void (@NotNull AnActionEvent e, @NotNull Project project, @NotNull FilePath filePath, @NotNull VcsFileRevision previousRevision, @NotNull VcsFileRevision revision) { GitFileRevision rev = (GitFileRevision)revision; Collection<String> parents = rev.getParents(); if (parents.size() < 2) { super.showDiffForOne(e, project, filePath, previousRevision, revision); } else { // merge showDiffForMergeCommit(e, filePath, rev, parents); } }