tests/test-remotefilelog-gcrepack.t

phases: invalidate the phases set less often on retract boundary

We already have the information to update the phase set, so we do so directly
instead of invalidating the cache.

This show a sizeable speedup in our `perf::unbundle` benchmark on the
many-draft mozilla-try repository.

### data-env-vars.name            = mozilla-try-2023-03-22-zstd-sparse-revlog
  # benchmark.name                = hg.perf.perf-unbundle
  # bin-env-vars.hg.flavor        = no-rust
  # bin-env-vars.hg.py-re2-module = default
  # benchmark.variants.issue6528  = disabled

  # benchmark.variants.revs = last-10
before: 2.055259 seconds
after:  1.887064 seconds (-8.18%)
  # benchmark.variants.revs = last-100
before: 2.409239 seconds
after:  2.222429 seconds (-7.75%)
  # benchmark.variants.revs = last-1000
before: 3.945648 seconds
after:  3.762480 seconds (-4.64%)

#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 | grep -E ".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 | grep -E ".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 | grep -E ".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 | grep -E ".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)