--- a/mercurial/dirstate.py	Tue Oct 26 10:23:14 2021 -0400
+++ b/mercurial/dirstate.py	Thu Oct 28 17:26:03 2021 +0200
@@ -242,68 +242,59 @@
         return self._rootdir + f
 
     def flagfunc(self, buildfallback):
-        if not (self._checklink and self._checkexec):
-            fallback = buildfallback()
+        """build a callable that returns flags associated with a filename
 
-        def check_both(x):
-            """This platform supports symlinks and exec permissions"""
+        The information is extracted from three possible layers:
+        1. the file system if it supports the information
+        2. the "fallback" information stored in the dirstate if any
+        3. a more expensive mechanism inferring the flags from the parents.
+        """
+
+        # small hack to cache the result of buildfallback()
+        fallback_func = []
+
+        def get_flags(x):
+            entry = None
+            fallback_value = None
             try:
                 st = os.lstat(self._join(x))
+            except OSError:
+                return b''
+
+            if self._checklink:
                 if util.statislink(st):
                     return b'l'
+            else:
+                entry = self.get_entry(x)
+                if entry.has_fallback_symlink:
+                    if entry.fallback_symlink:
+                        return b'l'
+                else:
+                    if not fallback_func:
+                        fallback_func.append(buildfallback())
+                    fallback_value = fallback_func[0](x)
+                    if b'l' in fallback_value:
+                        return b'l'
+
+            if self._checkexec:
                 if util.statisexec(st):
                     return b'x'
-            except OSError:
-                pass
-            return b''
-
-        def check_link(x):
-            """This platform only supports symlinks"""
-            if os.path.islink(self._join(x)):
-                return b'l'
-            entry = self.get_entry(x)
-            if entry.has_fallback_exec:
-                if entry.fallback_exec:
-                    return b'x'
-            elif b'x' in fallback(x):
-                return b'x'
+            else:
+                if entry is None:
+                    entry = self.get_entry(x)
+                if entry.has_fallback_exec:
+                    if entry.fallback_exec:
+                        return b'x'
+                else:
+                    if fallback_value is None:
+                        if not fallback_func:
+                            fallback_func.append(buildfallback())
+                        fallback_value = fallback_func[0](x)
+                    if b'x' in fallback_value:
+                        return b'x'
             return b''
 
-        def check_exec(x):
-            """This platform only supports exec permissions"""
-            if b'l' in fallback(x):
-                return b'l'
-            entry = self.get_entry(x)
-            if entry.has_fallback_symlink:
-                if entry.fallback_symlink:
-                    return b'l'
-            if util.isexec(self._join(x)):
-                return b'x'
-            return b''
-
-        def check_fallback(x):
-            """This platform supports neither symlinks nor exec permissions, so
-            check the fallback in the dirstate if it exists, otherwise figure it
-            out the more expensive way from the parents."""
-            entry = self.get_entry(x)
-            if entry.has_fallback_symlink:
-                if entry.fallback_symlink:
-                    return b'l'
-            if entry.has_fallback_exec:
-                if entry.fallback_exec:
-                    return b'x'
-                elif entry.has_fallback_symlink:
-                    return b''
-            return fallback(x)
-
-        if self._checklink and self._checkexec:
-            return check_both
-        elif self._checklink:
-            return check_link
-        elif self._checkexec:
-            return check_exec
-        else:
-            return check_fallback
+        return get_flags
 
     @propertycache
     def _cwd(self):

--- a/tests/test-share.t	Tue Oct 26 10:23:14 2021 -0400
+++ b/tests/test-share.t	Thu Oct 28 17:26:03 2021 +0200
@@ -47,8 +47,8 @@
   [1]
   $ ls -1 .hg/wcache || true
   checkisexec (execbit !)
-  checklink (symlink !)
-  checklink-target (symlink !)
+  checklink (symlink no-rust !)
+  checklink-target (symlink no-rust !)
   manifestfulltextcache (reporevlogstore !)
   $ ls -1 ../repo1/.hg/cache
   branch2-served

--- a/tests/test-subrepo.t	Tue Oct 26 10:23:14 2021 -0400
+++ b/tests/test-subrepo.t	Thu Oct 28 17:26:03 2021 +0200
@@ -1275,8 +1275,8 @@
   ../shared/subrepo-2/.hg/sharedpath
   ../shared/subrepo-2/.hg/wcache
   ../shared/subrepo-2/.hg/wcache/checkisexec (execbit !)
-  ../shared/subrepo-2/.hg/wcache/checklink (symlink !)
-  ../shared/subrepo-2/.hg/wcache/checklink-target (symlink !)
+  ../shared/subrepo-2/.hg/wcache/checklink (symlink no-rust !)
+  ../shared/subrepo-2/.hg/wcache/checklink-target (symlink no-rust !)
   ../shared/subrepo-2/.hg/wcache/manifestfulltextcache (reporevlogstore !)
   ../shared/subrepo-2/file
   $ hg -R ../shared in