view tests/test-copy.t @ 35098:66c5a8cf2868

lfs: import the Facebook git-lfs client extension

The purpose of this is the same as the built-in largefiles extension- to handle
huge files outside of the normal storage system, generally to keep the amount of
data cloned to a lower amount.  There are several benefits of implementing the
git-lfs protocol, instead of using the largefiles extension:

  - Bitbucket and Github support (and probably wider support in 3rd party
    hosting sites in general). [1][2]

  - The number of hg internals monkey patched are several orders of magnitude
    lower, so it will be easier to reason about and maintain.  Future commands
    will likely just work, without requiring various wrappers.

  - The "standin" files are only written to the filelog, not the disk.  That
    should avoid weird edge cases where the largefile and standin files get out
    of sync. [3]  It also avoids the occasional printing of the "hidden" standin
    file in various messages.

  - Filesets like size() will work, even if the file isn't present.  (It always
    says 41 bytes for largefiles, whether present or not.)

The only place that I see where largefiles comes out on top is that it works
with `hg serve` for simple sharing, without external infrastructure.  Getting
lfs-test-server working was a hassle, and took awhile to figure out.  Maybe we
can do something to make it work in the future.

Long term, I expect that this will be highly preferred over largefiles.  But if
we are to recommend this to largefile users, there are some UI issues to
bikeshed.  Until they are resolved, I've marked this experimental, and am not
putting a pointer to this in the largefiles help.  The (non exhaustive) list of
issues I've seen so far are:

  - It isn't sufficient to just enable the largefiles extension- you have to
    explicitly add a file with --large before it will pay attention to the
    configured sizes and patterns on future adds.  The justification being that
    once you use it, you're stuck with it.  I've seen people confused by this,
    and haven't liked it myself.  But it's also saved me a few times.  Should we
    do something like have a specific enabling config setting that must be set
    in the local repo config, so that enabling this extension in the user or
    system hgrc doesn't silently start storing lfs files?

  - The largefiles extension adds a repo requirement when the first largefile is
    committed, so that the extension must always be enabled in the future.  This
    extension is not doing that, and since I only enabled it locally to avoid
    infecting other repos, I got a cryptic error about missing flag processors
    when I cloned.  Is there no repo requirement due to shallow/narrow clone
    considerations (or other future advanced things)?

  - In the (small amount of) reading I've done about the git implementation, it
    seems that the files and sizes are stored in a tracked .gitattributes file.
    I think a tracked file for this would be extremely useful for consistency
    across developers, but this kind of touches on the tracked hgrc file
    proposal a few months back.

  - The git client can specify file patterns, not just sizes.

  - The largefiles extension has a cache directory in the local repo, but also a
    system wide one.  We should probably implement a system wide cache too, so
    that multiple clones don't have to refetch the files from the server.

  - Jun mentioned other missing features, like SSH authentication, gc, etc.

The code corresponds to c0492b73c7ef in hg-experimental. [4]  The only tweaks
are to load the extension in the tests with 'lfs=' instead of
'lfs=$TESTDIR/../hgext3rd/lfs', change the import in the *.py test to hgext
(from hgext3rd), add the 'testedwith' declaration, and mark it experimental for
now.  The infinite-push, p4fastimport, and remotefilelog tests were left behind.

The devel-warnings for unregistered config options are not corrected yet, nor
are the import check warnings.

[1] https://www.mercurial-scm.org/pipermail/mercurial/2017-November/050699.html
[2] https://bitbucket.org/site/master/issues/3843/largefiles-support-bb-3903
[3] https://bz.mercurial-scm.org/show_bug.cgi?id=5738
[4] https://bitbucket.org/facebook/hg-experimental

# enable bundle2 in advance

  $ cat << EOF >> $HGRCPATH
  > [format]
  > usegeneraldelta=yes
  > EOF

  $ mkdir part1
  $ cd part1

  $ hg init
  $ echo a > a
  $ hg add a
  $ hg commit -m "1"
  $ hg status
  $ hg copy a b
  $ hg --config ui.portablefilenames=abort copy a con.xml
  abort: filename contains 'con', which is reserved on Windows: con.xml
  [255]
  $ hg status
  A b
  $ hg sum
  parent: 0:c19d34741b0a tip
   1
  branch: default
  commit: 1 copied
  update: (current)
  phases: 1 draft
  $ hg --debug commit -m "2"
  committing files:
  b
   b: copy a:b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3
  committing manifest
  committing changelog
  updating the branch cache
  committed changeset 1:93580a2c28a50a56f63526fb305067e6fbf739c4

we should see two history entries

  $ hg history -v
  changeset:   1:93580a2c28a5
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       b
  description:
  2
  
  
  changeset:   0:c19d34741b0a
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       a
  description:
  1
  
  

we should see one log entry for a

  $ hg log a
  changeset:   0:c19d34741b0a
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     1
  

this should show a revision linked to changeset 0

  $ hg debugindex a
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       3  .....       0 b789fdd96dc2 000000000000 000000000000 (re)

we should see one log entry for b

  $ hg log b
  changeset:   1:93580a2c28a5
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     2
  

this should show a revision linked to changeset 1

  $ hg debugindex b
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0      65  .....       1 37d9b5d994ea 000000000000 000000000000 (re)

this should show the rename information in the metadata

  $ hg debugdata b 0 | head -3 | tail -2
  copy: a
  copyrev: b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3

  $ md5sum.py .hg/store/data/b.i
  44913824c8f5890ae218f9829535922e  .hg/store/data/b.i
  $ hg cat b > bsum
  $ md5sum.py bsum
  60b725f10c9c85c70d97880dfe8191b3  bsum
  $ hg cat a > asum
  $ md5sum.py asum
  60b725f10c9c85c70d97880dfe8191b3  asum
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  2 files, 2 changesets, 2 total revisions

  $ cd ..


  $ mkdir part2
  $ cd part2

  $ hg init
  $ echo foo > foo
should fail - foo is not managed
  $ hg mv foo bar
  foo: not copying - file is not managed
  abort: no files to copy
  [255]
  $ hg st -A
  ? foo
  $ hg add foo
dry-run; print a warning that this is not a real copy; foo is added
  $ hg mv --dry-run foo bar
  foo has not been committed yet, so no copy data will be stored for bar.
  $ hg st -A
  A foo
should print a warning that this is not a real copy; bar is added
  $ hg mv foo bar
  foo has not been committed yet, so no copy data will be stored for bar.
  $ hg st -A
  A bar
should print a warning that this is not a real copy; foo is added
  $ hg cp bar foo
  bar has not been committed yet, so no copy data will be stored for foo.
  $ hg rm -f bar
  $ rm bar
  $ hg st -A
  A foo
  $ hg commit -m1

moving a missing file
  $ rm foo
  $ hg mv foo foo3
  foo: deleted in working directory
  foo3 does not exist!
  $ hg up -qC .

copy --after to a nonexistent target filename
  $ hg cp -A foo dummy
  foo: not recording copy - dummy does not exist

dry-run; should show that foo is clean
  $ hg copy --dry-run foo bar
  $ hg st -A
  C foo
should show copy
  $ hg copy foo bar
  $ hg st -C
  A bar
    foo

shouldn't show copy
  $ hg commit -m2
  $ hg st -C

should match
  $ hg debugindex foo
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       5  .....       0 2ed2a3912a0b 000000000000 000000000000 (re)
  $ hg debugrename bar
  bar renamed from foo:2ed2a3912a0b24502043eae84ee4b279c18b90dd

  $ echo bleah > foo
  $ echo quux > bar
  $ hg commit -m3

should not be renamed
  $ hg debugrename bar
  bar not renamed

  $ hg copy -f foo bar
should show copy
  $ hg st -C
  M bar
    foo

XXX: filtering lfilesrepo.status() in 3.3-rc causes the copy source to not be
displayed.
  $ hg st -C --config extensions.largefiles=
  The fsmonitor extension is incompatible with the largefiles extension and has been disabled. (fsmonitor !)
  M bar
    foo

  $ hg commit -m3

should show no parents for tip
  $ hg debugindex bar
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0      69  .....       1 7711d36246cc 000000000000 000000000000 (re)
       1        69       6  .....       2 bdf70a2b8d03 7711d36246cc 000000000000 (re)
       2        75      71  .....       3 b2558327ea8d 000000000000 000000000000 (re)
should match
  $ hg debugindex foo
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       5  .....       0 2ed2a3912a0b 000000000000 000000000000 (re)
       1         5       7  .....       2 dd12c926cf16 2ed2a3912a0b 000000000000 (re)
  $ hg debugrename bar
  bar renamed from foo:dd12c926cf165e3eb4cf87b084955cb617221c17

should show no copies
  $ hg st -C

copy --after on an added file
  $ cp bar baz
  $ hg add baz
  $ hg cp -A bar baz
  $ hg st -C
  A baz
    bar

foo was clean:
  $ hg st -AC foo
  C foo
Trying to copy on top of an existing file fails,
  $ hg copy -A bar foo
  foo: not overwriting - file already committed
  (hg copy --after --force to replace the file by recording a copy)
same error without the --after, so the user doesn't have to go through
two hints:
  $ hg copy bar foo
  foo: not overwriting - file already committed
  (hg copy --force to replace the file by recording a copy)
but it's considered modified after a copy --after --force
  $ hg copy -Af bar foo
  $ hg st -AC foo
  M foo
    bar
The hint for a file that exists but is not in file history doesn't
mention --force:
  $ touch xyzzy
  $ hg cp bar xyzzy
  xyzzy: not overwriting - file exists
  (hg copy --after to record the copy)

  $ cd ..