diff --git a/mercurial/bundle2.py b/mercurial/bundle2.py
--- a/mercurial/bundle2.py
+++ b/mercurial/bundle2.py
@@ -2527,7 +2527,8 @@ def bundle2getvars(op, part):
 @parthandler(b'stream2', (b'requirements', b'filecount', b'bytecount'))
 def handlestreamv2bundle(op, part):
 
-    requirements = urlreq.unquote(part.params[b'requirements']).split(b',')
+    requirements = urlreq.unquote(part.params[b'requirements'])
+    requirements = requirements.split(b',') if requirements else []
     filecount = int(part.params[b'filecount'])
     bytecount = int(part.params[b'bytecount'])
 
diff --git a/mercurial/cext/parsers.c b/mercurial/cext/parsers.c
--- a/mercurial/cext/parsers.c
+++ b/mercurial/cext/parsers.c
@@ -501,6 +501,8 @@ static PyObject *dirstate_item_set_track
 static PyObject *dirstate_item_set_untracked(dirstateItemObject *self)
 {
 	self->flags &= ~dirstate_flag_wc_tracked;
+	self->flags &= ~dirstate_flag_has_meaningful_data;
+	self->flags &= ~dirstate_flag_has_mtime;
 	self->mode = 0;
 	self->size = 0;
 	self->mtime_s = 0;
diff --git a/mercurial/rewriteutil.py b/mercurial/rewriteutil.py
--- a/mercurial/rewriteutil.py
+++ b/mercurial/rewriteutil.py
@@ -48,10 +48,13 @@ def _formatrevs(repo, revs, maxrevs=4):
     return summary
 
 
-def precheck(repo, revs, action=b'rewrite'):
+def precheck(repo, revs, action=b'rewrite', check_divergence=True):
     """check if revs can be rewritten
     action is used to control the error message.
 
+    check_divergence allows skipping the divergence checks in cases like adding
+    a prune marker (A, ()) to obsstore (which can't be diverging).
+
     Make sure this function is called after taking the lock.
     """
     if nullrev in revs:
@@ -84,6 +87,9 @@ def precheck(repo, revs, action=b'rewrit
             hint=hint,
         )
 
+    if not check_divergence:
+        return
+
     if not obsolete.isenabled(repo, obsolete.allowdivergenceopt):
         new_divergence = _find_new_divergence(repo, revs)
         if new_divergence:
diff --git a/mercurial/tags.py b/mercurial/tags.py
--- a/mercurial/tags.py
+++ b/mercurial/tags.py
@@ -806,7 +806,7 @@ class hgtagsfnodescache:
             # There is some no-merge changeset where p1 is null and p2 is set
             # Processing them as merge is just slower, but still gives a good
             # result.
-            p2node = cl.node(p1rev)
+            p2node = cl.node(p2rev)
             p2fnode = self.getfnode(p2node, computemissing=False)
             if p1fnode != p2fnode:
                 # we cannot rely on readfast because we don't know against what
diff --git a/tests/test-clone-stream.t b/tests/test-clone-stream.t
--- a/tests/test-clone-stream.t
+++ b/tests/test-clone-stream.t
@@ -817,3 +817,9 @@ Clone non-publishing with obsolescence
   $ killdaemons.py
 
 #endif
+
+Cloning a repo with no requirements doesn't give some obscure error
+
+  $ mkdir -p empty-repo/.hg
+  $ hg clone -q --stream ssh://user@dummy/empty-repo empty-repo2
+  $ hg --cwd empty-repo2 verify -q
diff --git a/tests/test-tags.t b/tests/test-tags.t
--- a/tests/test-tags.t
+++ b/tests/test-tags.t
@@ -933,3 +933,58 @@ Avoid writing logs on trying to delete a
   a8a82d372bb35b42ff736e74f07c23bcd99c371f a
   a8a82d372bb35b42ff736e74f07c23bcd99c371f a
   0000000000000000000000000000000000000000 a
+
+  $ cd ..
+
+.hgtags fnode should be properly resolved at merge revision (issue6673)
+
+  $ hg init issue6673
+  $ cd issue6673
+
+  $ touch a
+  $ hg ci -qAm a
+  $ hg branch -q stable
+  $ hg ci -m branch
+
+  $ hg up -q default
+  $ hg merge -q stable
+  $ hg ci -m merge
+
+ add tag to stable branch:
+
+  $ hg up -q stable
+  $ echo a >> a
+  $ hg ci -m a
+  $ hg tag whatever
+  $ hg log -GT'{rev} {tags}\n'
+  @  4 tip
+  |
+  o  3 whatever
+  |
+  | o  2
+  |/|
+  o |  1
+  |/
+  o  0
+  
+
+ merge tagged stable into default:
+
+  $ hg up -q default
+  $ hg merge -q  stable
+  $ hg ci -m merge
+  $ hg log -GT'{rev} {tags}\n'
+  @    5 tip
+  |\
+  | o  4
+  | |
+  | o  3 whatever
+  | |
+  o |  2
+  |\|
+  | o  1
+  |/
+  o  0
+  
+
+  $ cd ..