revlog: introduce a mandatory `_writing` context to update revlog content
Before this change, various revlog methods where managing the opening and
closing of the revlog files manually and passing the file descriptor alors the
call path. To simplify the tracking of the write operation by a future docket,
we need something more organised. As a result, we introduce a `revlog._writing`
context manager that will wrap each revlog update operation. The file
descriptor are kept in the existing `revlog._writinghandles` parameter that
was already used by the `addgroup` logic.
All this change is internal to the revlog only, the "public" interface is not
affected. The `addrevision` and `addgroup` logic are still responsible for
setup up this context. However this new context give us multiple benefits:
* all writer use a same, unified, logic,
* this context is programmatically enforced,
* each write "session" as a clearly identified start and end.
The post-pull sidedata update logic is still doing writing by end and will be
adjusted in a later changesets.
This change affect the concurrency checker test, because register the state of
the file in the transaction sooner in `addrevision` (about as early as what
`addgroup` would do), so the abort is rollbacking the other commit. I don't want
to weaken the current main logic.
Differential Revision: https://phab.mercurial-scm.org/D10605
#require no-windows
$ . "$TESTDIR/remotefilelog-library.sh"
$ hg init master
$ cd master
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> server=True
> EOF
$ echo x > x
$ hg commit -qAm x
$ echo y > y
$ rm x
$ hg commit -qAm DxAy
$ echo yy > y
$ hg commit -qAm y
$ cd ..
$ hgcloneshallow ssh://user@dummy/master shallow -q
1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
# Set the prefetchdays config to zero so that all commits are prefetched
# no matter what their creation date is.
$ cd shallow
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> prefetchdays=0
> EOF
$ cd ..
# Prefetch all data and repack
$ cd shallow
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> bgprefetchrevs=all()
> EOF
$ hg prefetch
2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob)
$ hg repack
$ find $CACHEDIR | sort | egrep ".datapack|.histpack"
$TESTTMP/hgcache/master/packs/7bcd2d90b99395ca43172a0dd24e18860b2902f9.histpack
$TESTTMP/hgcache/master/packs/dc8f8fdc76690ce27791ce9f53a18da379e50d37.datapack
# Ensure that all file versions were prefetched
$ hg debugdatapack `ls -ct $TESTTMP/hgcache/master/packs/*.datapack | head -n 1`
$TESTTMP/hgcache/master/packs/dc8f8fdc76690ce27791ce9f53a18da379e50d37:
x:
Node Delta Base Delta Length Blob Size
1406e7411862 000000000000 2 2
Total: 2 2 (0.0% bigger)
y:
Node Delta Base Delta Length Blob Size
50dbc4572b8e 000000000000 3 3
076f5e2225b3 50dbc4572b8e 14 2
Total: 17 5 (240.0% bigger)
# Test garbage collection during repack
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> bgprefetchrevs=tip
> gcrepack=True
> nodettl=86400
> EOF
$ hg repack
$ find $CACHEDIR | sort | egrep ".datapack|.histpack"
$TESTTMP/hgcache/master/packs/7bcd2d90b99395ca43172a0dd24e18860b2902f9.histpack
$TESTTMP/hgcache/master/packs/a4e1d094ec2aee8a08a4d6d95a13c634cc7d7394.datapack
# Ensure that file 'x' was garbage collected. It should be GCed because it is not in the keepset
# and is old (commit date is 0.0 in tests). Ensure that file 'y' is present as it is in the keepset.
$ hg debugdatapack `ls -ct $TESTTMP/hgcache/master/packs/*.datapack | head -n 1`
$TESTTMP/hgcache/master/packs/a4e1d094ec2aee8a08a4d6d95a13c634cc7d7394:
y:
Node Delta Base Delta Length Blob Size
50dbc4572b8e 000000000000 3 3
Total: 3 3 (0.0% bigger)
# Prefetch all data again and repack for later garbage collection
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> bgprefetchrevs=all()
> EOF
$ hg prefetch
2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob)
$ hg repack
$ find $CACHEDIR | sort | egrep ".datapack|.histpack"
$TESTTMP/hgcache/master/packs/7bcd2d90b99395ca43172a0dd24e18860b2902f9.histpack
$TESTTMP/hgcache/master/packs/dc8f8fdc76690ce27791ce9f53a18da379e50d37.datapack
# Ensure that all file versions were prefetched
$ hg debugdatapack `ls -ct $TESTTMP/hgcache/master/packs/*.datapack | head -n 1`
$TESTTMP/hgcache/master/packs/dc8f8fdc76690ce27791ce9f53a18da379e50d37:
x:
Node Delta Base Delta Length Blob Size
1406e7411862 000000000000 2 2
Total: 2 2 (0.0% bigger)
y:
Node Delta Base Delta Length Blob Size
50dbc4572b8e 000000000000 3 3
076f5e2225b3 50dbc4572b8e 14 2
Total: 17 5 (240.0% bigger)
# Test garbage collection during repack. Ensure that new files are not removed even though they are not in the keepset
# For the purposes of the test the TTL of a file is set to current time + 100 seconds. i.e. all commits in tests have
# a date of 1970 and therefore to prevent garbage collection we have to set nodettl to be farther from 1970 than we are now.
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> bgprefetchrevs=
> nodettl=$(($(date +%s) + 100))
> EOF
$ hg repack
$ find $CACHEDIR | sort | egrep ".datapack|.histpack"
$TESTTMP/hgcache/master/packs/7bcd2d90b99395ca43172a0dd24e18860b2902f9.histpack
$TESTTMP/hgcache/master/packs/dc8f8fdc76690ce27791ce9f53a18da379e50d37.datapack
# Ensure that all file versions were prefetched
$ hg debugdatapack `ls -ct $TESTTMP/hgcache/master/packs/*.datapack | head -n 1`
$TESTTMP/hgcache/master/packs/dc8f8fdc76690ce27791ce9f53a18da379e50d37:
x:
Node Delta Base Delta Length Blob Size
1406e7411862 000000000000 2 2
Total: 2 2 (0.0% bigger)
y:
Node Delta Base Delta Length Blob Size
50dbc4572b8e 000000000000 3 3
076f5e2225b3 50dbc4572b8e 14 2
Total: 17 5 (240.0% bigger)