fix: 粘贴图片的内容哈希键被占用时改用空闲键

crates/engine/src/cmd/edit/props.rs

@@ -391,8 +391,19 @@ pub(super) fn paint_paste(s: &mut Session, p: &Value, fills: bool) -> Result<Val
         if let Some(d) = s.clipboard.paint_images.get(&copied).cloned() {
             let doc = s.doc_mut()?;
             // The destination may already use that key for different data (other layers keep
-            // that image): the pasted paint takes the copied data's content hash instead.
-            let key = if doc.images.get(&copied).is_some_and(|existing| existing != &d) { figcraft_format::image_hash(&d.bytes) } else { copied };
+            // that image): the pasted paint takes the copied data's content hash instead. That key
+            // can be taken too — images are usually keyed by their hash, so the copied key often
+            // is that hash — and then a numbered variant of it.
+            let base = if doc.images.get(&copied).is_some_and(|existing| existing != &d) { figcraft_format::image_hash(&d.bytes) } else { copied };
+            let mut key = base.clone();
+            let mut n = 0u32;
+            while doc.images.get(&key).is_some_and(|existing| existing != &d) {
+                n = n.saturating_add(1);
+                if n > 999 {
+                    return Err(bad(cmd, "no free image key for the copied image"));
+                }
+                key = format!("{base}-{n}");
+            }
             doc.images.entry(key.clone()).or_insert(d);
             img.image = key;
         }

crates/engine/src/property_copy_tests.rs

@@ -143,6 +143,30 @@ fn a_copied_image_key_taken_in_another_file_gets_the_copied_data() {
     assert_eq!(doc.images.get("img-key"), Some(&taken), "the destination's image stays");
 }
 
+#[test]
+fn a_copied_image_whose_hash_key_is_also_taken_gets_a_free_key() {
+    let mut s = Session::new();
+    let a = rect(&mut s);
+    let bytes = vec![1, 2, 3];
+    let copied = figcraft_doc::ImageData { bytes: std::sync::Arc::new(bytes.clone()), width: 2, height: 2 };
+    let taken = figcraft_doc::ImageData { bytes: std::sync::Arc::new(vec![9, 9, 9]), width: 3, height: 3 };
+    // Images are usually keyed by their content hash: here the copied key is that hash, and the
+    // other file already uses it for other data, so the replacement key is taken as well.
+    let hash = figcraft_format::image_hash(&bytes);
+    ex(&mut s, "fill.add", json!({"ids": [a], "paint": {"type": "image", "image": hash}}));
+    s.doc_mut().unwrap().images.insert(hash.clone(), copied.clone());
+    ex(&mut s, "fill.copy", json!({"id": a, "index": 1}));
+    ex(&mut s, "file.new", json!({}));
+    let b = rect(&mut s);
+    s.doc_mut().unwrap().images.insert(hash.clone(), taken.clone());
+    ex(&mut s, "fill.paste", json!({"ids": [b], "index": 0}));
+    let doc = s.doc().unwrap();
+    let figcraft_color::PaintKind::Image(img) = &doc.node(b).unwrap().fills[0].kind else { panic!("the pasted fill is an image") };
+    assert_ne!(img.image, hash, "the taken hash is not reused");
+    assert_eq!(doc.images.get(&img.image), Some(&copied), "the pasted paint points at the copied data");
+    assert_eq!(doc.images.get(&hash), Some(&taken), "the destination's image stays");
+}
+
 #[test]
 fn a_copied_pattern_does_not_paste_into_another_file() {
     let mut s = Session::new();