amend: add noise in extra to avoid creating obsolescence cycle (
issue3664)
Obsolescence cycle are bad and should be avoided as much as possible. The
current amend implemented touch changeset meta data as few as possible. This
make is easy for amend to result in the same node than a precursors. We add some
deterministic noise in extra to avoid this. In practice, the hex of the amended
changeset is stored in 'amend_source' extra key.
http://mercurial.selenic.com/bts/issue1175
$ hg init
$ touch a
$ hg ci -Am0
adding a
$ hg mv a a1
$ hg ci -m1
$ hg co 0
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg mv a a2
$ hg up
note: possible conflict - a was renamed multiple times to:
a2
a1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg ci -m2
$ touch a
$ hg ci -Am3
adding a
$ hg mv a b
$ hg ci -Am4 a
$ hg ci --debug --traceback -Am5 b
b
b: searching for copy revision for a
b: copy a:b80de5d138758541c5f05265ad144ab9fa86d1db
committed changeset 5:89e8e4be0de296fa3d6dd7825ccc44d7dc0f1f3b
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
4 files, 6 changesets, 4 total revisions
$ hg export --git tip
# HG changeset patch
# User test
# Date 0 0
# Node ID 89e8e4be0de296fa3d6dd7825ccc44d7dc0f1f3b
# Parent 7fc86ba705e717a721dbc361bf8c9bc05a18ca2f
5
diff --git a/b b/b
new file mode 100644