Fix unstaging a submodule with dirty content

The stage/unstage toggle decides what to do based on whether a node has
unstaged changes: if it does, it stages; otherwise it unstages. For a
submodule this breaks down, because dirty or untracked content inside the
submodule always reports as an unstaged change in the parent repo but can
never be staged from there. Once such a submodule's commit pointer is
staged it sits at "MM", and every subsequent press keeps trying to stage
the unstageable dirty content, so it can never be unstaged.

Treat a submodule's unstaged change as stageable only when its commit
isn't already staged, so that a staged submodule unstages on the next
press regardless of leftover dirty content. Because the decision is now
shared by press and stage-all, this fixes both at once.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

pkg/gui/controllers/files_controller.go

@@ -471,7 +471,7 @@ func (self *FilesController) toggleStaged(
 
 	nodes = normalisedSelectedNodes(nodes)
 
-	unstagedNodes := filterNodesHaveUnstagedChanges(nodes)
+	unstagedNodes := filterNodesHaveUnstagedChanges(nodes, self.c.Model().Submodules)
 
 	if len(unstagedNodes) > 0 {
 		self.c.LogAction(stageAction)
@@ -1421,12 +1421,32 @@ func someNodesHaveStagedChanges(nodes []*filetree.FileNode) bool {
 	return lo.SomeBy(nodes, (*filetree.FileNode).GetHasStagedChanges)
 }
 
-func filterNodesHaveUnstagedChanges(nodes []*filetree.FileNode) []*filetree.FileNode {
+func filterNodesHaveUnstagedChanges(nodes []*filetree.FileNode, submodules []*models.SubmoduleConfig) []*filetree.FileNode {
 	return lo.Filter(nodes, func(node *filetree.FileNode, _ int) bool {
-		return node.GetHasUnstagedChanges()
+		return node.SomeFile(func(file *models.File) bool {
+			return fileHasStageableUnstagedChanges(file, submodules)
+		})
 	})
 }
 
+// For a submodule, the only thing the parent repo can stage is the
+// commit-pointer change; dirty or untracked content within the submodule
+// shows up as an unstaged change but can never be staged from the parent. So
+// once the submodule's commit is staged (leaving it at e.g. "MM"), we mustn't
+// treat the leftover unstaged change as stageable, or pressing space would
+// keep trying to stage it instead of unstaging it.
+func fileHasStageableUnstagedChanges(file *models.File, submodules []*models.SubmoduleConfig) bool {
+	if !file.HasUnstagedChanges {
+		return false
+	}
+
+	if file.IsSubmodule(submodules) {
+		return !file.HasStagedChanges
+	}
+
+	return true
+}
+
 func findSubmoduleNode(nodes []*filetree.FileNode, submodules []*models.SubmoduleConfig) *models.File {
 	for _, node := range nodes {
 		submoduleNode := node.FindFirstFileBy(func(f *models.File) bool {

pkg/integration/tests/submodule/stage.go

@@ -39,13 +39,8 @@ var Stage = NewIntegrationTest(NewIntegrationTestArgs{
 			// Pressing again must unstage the submodule, taking us back to
 			// " M" rather than trying (and failing) to stage the dirty content.
 			PressPrimaryAction().
-			/* EXPECTED:
 			Lines(
 				Equals(" M my_submodule_path (submodule)").IsSelected(),
 			)
-			ACTUAL: */
-			Lines(
-				Equals("MM my_submodule_path (submodule)").IsSelected(),
-			)
 	},
 })