merge: improve error messages for path conflicts during update

Differential Revision: https://phab.mercurial-scm.org/D782

mercurial/merge.py

@@ -741,13 +741,23 b' def _checkunknownfiles(repo, wctx, mctx,'
                     actions[f] = ('g', (fl2, True), "remote created")
 
     for f in sorted(abortconflicts):
-        repo.ui.warn(_("%s: untracked file differs\n") % f)
+        warn = repo.ui.warn
+        if f in pathconflicts:
+            if repo.wvfs.isfileorlink(f):
+                warn(_("%s: untracked file conflicts with directory\n") % f)
+            else:
+                warn(_("%s: untracked directory conflicts with file\n") % f)
+        else:
+            warn(_("%s: untracked file differs\n") % f)
     if abortconflicts:
         raise error.Abort(_("untracked files in working directory "
                             "differ from files in requested revision"))
 
     for f in sorted(warnconflicts):
-        repo.ui.warn(_("%s: replacing untracked file\n") % f)
+        if repo.wvfs.isfileorlink(f):
+            repo.ui.warn(_("%s: replacing untracked file\n") % f)
+        else:
+            repo.ui.warn(_("%s: replacing untracked files in directory\n") % f)
 
     for f, (m, args, msg) in actions.iteritems():
         if m == 'c':

tests/test-merge1.t

@@ -30,7 +30,7 b" of the files in a commit we're updating "
 
   $ mkdir b && touch b/nonempty
   $ hg up
-  b: untracked file differs
+  b: untracked directory conflicts with file
   abort: untracked files in working directory differ from files in requested revision
   [255]
   $ hg ci

tests/test-pathconflicts-basic.t

@@ -37,7 +37,7 b' Basic update - local directory conflicts'
   $ mkdir a
   $ echo 3 > a/b
   $ hg up file
-  a: untracked file differs
+  a: untracked directory conflicts with file
   abort: untracked files in working directory differ from files in requested revision
   [255]
   $ hg up --clean file

tests/test-update-names.t

@@ -50,7 +50,7 b' make sure that this does not erase untra'
   $ hg st
   ? name/file
   $ hg up 1
-  name: untracked file differs
+  name: untracked directory conflicts with file
   abort: untracked files in working directory differ from files in requested revision
   [255]
   $ cd ..