diff tests/test-topic-merge.t @ 5601:3946ee4ee3ae

topic: add a `exp….topic.linear-merge` option to allow some oedipus

If this option is set to `from-branch`, a user can call `hg merge some-topic`
from a bare branch even if `some-topic` is a direct descendant of the current
working copy parents. This was previously denied if the changesets was on the
same branch, since the result would be an "oedipus merge".

Some user have been requesting this, and this type of merge is one of Gitlab
standard way of merging a "Merge Request". That new option will unlock issue
`heptapod#200` and make this mode available for those who wants it.

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/test-topic-merge.t	Wed Oct 14 15:48:37 2020 +0200
@@ -0,0 +1,175 @@
+==========================================================
+Testing the ability to control merge behavior around topic
+==========================================================
+
+Especially, we want to test mode allowing the creation of merge that will
+eventually become "oedipus" merge.
+
+  $ . "$TESTDIR/testlib/topic_setup.sh"
+  $ . "$TESTDIR/testlib/common.sh"
+
+
+
+Setup a test repository
+=======================
+
+  $ hg init test-repo
+  $ cd test-repo
+  $ mkcommit root
+  $ mkcommit default-1
+  $ mkcommit default-2
+  $ hg up 'desc("default-2")'
+  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ hg topic test-topic
+  marked working directory as topic: test-topic
+  $ mkcommit topic-1
+  active topic 'test-topic' grew its first changeset
+  (see 'hg help topics' for more information)
+  $ mkcommit topic-2
+  $ hg up null
+  0 files updated, 0 files merged, 5 files removed, 0 files unresolved
+  $ hg log -G
+  o  changeset:   4:c3ec1ef2bf00
+  |  tag:         tip
+  |  topic:       test-topic
+  |  user:        test
+  |  date:        Thu Jan 01 00:00:00 1970 +0000
+  |  summary:     topic-2
+  |
+  o  changeset:   3:3300cececc85
+  |  topic:       test-topic
+  |  user:        test
+  |  date:        Thu Jan 01 00:00:00 1970 +0000
+  |  summary:     topic-1
+  |
+  o  changeset:   2:b05d997f9ab0
+  |  user:        test
+  |  date:        Thu Jan 01 00:00:00 1970 +0000
+  |  summary:     default-2
+  |
+  o  changeset:   1:ccab697ce421
+  |  user:        test
+  |  date:        Thu Jan 01 00:00:00 1970 +0000
+  |  summary:     default-1
+  |
+  o  changeset:   0:1e4be0697311
+     user:        test
+     date:        Thu Jan 01 00:00:00 1970 +0000
+     summary:     root
+  
+
+Test that the merge is rejected by default
+==========================================
+
+from the topic
+
+  $ hg up test-topic
+  switching to topic test-topic
+  5 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ hg merge default
+  abort: merging with a working directory ancestor has no effect
+  [255]
+
+from the bare branch
+
+  $ hg up default
+  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
+  $ hg merge test-topic
+  abort: nothing to merge
+  (use 'hg update' or check 'hg heads')
+  [255]
+
+Test that the merge is rejected if set to reject
+================================================
+
+Actually, this also work with any unvalid value, but:
+
+- the default value might change in the future,
+- this make sure we read the config right.
+
+Same result when setting the config to be strict
+
+  $ cat >> .hg/hgrc << EOF
+  > [experimental]
+  > topic.linear-merge = reject
+  > EOF
+
+from the topic
+
+  $ hg up test-topic
+  switching to topic test-topic
+  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ hg merge default
+  abort: merging with a working directory ancestor has no effect
+  [255]
+
+from the bare branch
+
+  $ hg up default
+  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
+  $ hg merge test-topic
+  abort: nothing to merge
+  (use 'hg update' or check 'hg heads')
+  [255]
+
+Test that the merge is accepted if configured to allow them
+===========================================================
+
+  $ cat >> .hg/hgrc << EOF
+  > [experimental]
+  > topic.linear-merge = allow-from-bare-branch
+  > EOF
+
+from the topic, this is rejected since the resulting merge would be in the topic itself
+
+  $ hg up test-topic
+  switching to topic test-topic
+  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ hg merge default
+  abort: merging with a working directory ancestor has no effect
+  [255]
+
+from the bare branch this is allowed since the resulting merge will be in the branch
+
+  $ hg up default
+  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
+  $ hg merge test-topic --traceback
+  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  (branch merge, don't forget to commit)
+  $ hg ci -m "How dreadful the knowledge of the truth can be when there's no help in truth."
+  $ hg log -G
+  @    changeset:   5:42ca2e8cb810
+  |\   tag:         tip
+  | |  parent:      2:b05d997f9ab0
+  | |  parent:      4:c3ec1ef2bf00
+  | |  user:        test
+  | |  date:        Thu Jan 01 00:00:00 1970 +0000
+  | |  summary:     How dreadful the knowledge of the truth can be when there's no help in truth.
+  | |
+  | o  changeset:   4:c3ec1ef2bf00
+  | |  topic:       test-topic
+  | |  user:        test
+  | |  date:        Thu Jan 01 00:00:00 1970 +0000
+  | |  summary:     topic-2
+  | |
+  | o  changeset:   3:3300cececc85
+  |/   topic:       test-topic
+  |    user:        test
+  |    date:        Thu Jan 01 00:00:00 1970 +0000
+  |    summary:     topic-1
+  |
+  o  changeset:   2:b05d997f9ab0
+  |  user:        test
+  |  date:        Thu Jan 01 00:00:00 1970 +0000
+  |  summary:     default-2
+  |
+  o  changeset:   1:ccab697ce421
+  |  user:        test
+  |  date:        Thu Jan 01 00:00:00 1970 +0000
+  |  summary:     default-1
+  |
+  o  changeset:   0:1e4be0697311
+     user:        test
+     date:        Thu Jan 01 00:00:00 1970 +0000
+     summary:     root
+