Open files with o from the worktree that has the branch checked out

Do the same for `o` in the commit files panel as the previous commits
do for `e`. If the panel was entered from a branch that another worktree
has checked out, open the file from that worktree.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

pkg/gui/controllers/commits_files_controller.go

@@ -428,7 +428,7 @@ func (self *CommitFilesController) canDiscardFileChanges(nodes []*filetree.Commi
 }
 
 func (self *CommitFilesController) open(node *filetree.CommitFileNode) error {
-	return self.c.Helpers().Files.OpenFile(node.GetPath())
+	return self.c.Helpers().Diff.OpenFileOfDiff(node.GetPath())
 }
 
 func (self *CommitFilesController) edit(nodes []*filetree.CommitFileNode) error {

pkg/gui/controllers/helpers/diff_helper.go

@@ -245,6 +245,13 @@ func (self *DiffHelper) EditFileOfDiffAtLine(path string, lineNumber int, viewNa
 	return self.filesHelper.EditFileAtLine(path, lineNumber)
 }
 
+// OpenFileOfDiff opens a file of the diff that the current side panel shows with the
+// default application for it. Like EditFilesOfDiff, it opens the file from the
+// worktree of the diff.
+func (self *DiffHelper) OpenFileOfDiff(path string) error {
+	return self.filesHelper.OpenFile(self.pathInWorktreeOfDiff(path))
+}
+
 // otherWorktreeOfDiff returns the path of the worktree to open files of the diff in
 // the current side panel from, if that isn't the current worktree. If the diff is of a
 // commit of a branch, and another worktree has that branch checked out, that is the

pkg/integration/tests/worktree/open_file_of_branch_in_other_worktree.go

@@ -47,10 +47,7 @@ var OpenFileOfBranchInOtherWorktree = NewIntegrationTest(NewIntegrationTestArgs{
 			).
 			Press(keys.Universal.OpenFile).
 			Tap(func() {
-				/* EXPECTED:
 				t.FileSystem().FileContent("open-command", Contains("/linked-worktree/file.txt\n"))
-				ACTUAL: */
-				t.FileSystem().FileContent("open-command", Contains("/repo/file.txt\n"))
 			}).
 			Press(keys.Files.CopyFileInfoToClipboard).
 			Tap(func() {