diff: deprecate xdir diff feature for diff command

Summary:
This diff deprecate xdir diff feature for diff command. `subtree diff` is
the recommended command for xdir diff feature.

Reviewed By: muirdm

Differential Revision: D67242555

fbshipit-source-id: 28cd041c2dc29ecf084fcef136a81fb53844f840

Author: zzl0

eden/scm/sapling/commands/__init__.py

@@ -2192,6 +2192,11 @@ def diff(ui, repo, *pats, **opts):
 
     Returns 0 on success.
     """
+    if opts.get("from_path") or opts.get("to_path"):
+        raise error.Abort(
+            _("'--from-path' and '--to-path' are deprecated for '@prog@ diff' command"),
+            hint=_("use '@prog@ subtree diff' to diff between directories"),
+        )
 
     do_diff(ui, repo, *pats, **opts)
 

eden/scm/sapling/helptext.py

@@ -4683,7 +4683,7 @@
 
     $ echo a > my-project/file
     $ echo b > my-branch/file
-    $ @prog@ diff --from-path my-project --to-path my-branch
+    $ @prog@ subtree diff --from-path my-project --to-path my-branch
 
 Files outside ``--from-path`` in the left side are ignored, and files
 outside ``--to-path`` on the right side are ignored.
@@ -4706,5 +4706,5 @@
     # Modify "file" in both branches and then diff both branches against "my-project":
     $ echo branch1 > my-branch1/file
     $ echo branch2 > my-branch2/file
-    $ @prog@ diff --from-path my-project --to-path my-branch1 --from-path my-project --to-path my-branch2
+    $ @prog@ subtree diff --from-path my-project --to-path my-branch1 --from-path my-project --to-path my-branch2
 """

eden/scm/tests/test-diff-xdir.t

@@ -19,6 +19,12 @@ validate from/to paths:
   abort: path 'foofoo' does not exist in commit 112bacaa6bb9
   [255]
 
+diff command does not support xdir diff:
+  $ hg diff -r $A -r $A --from-path foo --to-path bar
+  abort: '--from-path' and '--to-path' are deprecated for 'hg diff' command
+  (use 'hg subtree diff' to diff between directories)
+  [255]
+
 Basic diff with add, modify, and remove:
   $ hg subtree diff -r $A -r $A --from-path foo --to-path bar
   diff --git a/foo/differs b/bar/differs