fix(config): report unknown theme names

refs #2452

docs/next/CHANGELOG.md

@@ -8,6 +8,7 @@
 - The plugin marketplace now discovers valid manifests at repository roots and subdirectories, groups multiple plugins under each repository, and publishes their versions and exact default-branch commits.
 
 ### Fixed
+- `herdr config check` now reports unknown built-in theme names instead of silently accepting them. (#2452)
 - macOS `herdr --remote` clients now keep the accepted bridge socket blocking, preventing an immediate disconnect after the protocol handshake. (#2478, thanks @mathijshenquet)
 - Prefix keybindings now preserve Shift in WezTerm Kitty keyboard mode, so commands such as config reload no longer trigger their unshifted action. (#2435)
 - Stable direct installs, self-updates, and remote helper downloads now require and verify the SHA-256 digest published for each GitHub release asset.

src/app/state.rs

@@ -558,24 +558,24 @@ impl Palette {
 
     /// Resolve a theme by name. Returns None for unknown names.
     pub fn from_name(name: &str) -> Option<Self> {
-        match name.to_lowercase().replace([' ', '_'], "-").as_str() {
-            "catppuccin" | "catppuccin-mocha" => Some(Self::catppuccin()),
-            "catppuccin-latte" | "latte" | "light" => Some(Self::catppuccin_latte()),
+        match crate::config::canonical_theme_name(name)? {
+            "catppuccin" => Some(Self::catppuccin()),
+            "catppuccin-latte" => Some(Self::catppuccin_latte()),
             "terminal" => Some(Self::terminal()),
-            "tokyo-night" | "tokyonight" => Some(Self::tokyo_night()),
-            "tokyo-night-day" | "tokyo-day" | "tokyonight-day" => Some(Self::tokyo_night_day()),
+            "tokyo-night" => Some(Self::tokyo_night()),
+            "tokyo-night-day" => Some(Self::tokyo_night_day()),
             "dracula" => Some(Self::dracula()),
             "nord" => Some(Self::nord()),
-            "gruvbox" | "gruvbox-dark" => Some(Self::gruvbox()),
+            "gruvbox" => Some(Self::gruvbox()),
             "gruvbox-light" => Some(Self::gruvbox_light()),
-            "one-dark" | "onedark" => Some(Self::one_dark()),
-            "one-light" | "onelight" => Some(Self::one_light()),
-            "solarized" | "solarized-dark" => Some(Self::solarized()),
+            "one-dark" => Some(Self::one_dark()),
+            "one-light" => Some(Self::one_light()),
+            "solarized" => Some(Self::solarized()),
             "solarized-light" => Some(Self::solarized_light()),
             "kanagawa" => Some(Self::kanagawa()),
-            "kanagawa-lotus" | "lotus" => Some(Self::kanagawa_lotus()),
-            "rose-pine" | "rosepine" => Some(Self::rose_pine()),
-            "rose-pine-dawn" | "rosepine-dawn" | "dawn" => Some(Self::rose_pine_dawn()),
+            "kanagawa-lotus" => Some(Self::kanagawa_lotus()),
+            "rose-pine" => Some(Self::rose_pine()),
+            "rose-pine-dawn" => Some(Self::rose_pine_dawn()),
             "vesper" => Some(Self::vesper()),
             _ => None,
         }
@@ -1044,26 +1044,7 @@ impl SettingsSection {
 }
 
 /// All built-in theme names in display order.
-pub const THEME_NAMES: &[&str] = &[
-    "catppuccin",
-    "catppuccin-latte",
-    "terminal",
-    "tokyo-night",
-    "tokyo-night-day",
-    "dracula",
-    "nord",
-    "gruvbox",
-    "gruvbox-light",
-    "one-dark",
-    "one-light",
-    "solarized",
-    "solarized-light",
-    "kanagawa",
-    "kanagawa-lotus",
-    "rose-pine",
-    "rose-pine-dawn",
-    "vesper",
-];
+pub const THEME_NAMES: &[&str] = crate::config::THEME_NAMES;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct MenuListState {

src/config.rs

@@ -30,11 +30,11 @@ pub use self::{
         SpaceSidebarToken, SpacesSidebarConfig,
     },
     sound::SoundConfig,
-    theme::{parse_color, CustomThemeColors, ThemeConfig},
+    theme::{parse_color, CustomThemeColors, ThemeConfig, THEME_NAMES},
 };
 
-pub(crate) use self::io::upsert_top_level_bool;
 pub(crate) use self::keybinds::parse_key_combo;
+pub(crate) use self::{io::upsert_top_level_bool, theme::canonical_theme_name};
 
 pub const CONFIG_PATH_ENV_VAR: &str = "HERDR_CONFIG_PATH";
 pub const DEFAULT_SCROLLBACK_LIMIT_BYTES: usize = 10_000_000;
@@ -72,6 +72,7 @@ impl Config {
             .into_iter()
             .chain(keybind_diags)
             .chain(self.remote_image_paste_key().err())
+            .chain(self.theme.diagnostics())
             .chain(self.ui.sound.diagnostics())
             .chain(self.invalid_sidebar_bounds_diagnostic())
             .collect()

src/config/io.rs

@@ -341,6 +341,8 @@ fn load_live_config_from_str(content: &str) -> Result<LoadedConfig, Vec<String>>
         |section| config.remote = section,
     );
 
+    diagnostics.extend(config.theme.diagnostics());
+
     Ok(LoadedConfig {
         config,
         diagnostics,
@@ -863,6 +865,20 @@ resume_agents_on_restore = true
         assert!(loaded.invalid_sections.is_empty());
     }
 
+    #[test]
+    fn load_live_config_warns_about_unknown_theme_names() {
+        let loaded = load_live_config_from_str(
+            r#"
+[theme]
+name = "catppucin"
+"#,
+        )
+        .unwrap();
+
+        assert_eq!(loaded.diagnostics.len(), 1);
+        assert!(loaded.diagnostics[0].contains("theme.name = \"catppucin\""));
+    }
+
     #[test]
     fn load_live_config_warns_about_unknown_top_level_sections() {
         let loaded = load_live_config_from_str(

src/config/theme.rs

@@ -1,6 +1,51 @@
 use serde::Deserialize;
 use tracing::warn;
 
+pub const THEME_NAMES: &[&str] = &[
+    "catppuccin",
+    "catppuccin-latte",
+    "terminal",
+    "tokyo-night",
+    "tokyo-night-day",
+    "dracula",
+    "nord",
+    "gruvbox",
+    "gruvbox-light",
+    "one-dark",
+    "one-light",
+    "solarized",
+    "solarized-light",
+    "kanagawa",
+    "kanagawa-lotus",
+    "rose-pine",
+    "rose-pine-dawn",
+    "vesper",
+];
+
+pub(crate) fn canonical_theme_name(name: &str) -> Option<&'static str> {
+    match name.to_lowercase().replace([' ', '_'], "-").as_str() {
+        "catppuccin" | "catppuccin-mocha" => Some("catppuccin"),
+        "catppuccin-latte" | "latte" | "light" => Some("catppuccin-latte"),
+        "terminal" => Some("terminal"),
+        "tokyo-night" | "tokyonight" => Some("tokyo-night"),
+        "tokyo-night-day" | "tokyo-day" | "tokyonight-day" => Some("tokyo-night-day"),
+        "dracula" => Some("dracula"),
+        "nord" => Some("nord"),
+        "gruvbox" | "gruvbox-dark" => Some("gruvbox"),
+        "gruvbox-light" => Some("gruvbox-light"),
+        "one-dark" | "onedark" => Some("one-dark"),
+        "one-light" | "onelight" => Some("one-light"),
+        "solarized" | "solarized-dark" => Some("solarized"),
+        "solarized-light" => Some("solarized-light"),
+        "kanagawa" => Some("kanagawa"),
+        "kanagawa-lotus" | "lotus" => Some("kanagawa-lotus"),
+        "rose-pine" | "rosepine" => Some("rose-pine"),
+        "rose-pine-dawn" | "rosepine-dawn" | "dawn" => Some("rose-pine-dawn"),
+        "vesper" => Some("vesper"),
+        _ => None,
+    }
+}
+
 /// Theme configuration: pick a built-in or override individual tokens.
 ///
 /// ```toml
@@ -26,6 +71,31 @@ pub struct ThemeConfig {
     pub custom: Option<CustomThemeColors>,
 }
 
+impl ThemeConfig {
+    pub(crate) fn diagnostics(&self) -> Vec<String> {
+        let valid = THEME_NAMES.join(", ");
+        [
+            ("theme.name", self.name.as_deref(), "catppuccin"),
+            ("theme.dark_name", self.dark_name.as_deref(), "catppuccin"),
+            (
+                "theme.light_name",
+                self.light_name.as_deref(),
+                "catppuccin-latte",
+            ),
+        ]
+        .into_iter()
+        .filter_map(|(field, value, fallback)| {
+            let value = value?;
+            canonical_theme_name(value).is_none().then(|| {
+                format!(
+                    "unknown theme name {field} = {value:?}; using {fallback:?}; valid themes: {valid}"
+                )
+            })
+        })
+        .collect()
+    }
+}
+
 /// Per-token color overrides. All fields optional — only set what you want to change.
 #[derive(Debug, Clone, Default, Deserialize)]
 #[serde(default)]
@@ -132,6 +202,34 @@ name = "dracula"
         assert_eq!(config.theme.name.as_deref(), Some("dracula"));
     }
 
+    #[test]
+    fn unknown_theme_names_are_diagnosed() {
+        let config: Config = toml::from_str(
+            r#"
+[theme]
+name = "catppucin"
+dark_name = "tokio-night"
+light_name = "lattee"
+"#,
+        )
+        .unwrap();
+
+        let diagnostics = config.theme.diagnostics();
+        assert_eq!(diagnostics.len(), 3);
+        assert!(diagnostics[0].contains("theme.name = \"catppucin\""));
+        assert!(diagnostics[0].contains("using \"catppuccin\""));
+        assert!(diagnostics[1].contains("theme.dark_name = \"tokio-night\""));
+        assert!(diagnostics[2].contains("theme.light_name = \"lattee\""));
+        assert!(diagnostics[2].contains("using \"catppuccin-latte\""));
+    }
+
+    #[test]
+    fn theme_name_aliases_are_valid() {
+        for name in ["catppuccin-mocha", "tokyonight", "gruvbox-dark", "dawn"] {
+            assert!(canonical_theme_name(name).is_some(), "alias: {name}");
+        }
+    }
+
     #[test]
     fn parse_color_accepts_reset_aliases() {
         use ratatui::style::Color;

tests/cli/workspace.rs

@@ -496,6 +496,33 @@ new_tabb = "ctrl+t"
     cleanup_test_base(&base);
 }
 
+#[test]
+fn config_check_reports_unknown_theme_names() {
+    let base = unique_test_dir();
+    let config_home = base.join("config");
+    let runtime_dir = base.join("runtime");
+    let config_dir = config_home.join(app_dir_name());
+    fs::create_dir_all(&config_dir).unwrap();
+    fs::write(
+        config_dir.join("config.toml"),
+        "[theme]\nname = \"catppucin\"\n",
+    )
+    .unwrap();
+
+    let checked = run_named_cli(&config_home, &runtime_dir, &["config", "check"]);
+
+    assert_eq!(checked.status.code(), Some(1));
+    let stdout = String::from_utf8_lossy(&checked.stdout);
+    assert!(stdout.contains("config: issues found"), "{stdout}");
+    assert!(
+        stdout.contains("unknown theme name theme.name = \"catppucin\"; using \"catppuccin\""),
+        "{stdout}"
+    );
+    assert!(stdout.contains("valid themes: catppuccin"), "{stdout}");
+
+    cleanup_test_base(&base);
+}
+
 #[test]
 fn config_check_reports_unreadable_config_path() {
     let base = unique_test_dir();