tests/test-demandimport.py

build: for the bootstrap phase of a deb/rpm build pure-py mercurial is enough

When bootstrapping a deb/rpm build, packagelib.sh starts performing a local
build for the sole purpose of parsing the output of "hg version".
Then it "hg archive"s the source code, and builds everything again.

For that initial step, we are perfectly good in using a pure python mercurial,
without compiling the c modules (base85, bdiff, zstdlib, ...).

On my personal system, this cuts down 22 seconds for a package build (the
bootstrapping build goes from ~30 to ~8 seconds).

from __future__ import absolute_import, print_function

from mercurial import demandimport
demandimport.enable()

import os
import subprocess
import sys

# Only run if demandimport is allowed
if subprocess.call(['python', '%s/hghave' % os.environ['TESTDIR'],
                    'demandimport']):
    sys.exit(80)

if os.name != 'nt':
    try:
        import distutils.msvc9compiler
        print('distutils.msvc9compiler needs to be an immediate '
              'importerror on non-windows platforms')
        distutils.msvc9compiler
    except ImportError:
        pass

import re

rsub = re.sub
def f(obj):
    l = repr(obj)
    l = rsub("0x[0-9a-fA-F]+", "0x?", l)
    l = rsub("from '.*'", "from '?'", l)
    l = rsub("'<[a-z]*>'", "'<whatever>'", l)
    return l

import os

print("os =", f(os))
print("os.system =", f(os.system))
print("os =", f(os))

from mercurial import util

print("util =", f(util))
print("util.system =", f(util.system))
print("util =", f(util))
print("util.system =", f(util.system))

from mercurial import hgweb
print("hgweb =", f(hgweb))
print("hgweb_mod =", f(hgweb.hgweb_mod))
print("hgweb =", f(hgweb))

import re as fred
print("fred =", f(fred))

import re as remod
print("remod =", f(remod))

import sys as re
print("re =", f(re))

print("fred =", f(fred))
print("fred.sub =", f(fred.sub))
print("fred =", f(fred))

remod.escape  # use remod
print("remod =", f(remod))

print("re =", f(re))
print("re.stderr =", f(re.stderr))
print("re =", f(re))

# Test access to special attributes through demandmod proxy
from mercurial import pvec as pvecproxy
print("pvecproxy =", f(pvecproxy))
print("pvecproxy.__doc__ = %r"
      % (' '.join(pvecproxy.__doc__.split()[:3]) + ' ...'))
print("pvecproxy.__name__ = %r" % pvecproxy.__name__)
# __name__ must be accessible via __dict__ so the relative imports can be
# resolved
print("pvecproxy.__dict__['__name__'] = %r" % pvecproxy.__dict__['__name__'])
print("pvecproxy =", f(pvecproxy))

import contextlib
print("contextlib =", f(contextlib))
try:
    from contextlib import unknownattr
    print('no demandmod should be created for attribute of non-package '
          'module:\ncontextlib.unknownattr =', f(unknownattr))
except ImportError as inst:
    print('contextlib.unknownattr = ImportError: %s'
          % rsub(r"'", '', str(inst)))

# Unlike the import statement, __import__() function should not raise
# ImportError even if fromlist has an unknown item
# (see Python/import.c:import_module_level() and ensure_fromlist())
contextlibimp = __import__('contextlib', globals(), locals(), ['unknownattr'])
print("__import__('contextlib', ..., ['unknownattr']) =", f(contextlibimp))
print("hasattr(contextlibimp, 'unknownattr') =",
      util.safehasattr(contextlibimp, 'unknownattr'))

demandimport.disable()
os.environ['HGDEMANDIMPORT'] = 'disable'
# this enable call should not actually enable demandimport!
demandimport.enable()
from mercurial import node
print("node =", f(node))