fix: Submodule::status() now konws about tree-index changes as well.

This completes the status implementation.

Author: Byron

gix/src/submodule/mod.rs

@@ -323,6 +323,9 @@ pub mod status {
         /// Return the status of the submodule, just like [`status`](Self::status), but allows to adjust options
         /// for more control over how the status is performed.
         ///
+        /// If `check_dirty` is `true`, the computation will stop once the first in a ladder operations
+        /// ordered from cheap to expensive shows that the submodule is dirty.
+        ///
         /// Use `&mut std::convert::identity` for `adjust_options` if no specific options are desired.
         /// A reason to change them might be to enable sorting to enjoy deterministic order of changes.
         ///

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

@@ -21,6 +21,17 @@ git init submodule-head-changed
   cd m1 && git checkout @~1
 )
 
+git init submodule-index-changed
+(cd submodule-index-changed
+  git submodule add ../module1 m1
+  git commit -m "add submodule"
+
+  (cd m1
+    git mv subdir  subdir-renamed
+    git mv this that
+  )
+)
+
 git init submodule-head-changed-no-worktree
 (cd submodule-head-changed-no-worktree
   git submodule add ../module1 m1

gix/tests/fixtures/make_submodules.sh

@@ -186,6 +186,37 @@ mod open {
             Ok(())
         }
 
+        #[test]
+        fn modified_in_index_only() -> crate::Result {
+            let repo = repo("submodule-index-changed")?;
+            let sm = repo.submodules()?.into_iter().flatten().next().expect("one submodule");
+
+            for mode in [
+                gix::submodule::config::Ignore::Untracked,
+                gix::submodule::config::Ignore::None,
+            ] {
+                for check_dirty in [false, true] {
+                    let status = sm.status_opts(mode, check_dirty, &mut |platform| platform)?;
+                    assert_eq!(
+                        status.is_dirty(),
+                        Some(true),
+                        "two files were renamed using `git mv` for an HEAD^{tree}-index change"
+                    );
+                    assert_eq!(
+                        status.changes.expect("present").len(),
+                        if check_dirty { 1 } else { 2 },
+                        "in is-dirty mode, we don't collect all changes"
+                    );
+                }
+            }
+
+            assert!(
+                repo.is_dirty()?,
+                "superproject should see submodule changes in the index as well"
+            );
+            Ok(())
+        }
+
         #[test]
         fn modified_and_untracked() -> crate::Result {
             let repo = repo("modified-and-untracked")?;