diff --git a/mercurial/bundlecaches.py b/mercurial/bundlecaches.py
--- a/mercurial/bundlecaches.py
+++ b/mercurial/bundlecaches.py
@@ -9,6 +9,7 @@
 
 from . import (
     error,
+    requirements as requirementsmod,
     sslutil,
     util,
 )
@@ -164,7 +165,7 @@
             compression = spec
             version = b'v1'
             # Generaldelta repos require v2.
-            if b'generaldelta' in repo.requirements:
+            if requirementsmod.GENERALDELTA_REQUIREMENT in repo.requirements:
                 version = b'v2'
             # Modern compression engines require v2.
             if compression not in _bundlespecv1compengines:
diff --git a/mercurial/changegroup.py b/mercurial/changegroup.py
--- a/mercurial/changegroup.py
+++ b/mercurial/changegroup.py
@@ -1549,7 +1549,7 @@
     # will support. For example, all hg versions that support generaldelta also
     # support changegroup 02.
     versions = supportedoutgoingversions(repo)
-    if b'generaldelta' in repo.requirements:
+    if requirements.GENERALDELTA_REQUIREMENT in repo.requirements:
         versions.discard(b'01')
     assert versions
     return min(versions)
diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -1003,7 +1003,7 @@
     if requirementsmod.REVLOGV2_REQUIREMENT in requirements:
         options[b'revlogv2'] = True
 
-    if b'generaldelta' in requirements:
+    if requirementsmod.GENERALDELTA_REQUIREMENT in requirements:
         options[b'generaldelta'] = True
 
     # experimental config: format.chunkcachesize
@@ -1200,7 +1200,7 @@
     #    chains), and the code was deleted in 4.6.
     supportedformats = {
         requirementsmod.REVLOGV1_REQUIREMENT,
-        b'generaldelta',
+        requirementsmod.GENERALDELTA_REQUIREMENT,
         requirementsmod.TREEMANIFEST_REQUIREMENT,
         requirementsmod.COPIESSDC_REQUIREMENT,
         requirementsmod.REVLOGV2_REQUIREMENT,
@@ -3442,7 +3442,7 @@
         requirements.add(b'exp-compression-%s' % compengine)
 
     if scmutil.gdinitconfig(ui):
-        requirements.add(b'generaldelta')
+        requirements.add(requirementsmod.GENERALDELTA_REQUIREMENT)
         if ui.configbool(b'format', b'sparse-revlog'):
             requirements.add(requirementsmod.SPARSEREVLOG_REQUIREMENT)
 
@@ -3460,7 +3460,7 @@
     if revlogv2 == b'enable-unstable-format-and-corrupt-my-data':
         requirements.remove(requirementsmod.REVLOGV1_REQUIREMENT)
         # generaldelta is implied by revlogv2.
-        requirements.discard(b'generaldelta')
+        requirements.discard(requirementsmod.GENERALDELTA_REQUIREMENT)
         requirements.add(requirementsmod.REVLOGV2_REQUIREMENT)
     # experimental config: format.internal-phase
     if ui.configbool(b'format', b'internal-phase'):
diff --git a/mercurial/requirements.py b/mercurial/requirements.py
--- a/mercurial/requirements.py
+++ b/mercurial/requirements.py
@@ -7,6 +7,8 @@
 
 from __future__ import absolute_import
 
+GENERALDELTA_REQUIREMENT = b'generaldelta'
+
 # When narrowing is finalized and no longer subject to format changes,
 # we should move this to just "narrow" or similar.
 NARROW_REQUIREMENT = b'narrowhg-experimental'
diff --git a/mercurial/upgrade_utils/actions.py b/mercurial/upgrade_utils/actions.py
--- a/mercurial/upgrade_utils/actions.py
+++ b/mercurial/upgrade_utils/actions.py
@@ -20,7 +20,7 @@
 
 # list of requirements that request a clone of all revlog if added/removed
 RECLONES_REQUIREMENTS = {
-    b'generaldelta',
+    requirements.GENERALDELTA_REQUIREMENT,
     requirements.SPARSEREVLOG_REQUIREMENT,
 }
 
@@ -236,7 +236,7 @@
 class generaldelta(requirementformatvariant):
     name = b'generaldelta'
 
-    _requirement = b'generaldelta'
+    _requirement = requirements.GENERALDELTA_REQUIREMENT
 
     default = True
 
@@ -936,7 +936,7 @@
     supported = {
         b'dotencode',
         b'fncache',
-        b'generaldelta',
+        requirements.GENERALDELTA_REQUIREMENT,
         requirements.REVLOGV1_REQUIREMENT,
         b'store',
         requirements.SPARSEREVLOG_REQUIREMENT,
@@ -967,7 +967,7 @@
     supported = {
         b'dotencode',
         b'fncache',
-        b'generaldelta',
+        requirements.GENERALDELTA_REQUIREMENT,
         requirements.SPARSEREVLOG_REQUIREMENT,
         requirements.SIDEDATA_REQUIREMENT,
         requirements.COPIESSDC_REQUIREMENT,
diff --git a/mercurial/wireprotov1server.py b/mercurial/wireprotov1server.py
--- a/mercurial/wireprotov1server.py
+++ b/mercurial/wireprotov1server.py
@@ -109,7 +109,7 @@
     4. server.bundle1
     """
     ui = repo.ui
-    gd = b'generaldelta' in repo.requirements
+    gd = requirementsmod.GENERALDELTA_REQUIREMENT in repo.requirements
 
     if gd:
         v = ui.configbool(b'server', b'bundle1gd.%s' % action)