checkout: print removed cwd warning in nativecheckout

Summary:
This warning was printed by old checkout, keeping it in nativecheckout too
The warning tells user that current working directory was removed during checkout

This diff also makes test-update-names.t to use nativecheckout. Otherwise last test fails on remote repo, because pyworker does not emit the deleted cwd warning

Reviewed By: quark-zju

Differential Revision: D26558188

fbshipit-source-id: 1f6ea2ea1ac7358ce2f06fed25069656481b30e6

eden/scm/edenscm/mercurial/merge.py

@@ -2305,6 +2305,7 @@ def update(
                     repo.localvfs.writeutf8("updatestate", p2.hex())
 
                 fp1, fp2, xp1, xp2 = fp2, nullid, xp2, ""
+                cwd = pycompat.getcwdsafe()
 
                 with progress.spinner(repo.ui, _("updating")):
                     repo.ui.debug("Applying to %s \n" % repo.wvfs.base)
@@ -2312,6 +2313,17 @@ def update(
                     repo.ui.debug("Apply done\n")
                 stats = plan.stats()
 
+                if cwd and not pycompat.getcwdsafe():
+                    # cwd was removed in the course of removing files; print a helpful
+                    # warning.
+                    repo.ui.warn(
+                        _(
+                            "current directory was removed\n"
+                            "(consider changing to repo root: %s)\n"
+                        )
+                        % repo.root
+                    )
+
                 if not partial and not wc.isinmemory():
                     with repo.dirstate.parentchange():
                         repo.setparents(fp1, fp2)

eden/scm/tests/test-update-names.t

@@ -3,6 +3,8 @@
 Test update logic when there are renames or weird same-name cases between dirs
 and files
 
+  $ setconfig experimental.nativecheckout=true
+
 Setup server
   $ newserver server
 
@@ -80,7 +82,7 @@ Test update when two commits have symlinks that point to different folders
 #if rmcwd
 
 Test that warning is printed if cwd is deleted during update
-  $ newrepo r4
+  $ newremoterepo r4
   $ mkdir dir
   $ cd dir
   $ echo a > a