test: add test-transaction-rollback-on-sigpipe.t demonstrating py3 regression
When an hg push is interrupted with C-c, the remote [hg serve] command
receives SIGPIPE.
If a pretxnchangegroup hook fails, the remote hg then tries to
rollback the transaction. It begins by printing "transaction
abort!\n". This returns EPIPE, but ui.py ignores that error.
In python3 (but not python2), this "transaction abort!\n" message
stays in a buffer, so future flushes of stderr will try to print the
message again, and so those flushes will also hit EPIPE.
This test demonstrates such a case where this EPIPE causes the
transaction rollback to fail, leaving behind an abandoned transaction.
Differential Revision: https://phab.mercurial-scm.org/D9151
$ hg init
$ echo foo > a
$ hg add a
$ hg commit -m "1"
$ echo bar > b
$ hg add b
$ hg remove a
Should show a removed and b added:
$ hg status
A b
R a
$ hg revert --all
forgetting b
undeleting a
Should show b unknown and a back to normal:
$ hg status
? b
$ rm b
$ hg co -C 0
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo foo-a > a
$ hg commit -m "2a"
$ hg co -C 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo foo-b > a
$ hg commit -m "2b"
created new head
$ HGMERGE=true hg merge 1
merging a
0 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
Should show foo-b:
$ cat a
foo-b
$ echo bar > b
$ hg add b
$ rm a
$ hg remove a
Should show a removed and b added:
$ hg status
A b
R a
Revert should fail:
$ hg revert
abort: uncommitted merge with no revision specified
(use 'hg update' or see 'hg help revert')
[255]
Revert should be ok now:
$ hg revert -r2 --all
forgetting b
undeleting a
Should show b unknown and a marked modified (merged):
$ hg status
M a
? b
Should show foo-b:
$ cat a
foo-b