view tests/test-remotefilelog-gcrepack.t @ 42377:0546ead39a7e stable

manifest: avoid corruption by dropping removed files with pure (issue5801)

Previously, removed files would simply be marked by overwriting the first byte
with NUL and dropping their entry in `self.position`.  But no effort was made to
ignore them when compacting the dictionary into text form.  This allowed them to
slip into the manifest revision, since the code seems to be trying to minimize
the string operations by copying as large a chunk as possible.  As part of this,
compact() walks the existing text based on entries in the `positions` list, and
consumed everything up to the next position entry.   This typically resulted in
a ValueError complaining about unsorted manifest entries.

Sometimes it seems that files do get dropped in large repos- it seems to
correspond to there being a new entry that would take the same slot.  A much
more trivial problem is that if the only changes were removals, `_compact()`
didn't even run because `__delitem__` doesn't add anything to `self.extradata`.
Now there's an explicit variable to flag this, both to allow `_compact()` to
run, and to avoid searching the manifest in cases where there are no removals.

In practice, this behavior was mostly obscured by the check in fastdelta() which
takes a different path that explicitly drops removed files if there are fewer
than 1000 changes.  However, timeless has a repo where after rebasing tens of
commits, a totally different path[1] is taken that bypasses the change count
check and hits this problem.

[1] https://www.mercurial-scm.org/repo/hg/file/2338bdea4474/mercurial/manifest.py#l1511

#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
  $ sleep 0.5
  $ hg debugwaitonrepack >/dev/null 2>%1

  $ find $CACHEDIR | sort | grep ".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
  $ sleep 0.5
  $ hg debugwaitonrepack >/dev/null 2>%1

  $ find $CACHEDIR | sort | grep ".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
  $ sleep 0.5
  $ hg debugwaitonrepack >/dev/null 2>%1

  $ find $CACHEDIR | sort | grep ".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
  $ sleep 0.5
  $ hg debugwaitonrepack >/dev/null 2>%1

  $ find $CACHEDIR | sort | grep ".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)