catalog: slice captured dates on char boundaries so non-ASCII dates don't panic

crates/catalog/src/query.rs

@@ -397,10 +397,13 @@ impl Catalog {
         let mut years: BTreeMap<&str, (BTreeMap<&str, usize>, BTreeMap<&str, usize>)> = BTreeMap::new();
         for p in self.photos().filter(|p| p.in_library()) {
             let Some(d) = p.captured.as_deref() else { continue };
-            if d.len() >= 10 {
-                let (months, days) = years.entry(&d[..4]).or_default();
-                *months.entry(&d[..7]).or_default() += 1;
-                *days.entry(&d[..10]).or_default() += 1;
+            // `get`, not `[..]`: a corrupt or foreign `captured` (a Lightroom catalog's
+            // captureTime is copied verbatim) may not be ASCII, and slicing it on a byte index
+            // would panic — the same rule as `dates::group_label`.
+            if let (Some(year), Some(month), Some(day)) = (d.get(..4), d.get(..7), d.get(..10)) {
+                let (months, days) = years.entry(year).or_default();
+                *months.entry(month).or_default() += 1;
+                *days.entry(day).or_default() += 1;
             }
         }
         let newest_first = |m: BTreeMap<&str, usize>| m.into_iter().rev().map(|(k, n)| (k.to_string(), n)).collect::<Vec<_>>();

crates/catalog/src/tests.rs

@@ -123,6 +123,23 @@ fn filter_search_sort() {
     assert_eq!(c.keywords(), vec![("ocean".to_string(), 1), ("summer".to_string(), 1)]);
 }
 
+/// A `captured` string that is not ASCII (the Lightroom importer copies `captureTime` into an
+/// `AddPhoto` op verbatim, and a JSON snapshot is valid UTF-8 whatever it holds) must not be
+/// sliced on a byte index in `date_groups`: grouping counts the well-formed dates and ignores
+/// the rest instead of panicking on a char boundary.
+#[test]
+fn date_groups_ignores_a_non_ascii_captured() {
+    let mut c = Catalog::new();
+    let ok = photo(&mut c, "ok.jpg", "2026-05-01T10:00:00");
+    // `AddPhoto` takes the field as it is, like `library.importLightroom` building the op
+    let bad = photo(&mut c, "bad.jpg", "日本語日本語");
+    assert_ne!(ok, bad);
+    let g = c.date_groups();
+    assert_eq!(g.len(), 1, "the one well-formed date still groups");
+    assert_eq!((g[0].year.as_str(), g[0].count), ("2026", 1));
+    assert_eq!(g[0].days.iter().map(|d| d.1).sum::<usize>(), 1);
+}
+
 #[test]
 fn snapshot_and_log_replay() {
     let mut c = Catalog::new();