view tests/test-diff-upgrade.t @ 35121:66c5a8cf2868

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

#require execbit

  $ cat <<EOF >> $HGRCPATH
  > [extensions]
  > autodiff = $TESTDIR/autodiff.py
  > [diff]
  > nodates = 1
  > EOF

  $ hg init repo
  $ cd repo



make a combination of new, changed and deleted file

  $ echo regular > regular
  $ echo rmregular > rmregular
  $ $PYTHON -c "file('bintoregular', 'wb').write('\0')"
  $ touch rmempty
  $ echo exec > exec
  $ chmod +x exec
  $ echo rmexec > rmexec
  $ chmod +x rmexec
  $ echo setexec > setexec
  $ echo unsetexec > unsetexec
  $ chmod +x unsetexec
  $ echo binary > binary
  $ $PYTHON -c "file('rmbinary', 'wb').write('\0')"
  $ hg ci -Am addfiles
  adding binary
  adding bintoregular
  adding exec
  adding regular
  adding rmbinary
  adding rmempty
  adding rmexec
  adding rmregular
  adding setexec
  adding unsetexec
  $ echo regular >> regular
  $ echo newregular >> newregular
  $ rm rmempty
  $ touch newempty
  $ rm rmregular
  $ echo exec >> exec
  $ echo newexec > newexec
  $ echo bintoregular > bintoregular
  $ chmod +x newexec
  $ rm rmexec
  $ chmod +x setexec
  $ chmod -x unsetexec
  $ $PYTHON -c "file('binary', 'wb').write('\0\0')"
  $ $PYTHON -c "file('newbinary', 'wb').write('\0')"
  $ rm rmbinary
  $ hg addremove -s 0
  adding newbinary
  adding newempty
  adding newexec
  adding newregular
  removing rmbinary
  removing rmempty
  removing rmexec
  removing rmregular

git=no: regular diff for all files

  $ hg autodiff --git=no
  diff -r a66d19b9302d binary
  Binary file binary has changed
  diff -r a66d19b9302d bintoregular
  Binary file bintoregular has changed
  diff -r a66d19b9302d exec
  --- a/exec
  +++ b/exec
  @@ -1,1 +1,2 @@
   exec
  +exec
  diff -r a66d19b9302d newbinary
  Binary file newbinary has changed
  diff -r a66d19b9302d newexec
  --- /dev/null
  +++ b/newexec
  @@ -0,0 +1,1 @@
  +newexec
  diff -r a66d19b9302d newregular
  --- /dev/null
  +++ b/newregular
  @@ -0,0 +1,1 @@
  +newregular
  diff -r a66d19b9302d regular
  --- a/regular
  +++ b/regular
  @@ -1,1 +1,2 @@
   regular
  +regular
  diff -r a66d19b9302d rmbinary
  Binary file rmbinary has changed
  diff -r a66d19b9302d rmexec
  --- a/rmexec
  +++ /dev/null
  @@ -1,1 +0,0 @@
  -rmexec
  diff -r a66d19b9302d rmregular
  --- a/rmregular
  +++ /dev/null
  @@ -1,1 +0,0 @@
  -rmregular

git=yes: git diff for single regular file

  $ hg autodiff --git=yes regular
  diff --git a/regular b/regular
  --- a/regular
  +++ b/regular
  @@ -1,1 +1,2 @@
   regular
  +regular

git=auto: regular diff for regular files and non-binary removals

  $ hg autodiff --git=auto regular newregular rmregular rmexec
  diff -r a66d19b9302d newregular
  --- /dev/null
  +++ b/newregular
  @@ -0,0 +1,1 @@
  +newregular
  diff -r a66d19b9302d regular
  --- a/regular
  +++ b/regular
  @@ -1,1 +1,2 @@
   regular
  +regular
  diff -r a66d19b9302d rmexec
  --- a/rmexec
  +++ /dev/null
  @@ -1,1 +0,0 @@
  -rmexec
  diff -r a66d19b9302d rmregular
  --- a/rmregular
  +++ /dev/null
  @@ -1,1 +0,0 @@
  -rmregular

  $ for f in exec newexec setexec unsetexec binary newbinary newempty rmempty rmbinary bintoregular; do
  >     echo
  >     echo '% git=auto: git diff for' $f
  >     hg autodiff --git=auto $f
  > done
  
  % git=auto: git diff for exec
  diff -r a66d19b9302d exec
  --- a/exec
  +++ b/exec
  @@ -1,1 +1,2 @@
   exec
  +exec
  
  % git=auto: git diff for newexec
  diff --git a/newexec b/newexec
  new file mode 100755
  --- /dev/null
  +++ b/newexec
  @@ -0,0 +1,1 @@
  +newexec
  
  % git=auto: git diff for setexec
  diff --git a/setexec b/setexec
  old mode 100644
  new mode 100755
  
  % git=auto: git diff for unsetexec
  diff --git a/unsetexec b/unsetexec
  old mode 100755
  new mode 100644
  
  % git=auto: git diff for binary
  diff --git a/binary b/binary
  index a9128c283485202893f5af379dd9beccb6e79486..09f370e38f498a462e1ca0faa724559b6630c04f
  GIT binary patch
  literal 2
  Jc${Nk0000200961
  
  
  % git=auto: git diff for newbinary
  diff --git a/newbinary b/newbinary
  new file mode 100644
  index e69de29bb2d1d6434b8b29ae775ad8c2e48c5391..f76dd238ade08917e6712764a16a22005a50573d
  GIT binary patch
  literal 1
  Ic${MZ000310RR91
  
  
  % git=auto: git diff for newempty
  diff --git a/newempty b/newempty
  new file mode 100644
  
  % git=auto: git diff for rmempty
  diff --git a/rmempty b/rmempty
  deleted file mode 100644
  
  % git=auto: git diff for rmbinary
  diff --git a/rmbinary b/rmbinary
  deleted file mode 100644
  index f76dd238ade08917e6712764a16a22005a50573d..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
  GIT binary patch
  literal 0
  Hc$@<O00001
  
  
  % git=auto: git diff for bintoregular
  diff --git a/bintoregular b/bintoregular
  index f76dd238ade08917e6712764a16a22005a50573d..9c42f2b6427d8bf034b7bc23986152dc01bfd3ab
  GIT binary patch
  literal 13
  Uc$`bh%qz(+N=+}#Ni5<5043uE82|tP
  


git=warn: regular diff with data loss warnings

  $ hg autodiff --git=warn
  diff -r a66d19b9302d binary
  Binary file binary has changed
  diff -r a66d19b9302d bintoregular
  Binary file bintoregular has changed
  diff -r a66d19b9302d exec
  --- a/exec
  +++ b/exec
  @@ -1,1 +1,2 @@
   exec
  +exec
  diff -r a66d19b9302d newbinary
  Binary file newbinary has changed
  diff -r a66d19b9302d newexec
  --- /dev/null
  +++ b/newexec
  @@ -0,0 +1,1 @@
  +newexec
  diff -r a66d19b9302d newregular
  --- /dev/null
  +++ b/newregular
  @@ -0,0 +1,1 @@
  +newregular
  diff -r a66d19b9302d regular
  --- a/regular
  +++ b/regular
  @@ -1,1 +1,2 @@
   regular
  +regular
  diff -r a66d19b9302d rmbinary
  Binary file rmbinary has changed
  diff -r a66d19b9302d rmexec
  --- a/rmexec
  +++ /dev/null
  @@ -1,1 +0,0 @@
  -rmexec
  diff -r a66d19b9302d rmregular
  --- a/rmregular
  +++ /dev/null
  @@ -1,1 +0,0 @@
  -rmregular
  data lost for: binary
  data lost for: bintoregular
  data lost for: newbinary
  data lost for: newempty
  data lost for: newexec
  data lost for: rmbinary
  data lost for: rmempty
  data lost for: setexec
  data lost for: unsetexec

git=abort: fail on execute bit change

  $ hg autodiff --git=abort regular setexec
  abort: losing data for setexec
  [255]

git=abort: succeed on regular file

  $ hg autodiff --git=abort regular
  diff -r a66d19b9302d regular
  --- a/regular
  +++ b/regular
  @@ -1,1 +1,2 @@
   regular
  +regular

  $ cd ..