phase: use a binary phase part to push through bundle2 (BC)

phase: use a binary phase part to push through bundle2 (BC)

The part we are using for pull is now used for push too. As we no longer use
pushkey, pushkey hooks are no longer triggered. This is an obvious backward
incompatible change. We could artificially trigger the pushkey hook within the
bundle2 part, but this seemed too hacky to me.

An option would be to disable by default this new mechanism for a couple of
versions to help people migrate to `txnclose-phase`. I took the liberal and
optimistic path to just turn it on by default directly.

.. bc::

   Push no longer triggers a pushkey hook when updating phases. Use the new
   `txnclose-phase` and `txnclose-phase` hooks instead.
   (Applies when both server and client use version 4.4 or above).

--- a/mercurial/exchange.py	Tue Oct 17 12:41:24 2017 -0700
+++ b/mercurial/exchange.py	Wed Sep 20 19:38:06 2017 +0200
@@ -806,9 +806,26 @@
     if 'phases' in pushop.stepsdone:
         return
     b2caps = bundle2.bundle2caps(pushop.remote)
-    if 'pushkey' in b2caps:
+    ui = pushop.repo.ui
+
+    legacyphase = 'phases' in ui.configlist('devel', 'legacy.exchange')
+    haspushkey = 'pushkey' in b2caps
+    hasphaseheads = 'heads' in b2caps.get('phases', ())
+
+    if hasphaseheads and not legacyphase:
+        _pushb2phaseheads(pushop, bundler)
+    elif haspushkey:
         _pushb2phasespushkey(pushop, bundler)
 
+def _pushb2phaseheads(pushop, bundler):
+    """push phase information through a bundle2 - binary part"""
+    pushop.stepsdone.add('phases')
+    if pushop.outdatedphases:
+        updates = [[] for p in phases.allphases]
+        updates[0].extend(h.node() for h in pushop.outdatedphases)
+        phasedata = phases.binaryencode(updates)
+        bundler.newpart('phase-heads', data=phasedata)
+
 def _pushb2phasespushkey(pushop, bundler):
     """push phase information through a bundle2 - pushkey part"""
     pushop.stepsdone.add('phases')

--- a/tests/test-acl.t	Tue Oct 17 12:41:24 2017 -0700
+++ b/tests/test-acl.t	Wed Sep 20 19:38:06 2017 +0200
@@ -97,7 +97,7 @@
   bundle2-output-part: "check:phases" 24 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 24 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -117,17 +117,15 @@
   adding quux/file.py revisions
   added 3 changesets with 3 changes to 3 files
   bundle2-input-part: total payload size 1553
-  bundle2-input-part: "pushkey" (params: 4 mandatory) supported
-  pushing key for "phases:911600dab2ae7a9baff75958b84fe606851ce955"
+  bundle2-input-part: "phase-heads" supported
+  bundle2-input-part: total payload size 24
   bundle2-input-bundle: 4 parts total
   updating the branch cache
-  bundle2-output-bundle: "HG20", 2 parts total
+  bundle2-output-bundle: "HG20", 1 parts total
   bundle2-output-part: "reply:changegroup" (advisory) (params: 0 advisory) empty payload
-  bundle2-output-part: "reply:pushkey" (params: 0 advisory) empty payload
   bundle2-input-bundle: no-transaction
   bundle2-input-part: "reply:changegroup" (advisory) (params: 0 advisory) supported
-  bundle2-input-part: "reply:pushkey" (params: 0 advisory) supported
-  bundle2-input-bundle: 1 parts total
+  bundle2-input-bundle: 0 parts total
   listing keys for "phases"
   repository tip rolled back to revision 0 (undo push)
   0:6675d58eff77
@@ -162,7 +160,7 @@
   bundle2-output-part: "check:phases" 24 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 24 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -184,17 +182,15 @@
   calling hook pretxnchangegroup.acl: hgext.acl.hook
   acl: changes have source "push" - skipping
   bundle2-input-part: total payload size 1553
-  bundle2-input-part: "pushkey" (params: 4 mandatory) supported
-  pushing key for "phases:911600dab2ae7a9baff75958b84fe606851ce955"
+  bundle2-input-part: "phase-heads" supported
+  bundle2-input-part: total payload size 24
   bundle2-input-bundle: 4 parts total
   updating the branch cache
-  bundle2-output-bundle: "HG20", 2 parts total
+  bundle2-output-bundle: "HG20", 1 parts total
   bundle2-output-part: "reply:changegroup" (advisory) (params: 0 advisory) empty payload
-  bundle2-output-part: "reply:pushkey" (params: 0 advisory) empty payload
   bundle2-input-bundle: no-transaction
   bundle2-input-part: "reply:changegroup" (advisory) (params: 0 advisory) supported
-  bundle2-input-part: "reply:pushkey" (params: 0 advisory) supported
-  bundle2-input-bundle: 1 parts total
+  bundle2-input-bundle: 0 parts total
   listing keys for "phases"
   repository tip rolled back to revision 0 (undo push)
   0:6675d58eff77
@@ -230,7 +226,7 @@
   bundle2-output-part: "check:phases" 24 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 24 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -262,17 +258,15 @@
   acl: branch access granted: "911600dab2ae" on branch "default"
   acl: path access granted: "911600dab2ae"
   bundle2-input-part: total payload size 1553
-  bundle2-input-part: "pushkey" (params: 4 mandatory) supported
-  pushing key for "phases:911600dab2ae7a9baff75958b84fe606851ce955"
+  bundle2-input-part: "phase-heads" supported
+  bundle2-input-part: total payload size 24
   bundle2-input-bundle: 4 parts total
   updating the branch cache
-  bundle2-output-bundle: "HG20", 2 parts total
+  bundle2-output-bundle: "HG20", 1 parts total
   bundle2-output-part: "reply:changegroup" (advisory) (params: 0 advisory) empty payload
-  bundle2-output-part: "reply:pushkey" (params: 0 advisory) empty payload
   bundle2-input-bundle: no-transaction
   bundle2-input-part: "reply:changegroup" (advisory) (params: 0 advisory) supported
-  bundle2-input-part: "reply:pushkey" (params: 0 advisory) supported
-  bundle2-input-bundle: 1 parts total
+  bundle2-input-bundle: 0 parts total
   listing keys for "phases"
   repository tip rolled back to revision 0 (undo push)
   0:6675d58eff77
@@ -308,7 +302,7 @@
   bundle2-output-part: "check:phases" 24 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 24 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -336,6 +330,7 @@
   acl: branch access granted: "ef1ea85a6374" on branch "default"
   error: pretxnchangegroup.acl hook failed: acl: user "fred" not allowed on "foo/file.txt" (changeset "ef1ea85a6374")
   bundle2-input-part: total payload size 1553
+  bundle2-input-part: total payload size 24
   bundle2-input-bundle: 4 parts total
   transaction abort!
   rollback completed
@@ -375,7 +370,7 @@
   bundle2-output-part: "check:phases" 24 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 24 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -407,6 +402,7 @@
   acl: branch access granted: "911600dab2ae" on branch "default"
   error: pretxnchangegroup.acl hook failed: acl: user "fred" not allowed on "quux/file.py" (changeset "911600dab2ae")
   bundle2-input-part: total payload size 1553
+  bundle2-input-part: total payload size 24
   bundle2-input-bundle: 4 parts total
   transaction abort!
   rollback completed
@@ -447,7 +443,7 @@
   bundle2-output-part: "check:phases" 24 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 24 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -475,6 +471,7 @@
   acl: branch access granted: "ef1ea85a6374" on branch "default"
   error: pretxnchangegroup.acl hook failed: acl: user "barney" not allowed on "foo/file.txt" (changeset "ef1ea85a6374")
   bundle2-input-part: total payload size 1553
+  bundle2-input-part: total payload size 24
   bundle2-input-bundle: 4 parts total
   transaction abort!
   rollback completed
@@ -516,7 +513,7 @@
   bundle2-output-part: "check:phases" 24 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 24 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -548,6 +545,7 @@
   acl: branch access granted: "911600dab2ae" on branch "default"
   error: pretxnchangegroup.acl hook failed: acl: user "fred" not allowed on "quux/file.py" (changeset "911600dab2ae")
   bundle2-input-part: total payload size 1553
+  bundle2-input-part: total payload size 24
   bundle2-input-bundle: 4 parts total
   transaction abort!
   rollback completed
@@ -590,7 +588,7 @@
   bundle2-output-part: "check:phases" 24 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 24 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -620,6 +618,7 @@
   acl: branch access granted: "f9cafe1212c8" on branch "default"
   error: pretxnchangegroup.acl hook failed: acl: user "fred" denied on "foo/Bar/file.txt" (changeset "f9cafe1212c8")
   bundle2-input-part: total payload size 1553
+  bundle2-input-part: total payload size 24
   bundle2-input-bundle: 4 parts total
   transaction abort!
   rollback completed
@@ -661,7 +660,7 @@
   bundle2-output-part: "check:phases" 24 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 24 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -689,6 +688,7 @@
   acl: branch access granted: "ef1ea85a6374" on branch "default"
   error: pretxnchangegroup.acl hook failed: acl: user "barney" not allowed on "foo/file.txt" (changeset "ef1ea85a6374")
   bundle2-input-part: total payload size 1553
+  bundle2-input-part: total payload size 24
   bundle2-input-bundle: 4 parts total
   transaction abort!
   rollback completed
@@ -734,7 +734,7 @@
   bundle2-output-part: "check:phases" 24 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 24 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -766,17 +766,15 @@
   acl: branch access granted: "911600dab2ae" on branch "default"
   acl: path access granted: "911600dab2ae"
   bundle2-input-part: total payload size 1553
-  bundle2-input-part: "pushkey" (params: 4 mandatory) supported
-  pushing key for "phases:911600dab2ae7a9baff75958b84fe606851ce955"
+  bundle2-input-part: "phase-heads" supported
+  bundle2-input-part: total payload size 24
   bundle2-input-bundle: 4 parts total
   updating the branch cache
-  bundle2-output-bundle: "HG20", 2 parts total
+  bundle2-output-bundle: "HG20", 1 parts total
   bundle2-output-part: "reply:changegroup" (advisory) (params: 0 advisory) empty payload
-  bundle2-output-part: "reply:pushkey" (params: 0 advisory) empty payload
   bundle2-input-bundle: no-transaction
   bundle2-input-part: "reply:changegroup" (advisory) (params: 0 advisory) supported
-  bundle2-input-part: "reply:pushkey" (params: 0 advisory) supported
-  bundle2-input-bundle: 1 parts total
+  bundle2-input-bundle: 0 parts total
   listing keys for "phases"
   repository tip rolled back to revision 0 (undo push)
   0:6675d58eff77
@@ -819,7 +817,7 @@
   bundle2-output-part: "check:phases" 24 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 24 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -851,6 +849,7 @@
   acl: branch access granted: "911600dab2ae" on branch "default"
   error: pretxnchangegroup.acl hook failed: acl: user "wilma" not allowed on "quux/file.py" (changeset "911600dab2ae")
   bundle2-input-part: total payload size 1553
+  bundle2-input-part: total payload size 24
   bundle2-input-bundle: 4 parts total
   transaction abort!
   rollback completed
@@ -899,7 +898,7 @@
   bundle2-output-part: "check:phases" 24 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 24 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -922,6 +921,7 @@
   acl: checking access for user "barney"
   error: pretxnchangegroup.acl hook raised an exception: [Errno *] * (glob)
   bundle2-input-part: total payload size 1553
+  bundle2-input-part: total payload size 24
   bundle2-input-bundle: 4 parts total
   transaction abort!
   rollback completed
@@ -974,7 +974,7 @@
   bundle2-output-part: "check:phases" 24 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 24 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -1006,6 +1006,7 @@
   acl: branch access granted: "911600dab2ae" on branch "default"
   error: pretxnchangegroup.acl hook failed: acl: user "betty" not allowed on "quux/file.py" (changeset "911600dab2ae")
   bundle2-input-part: total payload size 1553
+  bundle2-input-part: total payload size 24
   bundle2-input-bundle: 4 parts total
   transaction abort!
   rollback completed
@@ -1060,7 +1061,7 @@
   bundle2-output-part: "check:phases" 24 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 24 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -1092,17 +1093,15 @@
   acl: branch access granted: "911600dab2ae" on branch "default"
   acl: path access granted: "911600dab2ae"
   bundle2-input-part: total payload size 1553
-  bundle2-input-part: "pushkey" (params: 4 mandatory) supported
-  pushing key for "phases:911600dab2ae7a9baff75958b84fe606851ce955"
+  bundle2-input-part: "phase-heads" supported
+  bundle2-input-part: total payload size 24
   bundle2-input-bundle: 4 parts total
   updating the branch cache
-  bundle2-output-bundle: "HG20", 2 parts total
+  bundle2-output-bundle: "HG20", 1 parts total
   bundle2-output-part: "reply:changegroup" (advisory) (params: 0 advisory) empty payload
-  bundle2-output-part: "reply:pushkey" (params: 0 advisory) empty payload
   bundle2-input-bundle: no-transaction
   bundle2-input-part: "reply:changegroup" (advisory) (params: 0 advisory) supported
-  bundle2-input-part: "reply:pushkey" (params: 0 advisory) supported
-  bundle2-input-bundle: 1 parts total
+  bundle2-input-bundle: 0 parts total
   listing keys for "phases"
   repository tip rolled back to revision 0 (undo push)
   0:6675d58eff77
@@ -1148,7 +1147,7 @@
   bundle2-output-part: "check:phases" 24 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 24 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -1180,17 +1179,15 @@
   acl: branch access granted: "911600dab2ae" on branch "default"
   acl: path access granted: "911600dab2ae"
   bundle2-input-part: total payload size 1553
-  bundle2-input-part: "pushkey" (params: 4 mandatory) supported
-  pushing key for "phases:911600dab2ae7a9baff75958b84fe606851ce955"
+  bundle2-input-part: "phase-heads" supported
+  bundle2-input-part: total payload size 24
   bundle2-input-bundle: 4 parts total
   updating the branch cache
-  bundle2-output-bundle: "HG20", 2 parts total
+  bundle2-output-bundle: "HG20", 1 parts total
   bundle2-output-part: "reply:changegroup" (advisory) (params: 0 advisory) empty payload
-  bundle2-output-part: "reply:pushkey" (params: 0 advisory) empty payload
   bundle2-input-bundle: no-transaction
   bundle2-input-part: "reply:changegroup" (advisory) (params: 0 advisory) supported
-  bundle2-input-part: "reply:pushkey" (params: 0 advisory) supported
-  bundle2-input-bundle: 1 parts total
+  bundle2-input-bundle: 0 parts total
   listing keys for "phases"
   repository tip rolled back to revision 0 (undo push)
   0:6675d58eff77
@@ -1232,7 +1229,7 @@
   bundle2-output-part: "check:phases" 24 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 24 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -1262,6 +1259,7 @@
   acl: branch access granted: "f9cafe1212c8" on branch "default"
   error: pretxnchangegroup.acl hook failed: acl: user "fred" denied on "foo/Bar/file.txt" (changeset "f9cafe1212c8")
   bundle2-input-part: total payload size 1553
+  bundle2-input-part: total payload size 24
   bundle2-input-bundle: 4 parts total
   transaction abort!
   rollback completed
@@ -1310,7 +1308,7 @@
   bundle2-output-part: "check:phases" 24 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 24 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -1343,17 +1341,15 @@
   acl: branch access granted: "911600dab2ae" on branch "default"
   acl: path access granted: "911600dab2ae"
   bundle2-input-part: total payload size 1553
-  bundle2-input-part: "pushkey" (params: 4 mandatory) supported
-  pushing key for "phases:911600dab2ae7a9baff75958b84fe606851ce955"
+  bundle2-input-part: "phase-heads" supported
+  bundle2-input-part: total payload size 24
   bundle2-input-bundle: 4 parts total
   updating the branch cache
-  bundle2-output-bundle: "HG20", 2 parts total
+  bundle2-output-bundle: "HG20", 1 parts total
   bundle2-output-part: "reply:changegroup" (advisory) (params: 0 advisory) empty payload
-  bundle2-output-part: "reply:pushkey" (params: 0 advisory) empty payload
   bundle2-input-bundle: no-transaction
   bundle2-input-part: "reply:changegroup" (advisory) (params: 0 advisory) supported
-  bundle2-input-part: "reply:pushkey" (params: 0 advisory) supported
-  bundle2-input-bundle: 1 parts total
+  bundle2-input-bundle: 0 parts total
   listing keys for "phases"
   repository tip rolled back to revision 0 (undo push)
   0:6675d58eff77
@@ -1395,7 +1391,7 @@
   bundle2-output-part: "check:phases" 24 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 24 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -1427,6 +1423,7 @@
   acl: branch access granted: "f9cafe1212c8" on branch "default"
   error: pretxnchangegroup.acl hook failed: acl: user "fred" denied on "foo/Bar/file.txt" (changeset "f9cafe1212c8")
   bundle2-input-part: total payload size 1553
+  bundle2-input-part: total payload size 24
   bundle2-input-bundle: 4 parts total
   transaction abort!
   rollback completed
@@ -1509,13 +1506,12 @@
   f9cafe1212c8c6fa1120d14a556e18cc44ff8bdd
   911600dab2ae7a9baff75958b84fe606851ce955
   e8fc755d4d8217ee5b0c2bb41558c40d43b92c01
-  bundle2-output-bundle: "HG20", 6 parts total
+  bundle2-output-bundle: "HG20", 5 parts total
   bundle2-output-part: "replycaps" 168 bytes payload
   bundle2-output-part: "check:phases" 48 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 48 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -1551,21 +1547,15 @@
   acl: branch access granted: "e8fc755d4d82" on branch "foobar"
   acl: path access granted: "e8fc755d4d82"
   bundle2-input-part: total payload size 2068
-  bundle2-input-part: "pushkey" (params: 4 mandatory) supported
-  pushing key for "phases:911600dab2ae7a9baff75958b84fe606851ce955"
-  bundle2-input-part: "pushkey" (params: 4 mandatory) supported
-  pushing key for "phases:e8fc755d4d8217ee5b0c2bb41558c40d43b92c01"
-  bundle2-input-bundle: 5 parts total
+  bundle2-input-part: "phase-heads" supported
+  bundle2-input-part: total payload size 48
+  bundle2-input-bundle: 4 parts total
   updating the branch cache
-  bundle2-output-bundle: "HG20", 3 parts total
+  bundle2-output-bundle: "HG20", 1 parts total
   bundle2-output-part: "reply:changegroup" (advisory) (params: 0 advisory) empty payload
-  bundle2-output-part: "reply:pushkey" (params: 0 advisory) empty payload
-  bundle2-output-part: "reply:pushkey" (params: 0 advisory) empty payload
   bundle2-input-bundle: no-transaction
   bundle2-input-part: "reply:changegroup" (advisory) (params: 0 advisory) supported
-  bundle2-input-part: "reply:pushkey" (params: 0 advisory) supported
-  bundle2-input-part: "reply:pushkey" (params: 0 advisory) supported
-  bundle2-input-bundle: 2 parts total
+  bundle2-input-bundle: 0 parts total
   listing keys for "phases"
   repository tip rolled back to revision 2 (undo push)
   2:fb35475503ef
@@ -1600,13 +1590,12 @@
   f9cafe1212c8c6fa1120d14a556e18cc44ff8bdd
   911600dab2ae7a9baff75958b84fe606851ce955
   e8fc755d4d8217ee5b0c2bb41558c40d43b92c01
-  bundle2-output-bundle: "HG20", 6 parts total
+  bundle2-output-bundle: "HG20", 5 parts total
   bundle2-output-part: "replycaps" 168 bytes payload
   bundle2-output-part: "check:phases" 48 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 48 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -1641,7 +1630,8 @@
   acl: path access granted: "911600dab2ae"
   error: pretxnchangegroup.acl hook failed: acl: user "astro" denied on branch "foobar" (changeset "e8fc755d4d82")
   bundle2-input-part: total payload size 2068
-  bundle2-input-bundle: 5 parts total
+  bundle2-input-part: total payload size 48
+  bundle2-input-bundle: 4 parts total
   transaction abort!
   rollback completed
   abort: acl: user "astro" denied on branch "foobar" (changeset "e8fc755d4d82")
@@ -1677,13 +1667,12 @@
   f9cafe1212c8c6fa1120d14a556e18cc44ff8bdd
   911600dab2ae7a9baff75958b84fe606851ce955
   e8fc755d4d8217ee5b0c2bb41558c40d43b92c01
-  bundle2-output-bundle: "HG20", 6 parts total
+  bundle2-output-bundle: "HG20", 5 parts total
   bundle2-output-part: "replycaps" 168 bytes payload
   bundle2-output-part: "check:phases" 48 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 48 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -1712,7 +1701,8 @@
   acl: acl.deny not enabled
   error: pretxnchangegroup.acl hook failed: acl: user "astro" not allowed on branch "default" (changeset "ef1ea85a6374")
   bundle2-input-part: total payload size 2068
-  bundle2-input-bundle: 5 parts total
+  bundle2-input-part: total payload size 48
+  bundle2-input-bundle: 4 parts total
   transaction abort!
   rollback completed
   abort: acl: user "astro" not allowed on branch "default" (changeset "ef1ea85a6374")
@@ -1750,13 +1740,12 @@
   f9cafe1212c8c6fa1120d14a556e18cc44ff8bdd
   911600dab2ae7a9baff75958b84fe606851ce955
   e8fc755d4d8217ee5b0c2bb41558c40d43b92c01
-  bundle2-output-bundle: "HG20", 6 parts total
+  bundle2-output-bundle: "HG20", 5 parts total
   bundle2-output-part: "replycaps" 168 bytes payload
   bundle2-output-part: "check:phases" 48 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 48 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -1785,7 +1774,8 @@
   acl: acl.deny not enabled
   error: pretxnchangegroup.acl hook failed: acl: user "astro" not allowed on branch "default" (changeset "ef1ea85a6374")
   bundle2-input-part: total payload size 2068
-  bundle2-input-bundle: 5 parts total
+  bundle2-input-part: total payload size 48
+  bundle2-input-bundle: 4 parts total
   transaction abort!
   rollback completed
   abort: acl: user "astro" not allowed on branch "default" (changeset "ef1ea85a6374")
@@ -1817,13 +1807,12 @@
   f9cafe1212c8c6fa1120d14a556e18cc44ff8bdd
   911600dab2ae7a9baff75958b84fe606851ce955
   e8fc755d4d8217ee5b0c2bb41558c40d43b92c01
-  bundle2-output-bundle: "HG20", 6 parts total
+  bundle2-output-bundle: "HG20", 5 parts total
   bundle2-output-part: "replycaps" 168 bytes payload
   bundle2-output-part: "check:phases" 48 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 48 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -1859,21 +1848,15 @@
   acl: branch access granted: "e8fc755d4d82" on branch "foobar"
   acl: path access granted: "e8fc755d4d82"
   bundle2-input-part: total payload size 2068
-  bundle2-input-part: "pushkey" (params: 4 mandatory) supported
-  pushing key for "phases:911600dab2ae7a9baff75958b84fe606851ce955"
-  bundle2-input-part: "pushkey" (params: 4 mandatory) supported
-  pushing key for "phases:e8fc755d4d8217ee5b0c2bb41558c40d43b92c01"
-  bundle2-input-bundle: 5 parts total
+  bundle2-input-part: "phase-heads" supported
+  bundle2-input-part: total payload size 48
+  bundle2-input-bundle: 4 parts total
   updating the branch cache
-  bundle2-output-bundle: "HG20", 3 parts total
+  bundle2-output-bundle: "HG20", 1 parts total
   bundle2-output-part: "reply:changegroup" (advisory) (params: 0 advisory) empty payload
-  bundle2-output-part: "reply:pushkey" (params: 0 advisory) empty payload
-  bundle2-output-part: "reply:pushkey" (params: 0 advisory) empty payload
   bundle2-input-bundle: no-transaction
   bundle2-input-part: "reply:changegroup" (advisory) (params: 0 advisory) supported
-  bundle2-input-part: "reply:pushkey" (params: 0 advisory) supported
-  bundle2-input-part: "reply:pushkey" (params: 0 advisory) supported
-  bundle2-input-bundle: 2 parts total
+  bundle2-input-bundle: 0 parts total
   listing keys for "phases"
   repository tip rolled back to revision 2 (undo push)
   2:fb35475503ef
@@ -1913,13 +1896,12 @@
   f9cafe1212c8c6fa1120d14a556e18cc44ff8bdd
   911600dab2ae7a9baff75958b84fe606851ce955
   e8fc755d4d8217ee5b0c2bb41558c40d43b92c01
-  bundle2-output-bundle: "HG20", 6 parts total
+  bundle2-output-bundle: "HG20", 5 parts total
   bundle2-output-part: "replycaps" 168 bytes payload
   bundle2-output-part: "check:phases" 48 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 48 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -1955,21 +1937,15 @@
   acl: branch access granted: "e8fc755d4d82" on branch "foobar"
   acl: path access granted: "e8fc755d4d82"
   bundle2-input-part: total payload size 2068
-  bundle2-input-part: "pushkey" (params: 4 mandatory) supported
-  pushing key for "phases:911600dab2ae7a9baff75958b84fe606851ce955"
-  bundle2-input-part: "pushkey" (params: 4 mandatory) supported
-  pushing key for "phases:e8fc755d4d8217ee5b0c2bb41558c40d43b92c01"
-  bundle2-input-bundle: 5 parts total
+  bundle2-input-part: "phase-heads" supported
+  bundle2-input-part: total payload size 48
+  bundle2-input-bundle: 4 parts total
   updating the branch cache
-  bundle2-output-bundle: "HG20", 3 parts total
+  bundle2-output-bundle: "HG20", 1 parts total
   bundle2-output-part: "reply:changegroup" (advisory) (params: 0 advisory) empty payload
-  bundle2-output-part: "reply:pushkey" (params: 0 advisory) empty payload
-  bundle2-output-part: "reply:pushkey" (params: 0 advisory) empty payload
   bundle2-input-bundle: no-transaction
   bundle2-input-part: "reply:changegroup" (advisory) (params: 0 advisory) supported
-  bundle2-input-part: "reply:pushkey" (params: 0 advisory) supported
-  bundle2-input-part: "reply:pushkey" (params: 0 advisory) supported
-  bundle2-input-bundle: 2 parts total
+  bundle2-input-bundle: 0 parts total
   listing keys for "phases"
   repository tip rolled back to revision 2 (undo push)
   2:fb35475503ef
@@ -2008,13 +1984,12 @@
   f9cafe1212c8c6fa1120d14a556e18cc44ff8bdd
   911600dab2ae7a9baff75958b84fe606851ce955
   e8fc755d4d8217ee5b0c2bb41558c40d43b92c01
-  bundle2-output-bundle: "HG20", 6 parts total
+  bundle2-output-bundle: "HG20", 5 parts total
   bundle2-output-part: "replycaps" 168 bytes payload
   bundle2-output-part: "check:phases" 48 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 48 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -2043,7 +2018,8 @@
   acl: acl.deny not enabled
   error: pretxnchangegroup.acl hook failed: acl: user "george" denied on branch "default" (changeset "ef1ea85a6374")
   bundle2-input-part: total payload size 2068
-  bundle2-input-bundle: 5 parts total
+  bundle2-input-part: total payload size 48
+  bundle2-input-bundle: 4 parts total
   transaction abort!
   rollback completed
   abort: acl: user "george" denied on branch "default" (changeset "ef1ea85a6374")
@@ -2080,13 +2056,12 @@
   f9cafe1212c8c6fa1120d14a556e18cc44ff8bdd
   911600dab2ae7a9baff75958b84fe606851ce955
   e8fc755d4d8217ee5b0c2bb41558c40d43b92c01
-  bundle2-output-bundle: "HG20", 6 parts total
+  bundle2-output-bundle: "HG20", 5 parts total
   bundle2-output-part: "replycaps" 168 bytes payload
   bundle2-output-part: "check:phases" 48 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 48 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -2122,21 +2097,15 @@
   acl: branch access granted: "e8fc755d4d82" on branch "foobar"
   acl: path access granted: "e8fc755d4d82"
   bundle2-input-part: total payload size 2068
-  bundle2-input-part: "pushkey" (params: 4 mandatory) supported
-  pushing key for "phases:911600dab2ae7a9baff75958b84fe606851ce955"
-  bundle2-input-part: "pushkey" (params: 4 mandatory) supported
-  pushing key for "phases:e8fc755d4d8217ee5b0c2bb41558c40d43b92c01"
-  bundle2-input-bundle: 5 parts total
+  bundle2-input-part: "phase-heads" supported
+  bundle2-input-part: total payload size 48
+  bundle2-input-bundle: 4 parts total
   updating the branch cache
-  bundle2-output-bundle: "HG20", 3 parts total
+  bundle2-output-bundle: "HG20", 1 parts total
   bundle2-output-part: "reply:changegroup" (advisory) (params: 0 advisory) empty payload
-  bundle2-output-part: "reply:pushkey" (params: 0 advisory) empty payload
-  bundle2-output-part: "reply:pushkey" (params: 0 advisory) empty payload
   bundle2-input-bundle: no-transaction
   bundle2-input-part: "reply:changegroup" (advisory) (params: 0 advisory) supported
-  bundle2-input-part: "reply:pushkey" (params: 0 advisory) supported
-  bundle2-input-part: "reply:pushkey" (params: 0 advisory) supported
-  bundle2-input-bundle: 2 parts total
+  bundle2-input-bundle: 0 parts total
   listing keys for "phases"
   repository tip rolled back to revision 2 (undo push)
   2:fb35475503ef
@@ -2169,13 +2138,12 @@
   f9cafe1212c8c6fa1120d14a556e18cc44ff8bdd
   911600dab2ae7a9baff75958b84fe606851ce955
   e8fc755d4d8217ee5b0c2bb41558c40d43b92c01
-  bundle2-output-bundle: "HG20", 6 parts total
+  bundle2-output-bundle: "HG20", 5 parts total
   bundle2-output-part: "replycaps" 168 bytes payload
   bundle2-output-part: "check:phases" 48 bytes payload
   bundle2-output-part: "check:heads" streamed payload
   bundle2-output-part: "changegroup" (params: 1 mandatory) streamed payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
-  bundle2-output-part: "pushkey" (params: 4 mandatory) empty payload
+  bundle2-output-part: "phase-heads" 48 bytes payload
   bundle2-input-bundle: with-transaction
   bundle2-input-part: "replycaps" supported
   bundle2-input-part: total payload size 168
@@ -2204,7 +2172,8 @@
   acl: acl.deny not enabled
   error: pretxnchangegroup.acl hook failed: acl: user "george" denied on branch "default" (changeset "ef1ea85a6374")
   bundle2-input-part: total payload size 2068
-  bundle2-input-bundle: 5 parts total
+  bundle2-input-part: total payload size 48
+  bundle2-input-bundle: 4 parts total
   transaction abort!
   rollback completed
   abort: acl: user "george" denied on branch "default" (changeset "ef1ea85a6374")

--- a/tests/test-bundle2-exchange.t	Tue Oct 17 12:41:24 2017 -0700
+++ b/tests/test-bundle2-exchange.t	Wed Sep 20 19:38:06 2017 +0200
@@ -252,9 +252,6 @@
   remote: added 1 changesets with 0 changes to 0 files (-1 heads)
   remote: 1 new obsolescence markers
   remote: pre-close-tip:eea13746799a public book_eea1
-  remote: pushkey: lock state after "phases"
-  remote: lock:  free
-  remote: wlock: free
   remote: pushkey: lock state after "bookmarks"
   remote: lock:  free
   remote: wlock: free
@@ -392,9 +389,6 @@
   remote: added 1 changesets with 1 changes to 1 files
   remote: 1 new obsolescence markers
   remote: pre-close-tip:32af7686d403 public book_32af
-  remote: pushkey: lock state after "phases"
-  remote: lock:  free
-  remote: wlock: free
   remote: pushkey: lock state after "bookmarks"
   remote: lock:  free
   remote: wlock: free

--- a/tests/test-push-http.t	Tue Oct 17 12:41:24 2017 -0700
+++ b/tests/test-push-http.t	Wed Sep 20 19:38:06 2017 +0200
@@ -70,7 +70,6 @@
   remote: adding manifests
   remote: adding file changes
   remote: added 1 changesets with 1 changes to 1 files
-  remote: pushkey hook: HG_HOOKNAME=pushkey HG_HOOKTYPE=pushkey HG_KEY=ba677d0156c1196c1a699fa53f390dcfc3ce3872 HG_NAMESPACE=phases HG_NEW=0 HG_OLD=1 HG_RET=1
   remote: phase-move: cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b:  1 -> 0
   remote: phase-move: ba677d0156c1196c1a699fa53f390dcfc3ce3872:   -> 0
   remote: changegroup hook: HG_BUNDLE2=1 HG_HOOKNAME=changegroup HG_HOOKTYPE=changegroup HG_NODE=ba677d0156c1196c1a699fa53f390dcfc3ce3872 HG_NODE_LAST=ba677d0156c1196c1a699fa53f390dcfc3ce3872 HG_SOURCE=serve HG_TXNID=TXN:$ID$ HG_URL=remote:http:$LOCALIP: (glob)
@@ -89,7 +88,6 @@
   remote: adding manifests
   remote: adding file changes
   remote: added 1 changesets with 1 changes to 1 files
-  remote: pushkey hook: HG_HOOKNAME=pushkey HG_HOOKTYPE=pushkey HG_KEY=ba677d0156c1196c1a699fa53f390dcfc3ce3872 HG_NAMESPACE=phases HG_NEW=0 HG_OLD=1 HG_RET=1
   remote: phase-move: cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b:  1 -> 0
   remote: phase-move: ba677d0156c1196c1a699fa53f390dcfc3ce3872:   -> 0
   remote: changegroup hook: HG_BUNDLE2=1 HG_HOOKNAME=changegroup HG_HOOKTYPE=changegroup HG_NODE=ba677d0156c1196c1a699fa53f390dcfc3ce3872 HG_NODE_LAST=ba677d0156c1196c1a699fa53f390dcfc3ce3872 HG_SOURCE=serve HG_TXNID=TXN:$ID$ HG_URL=remote:http:$LOCALIP: (glob)
@@ -108,7 +106,6 @@
   remote: adding manifests
   remote: adding file changes
   remote: added 1 changesets with 1 changes to 1 files
-  remote: pushkey hook: HG_HOOKNAME=pushkey HG_HOOKTYPE=pushkey HG_KEY=ba677d0156c1196c1a699fa53f390dcfc3ce3872 HG_NAMESPACE=phases HG_NEW=0 HG_OLD=1 HG_RET=1
   remote: phase-move: cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b:  1 -> 0
   remote: phase-move: ba677d0156c1196c1a699fa53f390dcfc3ce3872:   -> 0
   remote: changegroup hook: HG_BUNDLE2=1 HG_HOOKNAME=changegroup HG_HOOKTYPE=changegroup HG_NODE=ba677d0156c1196c1a699fa53f390dcfc3ce3872 HG_NODE_LAST=ba677d0156c1196c1a699fa53f390dcfc3ce3872 HG_SOURCE=serve HG_TXNID=TXN:$ID$ HG_URL=remote:http:$LOCALIP: (glob)
@@ -124,6 +121,8 @@
   > allow_push = *
   > [hooks]
   > prepushkey = sh -c "printenv.py prepushkey 1"
+  > [devel]
+  > legacy.exchange=phases
   > EOF
   $ req
   pushing to http://localhost:$HGPORT/
@@ -144,6 +143,8 @@
 
   $ cat >> .hg/hgrc <<EOF
   > prepushkey = sh -c "printenv.py prepushkey 0"
+  > [devel]
+  > legacy.exchange=
   > EOF
   $ req
   pushing to http://localhost:$HGPORT/
@@ -152,7 +153,6 @@
   remote: adding manifests
   remote: adding file changes
   remote: added 1 changesets with 1 changes to 1 files
-  remote: prepushkey hook: HG_BUNDLE2=1 HG_HOOKNAME=prepushkey HG_HOOKTYPE=prepushkey HG_KEY=ba677d0156c1196c1a699fa53f390dcfc3ce3872 HG_NAMESPACE=phases HG_NEW=0 HG_NODE=ba677d0156c1196c1a699fa53f390dcfc3ce3872 HG_NODE_LAST=ba677d0156c1196c1a699fa53f390dcfc3ce3872 HG_OLD=1 HG_PENDING=$TESTTMP/test HG_PHASES_MOVED=1 HG_SOURCE=serve HG_TXNID=TXN:$ID$ HG_URL=remote:http:$LOCALIP: (glob)
   % serve errors
   $ hg rollback
   repository tip rolled back to revision 0 (undo serve)