--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hgext3rd/evolve/obshashtree.py	Mon May 27 02:19:48 2019 +0200
@@ -0,0 +1,98 @@
+#############################
+### Tree Hash computation ###
+#############################
+
+# Status: dropable
+#
+# This module don't need to be upstreamed and can be dropped if its maintenance
+# become a burden
+
+import hashlib
+
+from mercurial import (
+    error,
+    node,
+    obsolete,
+)
+
+from mercurial.i18n import _
+
+from . import (
+    compat,
+    exthelper,
+)
+
+eh = exthelper.exthelper()
+
+# Dash computed from a given changesets using all markers relevant to it and
+# the obshash of its parents.  This is similar to what happend for changeset
+# node where the parent is used in the computation
+@eh.command(
+    'debugobsrelsethashtree',
+    [('', 'v0', None, 'hash on marker format "0"'),
+     ('', 'v1', None, 'hash on marker format "1" (default)')], _(''))
+def debugobsrelsethashtree(ui, repo, v0=False, v1=False):
+    """display Obsolete markers, Relevant Set, Hash Tree
+    changeset-node obsrelsethashtree-node
+
+    It computed form the "obs-hash-tree" value of its parent and markers
+    relevant to the changeset itself.
+
+    The obs-hash-tree is no longer used for any user facing logic. However the
+    debug command stayed as an inspection tool. It does not seem supseful to
+    upstream the command with the rest of evolve. We can safely drop it."""
+    if v0 and v1:
+        raise error.Abort('cannot only specify one format')
+    elif v0:
+        treefunc = _obsrelsethashtreefm0
+    else:
+        treefunc = _obsrelsethashtreefm1
+
+    for chg, obs in treefunc(repo):
+        ui.status('%s %s\n' % (node.hex(chg), node.hex(obs)))
+
+def _obsrelsethashtreefm0(repo):
+    return _obsrelsethashtree(repo, obsolete._fm0encodeonemarker)
+
+def _obsrelsethashtreefm1(repo):
+    return _obsrelsethashtree(repo, obsolete._fm1encodeonemarker)
+
+def _obsrelsethashtree(repo, encodeonemarker):
+    cache = []
+    unfi = repo.unfiltered()
+    markercache = {}
+    compat.progress(repo.ui, _("preparing locally"), 0, total=len(unfi),
+                    unit=_("changesets"))
+    for i in unfi:
+        ctx = unfi[i]
+        entry = 0
+        sha = hashlib.sha1()
+        # add data from p1
+        for p in ctx.parents():
+            p = p.rev()
+            if p < 0:
+                p = node.nullid
+            else:
+                p = cache[p][1]
+            if p != node.nullid:
+                entry += 1
+                sha.update(p)
+        tmarkers = repo.obsstore.relevantmarkers([ctx.node()])
+        if tmarkers:
+            bmarkers = []
+            for m in tmarkers:
+                if m not in markercache:
+                    markercache[m] = encodeonemarker(m)
+                bmarkers.append(markercache[m])
+            bmarkers.sort()
+            for m in bmarkers:
+                entry += 1
+                sha.update(m)
+        if entry:
+            cache.append((ctx.node(), sha.digest()))
+        else:
+            cache.append((ctx.node(), node.nullid))
+        compat.progress(repo.ui, _("preparing locally"), i, total=len(unfi),
+                        unit=_("changesets"))
+    compat.progress(repo.ui, _("preparing locally"), None)
+    return cache