run-tests: collect aggregate code coverage
Before this patch, every Python process during a code coverage run was
writing coverage data to the same file. I'm not sure if the coverage
package even tries to obtain a lock on the file. But what I do know is
there was some last write wins leading to loss of code coverage data, at
least with -j > 1.
This patch changes the code coverage mechanism to be multiple process
safe. The mechanism for initializing code coverage via sitecustomize.py
has been tweaked so each Python process will produce a separate coverage
data file on disk. Unless two processes generate the same random value,
there are no race conditions writing to the same file. At the end of the
test run, we combine all written files into an aggregate report.
On my machine, running the full test suite produces a little over
20,000 coverage files consuming ~350 MB. As you can imagine, it takes
several seconds to load and merge these coverage files. But when it is
done, you have an accurate picture of the aggregate code coverage for the
entire test suite, which is ~60% line coverage.
$ echo "[extensions]" >> $HGRCPATH
$ echo "mq=" >> $HGRCPATH
$ hg init foo
$ cd foo
$ echo a > a
$ hg ci -qAm a
Default queue:
$ hg qqueue
patches (active)
$ echo b > a
$ hg qnew -fgDU somestuff
Applied patches in default queue:
$ hg qap
somestuff
Try to change patch (create succeeds, switch fails):
$ hg qqueue foo --create
abort: new queue created, but cannot make active as patches are applied
[255]
$ hg qqueue
foo
patches (active)
Empty default queue:
$ hg qpop
popping somestuff
patch queue now empty
Switch queue:
$ hg qqueue foo
$ hg qqueue
foo (active)
patches
List queues, quiet:
$ hg qqueue --quiet
foo
patches
Fail creating queue with already existing name:
$ hg qqueue --create foo
abort: queue "foo" already exists
[255]
$ hg qqueue
foo (active)
patches
Create new queue for rename:
$ hg qqueue --create bar
$ hg qqueue
bar (active)
foo
patches
Rename queue, same name:
$ hg qqueue --rename bar
abort: can't rename "bar" to its current name
[255]
Rename queue to existing:
$ hg qqueue --rename foo
abort: queue "foo" already exists
[255]
Rename queue:
$ hg qqueue --rename buz
$ hg qqueue
buz (active)
foo
patches
Switch back to previous queue:
$ hg qqueue foo
$ hg qqueue --delete buz
$ hg qqueue
foo (active)
patches
Create queue for purge:
$ hg qqueue --create purge-me
$ hg qqueue
foo
patches
purge-me (active)
Create patch for purge:
$ hg qnew patch-purge-me
$ ls -1d .hg/patches-purge-me 2>/dev/null || true
.hg/patches-purge-me
$ hg qpop -a
popping patch-purge-me
patch queue now empty
Purge queue:
$ hg qqueue foo
$ hg qqueue --purge purge-me
$ hg qqueue
foo (active)
patches
$ ls -1d .hg/patches-purge-me 2>/dev/null || true
Unapplied patches:
$ hg qun
$ echo c > a
$ hg qnew -fgDU otherstuff
Fail switching back:
$ hg qqueue patches
abort: new queue created, but cannot make active as patches are applied
[255]
Fail deleting current:
$ hg qqueue foo --delete
abort: cannot delete currently active queue
[255]
Switch back and delete foo:
$ hg qpop -a
popping otherstuff
patch queue now empty
$ hg qqueue patches
$ hg qqueue foo --delete
$ hg qqueue
patches (active)
Tricky cases:
$ hg qqueue store --create
$ hg qnew journal
$ hg qqueue
patches
store (active)
$ hg qpop -a
popping journal
patch queue now empty
$ hg qqueue patches
$ hg qun
somestuff
Invalid names:
$ hg qqueue test/../../bar --create
abort: invalid queue name, may not contain the characters ":\/."
[255]
$ hg qqueue . --create
abort: invalid queue name, may not contain the characters ":\/."
[255]
$ cd ..