--- a/mercurial/revlogutils/nodemap.py Thu Feb 27 15:42:04 2020 +0100
+++ b/mercurial/revlogutils/nodemap.py Thu Feb 27 16:32:43 2020 +0100
@@ -38,10 +38,12 @@
return None
offset += S_VERSION.size
headers = S_HEADER.unpack(pdata[offset : offset + S_HEADER.size])
- uid_size, tip_rev, data_length, data_unused = headers
+ uid_size, tip_rev, data_length, data_unused, tip_node_size = headers
offset += S_HEADER.size
docket = NodeMapDocket(pdata[offset : offset + uid_size])
+ offset += uid_size
docket.tip_rev = tip_rev
+ docket.tip_node = pdata[offset : offset + tip_node_size]
docket.data_length = data_length
docket.data_unused = data_unused
@@ -164,6 +166,7 @@
new_data = util.buffer(util.mmapread(fd, len(data)))
target_docket.data_length = len(data)
target_docket.tip_rev = revlog.tiprev()
+ target_docket.tip_node = revlog.node(target_docket.tip_rev)
# EXP-TODO: if this is a cache, this should use a cache vfs, not a
# store vfs
with revlog.opener(revlog.nodemap_file, b'w', atomictemp=True) as fp:
@@ -214,7 +217,7 @@
# version 0 is experimental, no BC garantee, do no use outside of tests.
ONDISK_VERSION = 0
S_VERSION = struct.Struct(">B")
-S_HEADER = struct.Struct(">BQQQ")
+S_HEADER = struct.Struct(">BQQQQ")
ID_SIZE = 8
@@ -242,6 +245,15 @@
# the tipmost revision stored in the data file. This revision and all
# revision before it are expected to be encoded in the data file.
self.tip_rev = None
+ # the node of that tipmost revision, if it mismatch the current index
+ # data the docket is not valid for the current index and should be
+ # discarded.
+ #
+ # note: this method is not perfect as some destructive operation could
+ # preserve the same tip_rev + tip_node while altering lower revision.
+ # However this multiple other caches have the same vulnerability (eg:
+ # brancmap cache).
+ self.tip_node = None
# the size (in bytes) of the persisted data to encode the nodemap valid
# for `tip_rev`.
# - data file shorter than this are corrupted,
@@ -254,6 +266,7 @@
def copy(self):
new = NodeMapDocket(uid=self.uid)
new.tip_rev = self.tip_rev
+ new.tip_node = self.tip_node
new.data_length = self.data_length
new.data_unused = self.data_unused
return new
@@ -281,9 +294,11 @@
self.tip_rev,
self.data_length,
self.data_unused,
+ len(self.tip_node),
)
data.append(S_HEADER.pack(*headers))
data.append(self.uid)
+ data.append(self.tip_node)
return b''.join(data)