bookmarks: don't deactivate on no-op update (issue4901)

mercurial/commands.py

@@ -6619,7 +6619,9 b' def update(ui, repo, node=None, rev=None'
             ret = hg.update(repo, rev)
 
         if not ret and movemarkfrom:
-            if bookmarks.update(repo, [movemarkfrom], repo['.'].node()):
+            if movemarkfrom == repo['.'].node():
+                pass # no-op update
+            elif bookmarks.update(repo, [movemarkfrom], repo['.'].node()):
                 ui.status(_("updating bookmark %s\n") % repo._activebookmark)
             else:
                 # this can happen with a non-linear update

tests/test-bookmarks.t

@@ -732,6 +732,19 b' test non-linear update not clearing acti'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (activating bookmark four)
 
+no-op update doesn't deactive bookmarks
+
+  $ hg up
+  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ hg sum
+  parent: 3:9ba5f110a0b3 tip
+   y
+  branch: test
+  bookmarks: *four
+  commit: 2 unknown (clean)
+  update: (current)
+  phases: 4 draft
+
 test clearing divergent bookmarks of linear ancestors
 
   $ hg bookmark Z -r 0