fix: status-iterator won't swallow legitimate modification during 'racy-git'.

When a modification is marked as being racy, then previously the iterator would have
kept the whole modification even though it should just have tracked the single change.

This made the legitimate modification disappear.

Author: Byron

gix/src/status/iter/mod.rs

@@ -274,12 +274,15 @@ impl Iter {
 
 impl Iter {
     fn maybe_keep_index_change(&mut self, item: Item) -> Option<Item> {
-        let change = match item {
+        match item {
             Item::IndexWorktree(index_worktree::Item::Modification {
                 status: EntryStatus::NeedsUpdate(stat),
                 entry_index,
                 ..
-            }) => (entry_index, ApplyChange::NewStat(stat)),
+            }) => {
+                self.index_changes.push((entry_index, ApplyChange::NewStat(stat)));
+                return None;
+            }
             Item::IndexWorktree(index_worktree::Item::Modification {
                 status:
                     EntryStatus::Change(Change::Modification {
@@ -288,12 +291,12 @@ impl Iter {
                     }),
                 entry_index,
                 ..
-            }) if set_entry_stat_size_zero => (entry_index, ApplyChange::SetSizeToZero),
-            _ => return Some(item),
+            }) if set_entry_stat_size_zero => {
+                self.index_changes.push((entry_index, ApplyChange::SetSizeToZero));
+            }
+            _ => {}
         };
-
-        self.index_changes.push(change);
-        None
+        Some(item)
     }
 }
 

gix/tests/fixtures/generated-archives/make_status_repos.tar

@@ -21,3 +21,12 @@ git init git-mv
 
   git mv file renamed
 )
+
+git init racy-git
+(cd racy-git
+  echo hi >file
+  git add file && git commit -m "init"
+
+  echo ho >file && git add file
+  echo ha >file
+)

gix/tests/fixtures/make_status_repos.sh

@@ -73,6 +73,16 @@ mod into_iter {
         Ok(())
     }
 
+    #[test]
+    fn tree_index_modification_worktree_modification_racy_git() -> crate::Result {
+        let repo = repo("racy-git")?;
+        let mut status = repo.status(gix::progress::Discard)?.into_iter(None)?;
+        let mut items: Vec<_> = status.by_ref().filter_map(Result::ok).collect();
+        items.sort_by(|a, b| a.location().cmp(b.location()));
+        assert_eq!(items.len(), 2, "1 modified in index, the same in worktree");
+        Ok(())
+    }
+
     #[test]
     fn error_during_tree_traversal_causes_failure() -> crate::Result {
         let repo = repo("untracked-only")?;