CP6.13: hunspell.rs — Windows drives are probed for LibreOffice only when its language folders are wanted (CodeRabbit on craft-libs#489)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FypgCX8LsYYE8fsj4byBm2

crates/proof/src/hunspell.rs

@@ -105,16 +105,7 @@ fn search_tiers(lo_exts: Option<&[String]>) -> (Vec<PathBuf>, Vec<PathBuf>) {
                 system.extend(lo_dirs(&base.join("LibreOffice").join("share").join("extensions").to_string_lossy()));
             }
         }
-        // If LibreOffice is installed on another drive (e.g. D:\Program Files\LibreOffice), check drives C..Z
-        for drive in b'C'..=b'Z' {
-            let drive_char = drive as char;
-            for pf in ["Program Files", "Program Files (x86)"] {
-                let lo_base = PathBuf::from(format!(r"{drive_char}:\{pf}\LibreOffice\share\extensions"));
-                if lo_base.is_dir() {
-                    system.extend(lo_dirs(&lo_base.to_string_lossy()));
-                }
-            }
-        }
+        system.extend(lo_drive_dirs(lo_exts, Path::is_dir));
     } else if cfg!(target_os = "macos") {
         if let Some(h) = &home {
             // An app started from Finder or the Dock doesn't see `WORDCRAFT_DICTIONARIES`; this
@@ -144,6 +135,23 @@ fn search_tiers(lo_exts: Option<&[String]>) -> (Vec<PathBuf>, Vec<PathBuf>) {
     (dirs, system)
 }
 
+/// LibreOffice's language folders (`<drive>:\Program Files\LibreOffice\share\extensions\<ext>`)
+/// on the drives C to Z where `is_dir` finds LibreOffice installed. No drive is probed without
+/// `lo_exts` (no LibreOffice folders are wanted then).
+fn lo_drive_dirs(lo_exts: Option<&[String]>, is_dir: impl Fn(&Path) -> bool) -> Vec<PathBuf> {
+    let Some(exts) = lo_exts else { return Vec::new() };
+    let mut out = Vec::new();
+    for drive in 'C'..='Z' {
+        for pf in ["Program Files", "Program Files (x86)"] {
+            let base = PathBuf::from(format!(r"{drive}:\{pf}\LibreOffice\share\extensions"));
+            if is_dir(&base) {
+                out.extend(exts.iter().map(|e| base.join(e)));
+            }
+        }
+    }
+    out
+}
+
 /// The user's data folder on Linux and the BSDs: `$XDG_DATA_HOME` when it is an absolute path (the
 /// XDG Base Directory spec ignores a relative one), else `~/.local/share`.
 fn xdg_data_home(xdg: Option<std::ffi::OsString>, home: Option<&Path>) -> Option<PathBuf> {
@@ -610,6 +618,22 @@ fn decode_utf8_dic(dic: &[u8]) -> Result<String, String> {
 mod tests {
     use super::*;
 
+    /// CodeRabbit on craft-libs#489: without LibreOffice extension names no drive is probed; with
+    /// them, only drives where LibreOffice is found give folders.
+    #[test]
+    fn libreoffice_drives_are_probed_only_when_wanted() {
+        let probes = std::cell::Cell::new(0);
+        let count = |_: &Path| {
+            probes.set(probes.get() + 1);
+            false
+        };
+        assert!(lo_drive_dirs(None, count).is_empty());
+        assert_eq!(probes.get(), 0);
+        let exts = ["dict-tr".to_string()];
+        let found = lo_drive_dirs(Some(&exts), |p: &Path| p.to_string_lossy().starts_with(r"D:\Program Files\"));
+        assert_eq!(found, [PathBuf::from(r"D:\Program Files\LibreOffice\share\extensions").join("dict-tr")]);
+    }
+
     /// Another region's Language pack never beats the system's dictionary of the right region
     /// (`pt-pt` pack vs system `pt_BR`; `de-ch` vs `de_DE`; `en-gb` vs `en_US`), but beats the
     /// system's other names; the right region's pack beats the system; the dictionaries folder