Apply review fixes

- crates/engine/src/spell.rs

crates/engine/src/spell.rs

@@ -304,7 +304,12 @@ impl Dictionary {
 
     /// `w` made of dictionary parts allowed in compounds (`COMPOUNDFLAG`, or the begin, middle and
     /// end flags), each at least `COMPOUNDMIN` characters long.
-    fn compounded(&self, w: &[char], index: usize) -> bool {
+    fn compounded(&self, w: &[char], index: usize, failed: &mut HashSet<(usize, usize)>) -> bool {
+        // `w` is always a tail of the checked word, so its length names it: a (tail, part index)
+        // that failed once fails again however the earlier parts were split.
+        if failed.contains(&(w.len(), index)) {
+            return false;
+        }
         if self.compound.is_none() && self.compound_end.is_none() {
             return false;
         }
@@ -322,10 +327,11 @@ impl Dictionary {
             if [self.compound, self.compound_end].into_iter().flatten().any(|f| self.compound_part(rest, f, true)) {
                 return true;
             }
-            if self.compounded(rest, index + 1) {
+            if self.compounded(rest, index + 1, failed) {
                 return true;
             }
         }
+        failed.insert((w.len(), index));
         false
     }
 
@@ -352,7 +358,7 @@ impl Dictionary {
                 return true;
             }
         }
-        self.compounded(&w, 0)
+        self.compounded(&w, 0, &mut HashSet::new())
     }
 
     /// Is `word` spelt correctly? Capitalised and upper-case forms of a lower-case word pass.
@@ -931,6 +937,17 @@ SFX D Y 1\nSFX D 0 ed/S .\n";
         }
     }
 
+    #[test]
+    fn overlapping_compound_roots_with_a_failing_ending_stay_cheap() {
+        // Roots a..aaaaaaaa overlap, so many splits of "aaa…ab" reach the same (tail, part) state; unmemoized that is millions of searches.
+        let d = Dictionary::parse(
+            b"COMPOUNDFLAG X\nCOMPOUNDMIN 1\n".as_slice(),
+            b"8\na/X\naa/X\naaa/X\naaaa/X\naaaaa/X\naaaaaa/X\naaaaaaa/X\naaaaaaaa/X\n".as_slice(),
+        );
+        assert!(!d.check(&format!("{}b", "a".repeat(99))));
+        assert!(d.check(&"a".repeat(20)));
+    }
+
     #[test]
     fn runs_give_words_their_language() {
         use deckcraft_model::{Paragraph, Run, RunProps};

crates/fonts/src/fallback.rs

@@ -169,7 +169,7 @@ impl FontDb {
                 if bundled.contains(fam) {
                     continue;
                 }
-                if self.is_loaded(fam) || (self.system_fallback_enabled() && self.has_family(fam)) {
+                if self.is_loaded(fam) || self.has_family(fam) {
                     let f = self.face(fam, style);
                     if f.family.eq_ignore_ascii_case(fam) && covers_cluster(&f, cluster) {
                         return f;

crates/fonts/src/fontdb.rs

@@ -976,17 +976,6 @@ impl FontDb {
         let _ = on;
     }
 
-    /// Whether automatic system-font lookups (fallback by character, symbol and script families)
-    /// may touch installed fonts. Lookups of a family the document or host names are not gated.
-    pub(crate) fn system_fallback_enabled(&self) -> bool {
-        #[cfg(not(target_arch = "wasm32"))]
-        {
-            self.sys.lock().unwrap_or_else(std::sync::PoisonError::into_inner).enabled
-        }
-        #[cfg(target_arch = "wasm32")]
-        false
-    }
-
     /// Process-wide database: the bundled fonts, then the installed system fonts, cataloged the
     /// first time a lookup by family name needs them (or ahead of time by
     /// [`FontDb::scan_in_background`]).
@@ -1480,8 +1469,7 @@ impl FontDb {
         };
         #[cfg(not(target_arch = "wasm32"))]
         {
-            let cataloged: Vec<String> =
-                if self.system_fallback_enabled() { self.read_catalog().iter().map(|e| e.family.clone()).collect() } else { Vec::new() };
+            let cataloged: Vec<String> = self.read_catalog().iter().map(|e| e.family.clone()).collect();
             for fam in SYSTEM_FALLBACKS.iter().filter(|f| f.contains("Symbol")) {
                 if !self.is_loaded(fam) && cataloged.iter().any(|f| f.eq_ignore_ascii_case(fam)) {
                     self.load_cataloged(fam);

crates/fonts/src/tests.rs

@@ -425,11 +425,3 @@ fn the_font_scan_skips_fifos_folders_and_link_loops() {
     assert!(fifo || n >= 1);
     let _ = std::fs::remove_dir_all(&dir);
 }
-
-#[test]
-fn disabling_system_fallback_gates_automatic_family_loads() {
-    let db = FontDb::with_font_dirs(Vec::new());
-    assert!(cfg!(target_arch = "wasm32") || db.system_fallback_enabled());
-    db.set_system_fallback(false);
-    assert!(!db.system_fallback_enabled());
-}