1 files changed, 13 insertions, 0 deletions
diff --git a/tree-diff.c b/tree-diff.c
index 69031d7cba..a76e6dae61 100644
--- a/tree-diff.c
+++ b/tree-diff.c
@@ -7,6 +7,19 @@
 #include "tree.h"
 
 /*
+ * Some mode bits are also used internally for computations.
+ *
+ * They *must* not overlap with any valid modes, and they *must* not be emitted
+ * to outside world - i.e. appear on disk or network. In other words, it's just
+ * temporary fields, which we internally use, but they have to stay in-house.
+ *
+ * ( such approach is valid, as standard S_IF* fits into 16 bits, and in Git
+ *   codebase mode is `unsigned int` which is assumed to be at least 32 bits )
+ */
+
+#define S_DIFFTREE_IFXMIN_NEQ	0x80000000
+
+/*
  * internal mode marker, saying a tree entry != entry of tp[imin]
  * (see ll_diff_tree_paths for what it means there)
  *