tests/test-narrow-sparse.t

localrepo: stop doing special dirstate backup at transaction open

Since the dirstate writes are already managed by the transaction, we already do
a backup of the dirstate when necessary (and even trigger one to keep `hg
rollback` happy).

We needs some special code to deal with the initial empty checkout, but it is
not too complicated.

Managing variable filename (as dirstate-v2 uses) at the "journalfile" level, is
complex and fragile (which is consistent with the fact these files are not
journal…). If we no longer do it, our life is significantly simpler.

In some sense, we apply the xkcd-1134¹ solution to our savebackup/restorebackup
problem.

[1] https://xkcd.com/1134/

(the change to test-hardlink are expect as decreasing the number of duplicated
backup drive the hardlink count down)

Testing interaction of sparse and narrow when both are enabled on the client
side and we do a non-ellipsis clone

#testcases tree flat
  $ . "$TESTDIR/narrow-library.sh"
  $ cat << EOF >> $HGRCPATH
  > [extensions]
  > sparse =
  > EOF

#if tree
  $ cat << EOF >> $HGRCPATH
  > [experimental]
  > treemanifest = 1
  > EOF
#endif

  $ hg init master
  $ cd master

  $ mkdir inside
  $ echo 'inside' > inside/f
  $ hg add inside/f
  $ hg commit -m 'add inside'

  $ mkdir widest
  $ echo 'widest' > widest/f
  $ hg add widest/f
  $ hg commit -m 'add widest'

  $ mkdir outside
  $ echo 'outside' > outside/f
  $ hg add outside/f
  $ hg commit -m 'add outside'

  $ cd ..

narrow clone the inside file

  $ hg clone --narrow ssh://user@dummy/master narrow --include inside/f
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 1 changes to 1 files
  new changesets *:* (glob)
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd narrow
  $ hg tracked
  I path:inside/f
  $ hg files
  inside/f

XXX: we should have a flag in `hg debugsparse` to list the sparse profile
  $ test -f .hg/sparse
  [1]

  $ hg debugrequires
  dotencode
  dirstate-v2 (dirstate-v2 !)
  fncache
  generaldelta
  narrowhg-experimental
  persistent-nodemap (rust !)
  revlog-compression-zstd (zstd !)
  revlogv1
  share-safe
  sparserevlog
  store
  treemanifest (tree !)

  $ hg debugrebuilddirstate

We only make the following assertions for the flat test case since in the
treemanifest test case debugsparse fails with "path ends in directory
separator: outside/" which seems like a bug unrelated to the regression this is
testing for.

#if flat
widening with both sparse and narrow is possible

  $ cat >> .hg/hgrc <<EOF
  > [extensions]
  > sparse = 
  > narrow = 
  > EOF

  $ hg debugsparse -X outside/f -X widest/f
  $ hg tracked -q --addinclude outside/f
  $ find . -name .hg -prune -o -type f -print | sort
  ./inside/f

  $ hg debugsparse -d outside/f
  $ find . -name .hg -prune -o -type f -print | sort
  ./inside/f
  ./outside/f
#endif