Merge PR #1451

crates/engine/src/files.rs

@@ -2296,4 +2296,25 @@ mod tests {
         assert_eq!(s.quick_view_job(id, 1600, true).unwrap().run().quick, Some(QuickSource::Small));
         let _ = std::fs::remove_dir_all(&dir);
     }
+
+    /// Issue #1448: the grid renders nothing behind an unedited raw's quick thumbnail, so when the
+    /// embedded preview can't be read (and nothing is cached) the quick job itself must render the
+    /// raw, or the cell stays empty for good ("no quick preview").
+    #[test]
+    fn a_quick_thumbnail_without_an_embedded_preview_renders_the_raw() {
+        use crate::media::QuickSource;
+        let dir = std::env::temp_dir().join(format!("lc-quick-none-{}", std::process::id()));
+        std::fs::create_dir_all(&dir).unwrap();
+        let path = dir.join("a.cr3");
+        std::fs::write(&path, cr3_with_preview(96, 64)).unwrap();
+        let mut s = crate::Session::new().with_fs();
+        let r = s.execute("library.import", &serde_json::json!({"paths": [path.to_string_lossy()]})).unwrap();
+        let id = lightcraft_catalog::PhotoId(r["imported"][0].as_u64().unwrap());
+        s.media.preview_loader = Some(std::sync::Arc::new(|_: &str, _| None));
+        let job = s.thumb_job(id, 128).unwrap();
+        let q = s.quick_thumb_job(&job).unwrap().run();
+        assert_eq!((q.quick, q.key), (Some(QuickSource::Small), job.key));
+        assert!(q.rendered.is_ok(), "{:?}", q.rendered.err());
+        let _ = std::fs::remove_dir_all(&dir);
+    }
 }

crates/engine/src/media.rs

@@ -1427,8 +1427,10 @@ impl crate::Session {
 
     /// A first grid thumbnail for an unedited raw: the cached render for `job` (the real
     /// thumbnail job, from [`Self::thumb_job`]) if there is one — then the result carries
-    /// [`QuickSource::Cached`] and `job.key` and is final — else its embedded preview. `None` for
-    /// other photos (render them directly).
+    /// [`QuickSource::Cached`] and `job.key` and is final — else its embedded preview, else `job`
+    /// itself: the grid queues no render behind an unedited raw's quick thumbnail
+    /// ([`Self::embedded_thumb_is_final`]), so a preview that can't be read must not leave the
+    /// cell empty (issue #1448). `None` for other photos (render them directly).
     pub fn quick_thumb_job(&mut self, job: &RenderJob) -> Option<QuickJob> {
         let p = self.catalog.photo(job.photo)?.clone();
         let (path, l) = self.embedded_of(&p)?;
@@ -1439,7 +1441,7 @@ impl crate::Session {
             key: job.key,
             cached: job.cache.clone().into_iter().collect(),
             embedded: Some((path, l, edge)),
-            small: None,
+            small: Some(Box::new(job.clone())),
         })
     }
 

docs/raw-preview-reads.md

@@ -101,6 +101,9 @@ loupe render of a cold photo finished 174 s after the click, most of it spent be
 - `grid::skips_the_real_render(embedded_is_final, from_embedded)` is the decision, unit-tested:
   a **cached render** as the stand-in, an **edited photo** and a **raw with no embedded JPEG** all
   still render, because their thumbnail must show the pipeline's output rather than the camera's.
+- Whether the embedded JPEG can actually be read is only known when the quick job runs, so
+  `Session::quick_thumb_job` carries the real thumbnail job as its last resort: a raw whose preview
+  the loader can't read renders the raw instead of leaving the cell empty (issue #1448).
 - The thumbnail key still changes with the settings hash, so editing a photo re-renders its
   thumbnail through the ordinary background path.