D5130: lfs: autoload the extension when cloning from repo with lfs enabled

[mharbison72 (Matt Harbison)]

mharbison72 added a subscriber: yuja.
mharbison72 added a comment.


  In https://phab.mercurial-scm.org/D5130#76737, @indygreg wrote:
  
  > > ! In https://phab.mercurial-scm.org/D5130#76736, @mharbison72 wrote:
  > > Also, I need to see if this can be made to work with cloning from a local repo.
  >
  > I'm **really** not a fan of local / hardlink clones. They are very brittle. When you start throwing extra repo features like LFS into the mix, it becomes even more dangerous. Especially when we start talking about adding modifying `.hg/requires` automatically. The fundamental problem is the hardlink clone is strictly separate but it "inherits" some state from its parent. If we start varying behavior of the two repos, interaction between them can be wonky. In general, for advanced features, we should go through the "hg clone --pull" interface to create a clean break and minimize potential for wonkiness.
  
  
  What's brittle about it, assuming clone implies exact copy?  I'm vaguely aware of filesystem bugs around detecting hardlinks, but I thought that was basically solved by the whitelist of filesystems.
  
  I'm fine with picking this up next cycle, but I was tinkering with trying to address @yuja's concerns in https://phab.mercurial-scm.org/D4713, and it looks like this already works with a local clone.  It looks like local clone doesn't call localrepo.createrepository(), rather it just calls localrepo.makerepository() twice for the source and destination, and reads the existing requirements file.  So I don't see an obvious way to warn about autoloading largefiles when cloning, and not being obnoxious and warning when any command is run.  (I do see the different behavior below with `clone --pull`.)
  
    diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
    --- a/mercurial/localrepo.py
    +++ b/mercurial/localrepo.py
    @@ -456,6 +456,7 @@ def makelocalrepository(baseui, path, in
         else:
             extensions.loadall(ui)
    
    +    print('makerepo for %s, requirements are %s' % (path, requirements))
         # Set of module names of extensions loaded for this repository.
         extensionmodulenames = {m.__name__ for n, m in extensions.extensions(ui)}
    
    @@ -2809,6 +2810,7 @@ def undoname(fn):
     def instance(ui, path, create, intents=None, createopts=None):
         localpath = util.urllocalpath(path)
         if create:
    +        print('*** create repo on %s' % localpath)
             createrepository(ui, localpath, createopts=createopts)
    
         return makelocalrepository(ui, localpath, intents=intents)
    diff --git a/tests/test-largefiles-small-disk.t b/tests/test-largefiles-small-disk.t
    --- a/tests/test-largefiles-small-disk.t
    +++ b/tests/test-largefiles-small-disk.t
    @@ -28,14 +28,20 @@ Test how largefiles abort in case the di
       > util.oslink = oslink
       > EOF
    
    +  $ cp $HGRCPATH $HGRCPATH.orig
    +
       $ echo "[extensions]" >> $HGRCPATH
       $ echo "largefiles =" >> $HGRCPATH
    
       $ hg init alice
    +  *** create repo on alice
    +  makerepo for alice, requirements are set(['dotencode', 'generaldelta', 'fncache', 'store', 'revlogv1'])
       $ cd alice
       $ echo "this is a very big file" > big
       $ hg add --large big
    +  makerepo for $TESTTMP\alice, requirements are set(['dotencode', 'generaldelta', 'fncache', 'store', 'revlogv1'])
       $ hg commit --config extensions.criple=$TESTTMP/criple.py -m big
    +  makerepo for $TESTTMP\alice, requirements are set(['dotencode', 'generaldelta', 'fncache', 'store', 'revlogv1'])
       abort: No space left on device
       [255]
    
    @@ -52,12 +58,16 @@ The user cache is not even created:
     Make the commit with space on the device:
    
       $ hg commit -m big
    +  makerepo for $TESTTMP\alice, requirements are set(['dotencode', 'generaldelta', 'fncache', 'store', 'revlogv1'])
    
     Now make a clone with a full disk, and make sure lfutil.link function
     makes copies instead of hardlinks:
    
       $ cd ..
       $ hg --config extensions.criple=$TESTTMP/criple.py clone --pull alice bob
    +  makerepo for alice, requirements are set(['dotencode', 'largefiles', 'fncache', 'store', 'generaldelta', 'revlogv1'])
    +  *** create repo on bob
    +  makerepo for bob, requirements are set(['dotencode', 'generaldelta', 'fncache', 'store', 'revlogv1'])
       requesting all changes
       adding changesets
       adding manifests
    @@ -73,3 +83,30 @@ The largefile is not created in .hg/larg
    
       $ ls bob/.hg/largefiles
       dirstate
    +
    +  $ cp -f $HGRCPATH.orig $HGRCPATH
    +.  $ cat >> alice/.hg/hgrc <<EOF
    +.  > [extensions]
    +.  > largefiles =
    +.  > EOF
    +
    +  $ hg clone alice charlie
    +  makerepo for alice, requirements are set(['dotencode', 'largefiles', 'fncache', 'store', 'generaldelta', 'revlogv1'])
    +  makerepo for charlie, requirements are set(['dotencode', 'largefiles', 'fncache', 'store', 'generaldelta', 'revlogv1'])
    +  updating to branch default
    +  getting changed largefiles
    +  1 largefiles updated, 0 removed
    +  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
    +
    +  $ cd charlie
    +  $ grep largefiles .hg/requires
    +  largefiles
    +  $ hg init nested
    +  *** create repo on nested
    +  makerepo for nested, requirements are set(['dotencode', 'generaldelta', 'fncache', 'store', 'revlogv1'])
    +  $ cat nested/.hg/requires
    +  dotencode
    +  fncache
    +  generaldelta
    +  revlogv1
    +  store

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D5130

To: mharbison72, indygreg, #hg-reviewers
Cc: yuja, mercurial-devel