diff --git a/mercurial/configitems.py b/mercurial/configitems.py
--- a/mercurial/configitems.py
+++ b/mercurial/configitems.py
@@ -784,6 +784,9 @@
     b'format', b'exp-use-side-data', default=False, experimental=True,
 )
 coreconfigitem(
+    b'format', b'exp-share-safe', default=False, experimental=True,
+)
+coreconfigitem(
     b'format', b'internal-phase', default=False, experimental=True,
 )
 coreconfigitem(
diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -543,6 +543,20 @@
         raise error.RepoError(_(b'repository %s not found') % path)
 
     requirements = _readrequires(hgvfs, True)
+    shared = b'shared' in requirements or b'relshared' in requirements
+    if shared:
+        sharedvfs = _getsharedvfs(hgvfs, requirements)
+
+    # if .hg/requires contains the sharesafe requirement, it means
+    # there exists a `.hg/store/requires` too and we should read it
+    if requirementsmod.SHARESAFE_REQUIREMENT in requirements:
+        if shared:
+            # This is a shared repo
+            storevfs = vfsmod.vfs(sharedvfs.join(b'store'))
+        else:
+            storevfs = vfsmod.vfs(hgvfs.join(b'store'), cacheaudited=True)
+
+        requirements |= _readrequires(storevfs, False)
 
     # The .hg/hgrc file may load extensions or contain config options
     # that influence repository construction. Attempt to load it and
@@ -585,9 +599,7 @@
     # accessed is determined by various requirements. If `shared` or
     # `relshared` requirements are present, this indicates current repository
     # is a share and store exists in path mentioned in `.hg/sharedpath`
-    shared = b'shared' in requirements or b'relshared' in requirements
     if shared:
-        sharedvfs = _getsharedvfs(hgvfs, requirements)
         storebasepath = sharedvfs.base
         cachepath = sharedvfs.join(b'cache')
         features.add(repository.REPO_FEATURE_SHARED_STORAGE)
@@ -1043,6 +1055,7 @@
         requirementsmod.SPARSEREVLOG_REQUIREMENT,
         requirementsmod.NODEMAP_REQUIREMENT,
         bookmarks.BOOKMARKS_IN_STORE_REQUIREMENT,
+        requirementsmod.SHARESAFE_REQUIREMENT,
     }
     _basesupported = supportedformats | {
         b'store',
@@ -3321,6 +3334,11 @@
     if ui.configbool(b'format', b'use-persistent-nodemap'):
         requirements.add(requirementsmod.NODEMAP_REQUIREMENT)
 
+    # if share-safe is enabled, let's create the new repository with the new
+    # requirement
+    if ui.configbool(b'format', b'exp-share-safe'):
+        requirements.add(requirementsmod.SHARESAFE_REQUIREMENT)
+
     return requirements
 
 
@@ -3351,6 +3369,16 @@
                 )
             )
 
+        if requirementsmod.SHARESAFE_REQUIREMENT in requirements:
+            ui.warn(
+                _(
+                    b"ignoring enabled 'format.exp-share-safe' config because "
+                    b"it is incompatible with disabled 'format.usestore'"
+                    b" config\n"
+                )
+            )
+            dropped.add(requirementsmod.SHARESAFE_REQUIREMENT)
+
     return dropped
 
 
@@ -3475,7 +3503,26 @@
             b'layout',
         )
 
-    scmutil.writerequires(hgvfs, requirements)
+    if (
+        requirementsmod.SHARESAFE_REQUIREMENT in requirements
+        and b'store' in requirements
+    ):
+        if b'sharedrepo' in createopts:
+            req = set([b'shared', requirementsmod.SHARESAFE_REQUIREMENT])
+            if b'relshared' in requirements:
+                req.add(b'relshared')
+            scmutil.writerequires(hgvfs, req)
+        else:
+            scmutil.writerequires(
+                hgvfs, set([requirementsmod.SHARESAFE_REQUIREMENT])
+            )
+            storevfs = vfsmod.vfs(hgvfs.join(b'store'), cacheaudited=True)
+            scmutil.writerequires(
+                storevfs,
+                requirements - set([requirementsmod.SHARESAFE_REQUIREMENT]),
+            )
+    else:
+        scmutil.writerequires(hgvfs, requirements)
 
     # Write out file telling readers where to find the shared store.
     if b'sharedrepo' in createopts:
diff --git a/mercurial/requirements.py b/mercurial/requirements.py
--- a/mercurial/requirements.py
+++ b/mercurial/requirements.py
@@ -45,7 +45,14 @@
 # The repository use persistent nodemap for the changelog and the manifest.
 NODEMAP_REQUIREMENT = b'persistent-nodemap'
 
+# A repository with share implemented safely. The repository has different
+# store and working copy requirements i.e. both `.hg/requires` and
+# `.hg/store/requires` are present.
+SHARESAFE_REQUIREMENT = b'exp-sharesafe'
+
 # List of requirements which are working directory specific
 # These requirements cannot be shared between repositories if they
 # share the same store
-WORKING_DIR_REQUIREMENTS = set([SPARSE_REQUIREMENT])
\ No newline at end of file
+# SHARESAFE_REQUIREMENT needs to be stored in working dir to mark that rest of
+# the requirements are stored in store's requires
+WORKING_DIR_REQUIREMENTS = set([SPARSE_REQUIREMENT, SHARESAFE_REQUIREMENT])
diff --git a/mercurial/scmutil.py b/mercurial/scmutil.py
--- a/mercurial/scmutil.py
+++ b/mercurial/scmutil.py
@@ -1479,7 +1479,7 @@
 
     Returns (wcreq, storereq)
     """
-    if False:
+    if requirementsmod.SHARESAFE_REQUIREMENT in requirements:
         wc, store = set(), set()
         for r in requirements:
             if r in requirementsmod.WORKING_DIR_REQUIREMENTS:
diff --git a/mercurial/store.py b/mercurial/store.py
--- a/mercurial/store.py
+++ b/mercurial/store.py
@@ -384,6 +384,7 @@
     b'00changelog.i',
     b'phaseroots',
     b'obsstore',
+    b'requires',
 ]
 
 
@@ -455,7 +456,7 @@
             yield x
 
     def copylist(self):
-        return [b'requires'] + _data
+        return _data
 
     def write(self, tr):
         pass
@@ -704,6 +705,7 @@
             b'00manifest.i',
             b'00changelog.d',
             b'00changelog.i',
+            b'requires',
         )
         return [b'requires', b'00changelog.i'] + [b'store/' + f for f in d]
 
diff --git a/tests/test-journal-share.t b/tests/test-journal-share.t
--- a/tests/test-journal-share.t
+++ b/tests/test-journal-share.t
@@ -1,3 +1,10 @@
+#testcases safe normal
+
+#if safe
+  $ echo "[format]"         >> $HGRCPATH
+  $ echo "exp-share-safe = True" >> $HGRCPATH
+#endif
+
 Journal extension test: tests the share extension support
 
   $ cat >> testmocks.py << EOF
diff --git a/tests/test-narrow-share.t b/tests/test-narrow-share.t
--- a/tests/test-narrow-share.t
+++ b/tests/test-narrow-share.t
@@ -1,4 +1,10 @@
 #testcases flat tree
+#testcases safe normal
+
+#if safe
+  $ echo "[format]"         >> $HGRCPATH
+  $ echo "exp-share-safe = True" >> $HGRCPATH
+#endif
 
   $ . "$TESTDIR/narrow-library.sh"
 
diff --git a/tests/test-remotefilelog-share.t b/tests/test-remotefilelog-share.t
--- a/tests/test-remotefilelog-share.t
+++ b/tests/test-remotefilelog-share.t
@@ -1,5 +1,12 @@
 #require no-windows
 
+#testcases safe normal
+
+#if safe
+  $ echo "[format]"         >> $HGRCPATH
+  $ echo "exp-share-safe = True" >> $HGRCPATH
+#endif
+
   $ . "$TESTDIR/remotefilelog-library.sh"
 
   $ cat >> $HGRCPATH <<EOF
diff --git a/tests/test-share-bookmarks.t b/tests/test-share-bookmarks.t
--- a/tests/test-share-bookmarks.t
+++ b/tests/test-share-bookmarks.t
@@ -1,4 +1,10 @@
 #testcases vfs svfs
+#testcases safe normal
+
+#if safe
+  $ echo "[format]"         >> $HGRCPATH
+  $ echo "exp-share-safe = True" >> $HGRCPATH
+#endif
 
   $ echo "[extensions]"      >> $HGRCPATH
   $ echo "share = "          >> $HGRCPATH
@@ -284,3 +290,4 @@
 
   $ hg init brokenrepo --config format.bookmarks-in-store=True --config format.usestore=false
   ignoring enabled 'format.bookmarks-in-store' config beacuse it is incompatible with disabled 'format.usestore' config
+  ignoring enabled 'format.exp-share-safe' config because it is incompatible with disabled 'format.usestore' config (safe !)
diff --git a/tests/test-share-safe.t b/tests/test-share-safe.t
new file mode 100644
--- /dev/null
+++ b/tests/test-share-safe.t
@@ -0,0 +1,69 @@
+setup
+
+  $ cat >> $HGRCPATH <<EOF
+  > [extensions]
+  > share =
+  > [format]
+  > exp-share-safe = True
+  > EOF
+
+prepare source repo
+
+  $ hg init source
+  $ cd source
+  $ cat .hg/requires
+  exp-sharesafe
+  $ cat .hg/store/requires
+  dotencode
+  fncache
+  generaldelta
+  revlogv1
+  sparserevlog
+  store
+  $ hg debugrequirements
+  dotencode
+  exp-sharesafe
+  fncache
+  generaldelta
+  revlogv1
+  sparserevlog
+  store
+
+  $ echo a > a
+  $ hg ci -Aqm "added a"
+  $ echo b > b
+  $ hg ci -Aqm "added b"
+  $ cd ..
+
+Create a shared repo and check the requirements are shared and read correctly
+  $ hg share source shared1
+  updating working directory
+  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ cd shared1
+  $ cat .hg/requires
+  exp-sharesafe
+  shared
+
+  $ hg debugrequirements -R ../source
+  dotencode
+  exp-sharesafe
+  fncache
+  generaldelta
+  revlogv1
+  sparserevlog
+  store
+
+  $ hg debugrequirements
+  dotencode
+  exp-sharesafe
+  fncache
+  generaldelta
+  revlogv1
+  shared
+  sparserevlog
+  store
+
+  $ echo c > c
+  $ hg ci -Aqm "added c"
+
+  $ hg unshare
diff --git a/tests/test-share.t b/tests/test-share.t
--- a/tests/test-share.t
+++ b/tests/test-share.t
@@ -1,3 +1,10 @@
+#testcases safe normal
+
+#if safe
+  $ echo "[format]"         >> $HGRCPATH
+  $ echo "exp-share-safe = True" >> $HGRCPATH
+#endif
+
   $ echo "[extensions]"      >> $HGRCPATH
   $ echo "share = "          >> $HGRCPATH
 
@@ -255,6 +262,7 @@
 Test sharing a repository which was created with store requirement disable
 
   $ hg init nostore --config format.usestore=false
+  ignoring enabled 'format.exp-share-safe' config because it is incompatible with disabled 'format.usestore' config (safe !)
   $ hg share nostore sharednostore
   abort: cannot create shared repository as source was created with 'format.usestore' config disabled
   [255]