diff -r a1f51c7dce0f -r f025b97f3758 mercurial/localrepo.py
--- a/mercurial/localrepo.py	Sat Aug 08 10:06:32 2020 -0700
+++ b/mercurial/localrepo.py	Fri Aug 07 18:01:48 2020 +0530
@@ -1068,7 +1068,7 @@
         b'relshared',
         b'dotencode',
         repository.SPARSE_REQUIREMENT,
-        b'internal-phase',
+        repository.INTERNAL_PHASE_REQUIREMENT,
     }
 
     # list of prefix for file which can be written without 'wlock'
@@ -3324,7 +3324,7 @@
         requirements.add(REVLOGV2_REQUIREMENT)
     # experimental config: format.internal-phase
     if ui.configbool(b'format', b'internal-phase'):
-        requirements.add(b'internal-phase')
+        requirements.add(repository.INTERNAL_PHASE_REQUIREMENT)
 
     if createopts.get(b'narrowfiles'):
         requirements.add(repository.NARROW_REQUIREMENT)