backend_info().section)
+    }
 }

crates/pacdef/src/backend/todo_per_backend.rs

@@ -2,8 +2,7 @@ use std::fmt::Write;
 
 use anyhow::{Context, Result};
 
-use super::{AnyBackend, Backend};
+use crate::prelude::*;
-use crate::Package;
 
 /// A vector of tuples containing a Backends and a vector of unmanaged packages
 /// for that backend.
@@ -37,7 +36,7 @@ impl ToDoPerBackend {
 
             backend
                 .install_packages(packages, noconfirm)
-                .with_context(|| format!("installing packages for {}", backend.get_section()))?;
+                .with_context(|| format!("installing packages for {backend}"))?;
         }
         Ok(())
     }
@@ -50,7 +49,7 @@ impl ToDoPerBackend {
 
             backend
                 .remove_packages(packages, noconfirm)
-                .with_context(|| format!("removing packages for {}", backend.get_section()))?;
+                .with_context(|| format!("removing packages for {backend}"))?;
         }
         Ok(())
     }
@@ -65,7 +64,7 @@ impl ToDoPerBackend {
 
             let mut segment = String::new();
 
-            segment.write_str(&format!("[{}]", backend.get_section()))?;
+            segment.write_str(&format!("[{backend}]"))?;
             for package in packages {
                 segment.write_str(&format!("\n{package}"))?;
             }

crates/pacdef/src/config.rs

@@ -5,6 +5,8 @@ use std::path::Path;
 use anyhow::{bail, Context, Result};
 use serde::{Deserialize, Serialize};
 
+use crate::prelude::*;
+
 // Update the master README if fields change.
 /// Config for the program, as listed in `$XDG_CONFIG_HOME/pacdef/pacdef.toml`.
 #[derive(Debug, Serialize, Deserialize)]
@@ -55,7 +57,7 @@ impl Config {
             Ok(content) => content,
             Err(e) => {
                 if e.kind() == ErrorKind::NotFound {
-                    bail!(crate::Error::ConfigFileNotFound)
+                    bail!(Error::ConfigFileNotFound)
                 }
                 bail!("unexpected error occurred: {e:?}");
             }

crates/pacdef/src/core.rs

@@ -8,23 +8,14 @@ use std::process::Command;
 use anyhow::{bail, ensure, Context, Result};
 use const_format::formatcp;
 
-use crate::backend::backend_trait::Backend;
-use crate::backend::todo_per_backend::ToDoPerBackend;
-use crate::backend::AnyBackend;
-use crate::cli::{
-    CleanPackageAction, EditGroupAction, ExportGroupAction, GroupAction, GroupArguments,
-    ImportGroupAction, ListGroupAction, MainArguments, MainSubcommand, NewGroupAction,
-    PackageAction, PackageArguments, RemoveGroupAction, ReviewPackageAction, SearchPackageAction,
-    ShowGroupAction, SyncPackageAction, UnmanagedPackageAction, VersionArguments,
-};
 use crate::cmd::{run_edit_command, run_external_command};
 use crate::env::{get_editor, should_print_debug_info};
+use crate::grouping::group::groups_to_backend_packages;
 use crate::path::{binary_in_path, get_absolutized_file_paths, get_group_dir};
+use crate::prelude::*;
 use crate::review::review;
 use crate::search::search_packages;
 use crate::ui::get_user_confirmation;
-use crate::Group;
-use crate::{Config, Error, Groups};
 
 impl MainArguments {
     /// Run the action that was provided by the user as first argument.
@@ -39,7 +30,7 @@ impl MainArguments {
         match self.subcommand {
             MainSubcommand::Group(group) => group.run(groups),
             MainSubcommand::Package(package) => package.run(groups, config),
-            MainSubcommand::Version(version) => version.run(),
+            MainSubcommand::Version(version) => version.run(config),
         }
     }
 }
@@ -47,8 +38,8 @@ impl MainArguments {
 impl VersionArguments {
     /// If the crate was compiled from git, return `pacdef, <version> (<hash>)`.
     /// Otherwise return `pacdef, <version>`.
-    fn run(self) -> Result<()> {
+    fn run(self, config: &Config) -> Result<()> {
-        let backends = get_included_backends();
+        let backends = get_included_backends(config);
         let mut result = format!("pacdef, version: {}\n", get_version_string());
         result.push_str("supported backends:");
         for b in backends {
@@ -221,7 +212,7 @@ impl NewGroupAction {
         for new_group in &self.new_groups {
             ensure!(
                 new_group != "." && new_group != "..",
-                crate::Error::InvalidGroupName(new_group.clone())
+                Error::InvalidGroupName(new_group.clone())
             );
         }
 
@@ -236,10 +227,7 @@ impl NewGroupAction {
             .collect();
 
         for file in &paths {
-            ensure!(
+            ensure!(!file.exists(), Error::GroupAlreadyExists(file.clone()));
-                !file.exists(),
-                crate::Error::GroupAlreadyExists(file.clone())
-            );
         }
 
         for file in &paths {
@@ -284,10 +272,7 @@ impl ShowGroupAction {
         }
 
         // return an error if any arg was not found
-        ensure!(
+        ensure!(errors.is_empty(), Error::MultipleGroupsNotFound(errors));
-            errors.is_empty(),
-            crate::Error::MultipleGroupsNotFound(errors)
-        );
 
         let show_more_than_one_group = self.show_groups.len() > 1;
 
@@ -398,50 +383,38 @@ impl UnmanagedPackageAction {
 }
 
 fn get_missing_packages(groups: &Groups, config: &Config) -> Result<ToDoPerBackend> {
+    let backend_packages = groups_to_backend_packages(groups, config)?;
+
     let mut to_install = ToDoPerBackend::new();
 
-    for mut backend in AnyBackend::iter() {
+    for (any_backend, packages) in &backend_packages {
+        let backend_info = any_backend.backend_info();
+
         if config
             .disabled_backends
-            .contains(&backend.get_section().to_string())
+            .contains(&backend_info.section.to_string())
         {
             continue;
         }
 
-        if !binary_in_path(backend.get_binary())? {
+        if !binary_in_path(&backend_info.binary)? {
             continue;
         }
 
-        overwrite_values_from_config(&mut backend, config);
+        let managed_backend = ManagedBackend {
-        backend.load(groups);
+            packages: packages.clone(),
+            any_backend: any_backend.clone(),
+        };
 
-        match backend.get_missing_packages_sorted() {
+        match managed_backend.get_missing_packages_sorted() {
-            Ok(diff) => to_install.push((backend, diff)),
+            Ok(diff) => to_install.push((any_backend.clone(), diff)),
-            Err(error) => show_backend_query_error(&error, &backend),
+            Err(error) => show_backend_query_error(&error, any_backend),
         };
     }
 
     Ok(to_install)
 }
 
-fn overwrite_values_from_config(backend: &mut AnyBackend, config: &Config) {
-    #[cfg(feature = "arch")]
-    {
-        if let AnyBackend::Arch(arch) = backend {
-            arch.binary.clone_from(&config.aur_helper);
-            arch.aur_rm_args.clone_from(&config.aur_rm_args);
-        }
-    }
-
-    if let AnyBackend::Flatpak(flatpak) = backend {
-        flatpak.systemwide = config.flatpak_systemwide;
-    }
-
-    if let AnyBackend::Python(python) = backend {
-        python.binary.clone_from(&config.pip_binary);
-    }
-}
-
 /// Get a list of unmanaged packages per backend.
 ///
 /// This method loops through all enabled `Backend`s whose binary is in `PATH`.
@@ -450,29 +423,40 @@ fn overwrite_values_from_config(backend: &mut AnyBackend, config: &Config) {
 ///
 /// This function will propagate errors from the individual backends.
 fn get_unmanaged_packages(groups: &Groups, config: &Config) -> Result<ToDoPerBackend> {
-    let mut result = ToDoPerBackend::new();
+    let backend_packages = groups_to_backend_packages(groups, config)?;
 
-    for mut backend in AnyBackend::iter() {
+    let mut todo_unmanaged = ToDoPerBackend::new();
+
+    for (any_backend, packages) in &backend_packages {
+        let backend_info = any_backend.backend_info();
         if config
             .disabled_backends
-            .contains(&backend.get_section().to_string())
+            .contains(&backend_info.section.to_string())
         {
             continue;
         }
 
-        if !binary_in_path(backend.get_binary())? {
+        if !binary_in_path(&backend_info.binary)? {
             continue;
         }
 
-        overwrite_values_from_config(&mut backend, config);
+        let managed_backend = ManagedBackend {
-        backend.load(groups);
+            packages: packages.clone(),
+            any_backend: any_backend.clone(),
+        };
 
-        match backend.get_unmanaged_packages_sorted() {
+        match managed_backend.get_unmanaged_packages_sorted() {
-            Ok(unmanaged) => result.push((backend, unmanaged)),
+            Ok(diff) => todo_unmanaged.push((any_backend.clone(), diff)),
-            Err(error) => show_backend_query_error(&error, &backend),
+            Err(error) => show_backend_query_error(&error, any_backend),
+        };
+
+        match managed_backend.get_unmanaged_packages_sorted() {
+            Ok(unmanaged) => todo_unmanaged.push((any_backend.clone(), unmanaged)),
+            Err(error) => show_backend_query_error(&error, any_backend),
         };
     }
-    Ok(result)
+
+    Ok(todo_unmanaged)
 }
 
 /// Create the parent directory of the `path` if that directory does not exist.
@@ -553,14 +537,13 @@ fn find_groups_by_name<'a>(names: &[String], groups: &'a Groups) -> Result<Vec<&
 /// Show the error chain for an error that has occurred when a backend was queried
 /// if the `RUST_BACKTRACE` env variable is set to `1` or `full`.
 fn show_backend_query_error(error: &anyhow::Error, backend: &AnyBackend) {
-    let section = backend.get_section();
     if should_print_debug_info() {
         log::warn!(
-            "skipping backend '{section}': {}",
+            "skipping backend '{backend}': {}",
             error.chain().map(|x| x.to_string()).collect::<String>()
         );
     } else {
-        log::warn!("skipping backend '{section}': {error}");
+        log::warn!("skipping backend '{backend}': {error}");
     }
 }
 
@@ -578,10 +561,10 @@ pub const fn get_version_string() -> &'static str {
 }
 
 /// Get a vector with the names of all backends, sorted alphabetically.
-fn get_included_backends() -> Vec<&'static str> {
+fn get_included_backends(config: &Config) -> Vec<&'static str> {
     let mut result = vec![];
-    for backend in AnyBackend::iter() {
+    for backend in AnyBackend::all(config) {
-        result.push(backend.get_section());
+        result.push(backend.backend_info().section);
     }
     result.sort_unstable();
     result

crates/pacdef/src/grouping/group.rs

@@ -1,4 +1,4 @@
-use std::collections::{BTreeSet, HashSet};
+use std::collections::{BTreeMap, BTreeSet};
 use std::fmt::Display;
 use std::fs::{create_dir, read_to_string, File};
 use std::hash::Hash;
@@ -11,11 +11,27 @@ use walkdir::WalkDir;
 
 use crate::path::get_relative_path;
 
-use super::{Package, Section};
+use crate::prelude::*;
 
 /// A set of groups
 pub type Groups = BTreeSet<Group>;
 
+pub type BackendPackages = BTreeMap<AnyBackend, Packages>;
+pub fn groups_to_backend_packages(groups: &Groups, config: &Config) -> Result<BackendPackages> {
+    let mut backend_packages = BackendPackages::new();
+
+    for group in groups {
+        for section in &group.sections {
+            backend_packages
+                .entry(AnyBackend::from_section(&section.name, config)?)
+                .or_default()
+                .extend(section.packages.iter().cloned());
+        }
+    }
+
+    Ok(backend_packages)
+}
+
 /// Representation of a group file.
 #[derive(Debug, Clone)]
 pub struct Group {
@@ -23,7 +39,7 @@ pub struct Group {
     /// base dir).
     pub name: String,
     /// The sections in the file which in turn hold the packages.
-    pub sections: HashSet<Section>,
+    pub sections: Sections,
     /// The absolute path of the original file.
     pub path: PathBuf,
     /// Whether the main program should warn this group being loaded from a symlink.
@@ -143,7 +159,7 @@ impl Group {
         let name = extract_group_name(path, group_dir.as_ref());
 
         let mut lines = content.lines().peekable();
-        let mut sections = HashSet::new();
+        let mut sections = Sections::new();
 
         while lines.peek().is_some() {
             let result = Section::try_from_lines(&mut lines).context("reading section");

crates/pacdef/src/grouping/mod.rs

@@ -9,11 +9,6 @@ all groups using [`Group::load`], which in turn will get all packages from all
 sections.
 */
 
-mod group;
+pub mod group;
-mod package;
+pub mod package;
-mod section;
+pub mod section;
-
-pub use group::Group;
-pub use group::Groups;
-pub use package::Package;
-pub use section::Section;

crates/pacdef/src/grouping/package.rs

@@ -1,6 +1,9 @@
+use std::collections::BTreeSet;
 use std::fmt::{Display, Write};
 use std::hash::Hash;
 
+pub type Packages = BTreeSet<Package>;
+
 /// A struct to represent a single package, consisting of a `name`, and
 /// optionally a `repo`.
 #[derive(Debug, Eq, PartialOrd, Ord, Clone)]

crates/pacdef/src/grouping/section.rs

@@ -1,27 +1,29 @@
-use std::collections::HashSet;
+use std::collections::BTreeSet;
 use std::fmt::{Display, Write};
 use std::hash::Hash;
 use std::iter::Peekable;
 
 use anyhow::{ensure, Context, Result};
 
-use super::Package;
+use crate::prelude::*;
+
+pub type Sections = BTreeSet<Section>;
 
 #[derive(Debug, Clone)]
 pub struct Section {
     pub name: String,
-    pub packages: HashSet<Package>,
+    pub packages: Packages,
 }
 
 impl Section {
-    pub fn new(name: String, packages: HashSet<Package>) -> Self {
+    pub fn new(name: String, packages: Packages) -> Self {
         Self { name, packages }
     }
 
     pub fn try_from_lines<'a>(iter: &mut Peekable<impl Iterator<Item = &'a str>>) -> Result<Self> {
         let name = find_next_section_name(iter)?;
 
-        let mut packages = HashSet::new();
+        let mut packages = Packages::new();
 
         while next_line_might_be_package(iter) {
             if let Some(package) = Package::try_from(iter.next().expect("we checked this is some"))
@@ -36,7 +38,7 @@ impl Section {
     }
 }
 
-fn insert_package(package: Package, packages: &mut HashSet<Package>) {
+fn insert_package(package: Package, packages: &mut Packages) {
     let package_name = package.name.clone();
     let newly_inserted = packages.insert(package);
 

crates/pacdef/src/lib.rs

@@ -16,12 +16,10 @@
     clippy::unwrap_used,
     clippy::use_debug,
     clippy::use_self,
-    clippy::wildcard_dependencies,
+    clippy::wildcard_dependencies
-    missing_docs
 )]
 
 pub(crate) mod backend;
-#[allow(missing_docs)]
 pub mod cli;
 
 mod cmd;
@@ -35,10 +33,9 @@ mod review;
 mod search;
 mod ui;
 
+#[allow(unused_imports)]
+mod prelude;
+
 pub mod path;
 
-pub use crate::config::Config;
+pub use prelude::{Config, Error, Group};
-pub use crate::errors::Error;
-pub use crate::grouping::Group;
-pub use crate::grouping::Groups;
-pub use crate::grouping::Package;

crates/pacdef/src/main.rs

@@ -10,8 +10,7 @@
     clippy::unwrap_used,
     clippy::use_debug,
     clippy::use_self,
-    clippy::wildcard_dependencies,
+    clippy::wildcard_dependencies
-    missing_docs
 )]
 
 use std::path::Path;

crates/pacdef/src/prelude.rs

@@ -0,0 +1,46 @@
+#[cfg(feature = "arch")]
+pub use crate::backend::actual::arch::Arch;
+#[cfg(feature = "debian")]
+pub use crate::backend::actual::debian::Debian;
+pub use crate::backend::actual::{
+    fedora::Fedora, flatpak::Flatpak, python::Python, rust::Rust, rustup::Rustup, void::Void,
+};
+pub use crate::backend::backend_trait::{Backend, BackendInfo, Switches, Text};
+pub use crate::backend::todo_per_backend::ToDoPerBackend;
+pub use crate::backend::AnyBackend;
+pub use crate::backend::ManagedBackend;
+pub use crate::cli::CleanPackageAction;
+pub use crate::cli::EditGroupAction;
+pub use crate::cli::ExportGroupAction;
+pub use crate::cli::GroupAction;
+pub use crate::cli::GroupArguments;
+pub use crate::cli::ImportGroupAction;
+pub use crate::cli::ListGroupAction;
+pub use crate::cli::MainArguments;
+pub use crate::cli::MainSubcommand;
+pub use crate::cli::NewGroupAction;
+pub use crate::cli::PackageAction;
+pub use crate::cli::PackageArguments;
+pub use crate::cli::RemoveGroupAction;
+pub use crate::cli::ReviewPackageAction;
+pub use crate::cli::SearchPackageAction;
+pub use crate::cli::ShowGroupAction;
+pub use crate::cli::SyncPackageAction;
+pub use crate::cli::UnmanagedPackageAction;
+pub use crate::cli::VersionArguments;
+pub use crate::config::Config;
+pub use crate::errors::Error;
+pub use crate::grouping::{
+    group::{Group, Groups},
+    package::{Package, Packages},
+    section::{Section, Sections},
+};
+pub use crate::path::binary_in_path;
+pub use crate::path::get_absolutized_file_paths;
+pub use crate::path::get_cargo_home;
+pub use crate::path::get_config_path;
+pub use crate::path::get_config_path_old_version;
+pub use crate::path::get_group_dir;
+pub use crate::path::get_home_dir;
+pub use crate::path::get_pacdef_base_dir;
+pub use crate::path::get_relative_path;

crates/pacdef/src/review/datastructures.rs

@@ -1,4 +1,4 @@
-use crate::{backend::AnyBackend, Group, Package};
+use crate::prelude::*;
 
 use super::strategy::Strategy;
 

crates/pacdef/src/review/mod.rs

@@ -5,10 +5,8 @@ use std::io::{stdin, stdout, Write};
 
 use anyhow::Result;
 
-use crate::backend::backend_trait::Backend;
+use crate::prelude::*;
-use crate::backend::todo_per_backend::ToDoPerBackend;
 use crate::ui::{get_user_confirmation, read_single_char_from_terminal};
-use crate::{Group, Groups, Package};
 
 use self::datastructures::{ContinueWithReview, ReviewAction, ReviewIntention, ReviewsPerBackend};
 use self::strategy::Strategy;
@@ -24,7 +22,7 @@ pub fn review(todo_per_backend: ToDoPerBackend, groups: &Groups) -> Result<()> {
     'outer: for (backend, packages) in todo_per_backend {
         let mut actions = vec![];
         for package in packages {
-            println!("{}: {package}", backend.get_section());
+            println!("{}: {package}", backend.backend_info().section);
             match get_action_for_package(package, groups, &mut actions, &backend)? {
                 ContinueWithReview::Yes => continue,
                 ContinueWithReview::No => return Ok(()),

crates/pacdef/src/review/strategy.rs

@@ -1,9 +1,6 @@
 use anyhow::Result;
 
-use crate::{
+use crate::prelude::*;
-    backend::{backend_trait::Backend, AnyBackend},
-    Group, Package,
-};
 
 #[derive(Debug)]
 pub struct Strategy {
@@ -49,7 +46,7 @@ impl Strategy {
             return;
         }
 
-        println!("[{}]", self.backend.get_section());
+        println!("[{}]", self.backend.backend_info().section);
 
         if !self.delete.is_empty() {
             println!("delete:");

crates/pacdef/src/search.rs

@@ -1,14 +1,10 @@
 use std::iter::Peekable;
 use std::vec::IntoIter;
 
+use crate::prelude::*;
 use anyhow::{bail, Result};
 use regex::Regex;
 
-use crate::{
-    grouping::{Group, Package, Section},
-    Groups,
-};
-
 /// Find all packages in all groups whose name match the regex from the
 /// command-line arguments. Print the name of the packages per group and
 /// section.