t/t5320-delta-islands.sh

   1 #!/bin/sh
   2
   3 test_description='exercise delta islands'
   4
   5 TEST_PASSES_SANITIZE_LEAK=true
   6 . ./test-lib.sh
   7
   8 # returns true iff $1 is a delta based on $2
   9 is_delta_base () {
  10         delta_base=$(echo "$1" | git cat-file --batch-check='%(deltabase)') &&
  11         echo >&2 "$1 has base $delta_base" &&
  12         test "$delta_base" = "$2"
  13 }
  14
  15 # generate a commit on branch $1 with a single file, "file", whose
  16 # content is mostly based on the seed $2, but with a unique bit
  17 # of content $3 appended. This should allow us to see whether
  18 # blobs of different refs delta against each other.
  19 commit() {
  20         blob=$({ test-tool genrandom "$2" 10240 && echo "$3"; } |
  21                git hash-object -w --stdin) &&
  22         tree=$(printf '100644 blob %s\tfile\n' "$blob" | git mktree) &&
  23         commit=$(echo "$2-$3" | git commit-tree "$tree" ${4:+-p "$4"}) &&
  24         git update-ref "refs/heads/$1" "$commit" &&
  25         eval "$1"'=$(git rev-parse $1:file)' &&
  26         eval "echo >&2 $1=\$$1"
  27 }
  28
  29 test_expect_success 'setup commits' '
  30         commit one seed 1 &&
  31         commit two seed 12
  32 '
  33
  34 # Note: This is heavily dependent on the "prefer larger objects as base"
  35 # heuristic.
  36 test_expect_success 'vanilla repack deltas one against two' '
  37         git repack -adf &&
  38         is_delta_base $one $two
  39 '
  40
  41 test_expect_success 'island repack with no island definition is vanilla' '
  42         git repack -adfi &&
  43         is_delta_base $one $two
  44 '
  45
  46 test_expect_success 'island repack with no matches is vanilla' '
  47         git -c "pack.island=refs/foo" repack -adfi &&
  48         is_delta_base $one $two
  49 '
  50
  51 test_expect_success 'separate islands disallows delta' '
  52         git -c "pack.island=refs/heads/(.*)" repack -adfi &&
  53         ! is_delta_base $one $two &&
  54         ! is_delta_base $two $one
  55 '
  56
  57 test_expect_success 'same island allows delta' '
  58         git -c "pack.island=refs/heads" repack -adfi &&
  59         is_delta_base $one $two
  60 '
  61
  62 test_expect_success 'coalesce same-named islands' '
  63         git \
  64                 -c "pack.island=refs/(.*)/one" \
  65                 -c "pack.island=refs/(.*)/two" \
  66                 repack -adfi &&
  67         is_delta_base $one $two
  68 '
  69
  70 test_expect_success 'island restrictions drop reused deltas' '
  71         git repack -adfi &&
  72         is_delta_base $one $two &&
  73         git -c "pack.island=refs/heads/(.*)" repack -adi &&
  74         ! is_delta_base $one $two &&
  75         ! is_delta_base $two $one
  76 '
  77
  78 test_expect_success 'island regexes are left-anchored' '
  79         git -c "pack.island=heads/(.*)" repack -adfi &&
  80         is_delta_base $one $two
  81 '
  82
  83 test_expect_success 'island regexes follow last-one-wins scheme' '
  84         git \
  85                 -c "pack.island=refs/heads/(.*)" \
  86                 -c "pack.island=refs/heads/" \
  87                 repack -adfi &&
  88         is_delta_base $one $two
  89 '
  90
  91 test_expect_success 'setup shared history' '
  92         commit root shared root &&
  93         commit one shared 1 root &&
  94         commit two shared 12-long root
  95 '
  96
  97 # We know that $two will be preferred as a base from $one,
  98 # because we can transform it with a pure deletion.
  99 #
 100 # We also expect $root as a delta against $two by the "longest is base" rule.
 101 test_expect_success 'vanilla delta goes between branches' '
 102         git repack -adf &&
 103         is_delta_base $one $two &&
 104         is_delta_base $root $two
 105 '
 106
 107 # Here we should allow $one to base itself on $root; even though
 108 # they are in different islands, the objects in $root are in a superset
 109 # of islands compared to those in $one.
 110 #
 111 # Similarly, $two can delta against $root by our rules. And unlike $one,
 112 # in which we are just allowing it, the island rules actually put $root
 113 # as a possible base for $two, which it would not otherwise be (due to the size
 114 # sorting).
 115 test_expect_success 'deltas allowed against superset islands' '
 116         git -c "pack.island=refs/heads/(.*)" repack -adfi &&
 117         is_delta_base $one $root &&
 118         is_delta_base $two $root
 119 '
 120
 121 # We are going to test the packfile order here, so we again have to make some
 122 # assumptions. We assume that "$root", as part of our core "one", must come
 123 # before "$two". This should be guaranteed by the island code. However, for
 124 # this test to fail without islands, we are also assuming that it would not
 125 # otherwise do so. This is true by the current write order, which will put
 126 # commits (and their contents) before their parents.
 127 test_expect_success 'island core places core objects first' '
 128         cat >expect <<-EOF &&
 129         $root
 130         $two
 131         EOF
 132         git -c "pack.island=refs/heads/(.*)" \
 133             -c "pack.islandcore=one" \
 134             repack -adfi &&
 135         git verify-pack -v .git/objects/pack/*.pack |
 136         cut -d" " -f1 |
 137         grep -E "$root|$two" >actual &&
 138         test_cmp expect actual
 139 '
 140
 141 test_expect_success 'unmatched island core is not fatal' '
 142         git -c "pack.islandcore=one" repack -adfi
 143 '
 144
 145 test_done