diff --git a/hgext/largefiles/lfcommands.py b/hgext/largefiles/lfcommands.py
--- a/hgext/largefiles/lfcommands.py
+++ b/hgext/largefiles/lfcommands.py
@@ -163,7 +163,7 @@
             # to the destination repository's requirements.
             if lfiles:
                 rdst.requirements.add(b'largefiles')
-                rdst._writerequirements()
+                scmutil.writereporequirements(rdst)
         else:
 
             class lfsource(filemap.filemap_source):
diff --git a/hgext/largefiles/reposetup.py b/hgext/largefiles/reposetup.py
--- a/hgext/largefiles/reposetup.py
+++ b/hgext/largefiles/reposetup.py
@@ -448,7 +448,7 @@
             lfutil.shortname + b'/' in f[0] for f in repo.store.datafiles()
         ):
             repo.requirements.add(b'largefiles')
-            repo._writerequirements()
+            scmutil.writereporequirements(repo)
 
     ui.setconfig(
         b'hooks', b'changegroup.lfiles', checkrequireslfiles, b'largefiles'
diff --git a/hgext/lfs/__init__.py b/hgext/lfs/__init__.py
--- a/hgext/lfs/__init__.py
+++ b/hgext/lfs/__init__.py
@@ -255,7 +255,7 @@
                 ):
                     repo.requirements.add(b'lfs')
                     repo.features.add(repository.REPO_FEATURE_LFS)
-                    repo._writerequirements()
+                    scmutil.writereporequirements(repo)
                     repo.prepushoutgoinghooks.add(b'lfs', wrapper.prepush)
                     break
 
diff --git a/hgext/lfs/wrapper.py b/hgext/lfs/wrapper.py
--- a/hgext/lfs/wrapper.py
+++ b/hgext/lfs/wrapper.py
@@ -312,7 +312,7 @@
                     # membership before assuming it is in the context.
                     if any(f in ctx and ctx[f].islfs() for f, n in files):
                         self.repo.requirements.add(b'lfs')
-                        self.repo._writerequirements()
+                        scmutil.writereporequirements(self.repo)
 
                 return node
 
diff --git a/hgext/narrow/narrowbundle2.py b/hgext/narrow/narrowbundle2.py
--- a/hgext/narrow/narrowbundle2.py
+++ b/hgext/narrow/narrowbundle2.py
@@ -20,6 +20,7 @@
     localrepo,
     narrowspec,
     repair,
+    scmutil,
     util,
     wireprototypes,
 )
@@ -179,7 +180,7 @@
 
     if not repository.NARROW_REQUIREMENT in op.repo.requirements:
         op.repo.requirements.add(repository.NARROW_REQUIREMENT)
-        op.repo._writerequirements()
+        scmutil.writereporequirements(op.repo)
     op.repo.setnarrowpats(includepats, excludepats)
     narrowspec.copytoworkingcopy(op.repo)
 
@@ -195,7 +196,7 @@
 
     if repository.NARROW_REQUIREMENT not in op.repo.requirements:
         op.repo.requirements.add(repository.NARROW_REQUIREMENT)
-        op.repo._writerequirements()
+        scmutil.writereporequirements(op.repo)
     op.repo.setnarrowpats(includepats, excludepats)
     narrowspec.copytoworkingcopy(op.repo)
 
diff --git a/hgext/remotefilelog/__init__.py b/hgext/remotefilelog/__init__.py
--- a/hgext/remotefilelog/__init__.py
+++ b/hgext/remotefilelog/__init__.py
@@ -361,7 +361,7 @@
                         self.unfiltered().__class__,
                     )
                 self.requirements.add(constants.SHALLOWREPO_REQUIREMENT)
-                self._writerequirements()
+                scmutil.writereporequirements(self)
 
                 # Since setupclient hadn't been called, exchange.pull was not
                 # wrapped. So we need to manually invoke our version of it.
diff --git a/mercurial/bundle2.py b/mercurial/bundle2.py
--- a/mercurial/bundle2.py
+++ b/mercurial/bundle2.py
@@ -166,6 +166,7 @@
     phases,
     pushkey,
     pycompat,
+    scmutil,
     streamclone,
     tags,
     url,
@@ -1977,7 +1978,7 @@
         op.repo.svfs.options = localrepo.resolvestorevfsoptions(
             op.repo.ui, op.repo.requirements, op.repo.features
         )
-        op.repo._writerequirements()
+        scmutil.writereporequirements(op.repo)
 
     bundlesidedata = bool(b'exp-sidedata' in inpart.params)
     reposidedata = bool(b'exp-sidedata-flag' in op.repo.requirements)
diff --git a/mercurial/hg.py b/mercurial/hg.py
--- a/mercurial/hg.py
+++ b/mercurial/hg.py
@@ -356,7 +356,7 @@
 
             repo.requirements.discard(b'shared')
             repo.requirements.discard(b'relshared')
-            repo._writerequirements()
+            scmutil.writereporequirements(repo)
 
     # Removing share changes some fundamental properties of the repo instance.
     # So we instantiate a new repo object and operate on it rather than
diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -1298,9 +1298,6 @@
             caps.add(b'bundle2=' + urlreq.quote(capsblob))
         return caps
 
-    def _writerequirements(self):
-        scmutil.writerequires(self.vfs, self.requirements)
-
     # Don't cache auditor/nofsauditor, or you'll end up with reference cycle:
     # self -> auditor -> self._checknested -> self
 
diff --git a/mercurial/scmutil.py b/mercurial/scmutil.py
--- a/mercurial/scmutil.py
+++ b/mercurial/scmutil.py
@@ -1470,6 +1470,13 @@
     repo._quick_access_changeid_invalidate()
 
 
+def writereporequirements(repo, requirements=None):
+    """ writes requirements for the repo to .hg/requires """
+    if requirements:
+        repo.requirements = requirements
+    writerequires(repo.vfs, repo.requirements)
+
+
 def writerequires(opener, requirements):
     with opener(b'requires', b'w', atomictemp=True) as fp:
         for r in sorted(requirements):
diff --git a/mercurial/sparse.py b/mercurial/sparse.py
--- a/mercurial/sparse.py
+++ b/mercurial/sparse.py
@@ -601,10 +601,10 @@
 
     if b'exp-sparse' in oldrequires and removing:
         repo.requirements.discard(b'exp-sparse')
-        scmutil.writerequires(repo.vfs, repo.requirements)
+        scmutil.writereporequirements(repo)
     elif b'exp-sparse' not in oldrequires:
         repo.requirements.add(b'exp-sparse')
-        scmutil.writerequires(repo.vfs, repo.requirements)
+        scmutil.writereporequirements(repo)
 
     try:
         writeconfig(repo, includes, excludes, profiles)
@@ -613,7 +613,7 @@
         if repo.requirements != oldrequires:
             repo.requirements.clear()
             repo.requirements |= oldrequires
-            scmutil.writerequires(repo.vfs, repo.requirements)
+            scmutil.writereporequirements(repo)
         writeconfig(repo, oldincludes, oldexcludes, oldprofiles)
         raise
 
diff --git a/mercurial/streamclone.py b/mercurial/streamclone.py
--- a/mercurial/streamclone.py
+++ b/mercurial/streamclone.py
@@ -20,6 +20,7 @@
     narrowspec,
     phases,
     pycompat,
+    scmutil,
     store,
     util,
 )
@@ -187,7 +188,7 @@
         repo.svfs.options = localrepo.resolvestorevfsoptions(
             repo.ui, repo.requirements, repo.features
         )
-        repo._writerequirements()
+        scmutil.writereporequirements(repo)
 
         if rbranchmap:
             repo._branchcaches.replace(repo, rbranchmap)
@@ -730,4 +731,4 @@
     repo.svfs.options = localrepo.resolvestorevfsoptions(
         repo.ui, repo.requirements, repo.features
     )
-    repo._writerequirements()
+    scmutil.writereporequirements(repo)
diff --git a/mercurial/upgrade.py b/mercurial/upgrade.py
--- a/mercurial/upgrade.py
+++ b/mercurial/upgrade.py
@@ -1091,8 +1091,8 @@
             b'unable to read from repository\n'
         )
     )
-    scmutil.writerequires(
-        srcrepo.vfs, srcrepo.requirements | {b'upgradeinprogress'}
+    scmutil.writereporequirements(
+        srcrepo, srcrepo.requirements | {b'upgradeinprogress'}
     )
 
     ui.status(_(b'starting in-place swap of repository data\n'))
@@ -1122,7 +1122,7 @@
             b'again\n'
         )
     )
-    scmutil.writerequires(srcrepo.vfs, requirements)
+    scmutil.writereporequirements(srcrepo, requirements)
 
     # The lock file from the old store won't be removed because nothing has a
     # reference to its new location. So clean it up manually. Alternatively, we