dirstate-v2: add check of parent/child nodes being related when writing
This stems from a corruption seen in a private repository. We're not sure
of the source of the corruption, and it's very possible that we're seeing
compounded effects of multiple writes on a corrupted dirstate.
Adding this check is not expensive in itself and large writes of the dirstate
are not common.
This change does not catch this problem at the root node, the next one will.
$ hg init repo
$ cd repo
$ touch a
$ hg add a
$ hg commit -m "Added a"
$ touch main
$ hg add main
$ hg commit -m "Added main"
$ hg checkout 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
'main' should be gone:
$ ls -A
.hg
a
$ touch side1
$ hg add side1
$ hg commit -m "Added side1"
created new head
$ touch side2
$ hg add side2
$ hg commit -m "Added side2"
$ hg log
changeset: 3:91ebc10ed028
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Added side2
changeset: 2:b932d7dbb1e1
parent: 0:c2eda428b523
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Added side1
changeset: 1:71a760306caf
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Added main
changeset: 0:c2eda428b523
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Added a
$ hg heads
changeset: 3:91ebc10ed028
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Added side2
changeset: 1:71a760306caf
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Added main
$ ls -A
.hg
a
side1
side2
$ hg update --debug -C 1
resolving manifests
branchmerge: False, force: True, partial: False
ancestor: 91ebc10ed028+, local: 91ebc10ed028+, remote: 71a760306caf
side1: other deleted -> r
removing side1
side2: other deleted -> r
removing side2
main: remote created -> g
getting main
1 files updated, 0 files merged, 2 files removed, 0 files unresolved
$ ls -A
.hg
a
main