fix: audit LOW fixes — dead uid, home_dir warn, clippy sweep, debug value (v0.8.5)

- users::User: drop the unused `uid` field and its getuid() assignment.
  The compiler dead_code warning is gone, and the synthetic `u32::MAX`
  sentinel in the panel fallback is obsolete too.
- panel: surface a log::warn! when dirs::home_dir() returns None instead
  of silently falling back to an empty PathBuf that would make avatars
  look for .face in the current working directory.
- Apply three clippy suggestions: two collapsible if-let + && chains in
  users::get_avatar_path_with and config::resolve_background_path_with,
  and a redundant closure in panel::execute_action's spawn_blocking.
- main: require MOONSET_DEBUG=1 to escalate log verbosity — mere
  presence of the var must not dump path info into the journal.

Cargo.lock

@@ -616,7 +616,7 @@ dependencies = [
 
 [[package]]
 name = "moonset"
-version = "0.8.4"
+version = "0.8.5"
 dependencies = [
  "dirs",
  "gdk-pixbuf",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "moonset"
-version = "0.8.4"
+version = "0.8.5"
 edition = "2024"
 description = "Wayland session power menu with GTK4 and Layer Shell"
 license = "MIT"

DECISIONS.md

@@ -2,6 +2,13 @@
 
 Architectural and design decisions for Moonset, in reverse chronological order.
 
+## 2026-04-24 – Audit LOW fixes: dead uid field, home_dir warn, clippy sweep, debug value (v0.8.5)
+
+- **Who**: ClaudeCode, Dom
+- **Why**: Five LOW findings cleared in one pass. (1) `User::uid` was populated from `getuid()` but never read — a compiler `dead_code` warning for a field on the public API. (2) Falling back to a synthetic user when `get_current_user()` returned None used `uid: u32::MAX`, an undocumented sentinel that became moot once uid was removed. (3) `dirs::home_dir().unwrap_or_default()` silently yielded `PathBuf::new()` on failure; avatars would then look for `.face` in the current working directory. (4) `cargo clippy` flagged three suggestions (two collapsible `if`, one redundant closure) that had crept in. (5) `MOONSET_DEBUG` promoted log verbosity on mere presence, leaking path information into the journal.
+- **Tradeoffs**: Dropping `uid` from `User` is a minor API break for any internal caller expecting the field — none existed. The synthetic fallback now surfaces `log::warn!` when home resolution fails, which should be rare outside of pathological sandbox environments.
+- **How**: (1) Remove `pub uid: u32` from `User` and the `uid: uid.as_raw()` assignment in `get_current_user`. (2) Panel fallback drops the `uid` field entirely. (3) `dirs::home_dir().unwrap_or_else(|| { log::warn!(...); PathBuf::new() })`. (4) `cargo clippy --fix` for the two collapsible ifs, manual collapse of `if-let` + `&&` chain, redundant closure replaced with the function itself. (5) `MOONSET_DEBUG` now requires the literal value `"1"` to escalate to Debug.
+
 ## 2026-04-24 – Audit MEDIUM fixes: timeout guard, POSIX locale, button desensitize, wallpaper allowlist (v0.8.4)
 
 - **Who**: ClaudeCode, Dom

src/main.rs

@@ -88,10 +88,12 @@ fn setup_logging() {
             eprintln!("Failed to create journal logger: {e}");
         }
     }
-    let level = if std::env::var("MOONSET_DEBUG").is_ok() {
-        log::LevelFilter::Debug
-    } else {
-        log::LevelFilter::Info
+    // Require MOONSET_DEBUG=1 to raise verbosity so mere presence (empty
+    // value in a session script) cannot escalate journal noise with path
+    // information an attacker could use.
+    let level = match std::env::var("MOONSET_DEBUG").ok().as_deref() {
+        Some("1") => log::LevelFilter::Debug,
+        _ => log::LevelFilter::Info,
     };
     log::set_max_level(level);
 }

src/panel.rs

@@ -7,7 +7,7 @@ use glib::clone;
 use gtk4::prelude::*;
 use gtk4::{self as gtk, gio};
 use std::cell::RefCell;
-use std::path::Path;
+use std::path::{Path, PathBuf};
 use std::rc::Rc;
 use std::time::Duration;
 
@@ -208,11 +208,16 @@ pub fn create_panel_window(texture: Option<&gdk::Texture>, blur_radius: Option<f
     window.add_css_class("panel");
 
     let strings = load_strings(None);
-    let user = users::get_current_user().unwrap_or_else(|| users::User {
-        username: "user".to_string(),
-        display_name: "User".to_string(),
-        home: dirs::home_dir().unwrap_or_default(),
-        uid: u32::MAX,
+    let user = users::get_current_user().unwrap_or_else(|| {
+        let home = dirs::home_dir().unwrap_or_else(|| {
+            log::warn!("Could not resolve HOME — using an empty path");
+            PathBuf::new()
+        });
+        users::User {
+            username: "user".to_string(),
+            display_name: "User".to_string(),
+            home,
+        }
     });
     log::debug!("User: {} ({})", user.display_name, user.username);
 
@@ -571,7 +576,7 @@ fn execute_action(
         #[weak]
         button_box,
         async move {
-            let result = gio::spawn_blocking(move || action_fn()).await;
+            let result = gio::spawn_blocking(action_fn).await;
 
             match result {
                 Ok(Ok(())) => {

src/users.rs

@@ -12,7 +12,6 @@ pub struct User {
     pub username: String,
     pub display_name: String,
     pub home: PathBuf,
-    pub uid: u32,
 }
 
 /// Get the currently logged-in user's info from the system.
@@ -37,7 +36,6 @@ pub fn get_current_user() -> Option<User> {
         username: nix_user.name,
         display_name,
         home: nix_user.dir,
-        uid: uid.as_raw(),
     })
 }
 
@@ -65,16 +63,16 @@ pub fn get_avatar_path_with(
     }
 
     // AccountsService icon fallback
-    if let Some(name) = username {
-        if accountsservice_dir.exists() {
-            let icon = accountsservice_dir.join(name);
-            if let Ok(meta) = icon.symlink_metadata() {
-                if meta.file_type().is_symlink() {
-                    log::warn!("Rejecting symlink avatar: {}", icon.display());
-                } else if meta.is_file() {
-                    log::debug!("Avatar: using AccountsService icon ({})", icon.display());
-                    return Some(icon);
-                }
+    if let Some(name) = username
+        && accountsservice_dir.exists()
+    {
+        let icon = accountsservice_dir.join(name);
+        if let Ok(meta) = icon.symlink_metadata() {
+            if meta.file_type().is_symlink() {
+                log::warn!("Rejecting symlink avatar: {}", icon.display());
+            } else if meta.is_file() {
+                log::debug!("Avatar: using AccountsService icon ({})", icon.display());
+                return Some(icon);
             }
         }
     }