tests/test-check-py3-compat.t

template: add predecessors template

Add a 'predecessors' template that returns the list of all closest known
predecessors for a changectx. The elements of the list are row changectx node id
formatted by default as short nodes.

The "closest predecessors" are the first locally known revisions encountered
while, walking predecessors markers. For example:

  1) If a (A, (B)) markers exists and both A and B are locally known A is a
  closest predecessors of B.

  2) If a (A, (B)) and (B, (C)) markers exists and only A and C are known
  locally, A will be the closest precursors of C.

This logic respect repository filtering. So hidden revision will be skipped by
this logic unless --hidden is specified. Since we only display the visible
predecessors, this template will not display anything in most case. It makes a
good candidate for inclusion in the default log output.

I added a new test-file for testing the precursors in various scenarios. This
test file will also be used for the successors template.

A new "obsutil" module has been added to start gathering utility function
outside of the large obsolete.py module.

#require test-repo

  $ . "$TESTDIR/helpers-testrepo.sh"
  $ cd "$TESTDIR"/..

  $ hg files 'set:(**.py)' | sed 's|\\|/|g' | xargs python contrib/check-py3-compat.py
  contrib/python-zstandard/setup.py not using absolute_import
  contrib/python-zstandard/setup_zstd.py not using absolute_import
  contrib/python-zstandard/tests/common.py not using absolute_import
  contrib/python-zstandard/tests/test_buffer_util.py not using absolute_import
  contrib/python-zstandard/tests/test_compressor.py not using absolute_import
  contrib/python-zstandard/tests/test_compressor_fuzzing.py not using absolute_import
  contrib/python-zstandard/tests/test_data_structures.py not using absolute_import
  contrib/python-zstandard/tests/test_data_structures_fuzzing.py not using absolute_import
  contrib/python-zstandard/tests/test_decompressor.py not using absolute_import
  contrib/python-zstandard/tests/test_decompressor_fuzzing.py not using absolute_import
  contrib/python-zstandard/tests/test_estimate_sizes.py not using absolute_import
  contrib/python-zstandard/tests/test_module_attributes.py not using absolute_import
  contrib/python-zstandard/tests/test_train_dictionary.py not using absolute_import
  i18n/check-translation.py not using absolute_import
  setup.py not using absolute_import
  tests/test-demandimport.py not using absolute_import

#if py3exe
  $ hg files 'set:(**.py) - grep(pygments)' -X hgext/fsmonitor/pywatchman \
  > | sed 's|\\|/|g' | xargs $PYTHON3 contrib/check-py3-compat.py \
  > | sed 's/[0-9][0-9]*)$/*)/'
  hgext/convert/transport.py: error importing: <*Error> No module named 'svn.client' (error at transport.py:*) (glob)
  mercurial/cffi/bdiff.py: error importing: <ImportError> cannot import name '_bdiff' (error at bdiff.py:*)
  mercurial/cffi/bdiffbuild.py: error importing: <ImportError> No module named 'cffi' (error at bdiffbuild.py:*)
  mercurial/cffi/mpatch.py: error importing: <ImportError> cannot import name '_mpatch' (error at mpatch.py:*)
  mercurial/cffi/mpatchbuild.py: error importing: <ImportError> No module named 'cffi' (error at mpatchbuild.py:*)
  mercurial/cffi/osutilbuild.py: error importing: <ImportError> No module named 'cffi' (error at osutilbuild.py:*)
  mercurial/scmwindows.py: error importing: <*Error> No module named 'msvcrt' (error at win32.py:*) (glob)
  mercurial/win32.py: error importing: <*Error> No module named 'msvcrt' (error at win32.py:*) (glob)
  mercurial/windows.py: error importing: <*Error> No module named 'msvcrt' (error at windows.py:*) (glob)

#endif

#if py3exe py3pygments
  $ hg files 'set:(**.py) and grep(pygments)' | sed 's|\\|/|g' \
  > | xargs $PYTHON3 contrib/check-py3-compat.py \
  > | sed 's/[0-9][0-9]*)$/*)/'
#endif