view tests/test-lfs-largefiles.t @ 46582:b0a3ca02d17a

copies-rust: implement PartialEqual manually Now that we know that each (dest, rev) pair has at most a unique CopySource, we can simplify comparison a lot. This "simple" step buy a good share of the previous slowdown back in some case: Repo Case Source-Rev Dest-Rev # of revisions old time new time Difference Factor time per rev --------------------------------------------------------------------------------------------------------------------------------------------------------------- mozilla-try x00000_revs_x00000_added_x000_copies 9b2a99adc05e 8e29777b48e6 : 382065 revs, 43.304637 s, 34.443661 s, -8.860976 s, × 0.7954, 90 µs/rev Full benchmark: Repo Case Source-Rev Dest-Rev # of revisions old time new time Difference Factor time per rev --------------------------------------------------------------------------------------------------------------------------------------------------------------- mercurial x_revs_x_added_0_copies ad6b123de1c7 39cfcef4f463 : 1 revs, 0.000043 s, 0.000043 s, +0.000000 s, × 1.0000, 43 µs/rev mercurial x_revs_x_added_x_copies 2b1c78674230 0c1d10351869 : 6 revs, 0.000114 s, 0.000117 s, +0.000003 s, × 1.0263, 19 µs/rev mercurial x000_revs_x000_added_x_copies 81f8ff2a9bf2 dd3267698d84 : 1032 revs, 0.004937 s, 0.004892 s, -0.000045 s, × 0.9909, 4 µs/rev pypy x_revs_x_added_0_copies aed021ee8ae8 099ed31b181b : 9 revs, 0.000339 s, 0.000196 s, -0.000143 s, × 0.5782, 21 µs/rev pypy x_revs_x000_added_0_copies 4aa4e1f8e19a 359343b9ac0e : 1 revs, 0.000049 s, 0.000050 s, +0.000001 s, × 1.0204, 50 µs/rev pypy x_revs_x_added_x_copies ac52eb7bbbb0 72e022663155 : 7 revs, 0.000202 s, 0.000117 s, -0.000085 s, × 0.5792, 16 µs/rev pypy x_revs_x00_added_x_copies c3b14617fbd7 ace7255d9a26 : 1 revs, 0.000409 s, 0.6f1f4a s, -0.000087 s, × 0.7873, 322 µs/rev pypy x_revs_x000_added_x000_copies df6f7a526b60 a83dc6a2d56f : 6 revs, 0.011984 s, 0.011949 s, -0.000035 s, × 0.9971, 1991 µs/rev pypy x000_revs_xx00_added_0_copies 89a76aede314 2f22446ff07e : 4785 revs, 0.050820 s, 0.050802 s, -0.000018 s, × 0.9996, 10 µs/rev pypy x000_revs_x000_added_x_copies 8a3b5bfd266e 2c68e87c3efe : 6780 revs, 0.087953 s, 0.088090 s, +0.000137 s, × 1.0016, 12 µs/rev pypy x000_revs_x000_added_x000_copies 89a76aede314 7b3dda341c84 : 5441 revs, 0.062902 s, 0.062079 s, -0.000823 s, × 0.9869, 11 µs/rev pypy x0000_revs_x_added_0_copies d1defd0dc478 c9cb1334cc78 : 43645 revs, 0.679234 s, 0.635337 s, -0.043897 s, × 0.9354, 14 µs/rev pypy x0000_revs_xx000_added_0_copies bf2c629d0071 4ffed77c095c : 2 revs, 0.013095 s, 0.013262 s, +0.000167 s, × 1.0128, 6631 µs/rev pypy x0000_revs_xx000_added_x000_copies 08ea3258278e d9fa043f30c0 : 11316 revs, 0.120910 s, 0.120085 s, -0.000825 s, × 0.9932, 10 µs/rev netbeans x_revs_x_added_0_copies fb0955ffcbcd a01e9239f9e7 : 2 revs, 0.000087 s, 0.000085 s, -0.000002 s, × 0.9770, 42 µs/rev netbeans x_revs_x000_added_0_copies 6f360122949f 20eb231cc7d0 : 2 revs, 0.000107 s, 0.000110 s, +0.000003 s, × 1.0280, 55 µs/rev netbeans x_revs_x_added_x_copies 1ada3faf6fb6 5a39d12eecf4 : 3 revs, 0.000186 s, 0.000177 s, -0.000009 s, × 0.9516, 59 µs/rev netbeans x_revs_x00_added_x_copies 35be93ba1e2c 9eec5e90c05f : 9 revs, 0.000754 s, 0.000743 s, -0.000011 s, × 0.9854, 82 µs/rev netbeans x000_revs_xx00_added_0_copies eac3045b4fdd 51d4ae7f1290 : 1421 revs, 0.010443 s, 0.010168 s, -0.000275 s, × 0.9737, 7 µs/rev netbeans x000_revs_x000_added_x_copies e2063d266acd 6081d72689dc : 1533 revs, 0.015697 s, 0.015946 s, +0.000249 s, × 1.0159, 10 µs/rev netbeans x000_revs_x000_added_x000_copies ff453e9fee32 411350406ec2 : 5750 revs, 0.063528 s, 0.062712 s, -0.000816 s, × 0.9872, 10 µs/rev netbeans x0000_revs_xx000_added_x000_copies 588c2d1ced70 1aad62e59ddd : 66949 revs, 0.545515 s, 0.523832 s, -0.021683 s, × 0.9603, 7 µs/rev mozilla-central x_revs_x_added_0_copies 3697f962bb7b 7015fcdd43a2 : 2 revs, 0.000089 s, 0.000090 s, +0.000001 s, × 1.0112, 45 µs/rev mozilla-central x_revs_x000_added_0_copies dd390860c6c9 40d0c5bed75d : 8 revs, 0.000265 s, 0.000264 s, -0.000001 s, × 0.9962, 33 µs/rev mozilla-central x_revs_x_added_x_copies 8d198483ae3b 14207ffc2b2f : 9 revs, 0.000381 s, 0.000187 s, -0.000194 s, × 0.4908, 20 µs/rev mozilla-central x_revs_x00_added_x_copies 98cbc58cc6bc 446a150332c3 : 7 revs, 0.000672 s, 0.000665 s, -0.000007 s, × 0.9896, 95 µs/rev mozilla-central x_revs_x000_added_x000_copies 3c684b4b8f68 0a5e72d1b479 : 3 revs, 0.003497 s, 0.003556 s, +0.000059 s, × 1.0169, 1185 µs/rev mozilla-central x_revs_x0000_added_x0000_copies effb563bb7e5 c07a39dc4e80 : 6 revs, 0.073204 s, 0.071345 s, -0.001859 s, × 0.9746, 11890 µs/rev mozilla-central x000_revs_xx00_added_0_copies 6100d773079a 04a55431795e : 1593 revs, 0.006482 s, 0.006551 s, +0.000069 s, × 1.0106, 4 µs/rev mozilla-central x000_revs_x000_added_x_copies 9f17a6fc04f9 2d37b966abed : 41 revs, 0.005066 s, 0.005078 s, +0.000012 s, × 1.0024, 123 µs/rev mozilla-central x000_revs_x000_added_x000_copies 7c97034feb78 4407bd0c6330 : 7839 revs, 0.065707 s, 0.065823 s, +0.000116 s, × 1.0018, 8 µs/rev mozilla-central x0000_revs_xx000_added_0_copies 9eec5917337d 67118cc6dcad : 615 revs, 0.026800 s, 0.027050 s, +0.000250 s, × 1.0093, 43 µs/rev mozilla-central x0000_revs_xx000_added_x000_copies f78c615a656c 96a38b690156 : 30263 revs, 0.203856 s, 0.202443 s, -0.001413 s, × 0.9931, 6 µs/rev mozilla-central x00000_revs_x0000_added_x0000_copies 6832ae71433c 4c222a1d9a00 : 153721 revs, 1.293394 s, 1.261583 s, -0.031811 s, × 0.9754, 8 µs/rev mozilla-central x00000_revs_x00000_added_x000_copies 76caed42cf7c 1daa622bbe42 : 204976 revs, 1.698239 s, 1.643869 s, -0.054370 s, × 0.9680, 8 µs/rev mozilla-try x_revs_x_added_0_copies aaf6dde0deb8 9790f499805a : 2 revs, 0.000875 s, 0.000868 s, -0.000007 s, × 0.9920, 434 µs/rev mozilla-try x_revs_x000_added_0_copies d8d0222927b4 5bb8ce8c7450 : 2 revs, 0.000891 s, 0.000887 s, -0.000004 s, × 0.9955, 443 µs/rev mozilla-try x_revs_x_added_x_copies 092fcca11bdb 936255a0384a : 4 revs, 0.000292 s, 0.000168 s, -0.000124 s, × 0.5753, 42 µs/rev mozilla-try x_revs_x00_added_x_copies b53d2fadbdb5 017afae788ec : 2 revs, 0.003939 s, 0.001160 s, -0.002779 s, × 0.2945, 580 µs/rev mozilla-try x_revs_x000_added_x000_copies 20408ad61ce5 6f0ee96e21ad : 1 revs, 0.033027 s, 0.033016 s, -0.000011 s, × 0.9997, 33016 µs/rev mozilla-try x_revs_x0000_added_x0000_copies effb563bb7e5 c07a39dc4e80 : 6 revs, 0.073703 s, 0.073312 s, -0.39ae31 s, × 0.9947, 12218 µs/rev mozilla-try x000_revs_xx00_added_0_copies 6100d773079a 04a55431795e : 1593 revs, 0.006469 s, 0.006485 s, +0.000016 s, × 1.0025, 4 µs/rev mozilla-try x000_revs_x000_added_x_copies 9f17a6fc04f9 2d37b966abed : 41 revs, 0.005278 s, 0.005494 s, +0.000216 s, × 1.0409, 134 µs/rev mozilla-try x000_revs_x000_added_x000_copies 1346fd0130e4 4c65cbdabc1f : 6657 revs, 0.064995 s, 0.064879 s, -0.000116 s, × 0.9982, 9 µs/rev mozilla-try x0000_revs_x_added_0_copies 63519bfd42ee a36a2a865d92 : 40314 revs, 0.301041 s, 0.301469 s, +0.000428 s, × 1.0014, 7 µs/rev mozilla-try x0000_revs_x_added_x_copies 9fe69ff0762d bcabf2a78927 : 38690 revs, 0.285575 s, 0.297113 s, +0.011538 s, × 1.0404, 7 µs/rev mozilla-try x0000_revs_xx000_added_x_copies 156f6e2674f2 4d0f2c178e66 : 8598 revs, 0.085597 s, 0.085890 s, +0.000293 s, × 1.0034, 9 µs/rev mozilla-try x0000_revs_xx000_added_0_copies 9eec5917337d 67118cc6dcad : 615 revs, 0.027118 s, 0.027718 s, +0.000600 s, × 1.0221, 45 µs/rev mozilla-try x0000_revs_xx000_added_x000_copies 89294cd501d9 7ccb2fc7ccb5 : 97052 revs, 2.119204 s, 2.048949 s, -0.070255 s, × 0.9668, 21 µs/rev mozilla-try x0000_revs_x0000_added_x0000_copies e928c65095ed e951f4ad123a : 52031 revs, 0.701479 s, 0.685924 s, -0.015555 s, × 0.9778, 13 µs/rev mozilla-try x00000_revs_x_added_0_copies 6a320851d377 1ebb79acd503 : 363753 revs, 4.482399 s, 4.482891 s, +0.000492 s, × 1.0001, 12 µs/rev mozilla-try x00000_revs_x00000_added_0_copies dc8a3ca7010e d16fde900c9c : 34414 revs, 0.574082 s, 0.577633 s, +0.003551 s, × 1.0062, 16 µs/rev mozilla-try x00000_revs_x_added_x_copies 5173c4b6f97c 95d83ee7242d : 362229 revs, 4.480366 s, 4.397816 s, -0.082550 s, × 0.9816, 12 µs/rev mozilla-try x00000_revs_x000_added_x_copies 9126823d0e9c ca82787bb23c : 359344 revs, 4.369070 s, 4.370538 s, +0.001468 s, × 1.0003, 12 µs/rev mozilla-try x00000_revs_x0000_added_x0000_copies 8d3fafa80d4b eb884023b810 : 192665 revs, 1.592506 s, 1.570439 s, -0.022067 s, × 0.9861, 8 µs/rev mozilla-try x00000_revs_x00000_added_x0000_copies 1b661134e2ca 1ae03d022d6d : 228985 revs, 87.824489 s, 88.388512 s, +0.564023 s, × 1.0064, 386 µs/rev mozilla-try x00000_revs_x00000_added_x000_copies 9b2a99adc05e 8e29777b48e6 : 382065 revs, 43.304637 s, 34.443661 s, -8.860976 s, × 0.7954, 90 µs/rev private : 459513 revs, 33.853687 s, 27.370148 s, -6.483539 s, × 0.8085, 59 µs/rev Differential Revision: https://phab.mercurial-scm.org/D9653
author Pierre-Yves David <pierre-yves.david@octobus.net>
date Wed, 16 Dec 2020 11:11:05 +0100
parents a0886a4d6dce
children 84a93fa7ecfd
line wrap: on
line source

#require no-reposimplestore no-chg

This tests the interaction between the largefiles and lfs extensions, and
conversion from largefiles -> lfs.

  $ cat >> $HGRCPATH << EOF
  > [extensions]
  > largefiles =
  > 
  > [lfs]
  > # standin files are 41 bytes.  Stay bigger for clarity.
  > threshold = 42
  > EOF

Setup a repo with a normal file and a largefile, above and below the lfs
threshold to test lfconvert.  *.txt start life as a normal file; *.bin start as
an lfs/largefile.

  $ hg init largefiles
  $ cd largefiles
  $ echo 'normal' > normal.txt
  $ echo 'normal above lfs threshold 0000000000000000000000000' > lfs.txt
  $ hg ci -Am 'normal.txt'
  adding lfs.txt
  adding normal.txt
  $ echo 'largefile' > large.bin
  $ echo 'largefile above lfs threshold 0000000000000000000000' > lfs.bin
  $ hg add --large large.bin lfs.bin
  $ hg ci -m 'add largefiles'

  $ cat >> $HGRCPATH << EOF
  > [extensions]
  > lfs =
  > EOF

Add an lfs file and normal file that collide with files on the other branch.
large.bin is added as a normal file, and is named as such only to clash with the
largefile on the other branch.

  $ hg up -q '.^'
  $ echo 'below lfs threshold' > large.bin
  $ echo 'lfs above the lfs threshold for length 0000000000000' > lfs.bin
  $ hg ci -Am 'add with lfs extension'
  adding large.bin
  adding lfs.bin
  created new head

  $ hg log -G
  @  changeset:   2:e989d0fa3764
  |  tag:         tip
  |  parent:      0:29361292f54d
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     add with lfs extension
  |
  | o  changeset:   1:6513aaab9ca0
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    summary:     add largefiles
  |
  o  changeset:   0:29361292f54d
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     normal.txt
  
--------------------------------------------------------------------------------
Merge largefiles into lfs branch

The largefiles extension will prompt to use the normal or largefile when merged
into the lfs files.  `hg manifest` will show standins if present.  They aren't,
because largefiles merge doesn't merge content.  If it did, selecting (n)ormal
would convert to lfs on commit, if appropriate.

BUG: Largefiles isn't running the merge tool, like when two lfs files are
merged.  This is probably by design, but it should probably at least prompt if
content should be taken from (l)ocal or (o)ther as well.

  $ hg --config ui.interactive=True merge 6513aaab9ca0 <<EOF
  > n
  > n
  > EOF
  remote turned local normal file large.bin into a largefile
  use (l)argefile or keep (n)ormal file? n
  remote turned local normal file lfs.bin into a largefile
  use (l)argefile or keep (n)ormal file? n
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -m 'merge lfs with largefiles -> normal'
  $ hg manifest
  large.bin
  lfs.bin
  lfs.txt
  normal.txt

The merged lfs.bin resolved to lfs because the (n)ormal option was picked.  The
lfs.txt file is unchanged by the merge, because it was added before lfs was
enabled, and the content didn't change.
  $ hg debugdata lfs.bin 0
  version https://git-lfs.github.com/spec/v1
  oid sha256:81c7492b2c05e130431f65a87651b54a30c5da72c99ce35a1e9b9872a807312b
  size 53
  x-is-binary 0
  $ hg debugdata lfs.txt 0
  normal above lfs threshold 0000000000000000000000000

Another filelog entry is NOT made by the merge, so nothing is committed as lfs.
  $ hg log -r . -T '{join(lfs_files, ", ")}\n'
  

Replay the last merge, but pick (l)arge this time.  The manifest will show any
standins.

  $ hg up -Cq e989d0fa3764

  $ hg --config ui.interactive=True merge 6513aaab9ca0 <<EOF
  > l
  > l
  > EOF
  remote turned local normal file large.bin into a largefile
  use (l)argefile or keep (n)ormal file? l
  remote turned local normal file lfs.bin into a largefile
  use (l)argefile or keep (n)ormal file? l
  getting changed largefiles
  2 largefiles updated, 0 removed
  2 files updated, 0 files merged, 2 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -m 'merge lfs with largefiles -> large'
  created new head
  $ hg manifest
  .hglf/large.bin
  .hglf/lfs.bin
  lfs.txt
  normal.txt

--------------------------------------------------------------------------------
Merge lfs into largefiles branch

  $ hg up -Cq 6513aaab9ca0
  $ hg --config ui.interactive=True merge e989d0fa3764 <<EOF
  > n
  > n
  > EOF
  remote turned local largefile large.bin into a normal file
  keep (l)argefile or use (n)ormal file? n
  remote turned local largefile lfs.bin into a normal file
  keep (l)argefile or use (n)ormal file? n
  getting changed largefiles
  0 largefiles updated, 0 removed
  2 files updated, 0 files merged, 2 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -m 'merge largefiles with lfs -> normal'
  created new head
  $ hg manifest
  large.bin
  lfs.bin
  lfs.txt
  normal.txt

The merged lfs.bin got converted to lfs because the (n)ormal option was picked.
The lfs.txt file is unchanged by the merge, because it was added before lfs was
enabled.
  $ hg debugdata lfs.bin 0
  version https://git-lfs.github.com/spec/v1
  oid sha256:81c7492b2c05e130431f65a87651b54a30c5da72c99ce35a1e9b9872a807312b
  size 53
  x-is-binary 0
  $ hg debugdata lfs.txt 0
  normal above lfs threshold 0000000000000000000000000

Another filelog entry is NOT made by the merge, so nothing is committed as lfs.
  $ hg log -r . -T '{join(lfs_files, ", ")}\n'
  

Replay the last merge, but pick (l)arge this time.  The manifest will show the
standins.

  $ hg up -Cq 6513aaab9ca0

  $ hg --config ui.interactive=True merge e989d0fa3764 <<EOF
  > l
  > l
  > EOF
  remote turned local largefile large.bin into a normal file
  keep (l)argefile or use (n)ormal file? l
  remote turned local largefile lfs.bin into a normal file
  keep (l)argefile or use (n)ormal file? l
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -m 'merge largefiles with lfs -> large'
  created new head
  $ hg manifest
  .hglf/large.bin
  .hglf/lfs.bin
  lfs.txt
  normal.txt

--------------------------------------------------------------------------------

When both largefiles and lfs are configured to add by size, the tie goes to
largefiles since it hooks cmdutil.add() and lfs hooks the filelog write in the
commit.  By the time the commit occurs, the tracked file is smaller than the
threshold (assuming it is > 41, so the standins don't become lfs objects).

  $ "$PYTHON" -c 'import sys ; sys.stdout.write("y\n" * 1048576)' > large_by_size.bin
  $ hg --config largefiles.minsize=1 ci -Am 'large by size'
  adding large_by_size.bin as a largefile
  $ hg manifest
  .hglf/large.bin
  .hglf/large_by_size.bin
  .hglf/lfs.bin
  lfs.txt
  normal.txt

  $ hg rm large_by_size.bin
  $ hg ci -m 'remove large_by_size.bin'

Largefiles doesn't do anything special with diff, so it falls back to diffing
the standins.  Extdiff also is standin based comparison.  Diff and extdiff both
work on the original file for lfs objects.

Largefile -> lfs transition
  $ hg diff -r 1 -r 3
  diff -r 6513aaab9ca0 -r dcc5ce63e252 .hglf/large.bin
  --- a/.hglf/large.bin	Thu Jan 01 00:00:00 1970 +0000
  +++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,1 +0,0 @@
  -cef9a458373df9b0743a0d3c14d0c66fb19b8629
  diff -r 6513aaab9ca0 -r dcc5ce63e252 .hglf/lfs.bin
  --- a/.hglf/lfs.bin	Thu Jan 01 00:00:00 1970 +0000
  +++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,1 +0,0 @@
  -557fb6309cef935e1ac2c8296508379e4b15a6e6
  diff -r 6513aaab9ca0 -r dcc5ce63e252 large.bin
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/large.bin	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,1 @@
  +below lfs threshold
  diff -r 6513aaab9ca0 -r dcc5ce63e252 lfs.bin
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/lfs.bin	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,1 @@
  +lfs above the lfs threshold for length 0000000000000

lfs -> largefiles transition
  $ hg diff -r 2 -r 6
  diff -r e989d0fa3764 -r 95e1e80325c8 .hglf/large.bin
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/.hglf/large.bin	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,1 @@
  +cef9a458373df9b0743a0d3c14d0c66fb19b8629
  diff -r e989d0fa3764 -r 95e1e80325c8 .hglf/lfs.bin
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/.hglf/lfs.bin	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,1 @@
  +557fb6309cef935e1ac2c8296508379e4b15a6e6
  diff -r e989d0fa3764 -r 95e1e80325c8 large.bin
  --- a/large.bin	Thu Jan 01 00:00:00 1970 +0000
  +++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,1 +0,0 @@
  -below lfs threshold
  diff -r e989d0fa3764 -r 95e1e80325c8 lfs.bin
  --- a/lfs.bin	Thu Jan 01 00:00:00 1970 +0000
  +++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,1 +0,0 @@
  -lfs above the lfs threshold for length 0000000000000

A largefiles repo can be converted to lfs.  The lfconvert command uses the
convert extension under the hood with --to-normal.  So the --config based
parameters are available, but not --authormap, --branchmap, etc.

  $ cd ..
  $ hg lfconvert --to-normal largefiles nolargefiles 2>&1
  initializing destination nolargefiles
  0 additional largefiles cached
  scanning source...
  sorting...
  converting...
  8 normal.txt
  7 add largefiles
  6 add with lfs extension
  5 merge lfs with largefiles -> normal
  4 merge lfs with largefiles -> large
  3 merge largefiles with lfs -> normal
  2 merge largefiles with lfs -> large
  1 large by size
  0 remove large_by_size.bin
  $ cd nolargefiles

The requirement is added to the destination repo.

  $ cat .hg/requires
  dotencode
  fncache
  generaldelta
  lfs
  revlogv1
  sparserevlog
  store

  $ hg log -r 'all()' -G -T '{rev} {join(lfs_files, ", ")} ({desc})\n'
  o  8 large_by_size.bin (remove large_by_size.bin)
  |
  o  7 large_by_size.bin (large by size)
  |
  o    6  (merge largefiles with lfs -> large)
  |\
  +---o  5  (merge largefiles with lfs -> normal)
  | |/
  +---o  4 lfs.bin (merge lfs with largefiles -> large)
  | |/
  +---o  3  (merge lfs with largefiles -> normal)
  | |/
  | o  2 lfs.bin (add with lfs extension)
  | |
  o |  1 lfs.bin (add largefiles)
  |/
  o  0 lfs.txt (normal.txt)
  
  $ hg debugdata lfs.bin 0
  version https://git-lfs.github.com/spec/v1
  oid sha256:2172a5bd492dd41ec533b9bb695f7691b6351719407ac797f0ccad5348c81e62
  size 53
  x-is-binary 0
  $ hg debugdata lfs.bin 1
  version https://git-lfs.github.com/spec/v1
  oid sha256:81c7492b2c05e130431f65a87651b54a30c5da72c99ce35a1e9b9872a807312b
  size 53
  x-is-binary 0
  $ hg debugdata lfs.bin 2
  version https://git-lfs.github.com/spec/v1
  oid sha256:2172a5bd492dd41ec533b9bb695f7691b6351719407ac797f0ccad5348c81e62
  size 53
  x-is-binary 0
  $ hg debugdata lfs.bin 3
  abort: invalid revision identifier 3
  [255]

No diffs when comparing merge and p1 that kept p1's changes.  Diff of lfs to
largefiles no longer operates in standin files.

This `head -n 20` looks dumb (since we expect no output), but if something
breaks you can get 1048576 lines of +y in the output, which takes a looooooong
time to print.
  $ hg diff -r 2:3 | head -n 20
  $ hg diff -r 2:6
  diff -r e989d0fa3764 -r 752e3a0d8488 large.bin
  --- a/large.bin	Thu Jan 01 00:00:00 1970 +0000
  +++ b/large.bin	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,1 +1,1 @@
  -below lfs threshold
  +largefile
  diff -r e989d0fa3764 -r 752e3a0d8488 lfs.bin
  --- a/lfs.bin	Thu Jan 01 00:00:00 1970 +0000
  +++ b/lfs.bin	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,1 +1,1 @@
  -lfs above the lfs threshold for length 0000000000000
  +largefile above lfs threshold 0000000000000000000000