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.
====================================
Test delta choice with sparse revlog
====================================
Sparse-revlog usually shows the most gain on Manifest. However, it is simpler
to general an appropriate file, so we test with a single file instead. The
goal is to observe intermediate snapshot being created.
We need a large enough file. Part of the content needs to be replaced
repeatedly while some of it changes rarely.
$ bundlepath="$TESTDIR/artifacts/cache/big-file-churn.hg"
$ expectedhash=`cat "$bundlepath".md5`
#if slow
$ if [ ! -f "$bundlepath" ]; then
> "$TESTDIR"/artifacts/scripts/generate-churning-bundle.py > /dev/null
> fi
#else
$ if [ ! -f "$bundlepath" ]; then
> echo 'skipped: missing artifact, run "'"$TESTDIR"'/artifacts/scripts/generate-churning-bundle.py"'
> exit 80
> fi
#endif
$ currenthash=`f -M "$bundlepath" | cut -d = -f 2`
$ if [ "$currenthash" != "$expectedhash" ]; then
> echo 'skipped: outdated artifact, md5 "'"$currenthash"'" expected "'"$expectedhash"'" run "'"$TESTDIR"'/artifacts/scripts/generate-churning-bundle.py"'
> exit 80
> fi
$ cat >> $HGRCPATH << EOF
> [format]
> sparse-revlog = yes
> maxchainlen = 15
> [storage]
> revlog.optimize-delta-parent-choice = yes
> revlog.reuse-external-delta = no
> EOF
$ hg init sparse-repo
$ cd sparse-repo
$ hg unbundle $bundlepath
adding changesets
adding manifests
adding file changes
added 5001 changesets with 5001 changes to 1 files (+89 heads)
new changesets 9706f5af64f4:d9032adc8114 (5001 drafts)
(run 'hg heads' to see heads, 'hg merge' to merge)
$ hg up
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
updated to "d9032adc8114: commit #5000"
89 other heads for branch "default"
$ hg log --stat -r 0:3
changeset: 0:9706f5af64f4
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: initial commit
SPARSE-REVLOG-TEST-FILE | 10500 ++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 10500 insertions(+), 0 deletions(-)
changeset: 1:724907deaa5e
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: commit #1
SPARSE-REVLOG-TEST-FILE | 1068 +++++++++++++++++++++++-----------------------
1 files changed, 534 insertions(+), 534 deletions(-)
changeset: 2:62c41bce3e5d
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: commit #2
SPARSE-REVLOG-TEST-FILE | 1068 +++++++++++++++++++++++-----------------------
1 files changed, 534 insertions(+), 534 deletions(-)
changeset: 3:348a9cbd6959
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: commit #3
SPARSE-REVLOG-TEST-FILE | 1068 +++++++++++++++++++++++-----------------------
1 files changed, 534 insertions(+), 534 deletions(-)
$ f -s .hg/store/data/*.d
.hg/store/data/_s_p_a_r_s_e-_r_e_v_l_o_g-_t_e_s_t-_f_i_l_e.d: size=58616973
$ hg debugrevlog *
format : 1
flags : generaldelta
revisions : 5001
merges : 625 (12.50%)
normal : 4376 (87.50%)
revisions : 5001
empty : 0 ( 0.00%)
text : 0 (100.00%)
delta : 0 (100.00%)
snapshot : 383 ( 7.66%)
lvl-0 : 3 ( 0.06%)
lvl-1 : 18 ( 0.36%)
lvl-2 : 62 ( 1.24%)
lvl-3 : 108 ( 2.16%)
lvl-4 : 191 ( 3.82%)
lvl-5 : 1 ( 0.02%)
deltas : 4618 (92.34%)
revision size : 58616973
snapshot : 9247844 (15.78%)
lvl-0 : 539532 ( 0.92%)
lvl-1 : 1467743 ( 2.50%)
lvl-2 : 1873820 ( 3.20%)
lvl-3 : 2326874 ( 3.97%)
lvl-4 : 3029118 ( 5.17%)
lvl-5 : 10757 ( 0.02%)
deltas : 49369129 (84.22%)
chunks : 5001
0x28 : 5001 (100.00%)
chunks size : 58616973
0x28 : 58616973 (100.00%)
avg chain length : 9
max chain length : 15
max chain reach : 27366701
compression ratio : 29
uncompressed data size (min/max/avg) : 346468 / 346472 / 346471
full revision size (min/max/avg) : 179288 / 180786 / 179844
inter-snapshot size (min/max/avg) : 10757 / 169507 / 22916
level-1 (min/max/avg) : 13905 / 169507 / 81541
level-2 (min/max/avg) : 10887 / 83873 / 30222
level-3 (min/max/avg) : 10911 / 43047 / 21545
level-4 (min/max/avg) : 10838 / 21390 / 15859
level-5 (min/max/avg) : 10757 / 10757 / 10757
delta size (min/max/avg) : 9672 / 108072 / 10690
deltas against prev : 3906 (84.58%)
where prev = p1 : 3906 (100.00%)
where prev = p2 : 0 ( 0.00%)
other : 0 ( 0.00%)
deltas against p1 : 649 (14.05%)
deltas against p2 : 63 ( 1.36%)
deltas against other : 0 ( 0.00%)
Test `debug-delta-find`
-----------------------
$ ls -1
SPARSE-REVLOG-TEST-FILE
$ hg debugdeltachain SPARSE-REVLOG-TEST-FILE | grep snap | tail -1
4971 4970 -1 3 5 4930 snap 19179 346472 427596 1.23414 15994877 15567281 36.40652 427596 179288 1.00000 5
$ hg debug-delta-find SPARSE-REVLOG-TEST-FILE 4971
DBG-DELTAS-SEARCH: SEARCH rev=4971
DBG-DELTAS-SEARCH: ROUND #1 - 2 candidates - search-down
DBG-DELTAS-SEARCH: CANDIDATE: rev=4962
DBG-DELTAS-SEARCH: type=snapshot-4
DBG-DELTAS-SEARCH: size=18296
DBG-DELTAS-SEARCH: base=4930
DBG-DELTAS-SEARCH: uncompressed-delta-size=30377
DBG-DELTAS-SEARCH: delta-search-time=* (glob)
DBG-DELTAS-SEARCH: DELTA: length=16872 (BAD)
DBG-DELTAS-SEARCH: CANDIDATE: rev=4971
DBG-DELTAS-SEARCH: type=snapshot-4
DBG-DELTAS-SEARCH: size=19179
DBG-DELTAS-SEARCH: base=4930
DBG-DELTAS-SEARCH: TOO-HIGH
DBG-DELTAS-SEARCH: ROUND #2 - 1 candidates - search-down
DBG-DELTAS-SEARCH: CANDIDATE: rev=4930
DBG-DELTAS-SEARCH: type=snapshot-3
DBG-DELTAS-SEARCH: size=39228
DBG-DELTAS-SEARCH: base=4799
DBG-DELTAS-SEARCH: uncompressed-delta-size=33050
DBG-DELTAS-SEARCH: delta-search-time=* (glob)
DBG-DELTAS-SEARCH: DELTA: length=19179 (GOOD)
DBG-DELTAS-SEARCH: ROUND #3 - 1 candidates - refine-down
DBG-DELTAS-SEARCH: CONTENDER: rev=4930 - length=19179
DBG-DELTAS-SEARCH: CANDIDATE: rev=4799
DBG-DELTAS-SEARCH: type=snapshot-2
DBG-DELTAS-SEARCH: size=50213
DBG-DELTAS-SEARCH: base=4623
DBG-DELTAS-SEARCH: uncompressed-delta-size=82661
DBG-DELTAS-SEARCH: delta-search-time=* (glob)
DBG-DELTAS-SEARCH: DELTA: length=49132 (BAD)
DBG-DELTAS: FILELOG:SPARSE-REVLOG-TEST-FILE: rev=4971: search-rounds=3 try-count=3 - delta-type=snapshot snap-depth=4 - p1-chain-length=15 p2-chain-length=-1 - duration=* (glob)
$ cd ..