diff --git a/mercurial/debugcommands.py b/mercurial/debugcommands.py
--- a/mercurial/debugcommands.py
+++ b/mercurial/debugcommands.py
@@ -1356,7 +1356,7 @@ def debugobsolete(ui, repo, precursor=No
                     parents = tuple(p.node() for p in parents)
                 repo.obsstore.create(tr, prec, succs, opts['flags'],
                                      parents=parents, date=date,
-                                     metadata=metadata)
+                                     metadata=metadata, ui=ui)
                 tr.close()
             except ValueError as exc:
                 raise error.Abort(_('bad obsmarker input: %s') % exc)
diff --git a/mercurial/obsolete.py b/mercurial/obsolete.py
--- a/mercurial/obsolete.py
+++ b/mercurial/obsolete.py
@@ -584,7 +584,7 @@ class obsstore(object):
         return self._readonly
 
     def create(self, transaction, prec, succs=(), flag=0, parents=None,
-               date=None, metadata=None):
+               date=None, metadata=None, ui=None):
         """obsolete: add a new obsolete marker
 
         * ensuring it is hashable
@@ -603,6 +603,10 @@ class obsstore(object):
             if 'date' in metadata:
                 # as a courtesy for out-of-tree extensions
                 date = util.parsedate(metadata.pop('date'))
+            elif ui is not None:
+                date = ui.configdate('devel', 'default-date')
+                if date is None:
+                    date = util.makedate()
             else:
                 date = util.makedate()
         if len(prec) != 20:
@@ -1286,7 +1290,8 @@ def createmarkers(repo, relations, flag=
         for args in markerargs:
             nprec, nsucs, npare, localmetadata = args
             repo.obsstore.create(tr, nprec, nsucs, flag, parents=npare,
-                                 date=date, metadata=localmetadata)
+                                 date=date, metadata=localmetadata,
+                                 ui=repo.ui)
             repo.filteredrevcache.clear()
         tr.close()
     finally:
diff --git a/tests/test-obsolete.t b/tests/test-obsolete.t
--- a/tests/test-obsolete.t
+++ b/tests/test-obsolete.t
@@ -1252,7 +1252,7 @@ only a subset of those are displayed (be
   $ hg debugobsolete --index --rev "3+7" -Tjson
   [
    {
-    "date": *, (glob)
+    "date": [0.0, 0],
     "flag": 0,
     "index": 1,
     "metadata": {"user": "test"},
@@ -1260,7 +1260,7 @@ only a subset of those are displayed (be
     "succnodes": ["d27fb9b066076fd921277a4b9e8b9cb48c95bc6a"]
    },
    {
-    "date": *, (glob)
+    "date": [0.0, 0],
     "flag": 0,
     "index": 3,
     "metadata": {"operation": "amend", "user": "test"},
@@ -1271,15 +1271,15 @@ only a subset of those are displayed (be
 
 Test the --delete option of debugobsolete command
   $ hg debugobsolete --index
-  0 cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b f9bd49731b0b175e42992a3c8fa6c678b2bc11f1 0 \(.*\) {'user': 'test'} (re)
-  1 6fdef60fcbabbd3d50e9b9cbc2a240724b91a5e1 d27fb9b066076fd921277a4b9e8b9cb48c95bc6a 0 \(.*\) {'user': 'test'} (re)
-  2 1ab51af8f9b41ef8c7f6f3312d4706d870b1fb74 29346082e4a9e27042b62d2da0e2de211c027621 0 \(.*\) {'user': 'test'} (re)
-  3 4715cf767440ed891755448016c2b8cf70760c30 7ae79c5d60f049c7b0dd02f5f25b9d60aaf7b36d 0 (*) {'operation': 'amend', 'user': 'test'} (glob)
+  0 cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b f9bd49731b0b175e42992a3c8fa6c678b2bc11f1 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  1 6fdef60fcbabbd3d50e9b9cbc2a240724b91a5e1 d27fb9b066076fd921277a4b9e8b9cb48c95bc6a 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  2 1ab51af8f9b41ef8c7f6f3312d4706d870b1fb74 29346082e4a9e27042b62d2da0e2de211c027621 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  3 4715cf767440ed891755448016c2b8cf70760c30 7ae79c5d60f049c7b0dd02f5f25b9d60aaf7b36d 0 (Thu Jan 01 00:00:00 1970 +0000) {'operation': 'amend', 'user': 'test'}
   $ hg debugobsolete --delete 1 --delete 3
   deleted 2 obsolescence markers
   $ hg debugobsolete
-  cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b f9bd49731b0b175e42992a3c8fa6c678b2bc11f1 0 \(.*\) {'user': 'test'} (re)
-  1ab51af8f9b41ef8c7f6f3312d4706d870b1fb74 29346082e4a9e27042b62d2da0e2de211c027621 0 \(.*\) {'user': 'test'} (re)
+  cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b f9bd49731b0b175e42992a3c8fa6c678b2bc11f1 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
+  1ab51af8f9b41ef8c7f6f3312d4706d870b1fb74 29346082e4a9e27042b62d2da0e2de211c027621 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
 
 Test adding changeset after obsmarkers affecting it
 (eg: during pull, or unbundle)