view tests/test-merge-closedheads.out @ 10189:e451e599fbcf

patch: support diff data loss detection and upgrade

In worst case, generating diff in upgrade mode can be two times more expensive
than generating it in git mode directly: we may have to regenerate the whole
diff again whenever a git feature is detected. Also, the first diff attempt is
completely buffered instead of being streamed. That said, even without having
profiled it yet, I am convinced we can fast-path the upgrade mode if necessary
were it to be used in regular diff commands, and not only in mq where avoiding
data loss is worth the price.

adding foo
adding bar
adding baz
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
created new head
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
created new head
% fail with three heads
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
abort: branch 'default' has 3 heads - please merge with an explicit rev
% close one of the heads
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
% succeed with two open heads
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)