tests/test-sparse-import.t

interfaces: introduce and use a protocol class for the `charencoding` module

See f2832de2a46c for details when this was done for the `bdiff` module.

This lets us dump the hack where the `pure` implementation was imported during
the type checking phase to provide signatures for the module methods it
provides.  Now the protocol classes are starting to shine, because these methods
are provided by `pure.charencoding` and `cext.parsers`, and references to
`cffi.charencoding` and `cext.charencoding` are forwarded to them as appropriate
by the `policy` module.  But none of that matters, as long as the module
returned provides the listed methods.

The interface was copy/pasted from the `pure` module, but `jsonescapeu8fallback`
is omitted because it is accessed from the `pure` module directly when the
escaping fails in the primary module's `jsonescapeu8()`.

test sparse

  $ hg init myrepo
  $ cd myrepo
  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > sparse=
  > purge=
  > strip=
  > rebase=
  > EOF

  $ echo a > index.html
  $ echo x > data.py
  $ echo z > readme.txt
  $ cat > base.sparse <<EOF
  > [include]
  > *.sparse
  > EOF
  $ hg ci -Aqm 'initial'
  $ cat > webpage.sparse <<EOF
  > %include base.sparse
  > [include]
  > *.html
  > EOF
  $ hg ci -Aqm 'initial'

Import a rules file against a 'blank' sparse profile

  $ cat > $TESTTMP/rules_to_import <<EOF
  > [include]
  > *.py
  > EOF
  $ hg debugsparse --import-rules $TESTTMP/rules_to_import
  $ ls -A
  .hg
  data.py

  $ hg debugsparse --reset
  $ rm .hg/sparse

  $ cat > $TESTTMP/rules_to_import <<EOF
  > %include base.sparse
  > [include]
  > *.py
  > EOF
  $ hg debugsparse --import-rules $TESTTMP/rules_to_import
  $ ls -A
  .hg
  base.sparse
  data.py
  webpage.sparse

  $ hg debugsparse --reset
  $ rm .hg/sparse

Start against an existing profile; rules *already active* should be ignored

  $ hg debugsparse --enable-profile webpage.sparse
  $ hg debugsparse --include *.py
  $ cat > $TESTTMP/rules_to_import <<EOF
  > %include base.sparse
  > [include]
  > *.html
  > *.txt
  > [exclude]
  > *.py
  > EOF
  $ hg debugsparse --import-rules $TESTTMP/rules_to_import
  $ ls -A
  .hg
  base.sparse
  index.html
  readme.txt
  webpage.sparse
  $ cat .hg/sparse
  %include webpage.sparse
  [include]
  *.py
  *.txt
  [exclude]
  *.py

  $ hg debugsparse --reset
  $ rm .hg/sparse

Same tests, with -Tjson enabled to output summaries

  $ cat > $TESTTMP/rules_to_import <<EOF
  > [include]
  > *.py
  > EOF
  $ hg debugsparse --import-rules $TESTTMP/rules_to_import -Tjson
  [
   {
    "exclude_rules_added": 0,
    "files_added": 0,
    "files_conflicting": 0,
    "files_dropped": 4,
    "include_rules_added": 1,
    "profiles_added": 0
   }
  ]

  $ hg debugsparse --reset
  $ rm .hg/sparse

  $ cat > $TESTTMP/rules_to_import <<EOF
  > %include base.sparse
  > [include]
  > *.py
  > EOF
  $ hg debugsparse --import-rules $TESTTMP/rules_to_import -Tjson
  [
   {
    "exclude_rules_added": 0,
    "files_added": 0,
    "files_conflicting": 0,
    "files_dropped": 2,
    "include_rules_added": 1,
    "profiles_added": 1
   }
  ]

  $ hg debugsparse --reset
  $ rm .hg/sparse

  $ hg debugsparse --enable-profile webpage.sparse
  $ hg debugsparse --include *.py
  $ cat > $TESTTMP/rules_to_import <<EOF
  > %include base.sparse
  > [include]
  > *.html
  > *.txt
  > [exclude]
  > *.py
  > EOF
  $ hg debugsparse --import-rules $TESTTMP/rules_to_import -Tjson
  [
   {
    "exclude_rules_added": 1,
    "files_added": 1,
    "files_conflicting": 0,
    "files_dropped": 1,
    "include_rules_added": 1,
    "profiles_added": 0
   }
  ]

If importing results in no new rules being added, no refresh should take place!

  $ cat > $TESTTMP/trap_sparse_refresh.py <<EOF
  > from mercurial import error, sparse
  > def extsetup(ui):
  >     def abort_refresh(*args, **kwargs):
  >         raise error.Abort(b'sparse._refresh called!')
  >     sparse.refreshwdir = abort_refresh
  > EOF
  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > trap_sparse_refresh=$TESTTMP/trap_sparse_refresh.py
  > EOF
  $ cat > $TESTTMP/rules_to_import <<EOF
  > [include]
  > *.py
  > EOF
  $ hg debugsparse --import-rules $TESTTMP/rules_to_import

If an exception is raised during refresh, restore the existing rules again.

  $ cat > $TESTTMP/rules_to_import <<EOF
  > [exclude]
  > *.html
  > EOF
  $ hg debugsparse --import-rules $TESTTMP/rules_to_import
  abort: sparse._refresh called!
  [255]
  $ cat .hg/sparse
  %include webpage.sparse
  [include]
  *.py
  *.txt
  [exclude]
  *.py