diff --git a/.hgsigs b/.hgsigs
--- a/.hgsigs
+++ b/.hgsigs
@@ -221,3 +221,4 @@ 6ee0244fc1cf889ae543d2ce0ec45201ae0be6e1
 a44bb185f6bdbecc754996d8386722e2f0123b0a 0 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
 5d08b289e2e526259d7d5ea32b70fe76d5b327d7 0 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
 799fdf4cca80cb9ae40537a90995e6bd163ebc0b 0 iQHNBAABCgA3FiEEH2b4zfZU6QXBHaBhoR4BzQ4F2VYFAmHVzPMZHGFscGhhcmVAcmFwaGFlbGdvbWVzLmRldgAKCRChHgHNDgXZVmiyC/48p6+/JJi8WaY+Xdxh1IMK1/CB3dYcC99+V89asIW+g/X/0FacTSSAGkvDrjNSeYAkXGp3g/LbEbwoZhKxF8MyKU7TOn62lz8JETwebtjxehjVfPUy73RJbuLPDvn9m16YHxuC848hDZHnqk/PjaBVHeZ2cN8T7F9VgXkhyYStV9GT2PSQUsvkQAxjiLilyKs3RaZAduZPvOmGaq2CfK91PbScKaKgYShkKym7gfhU1o4pynNmuPqRwUJyihaZqsKDjOn8OHeJpqAm7ODmR+SIOvMvFbbfS8mTSfYMHsP+r+JgbqSVNG99qEqsIW3HznGe/OpG/1QS3MVVSyi87oHR1UcN91vKIiln92i+7Ct7GttjkgkkqfQEw1oAELCmiHacYEBbLvQGaXdHROeO6wqXUKvI4KeM3CPt2qsouPiKBzSF1eOPd967NNvgTgcabT2ob0YaXmWdZasJnZ74H/3FMMC98WhYe3ja+6cpl67PZlNUWlnIZBlyL63DWSJ09us=
+75676122c2bf7594ac732b7388db4c74c648b365 0 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
diff --git a/.hgtags b/.hgtags
--- a/.hgtags
+++ b/.hgtags
@@ -234,3 +234,4 @@ 6ee0244fc1cf889ae543d2ce0ec45201ae0be6e1
 a44bb185f6bdbecc754996d8386722e2f0123b0a 6.0rc0
 5d08b289e2e526259d7d5ea32b70fe76d5b327d7 6.0
 799fdf4cca80cb9ae40537a90995e6bd163ebc0b 6.0.1
+75676122c2bf7594ac732b7388db4c74c648b365 6.0.2
diff --git a/hgext/uncommit.py b/hgext/uncommit.py
--- a/hgext/uncommit.py
+++ b/hgext/uncommit.py
@@ -273,6 +273,8 @@ def unamend(ui, repo, **opts):
         curctx = repo[b'.']
 
         rewriteutil.precheck(repo, [curctx.rev()], b'unamend')
+        if len(curctx.parents()) > 1:
+            raise error.InputError(_(b"cannot unamend merge changeset"))
 
         # identify the commit to which to unamend
         markers = list(predecessormarkers(curctx))
diff --git a/mercurial/branchmap.py b/mercurial/branchmap.py
--- a/mercurial/branchmap.py
+++ b/mercurial/branchmap.py
@@ -149,6 +149,13 @@ class BranchMapCache(object):
     def clear(self):
         self._per_filter.clear()
 
+    def write_delayed(self, repo):
+        unfi = repo.unfiltered()
+        for filtername, cache in self._per_filter.items():
+            if cache._delayed:
+                repo = unfi.filtered(filtername)
+                cache.write(repo)
+
 
 def _unknownnode(node):
     """raises ValueError when branchcache found a node which does not exists"""
@@ -199,6 +206,7 @@ class branchcache(object):
         has a given node or not. If it's not provided, we assume that every node
         we have exists in changelog"""
         self._repo = repo
+        self._delayed = False
         if tipnode is None:
             self.tipnode = repo.nullid
         else:
@@ -403,6 +411,13 @@ class branchcache(object):
         )
 
     def write(self, repo):
+        tr = repo.currenttransaction()
+        if not getattr(tr, 'finalized', True):
+            # Avoid premature writing.
+            #
+            # (The cache warming setup by localrepo will update the file later.)
+            self._delayed = True
+            return
         try:
             f = repo.cachevfs(self._filename(repo), b"w", atomictemp=True)
             cachekey = [hex(self.tipnode), b'%d' % self.tiprev]
@@ -427,6 +442,7 @@ class branchcache(object):
                 len(self._entries),
                 nodecount,
             )
+            self._delayed = False
         except (IOError, OSError, error.Abort) as inst:
             # Abort may be raised by read only opener, so log and continue
             repo.ui.debug(
diff --git a/mercurial/configitems.py b/mercurial/configitems.py
--- a/mercurial/configitems.py
+++ b/mercurial/configitems.py
@@ -1277,9 +1277,10 @@ coreconfigitem(
     # Enable this dirstate format *when creating a new repository*.
     # Which format to use for existing repos is controlled by .hg/requires
     b'format',
-    b'exp-rc-dirstate-v2',
+    b'use-dirstate-v2',
     default=False,
     experimental=True,
+    alias=[(b'format', b'exp-rc-dirstate-v2')],
 )
 coreconfigitem(
     b'format',
@@ -1851,7 +1852,7 @@ coreconfigitem(
     default=b'skip',
     experimental=True,
 )
-# experimental as long as format.exp-rc-dirstate-v2 is.
+# experimental as long as format.use-dirstate-v2 is.
 coreconfigitem(
     b'storage',
     b'dirstate-v2.slow-path',
diff --git a/mercurial/helptext/config.txt b/mercurial/helptext/config.txt
--- a/mercurial/helptext/config.txt
+++ b/mercurial/helptext/config.txt
@@ -915,7 +915,7 @@ https://www.mercurial-scm.org/wiki/Missi
 
     Enabled by default.
 
-``exp-rc-dirstate-v2``
+``use-dirstate-v2``
     Enable or disable the experimental "dirstate-v2" feature. The dirstate
     functionality is shared by all commands interacting with the working copy.
     The new version is more robust, faster and stores more information.
@@ -939,7 +939,7 @@ https://www.mercurial-scm.org/wiki/Missi
 
     $ hg debugupgraderepo \
           --run \
-          --config format.exp-rc-dirstate-v2=False \
+          --config format.use-dirstate-v2=False \
           --config storage.dirstate-v2.slow-path=allow
 
     For a more comprehensive guide, see :hg:`help internals.dirstate-v2`.
diff --git a/mercurial/helptext/internals/dirstate-v2.txt b/mercurial/helptext/internals/dirstate-v2.txt
--- a/mercurial/helptext/internals/dirstate-v2.txt
+++ b/mercurial/helptext/internals/dirstate-v2.txt
@@ -37,12 +37,12 @@ Enabling `dirstate-v2` for new local rep
 ------------------------------------------------
 
 When creating a new local repository such as with `hg init` or `hg clone`,
-the `exp-rc-dirstate-v2` boolean in the `format` configuration section
+the `use-dirstate-v2` boolean in the `format` configuration section
 controls whether to use this file format.
 This is disabled by default as of this writing.
 To enable it for a single repository, run for example::
 
-    $ hg init my-project --config format.exp-rc-dirstate-v2=1
+    $ hg init my-project --config format.use-dirstate-v2=1
 
 Checking the format of an existing local repository
 --------------------------------------------------
@@ -63,15 +63,15 @@ Upgrading or downgrading an existing loc
 The `debugupgrade` command does various upgrades or downgrades
 on a local repository
 based on the current Mercurial version and on configuration.
-The same `format.exp-rc-dirstate-v2` configuration is used again.
+The same `format.use-dirstate-v2` configuration is used again.
 
 Example to upgrade::
 
-    $ hg debugupgrade --config format.exp-rc-dirstate-v2=1
+    $ hg debugupgrade --config format.use-dirstate-v2=1
 
 Example to downgrade to `dirstate-v1`::
 
-    $ hg debugupgrade --config format.exp-rc-dirstate-v2=0
+    $ hg debugupgrade --config format.use-dirstate-v2=0
 
 Both of this commands do nothing but print a list of proposed changes,
 which may include changes unrelated to the dirstate.
diff --git a/mercurial/helptext/rust.txt b/mercurial/helptext/rust.txt
--- a/mercurial/helptext/rust.txt
+++ b/mercurial/helptext/rust.txt
@@ -15,10 +15,11 @@ Features
 ========
 
 The following operations are sped up when using Rust:
+
     - discovery of differences between repositories (pull/push)
     - nodemap (see :hg:`help config.format.use-persistent-nodemap`)
     - all commands using the dirstate (status, commit, diff, add, update, etc.)
-    - dirstate-v2 (see :hg:`help config.format.exp-rc-dirstate-v2`)
+    - dirstate-v2 (see :hg:`help config.format.use-dirstate-v2`)
     - iteration over ancestors in a graph
 
 More features are in the works, and improvements on the above listed are still
diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -1190,7 +1190,7 @@ def resolverevlogstorevfsoptions(ui, req
             b"fast implementation."
         )
         hint = _(
-            b"check `hg help config.format.exp-rc-dirstate-v2` " b"for details"
+            b"check `hg help config.format.use-dirstate-v2` " b"for details"
         )
         if not dirstate.HAS_FAST_DIRSTATE_V2:
             if slow_path == b'warn':
@@ -2824,6 +2824,8 @@ class localrepository(object):
                 self.ui.debug(b'updating the branch cache\n')
                 self.filtered(b'served').branchmap()
                 self.filtered(b'served.hidden').branchmap()
+                # flush all possibly delayed write.
+                self._branchcaches.write_delayed(self)
 
         if repository.CACHE_CHANGELOG_CACHE in caches:
             self.changelog.update_caches(transaction=tr)
@@ -3618,9 +3620,9 @@ def newreporequirements(ui, createopts):
         if ui.configbool(b'format', b'sparse-revlog'):
             requirements.add(requirementsmod.SPARSEREVLOG_REQUIREMENT)
 
-    # experimental config: format.exp-rc-dirstate-v2
+    # experimental config: format.use-dirstate-v2
     # Keep this logic in sync with `has_dirstate_v2()` in `tests/hghave.py`
-    if ui.configbool(b'format', b'exp-rc-dirstate-v2'):
+    if ui.configbool(b'format', b'use-dirstate-v2'):
         requirements.add(requirementsmod.DIRSTATE_V2_REQUIREMENT)
 
     # experimental config: format.exp-use-copies-side-data-changeset
diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -1971,7 +1971,7 @@ class revlog(object):
             raise error.RevlogError(
                 _(b"%s not found in the transaction") % self._indexfile
             )
-        trindex = 0
+        trindex = None
         tr.add(self._datafile, 0)
 
         existing_handles = False
@@ -1994,10 +1994,17 @@ class revlog(object):
             with self._indexfp() as read_ifh:
                 for r in self:
                     new_dfh.write(self._getsegmentforrevs(r, r, df=read_ifh)[1])
-                    if troffset <= self.start(r) + r * self.index.entry_size:
+                    if (
+                        trindex is None
+                        and troffset
+                        <= self.start(r) + r * self.index.entry_size
+                    ):
                         trindex = r
                 new_dfh.flush()
 
+            if trindex is None:
+                trindex = 0
+
             with self.__index_new_fp() as fp:
                 self._format_flags &= ~FLAG_INLINE_DATA
                 self._inline = False
diff --git a/mercurial/transaction.py b/mercurial/transaction.py
--- a/mercurial/transaction.py
+++ b/mercurial/transaction.py
@@ -229,6 +229,10 @@ class transaction(util.transactional):
         if self._journal:
             self._abort()
 
+    @property
+    def finalized(self):
+        return self._finalizecallback is None
+
     @active
     def startgroup(self):
         """delay registration of file entry
diff --git a/relnotes/6.0 b/relnotes/6.0
--- a/relnotes/6.0
+++ b/relnotes/6.0
@@ -1,3 +1,25 @@
+= Mercurial 6.0.2 =
+
+  * Fix `hg incoming` and `hg outgoing` with remote subrepos on Windows
+  * Fix Rust build on MacOS
+  * Fix a (15 year old?) bug where some data loss could happen in a very tight race window (f38ae2d7390e + ccd9cb73125c)
+  * Remove support for running `hg unamend` on merge changesets at it was never actually implemented
+  * Fix stream-clone requirements filtering which caused some stream-clones to be unusable from an older version of Mercurial
+  * Rename dirstate-v2 configuration name from `exp-rc-dirstate-v2` to `use-dirstate-v2`. This was overlooked in `6.0`, the old name will be kept as an alias for compatibility.
+  * Fix a bug where the branchmap could point to uncommitted data 
+
+= Mercurial 6.0.1 =
+
+  * Improve documentation around Rust (see hg help rust) and rust-related actions
+  * Improve upgrade/downgrade edge cases for dirstate-v2
+  * Make the test suite nicer to big-endian platforms
+  * Make the test suite nicer to NetBSD
+  * Fix a performance regression on fsmonitor (issue6612)
+  * Add fixes for Python 3.10
+  * Fix a deadlock when using sparse and share-safe together 
+
+= Mercurial 6.0 =
+
 == New Features ==
   * `debugrebuildfncache` now has an option to rebuild only the index files
   * a new `bookmarks.mode` path option have been introduced to control the
diff --git a/tests/test-basic.t b/tests/test-basic.t
--- a/tests/test-basic.t
+++ b/tests/test-basic.t
@@ -6,7 +6,7 @@ Create a repository:
   devel.all-warnings=true
   devel.default-date=0 0
   extensions.fsmonitor= (fsmonitor !)
-  format.exp-rc-dirstate-v2=1 (dirstate-v2 !)
+  format.use-dirstate-v2=1 (dirstate-v2 !)
   largefiles.usercache=$TESTTMP/.cache/largefiles
   lfs.usercache=$TESTTMP/.cache/lfs
   ui.slash=True
diff --git a/tests/test-branches.t b/tests/test-branches.t
--- a/tests/test-branches.t
+++ b/tests/test-branches.t
@@ -1242,3 +1242,99 @@ Intermediary parents are on different br
   C                              3:4a546028fa8f (inactive)
   B                              1:0bc7d348d965 (inactive)
   $ cd ..
+
+Check that the cache are not written too early
+----------------------------------------------
+
+  $ hg log -R branchmap-testing1 -G
+  o    changeset:   3:71ca9a6d524e
+  |\   branch:      A
+  | |  tag:         tip
+  | |  parent:      2:a3b807b3ff0b
+  | |  parent:      1:99ba08759bc7
+  | |  user:        debugbuilddag
+  | |  date:        Thu Jan 01 00:00:03 1970 +0000
+  | |  summary:     r3
+  | |
+  | o  changeset:   2:a3b807b3ff0b
+  | |  branch:      A
+  | |  parent:      0:2ab8003a1750
+  | |  user:        debugbuilddag
+  | |  date:        Thu Jan 01 00:00:02 1970 +0000
+  | |  summary:     r2
+  | |
+  o |  changeset:   1:99ba08759bc7
+  |/   branch:      A
+  |    tag:         p1
+  |    user:        debugbuilddag
+  |    date:        Thu Jan 01 00:00:01 1970 +0000
+  |    summary:     r1
+  |
+  o  changeset:   0:2ab8003a1750
+     branch:      A
+     tag:         base
+     user:        debugbuilddag
+     date:        Thu Jan 01 00:00:00 1970 +0000
+     summary:     r0
+  
+  $ hg bundle -R branchmap-testing1 --base 1 bundle.hg --rev 'head()'
+  2 changesets found
+
+Unbundling revision should warm the served cache
+
+  $ hg clone branchmap-testing1 --rev 1 branchmap-update-01
+  adding changesets
+  adding manifests
+  adding file changes
+  added 2 changesets with 0 changes to 0 files
+  new changesets 2ab8003a1750:99ba08759bc7
+  updating to branch A
+  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ cat branchmap-update-01/.hg/cache/branch2-served
+  99ba08759bc7f6fdbe5304e83d0387f35c082479 1
+  99ba08759bc7f6fdbe5304e83d0387f35c082479 o A
+  $ hg -R branchmap-update-01 unbundle bundle.hg
+  adding changesets
+  adding manifests
+  adding file changes
+  added 2 changesets with 0 changes to 0 files
+  new changesets a3b807b3ff0b:71ca9a6d524e (2 drafts)
+  (run 'hg update' to get a working copy)
+  $ cat branchmap-update-01/.hg/cache/branch2-served
+  71ca9a6d524ed3c2a215119b2086ac3b8c4c8286 3
+  71ca9a6d524ed3c2a215119b2086ac3b8c4c8286 o A
+
+aborted Unbundle should not update the on disk cache
+
+  $ cat >> simplehook.py << EOF
+  > import sys
+  > from mercurial import node
+  > from mercurial import branchmap
+  > def hook(ui, repo, *args, **kwargs):
+  >     s = repo.filtered(b"served")
+  >     s.branchmap()
+  >     return 1
+  > EOF
+  $ hg clone branchmap-testing1 --rev 1 branchmap-update-02
+  adding changesets
+  adding manifests
+  adding file changes
+  added 2 changesets with 0 changes to 0 files
+  new changesets 2ab8003a1750:99ba08759bc7
+  updating to branch A
+  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
+
+  $ cat branchmap-update-02/.hg/cache/branch2-served
+  99ba08759bc7f6fdbe5304e83d0387f35c082479 1
+  99ba08759bc7f6fdbe5304e83d0387f35c082479 o A
+  $ hg -R branchmap-update-02 unbundle bundle.hg --config "hooks.pretxnclose=python:$TESTTMP/simplehook.py:hook"
+  adding changesets
+  adding manifests
+  adding file changes
+  transaction abort!
+  rollback completed
+  abort: pretxnclose hook failed
+  [40]
+  $ cat branchmap-update-02/.hg/cache/branch2-served
+  99ba08759bc7f6fdbe5304e83d0387f35c082479 1
+  99ba08759bc7f6fdbe5304e83d0387f35c082479 o A
diff --git a/tests/test-commandserver.t b/tests/test-commandserver.t
--- a/tests/test-commandserver.t
+++ b/tests/test-commandserver.t
@@ -218,7 +218,7 @@ check that local configs for the cached 
   devel.all-warnings=true
   devel.default-date=0 0
   extensions.fsmonitor= (fsmonitor !)
-  format.exp-rc-dirstate-v2=1 (dirstate-v2 !)
+  format.use-dirstate-v2=1 (dirstate-v2 !)
   largefiles.usercache=$TESTTMP/.cache/largefiles
   lfs.usercache=$TESTTMP/.cache/lfs
   ui.slash=True
diff --git a/tests/test-dirstate-race.t b/tests/test-dirstate-race.t
--- a/tests/test-dirstate-race.t
+++ b/tests/test-dirstate-race.t
@@ -3,7 +3,7 @@
 #if dirstate-v2
   $ cat >> $HGRCPATH << EOF
   > [format]
-  > exp-rc-dirstate-v2=1
+  > use-dirstate-v2=1
   > [storage]
   > dirstate-v2.slow-path=allow
   > EOF
diff --git a/tests/test-dirstate-race2.t b/tests/test-dirstate-race2.t
--- a/tests/test-dirstate-race2.t
+++ b/tests/test-dirstate-race2.t
@@ -3,7 +3,7 @@
 #if dirstate-v2
   $ cat >> $HGRCPATH << EOF
   > [format]
-  > exp-rc-dirstate-v2=1
+  > use-dirstate-v2=1
   > [storage]
   > dirstate-v2.slow-path=allow
   > EOF
diff --git a/tests/test-dirstate.t b/tests/test-dirstate.t
--- a/tests/test-dirstate.t
+++ b/tests/test-dirstate.t
@@ -3,7 +3,7 @@
 #if dirstate-v2
   $ cat >> $HGRCPATH << EOF
   > [format]
-  > exp-rc-dirstate-v2=1
+  > use-dirstate-v2=1
   > [storage]
   > dirstate-v2.slow-path=allow
   > EOF
diff --git a/tests/test-help.t b/tests/test-help.t
--- a/tests/test-help.t
+++ b/tests/test-help.t
@@ -1597,7 +1597,7 @@ Separate sections from subsections
   
       "usefncache"
   
-      "exp-rc-dirstate-v2"
+      "use-dirstate-v2"
   
       "use-persistent-nodemap"
   
diff --git a/tests/test-hgignore.t b/tests/test-hgignore.t
--- a/tests/test-hgignore.t
+++ b/tests/test-hgignore.t
@@ -3,7 +3,7 @@
 #if dirstate-v2
   $ cat >> $HGRCPATH << EOF
   > [format]
-  > exp-rc-dirstate-v2=1
+  > use-dirstate-v2=1
   > [storage]
   > dirstate-v2.slow-path=allow
   > EOF
diff --git a/tests/test-permissions.t b/tests/test-permissions.t
--- a/tests/test-permissions.t
+++ b/tests/test-permissions.t
@@ -5,7 +5,7 @@
 #if dirstate-v2
   $ cat >> $HGRCPATH << EOF
   > [format]
-  > exp-rc-dirstate-v2=1
+  > use-dirstate-v2=1
   > [storage]
   > dirstate-v2.slow-path=allow
   > EOF
diff --git a/tests/test-persistent-nodemap.t b/tests/test-persistent-nodemap.t
--- a/tests/test-persistent-nodemap.t
+++ b/tests/test-persistent-nodemap.t
@@ -800,7 +800,7 @@ downgrading
   requirements
      preserved: dotencode, fncache, generaldelta, revlogv1, share-safe, sparserevlog, store (no-zstd no-dirstate-v2 !)
      preserved: dotencode, fncache, generaldelta, revlog-compression-zstd, revlogv1, share-safe, sparserevlog, store (zstd no-dirstate-v2 !)
-     preserved: dotencode, exp-rc-dirstate-v2, fncache, generaldelta, revlog-compression-zstd, revlogv1, share-safe, sparserevlog, store (zstd dirstate-v2 !)
+     preserved: dotencode, use-dirstate-v2, fncache, generaldelta, revlog-compression-zstd, revlogv1, share-safe, sparserevlog, store (zstd dirstate-v2 !)
      removed: persistent-nodemap
   
   processed revlogs:
@@ -844,7 +844,7 @@ upgrading
   requirements
      preserved: dotencode, fncache, generaldelta, revlogv1, share-safe, sparserevlog, store (no-zstd no-dirstate-v2 !)
      preserved: dotencode, fncache, generaldelta, revlog-compression-zstd, revlogv1, share-safe, sparserevlog, store (zstd no-dirstate-v2 !)
-     preserved: dotencode, exp-rc-dirstate-v2, fncache, generaldelta, revlog-compression-zstd, revlogv1, share-safe, sparserevlog, store (zstd dirstate-v2 !)
+     preserved: dotencode, use-dirstate-v2, fncache, generaldelta, revlog-compression-zstd, revlogv1, share-safe, sparserevlog, store (zstd dirstate-v2 !)
      added: persistent-nodemap
   
   processed revlogs:
@@ -876,7 +876,7 @@ Running unrelated upgrade
   requirements
      preserved: dotencode, fncache, generaldelta, persistent-nodemap, revlogv1, share-safe, sparserevlog, store (no-zstd no-dirstate-v2 !)
      preserved: dotencode, fncache, generaldelta, persistent-nodemap, revlog-compression-zstd, revlogv1, share-safe, sparserevlog, store (zstd no-dirstate-v2 !)
-     preserved: dotencode, exp-rc-dirstate-v2, fncache, generaldelta, persistent-nodemap, revlog-compression-zstd, revlogv1, share-safe, sparserevlog, store (zstd dirstate-v2 !)
+     preserved: dotencode, use-dirstate-v2, fncache, generaldelta, persistent-nodemap, revlog-compression-zstd, revlogv1, share-safe, sparserevlog, store (zstd dirstate-v2 !)
   
   optimisations: re-delta-all
   
diff --git a/tests/test-purge.t b/tests/test-purge.t
--- a/tests/test-purge.t
+++ b/tests/test-purge.t
@@ -3,7 +3,7 @@
 #if dirstate-v2
   $ cat >> $HGRCPATH << EOF
   > [format]
-  > exp-rc-dirstate-v2=1
+  > use-dirstate-v2=1
   > [storage]
   > dirstate-v2.slow-path=allow
   > EOF
diff --git a/tests/test-share-safe.t b/tests/test-share-safe.t
--- a/tests/test-share-safe.t
+++ b/tests/test-share-safe.t
@@ -225,7 +225,7 @@ Disable zstd related tests because its n
   
   requirements
      preserved: dotencode, fncache, generaldelta, revlogv1, share-safe, sparserevlog, store (no-dirstate-v2 !)
-     preserved: dotencode, exp-rc-dirstate-v2, fncache, generaldelta, revlogv1, share-safe, sparserevlog, store (dirstate-v2 !)
+     preserved: dotencode, use-dirstate-v2, fncache, generaldelta, revlogv1, share-safe, sparserevlog, store (dirstate-v2 !)
      added: revlog-compression-zstd
   
   processed revlogs:
@@ -253,8 +253,8 @@ Disable zstd related tests because its n
   requirements
      preserved: dotencode, fncache, generaldelta, revlogv1, share-safe, sparserevlog, store (no-zstd no-dirstate-v2 !)
      preserved: dotencode, fncache, generaldelta, revlog-compression-zstd, revlogv1, share-safe, sparserevlog, store (zstd no-dirstate-v2 !)
-     preserved: dotencode, exp-rc-dirstate-v2, fncache, generaldelta, revlogv1, share-safe, sparserevlog, store (no-zstd dirstate-v2 !)
-     preserved: dotencode, exp-rc-dirstate-v2, fncache, generaldelta, revlog-compression-zstd, revlogv1, share-safe, sparserevlog, store (zstd dirstate-v2 !)
+     preserved: dotencode, use-dirstate-v2, fncache, generaldelta, revlogv1, share-safe, sparserevlog, store (no-zstd dirstate-v2 !)
+     preserved: dotencode, use-dirstate-v2, fncache, generaldelta, revlog-compression-zstd, revlogv1, share-safe, sparserevlog, store (zstd dirstate-v2 !)
      added: persistent-nodemap
   
   processed revlogs:
@@ -360,7 +360,7 @@ Upgrade
   $ hg debugupgraderepo -q
   requirements
      preserved: dotencode, fncache, generaldelta, revlogv1, sparserevlog, store (no-dirstate-v2 !)
-     preserved: dotencode, exp-rc-dirstate-v2, fncache, generaldelta, revlogv1, sparserevlog, store (dirstate-v2 !)
+     preserved: dotencode, use-dirstate-v2, fncache, generaldelta, revlogv1, sparserevlog, store (dirstate-v2 !)
      added: share-safe
   
   no revlogs to process
@@ -370,7 +370,7 @@ Upgrade
   
   requirements
      preserved: dotencode, fncache, generaldelta, revlogv1, sparserevlog, store (no-dirstate-v2 !)
-     preserved: dotencode, exp-rc-dirstate-v2, fncache, generaldelta, revlogv1, sparserevlog, store (dirstate-v2 !)
+     preserved: dotencode, use-dirstate-v2, fncache, generaldelta, revlogv1, sparserevlog, store (dirstate-v2 !)
      added: share-safe
   
   share-safe
@@ -448,7 +448,7 @@ Test that downgrading works too
   $ hg debugupgraderepo -q
   requirements
      preserved: dotencode, fncache, generaldelta, revlogv1, sparserevlog, store (no-dirstate-v2 !)
-     preserved: dotencode, exp-rc-dirstate-v2, fncache, generaldelta, revlogv1, sparserevlog, store (dirstate-v2 !)
+     preserved: dotencode, use-dirstate-v2, fncache, generaldelta, revlogv1, sparserevlog, store (dirstate-v2 !)
      removed: share-safe
   
   no revlogs to process
@@ -458,7 +458,7 @@ Test that downgrading works too
   
   requirements
      preserved: dotencode, fncache, generaldelta, revlogv1, sparserevlog, store (no-dirstate-v2 !)
-     preserved: dotencode, exp-rc-dirstate-v2, fncache, generaldelta, revlogv1, sparserevlog, store (dirstate-v2 !)
+     preserved: dotencode, use-dirstate-v2, fncache, generaldelta, revlogv1, sparserevlog, store (dirstate-v2 !)
      removed: share-safe
   
   no revlogs to process
@@ -541,7 +541,7 @@ Testing automatic upgrade of shares when
   
   requirements
      preserved: dotencode, fncache, generaldelta, revlogv1, sparserevlog, store (no-dirstate-v2 !)
-     preserved: dotencode, exp-rc-dirstate-v2, fncache, generaldelta, revlogv1, sparserevlog, store (dirstate-v2 !)
+     preserved: dotencode, use-dirstate-v2, fncache, generaldelta, revlogv1, sparserevlog, store (dirstate-v2 !)
      added: share-safe
   
   no revlogs to process
diff --git a/tests/test-status.t b/tests/test-status.t
--- a/tests/test-status.t
+++ b/tests/test-status.t
@@ -3,7 +3,7 @@
 #if dirstate-v2
   $ cat >> $HGRCPATH << EOF
   > [format]
-  > exp-rc-dirstate-v2=1
+  > use-dirstate-v2=1
   > [storage]
   > dirstate-v2.slow-path=allow
   > EOF
diff --git a/tests/test-symlinks.t b/tests/test-symlinks.t
--- a/tests/test-symlinks.t
+++ b/tests/test-symlinks.t
@@ -5,7 +5,7 @@
 #if dirstate-v2
   $ cat >> $HGRCPATH << EOF
   > [format]
-  > exp-rc-dirstate-v2=1
+  > use-dirstate-v2=1
   > [storage]
   > dirstate-v2.slow-path=allow
   > EOF
diff --git a/tests/test-transaction-rollback-on-revlog-split.t b/tests/test-transaction-rollback-on-revlog-split.t
--- a/tests/test-transaction-rollback-on-revlog-split.t
+++ b/tests/test-transaction-rollback-on-revlog-split.t
@@ -17,22 +17,28 @@ Helper extension to intercept renames.
   >     extensions.wrapfunction(util.atomictempfile, 'close', close)
   > EOF
 
-Test offset computation to correctly factor in the index entries themselve.
+Test offset computation to correctly factor in the index entries themselves.
 Also test that the new data size has the correct size if the transaction is aborted
 after the index has been replaced.
 
-Test repo has one small, one moderate and one big change. The clone has
-the small and moderate change and will transition to non-inline storage when
-adding the big change.
+Test repo has commits a, b, c, D, where D is large (grows the revlog enough that it
+transitions to non-inline storage). The clone initially has changes a, b
+and will transition to non-inline storage when adding c, D.
+
+If the transaction adding c, D is rolled back, then we don't undo the revlog split,
+but truncate the index and the data to remove both c and D.
 
   $ hg init troffset-computation --config format.revlog-compression=none
   $ cd troffset-computation
   $ printf '%20d' '1' > file
-  $ hg commit -Aqm_
+  $ hg commit -Aqma
   $ printf '%1024d' '1' > file
-  $ hg commit -Aqm_
+  $ hg commit -Aqmb
+  $ printf '%20d' '1' > file
+  $ hg commit -Aqmc
   $ dd if=/dev/zero of=file bs=1k count=128 > /dev/null 2>&1
-  $ hg commit -Aqm_
+  $ hg commit -AqmD
+
   $ cd ..
 
   $ hg clone -r 1 troffset-computation troffset-computation-copy --config format.revlog-compression=none -q
@@ -59,7 +65,7 @@ Reference size:
   $ cat .hg/store/journal | tr -s '\000' ' ' | grep data/file | tail -1
   data/file.i 128
 
-The first file.i entry should match the size above.
+The first file.i entry should match the "Reference size" above.
 The first file.d entry is the temporary record during the split,
 the second entry after the split happened. The sum of the second file.d
 and the second file.i entry should match the first file.i entry.
@@ -76,11 +82,11 @@ and the second file.i entry should match
   .hg/store/data/file.d: size=1046
   .hg/store/data/file.i: size=128
   $ hg tip
-  changeset:   1:3ce491143aec
+  changeset:   1:cfa8d6e60429
   tag:         tip
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
-  summary:     _
+  summary:     b
   
   $ hg verify -q
    warning: revlog 'data/file.d' not in fncache!
@@ -126,11 +132,11 @@ where the data file is left as garbage.
   .hg/store/data/file.d: size=1046
   .hg/store/data/file.i: size=1174
   $ hg tip
-  changeset:   1:3ce491143aec
+  changeset:   1:cfa8d6e60429
   tag:         tip
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
-  summary:     _
+  summary:     b
   
   $ hg verify -q
   $ cd ..
@@ -158,11 +164,11 @@ Repeat the original test but let hg roll
   .hg/store/data/file.d: size=1046
   .hg/store/data/file.i: size=128
   $ hg tip
-  changeset:   1:3ce491143aec
+  changeset:   1:cfa8d6e60429
   tag:         tip
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
-  summary:     _
+  summary:     b
   
   $ hg verify -q
    warning: revlog 'data/file.d' not in fncache!
diff --git a/tests/test-unamend.t b/tests/test-unamend.t
--- a/tests/test-unamend.t
+++ b/tests/test-unamend.t
@@ -421,3 +421,27 @@ Rename a->b, then amend b->c, and workin
   A d
     b
   R b
+
+Try to unamend a merge
+
+  $ cd ..
+  $ hg init merge
+  $ cd merge
+  $ echo initial > initial
+  $ hg ci -Aqm initial
+  $ echo left > left
+  $ hg ci -Aqm left
+  $ hg co -q 0
+  $ echo right > right
+  $ hg ci -Aqm right
+  $ hg merge -q 1
+  $ hg ci -m merge
+  $ echo accidental > initial
+  $ hg st --rev 1 --rev .
+  A right
+  $ hg st --rev 2 --rev .
+  A left
+  $ hg amend
+  $ hg unamend
+  abort: cannot unamend merge changeset
+  [10]
diff --git a/tests/test-upgrade-repo.t b/tests/test-upgrade-repo.t
--- a/tests/test-upgrade-repo.t
+++ b/tests/test-upgrade-repo.t
@@ -1713,9 +1713,9 @@ Demonstrate that nothing to perform upgr
 
 Upgrade to dirstate-v2
 
-  $ hg debugformat -v --config format.exp-rc-dirstate-v2=1 | grep dirstate-v2
+  $ hg debugformat -v --config format.use-dirstate-v2=1 | grep dirstate-v2
   dirstate-v2:         no    yes      no
-  $ hg debugupgraderepo --config format.exp-rc-dirstate-v2=1 --run
+  $ hg debugupgraderepo --config format.use-dirstate-v2=1 --run
   upgrade will perform the following actions:
   
   requirements
@@ -1769,14 +1769,14 @@ Downgrade from dirstate-v2
 dirstate-v2: upgrade and downgrade from and empty repository:
 -------------------------------------------------------------
 
-  $ hg init --config format.exp-rc-dirstate-v2=no dirstate-v2-empty
+  $ hg init --config format.use-dirstate-v2=no dirstate-v2-empty
   $ cd dirstate-v2-empty
   $ hg debugformat | grep dirstate-v2
   dirstate-v2:         no
 
 upgrade
 
-  $ hg debugupgraderepo --run --config format.exp-rc-dirstate-v2=yes
+  $ hg debugupgraderepo --run --config format.use-dirstate-v2=yes
   upgrade will perform the following actions:
   
   requirements
@@ -1800,7 +1800,7 @@ upgrade
 
 downgrade
 
-  $ hg debugupgraderepo --run --config format.exp-rc-dirstate-v2=no
+  $ hg debugupgraderepo --run --config format.use-dirstate-v2=no
   upgrade will perform the following actions:
   
   requirements