docs/SPEC.md

@@ -330,6 +330,22 @@ Open questions on the schema:
 
 - **Config loader**: parses `packages.d/*.toml` into an in-memory package
   list. *(Implemented — `src/config.rs`.)*
+- **Paths**: where config, state and work files live, resolved by
+  `src/paths.rs` per the XDG base-directory spec rather than the current
+  working directory, so an installed binary behaves the same wherever it's
+  launched from. *(Implemented.)*
+
+  | What | Default | XDG variable | Override |
+  |---|---|---|---|
+  | Package declarations (`packages.d/*.toml`) | `~/.config/pkgwatch/packages.d` | `XDG_CONFIG_HOME` | `PKGWATCH_CONFIG_DIR` (the dir *containing* `packages.d`) |
+  | Last-published / pending versions | `~/.local/state/pkgwatch` | `XDG_STATE_HOME` | `PKGWATCH_STATE_DIR` |
+  | Downloads and build trees (safe to delete) | `~/.cache/pkgwatch` | `XDG_CACHE_HOME` | `PKGWATCH_WORK_DIR` |
+
+  The overrides are used verbatim (no `pkgwatch/` suffix) and exist for
+  dry runs against scratch directories, like `PKGWATCH_REPO_DIR` does for
+  the pacman repo. Migrating from the old cwd-relative layout: move
+  `state/` to the state dir and copy or symlink `packages.d/` into the
+  config dir; `work/` is cache and can simply be dropped.
 - **Checker**: per source type, resolves "what's the latest version" —
   likely reuses `nvchecker`'s logic/sources conceptually for non-GitHub
   sources eventually. For GitHub sources, prefers the `github-atom` feed

src/main.rs

@@ -8,6 +8,7 @@ mod config;
 mod fetcher;
 mod github;
 mod hash;
+mod paths;
 mod pipeline;
 mod publisher;
 mod sanity;

src/paths.rs

@@ -0,0 +1,151 @@
+//! Decides where pkgwatch's config, state, and work directories live on
+//! disk. The only module that reads the environment to answer that — every
+//! other module takes the directories it needs as parameters.
+//!
+//! These follow the XDG base-directory spec instead of the current working
+//! directory, so an installed `/usr/bin/pkgwatch` behaves the same
+//! wherever it's launched from (a systemd unit, a shell, another checkout)
+//! instead of only working from inside the repo.
+
+use anyhow::{Context, Result};
+use std::path::{Path, PathBuf};
+
+const APP_DIR: &str = "pkgwatch";
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct Paths {
+    /// `*.toml` package declarations. Config: hand-edited, worth backing up.
+    pub packages_dir: PathBuf,
+    /// Last-published/pending versions. State: small, but losing it makes
+    /// every package look new, so it isn't cache.
+    pub state_dir: PathBuf,
+    /// Downloaded artifacts and build trees. Cache: safe to delete.
+    pub work_dir: PathBuf,
+}
+
+impl Paths {
+    pub fn from_env() -> Result<Self> {
+        Self::resolve(|key| std::env::var(key).ok())
+    }
+
+    /// `getenv` is injectable so tests don't mutate the process-global
+    /// environment, which would race with `cargo test`'s parallel threads.
+    ///
+    /// Each directory has a pkgwatch-specific override, then the matching
+    /// XDG variable, then the XDG default under `$HOME`. The overrides exist
+    /// for dry runs against scratch directories, like `PKGWATCH_REPO_DIR`
+    /// does for the pacman repo.
+    fn resolve(getenv: impl Fn(&str) -> Option<String>) -> Result<Self> {
+        let base = |override_var: &str, xdg_var: &str, home_subpath: &str| -> Result<PathBuf> {
+            if let Some(dir) = non_empty(&getenv, override_var) {
+                return Ok(PathBuf::from(dir));
+            }
+            if let Some(dir) = non_empty(&getenv, xdg_var) {
+                return Ok(Path::new(&dir).join(APP_DIR));
+            }
+            let home = non_empty(&getenv, "HOME").context("HOME is not set")?;
+            Ok(Path::new(&home).join(home_subpath).join(APP_DIR))
+        };
+
+        Ok(Self {
+            packages_dir: base("PKGWATCH_CONFIG_DIR", "XDG_CONFIG_HOME", ".config")?
+                .join("packages.d"),
+            state_dir: base("PKGWATCH_STATE_DIR", "XDG_STATE_HOME", ".local/state")?,
+            work_dir: base("PKGWATCH_WORK_DIR", "XDG_CACHE_HOME", ".cache")?,
+        })
+    }
+}
+
+/// The XDG spec says an empty variable must be treated as unset.
+fn non_empty(getenv: &impl Fn(&str) -> Option<String>, key: &str) -> Option<String> {
+    getenv(key).filter(|v| !v.is_empty())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::collections::HashMap;
+
+    fn env(pairs: &[(&str, &str)]) -> impl Fn(&str) -> Option<String> {
+        let map: HashMap<String, String> = pairs
+            .iter()
+            .map(|(k, v)| (k.to_string(), v.to_string()))
+            .collect();
+        move |key| map.get(key).cloned()
+    }
+
+    #[test]
+    fn defaults_live_under_home() {
+        let paths = Paths::resolve(env(&[("HOME", "/home/u")])).unwrap();
+        assert_eq!(
+            paths,
+            Paths {
+                packages_dir: "/home/u/.config/pkgwatch/packages.d".into(),
+                state_dir: "/home/u/.local/state/pkgwatch".into(),
+                work_dir: "/home/u/.cache/pkgwatch".into(),
+            }
+        );
+    }
+
+    #[test]
+    fn xdg_variables_override_home_defaults() {
+        let paths = Paths::resolve(env(&[
+            ("HOME", "/home/u"),
+            ("XDG_CONFIG_HOME", "/xdg/config"),
+            ("XDG_STATE_HOME", "/xdg/state"),
+            ("XDG_CACHE_HOME", "/xdg/cache"),
+        ]))
+        .unwrap();
+        assert_eq!(
+            paths.packages_dir,
+            Path::new("/xdg/config/pkgwatch/packages.d")
+        );
+        assert_eq!(paths.state_dir, Path::new("/xdg/state/pkgwatch"));
+        assert_eq!(paths.work_dir, Path::new("/xdg/cache/pkgwatch"));
+    }
+
+    #[test]
+    fn pkgwatch_overrides_win_and_are_used_verbatim() {
+        let paths = Paths::resolve(env(&[
+            ("HOME", "/home/u"),
+            ("XDG_STATE_HOME", "/xdg/state"),
+            ("PKGWATCH_CONFIG_DIR", "/scratch/cfg"),
+            ("PKGWATCH_STATE_DIR", "/scratch/state"),
+            ("PKGWATCH_WORK_DIR", "/scratch/work"),
+        ]))
+        .unwrap();
+        // No `pkgwatch/` suffix appended to an explicit override.
+        assert_eq!(paths.packages_dir, Path::new("/scratch/cfg/packages.d"));
+        assert_eq!(paths.state_dir, Path::new("/scratch/state"));
+        assert_eq!(paths.work_dir, Path::new("/scratch/work"));
+    }
+
+    #[test]
+    fn empty_variables_are_treated_as_unset() {
+        let paths = Paths::resolve(env(&[
+            ("HOME", "/home/u"),
+            ("XDG_STATE_HOME", ""),
+            ("PKGWATCH_WORK_DIR", ""),
+        ]))
+        .unwrap();
+        assert_eq!(paths.state_dir, Path::new("/home/u/.local/state/pkgwatch"));
+        assert_eq!(paths.work_dir, Path::new("/home/u/.cache/pkgwatch"));
+    }
+
+    #[test]
+    fn errors_when_nothing_locates_home() {
+        let err = Paths::resolve(env(&[])).unwrap_err();
+        assert!(err.to_string().contains("HOME"));
+    }
+
+    #[test]
+    fn no_home_needed_when_every_dir_is_overridden() {
+        let paths = Paths::resolve(env(&[
+            ("PKGWATCH_CONFIG_DIR", "/c"),
+            ("PKGWATCH_STATE_DIR", "/s"),
+            ("PKGWATCH_WORK_DIR", "/w"),
+        ]))
+        .unwrap();
+        assert_eq!(paths.state_dir, Path::new("/s"));
+    }
+}

src/pipeline.rs

@@ -10,6 +10,7 @@ use crate::checker;
 use crate::config::{self, Package};
 use crate::fetcher::{self, DownloadedAsset};
 use crate::github::GithubEndpoints;
+use crate::paths::Paths;
 use crate::publisher;
 use crate::sanity;
 use crate::state;
@@ -17,9 +18,6 @@ use crate::verifier::{self, VerificationResult};
 use anyhow::{Context, Result, bail};
 use std::path::{Path, PathBuf};
 
-const PACKAGES_DIR: &str = "packages.d";
-const STATE_DIR: &str = "state";
-const WORK_DIR: &str = "work";
 /// Not a repo pkgwatch invents: this is the existing, already-registered
 /// local pacman repo on this box (see `[custom]` in /etc/pacman.conf and
 /// its `Server = file://...` line). pkgwatch adds packages to it; it does
@@ -46,11 +44,13 @@ fn custom_repo_dir() -> Result<PathBuf> {
 pub fn run_check() -> Result<()> {
     let client = build_client()?;
     let endpoints = GithubEndpoints::default();
-    let packages_dir = Path::new(PACKAGES_DIR);
-    let state_dir = Path::new(STATE_DIR);
-    let work_dir = Path::new(WORK_DIR);
+    let Paths {
+        packages_dir,
+        state_dir,
+        work_dir,
+    } = Paths::from_env()?;
 
-    let packages = config::load_packages_dir(packages_dir)?;
+    let packages = config::load_packages_dir(&packages_dir)?;
     if packages.is_empty() {
         println!("no packages configured under {}/", packages_dir.display());
         return Ok(());
@@ -59,7 +59,7 @@ pub fn run_check() -> Result<()> {
     let mut any_failed = false;
     for (name, pkg) in &packages {
         println!("== {name} ({}) ==", pkg.repo);
-        if let Err(err) = process_package(&client, &endpoints, state_dir, work_dir, name, pkg) {
+        if let Err(err) = process_package(&client, &endpoints, &state_dir, &work_dir, name, pkg) {
             eprintln!("  error: {err:#}");
             any_failed = true;
         }
@@ -258,16 +258,18 @@ fn build_and_publish(
 }
 
 pub fn run_review(args: &[String]) -> Result<()> {
-    let packages_dir = Path::new(PACKAGES_DIR);
-    let state_dir = Path::new(STATE_DIR);
-    let work_dir = Path::new(WORK_DIR);
-    let packages = config::load_packages_dir(packages_dir)?;
+    let Paths {
+        packages_dir,
+        state_dir,
+        work_dir,
+    } = Paths::from_env()?;
+    let packages = config::load_packages_dir(&packages_dir)?;
 
     match args {
         [] => {
             let mut any = false;
             for (name, _) in &packages {
-                if let Some(pending) = state::load_pending_version(state_dir, name) {
+                if let Some(pending) = state::load_pending_version(&state_dir, name) {
                     println!(
                         "{name}: {pending} pending review (run `pkgwatch review {name} --approve`)"
                     );
@@ -283,9 +285,9 @@ pub fn run_review(args: &[String]) -> Result<()> {
             let (_, pkg) = packages.iter().find(|(n, _)| n == name).with_context(|| {
                 format!("no package named '{name}' in {}/", packages_dir.display())
             })?;
-            let tag = state::load_pending_version(state_dir, name)
+            let tag = state::load_pending_version(&state_dir, name)
                 .with_context(|| format!("'{name}' has no pending review"))?;
-            approve(state_dir, work_dir, name, pkg, &tag)
+            approve(&state_dir, &work_dir, name, pkg, &tag)
         }
         _ => bail!("usage: pkgwatch review [<name> --approve]"),
     }