fix: get is span should consider unapplied status

.gitignore

@@ -1,3 +1,4 @@
 /target
 *.log
 flamegraph.svg
+target

crates/loro-core/fuzz/.gitignore

@@ -1,3 +1,4 @@
 target
 corpus
 artifacts
+coverage

crates/loro-core/justfile

@@ -18,7 +18,7 @@ crev:
   cargo crev crate check
 
 fuzz:
-  cargo fuzz run yata -- -max_total_time=300 -max_len=1000 -jobs=2
+  cargo fuzz run yata -- -max_total_time=300 -max_len=4000 -jobs=2
 
 flame:
   cargo flamegraph --example test --features=fuzzing --root

crates/loro-core/src/container/text/tracker/content_map.rs

@@ -7,7 +7,7 @@ use rle::{
 
 use crate::{id::ID, span::IdSpan};
 
-use super::y_span::{StatusChange, YSpan, YSpanTreeTrait};
+use super::y_span::{Status, StatusChange, YSpan, YSpanTreeTrait};
 
 /// It stores all the [YSpan] data, including the deleted/undo ones
 ///
@@ -80,22 +80,33 @@ impl ContentMap {
                 }
             }
 
-            let next = if prev.is_some() {
+            if prev.is_some() {
-                let next_cursor = cursor.next_elem_start();
+                let mut next_cursor = cursor.next_elem_start();
                 let mut ans = None;
-                if let Some(next_inner) = next_cursor {
+                while let Some(next_inner) = next_cursor {
+                    if next_inner.as_ref().status.unapplied {
                         let mut cursor = next_inner.unwrap();
                         cursor.offset = 0;
                         cursor.pos = Position::Start;
                         ans = Some(next_inner.as_ref().id);
+                        break;
                     }
 
-                ans
+                    next_cursor = next_inner.next_elem_start();
-            } else {
+                }
-                Some(cursor.as_ref().id)
-            };
 
-            (prev, next)
+                (prev, ans)
+            } else {
+                while cursor.as_ref().status.unapplied {
+                    if let Some(next) = cursor.next_elem_start() {
+                        cursor = next;
+                    } else {
+                        return (prev, None);
+                    }
+                }
+
+                (prev, Some(cursor.as_ref().id))
+            }
         } else {
             (None, None)
         }

crates/loro-core/src/container/text/tracker/y_span.rs

@@ -72,7 +72,6 @@ impl YSpan {
 
     #[inline]
     pub fn can_be_origin(&self) -> bool {
-        debug_assert!(self.len > 0);
         self.status.is_activated()
     }