procutil: make stream detection in make_line_buffered more correct and strict
In make_line_buffered(), we don’t want to wrap the stream if we know that lines
get flushed to the underlying raw stream already.
Previously, the heuristic was too optimistic. It assumed that any stream which
is not an instance of io.BufferedIOBase doesn’t need wrapping. However, there
are buffered streams that aren’t instances of io.BufferedIOBase, like
Mercurial’s own winstdout.
The new logic is different in two ways:
First, only for the check, if unwraps any combination of WriteAllWrapper and
winstdout.
Second, it skips wrapping the stream only if it is an instance of io.RawIOBase
(or already wrapped). If it is an instance of io.BufferedIOBase, it gets
wrapped. In any other case, the function raises an exception. This ensures
that, if an unknown stream is passed or we add another wrapper in the future,
we don’t wrap the stream if it’s already line buffered or not wrap the stream
if it’s not line buffered. In fact, this was already helpful during development
of this change. Without it, I possibly would have forgot that WriteAllWrapper
needs to be ignored for the check, leading to unnecessary wrapping if stdout is
unbuffered.
The alternative would have been to always wrap unknown streams. However, I
don’t think that anyone would benefit from being less strict. We can expect
streams from the standard library to be subclassing either io.RawIOBase or
io.BufferedIOBase, so running Mercurial in the standard way should not regress
by this change. Py2exe might replace sys.stdout and sys.stderr, but that
currently breaks Mercurial anyway and also these streams don’t claim to be
interactive, so this function is not called for them.
$ cat >> $HGRCPATH << EOF
> [extensions]
> blackbox=
> rebase=
> mock=$TESTDIR/mockblackbox.py
>
> [blackbox]
> track = command, commandfinish, tagscache
>
> [experimental]
> evolution.createmarkers=True
> EOF
Create a repo with some tags
$ hg init repo
$ cd repo
$ echo initial > foo
$ hg -q commit -A -m initial
$ hg tag -m 'test tag' test1
$ echo first > first
$ hg -q commit -A -m first
$ hg tag -m 'test2 tag' test2
$ hg -q up -r 0
$ echo newhead > newhead
$ hg commit -A -m newhead
adding newhead
created new head
$ hg tag -m 'test head 2 tag' head2
$ hg log -G -T '{rev}:{node|short} {tags} {desc}\n'
@ 5:2942a772f72a tip test head 2 tag
|
o 4:042eb6bfcc49 head2 newhead
|
| o 3:c3cb30f2d2cd test2 tag
| |
| o 2:d75775ffbc6b test2 first
| |
| o 1:5f97d42da03f test tag
|/
o 0:55482a6fb4b1 test1 initial
Trigger tags cache population by doing something that accesses tags info
$ hg tags
tip 5:2942a772f72a
head2 4:042eb6bfcc49
test2 2:d75775ffbc6b
test1 0:55482a6fb4b1
$ cat .hg/cache/tags2-visible
5 2942a772f72a444bef4bef13874d515f50fa27b6
042eb6bfcc4909bad84a1cbf6eb1ddf0ab587d41 head2
55482a6fb4b1881fa8f746fd52cf6f096bb21c89 test1
d75775ffbc6bca1794d300f5571272879bd280da test2
Hiding a non-tip changeset should change filtered hash and cause tags recompute
$ hg debugobsolete -d '0 0' c3cb30f2d2cd0aae008cc91a07876e3c5131fd22 -u dummyuser
1 new obsolescence markers
obsoleted 1 changesets
$ hg tags
tip 5:2942a772f72a
head2 4:042eb6bfcc49
test1 0:55482a6fb4b1
$ cat .hg/cache/tags2-visible
5 2942a772f72a444bef4bef13874d515f50fa27b6 f34fbc9a9769ba9eff5aff3d008a6b49f85c08b1
042eb6bfcc4909bad84a1cbf6eb1ddf0ab587d41 head2
55482a6fb4b1881fa8f746fd52cf6f096bb21c89 test1
$ hg blackbox -l 5
1970-01-01 00:00:00.000 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> tags
1970-01-01 00:00:00.000 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> 2/2 cache hits/lookups in * seconds (glob)
1970-01-01 00:00:00.000 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> writing .hg/cache/tags2-visible with 2 tags
1970-01-01 00:00:00.000 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> tags exited 0 after * seconds (glob)
1970-01-01 00:00:00.000 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> blackbox -l 5
Hiding another changeset should cause the filtered hash to change
$ hg debugobsolete -d '0 0' d75775ffbc6bca1794d300f5571272879bd280da -u dummyuser
1 new obsolescence markers
obsoleted 1 changesets
$ hg debugobsolete -d '0 0' 5f97d42da03fd56f3b228b03dfe48af5c0adf75b -u dummyuser
1 new obsolescence markers
obsoleted 1 changesets
$ hg tags
tip 5:2942a772f72a
head2 4:042eb6bfcc49
$ cat .hg/cache/tags2-visible
5 2942a772f72a444bef4bef13874d515f50fa27b6 2fce1eec33263d08a4d04293960fc73a555230e4
042eb6bfcc4909bad84a1cbf6eb1ddf0ab587d41 head2
$ hg blackbox -l 5
1970-01-01 00:00:00.000 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> tags
1970-01-01 00:00:00.000 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> 1/1 cache hits/lookups in * seconds (glob)
1970-01-01 00:00:00.000 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> writing .hg/cache/tags2-visible with 1 tags
1970-01-01 00:00:00.000 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> tags exited 0 after * seconds (glob)
1970-01-01 00:00:00.000 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> blackbox -l 5
Resolving tags on an unfiltered repo writes a separate tags cache
$ hg --hidden tags
tip 5:2942a772f72a
head2 4:042eb6bfcc49
test2 2:d75775ffbc6b
test1 0:55482a6fb4b1
$ cat .hg/cache/tags2
5 2942a772f72a444bef4bef13874d515f50fa27b6
042eb6bfcc4909bad84a1cbf6eb1ddf0ab587d41 head2
55482a6fb4b1881fa8f746fd52cf6f096bb21c89 test1
d75775ffbc6bca1794d300f5571272879bd280da test2
$ hg blackbox -l 5
1970-01-01 00:00:00.000 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> --hidden tags
1970-01-01 00:00:00.000 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> 2/2 cache hits/lookups in * seconds (glob)
1970-01-01 00:00:00.000 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> writing .hg/cache/tags2 with 3 tags
1970-01-01 00:00:00.000 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> --hidden tags exited 0 after * seconds (glob)
1970-01-01 00:00:00.000 bob @2942a772f72a444bef4bef13874d515f50fa27b6 (5000)> blackbox -l 5