view tests/test-extensions-wrapfunction.py @ 47055:553451522113 stable

extensions: ignore exceptions from an extension's `getversion()` method

This method is usually called when there's a stacktrace being generated, or with
`hg version -v`.  Raising another exception risks mangling the bug report info.

I hit this issue when trying to add the method to the keyring extension to
report the version of the extension and the underlying module, and ran into
demandimport issues prior to py3.8.  It seems like a wise thing to do anyway,
though unfortunately there's no convenient `ui` object around to issue a
warning.  Use 'unknown' to signal that it tried to report a version and failed,
unlike the default case of printing nothing.

Differential Revision: https://phab.mercurial-scm.org/D10540

from __future__ import absolute_import, print_function

from mercurial import extensions


def genwrapper(x):
    def f(orig, *args, **kwds):
        return [x] + orig(*args, **kwds)

    f.x = x
    return f


def getid(wrapper):
    return getattr(wrapper, 'x', '-')


wrappers = [genwrapper(i) for i in range(5)]


class dummyclass(object):
    def getstack(self):
        return ['orig']


dummy = dummyclass()


def batchwrap(wrappers):
    for w in wrappers:
        extensions.wrapfunction(dummy, 'getstack', w)
        print('wrap %d: %s' % (getid(w), dummy.getstack()))


def batchunwrap(wrappers):
    for w in wrappers:
        result = None
        try:
            result = extensions.unwrapfunction(dummy, 'getstack', w)
            msg = str(dummy.getstack())
        except (ValueError, IndexError) as e:
            msg = e.__class__.__name__
        print('unwrap %s: %s: %s' % (getid(w), getid(result), msg))


batchwrap(wrappers + [wrappers[0]])
batchunwrap(
    [
        (wrappers[i] if i is not None and i >= 0 else None)
        for i in [3, None, 0, 4, 0, 2, 1, None]
    ]
)

wrap0 = extensions.wrappedfunction(dummy, 'getstack', wrappers[0])
wrap1 = extensions.wrappedfunction(dummy, 'getstack', wrappers[1])

# Use them in a different order from how they were created to check that
# the wrapping happens in __enter__, not in __init__
print('context manager', dummy.getstack())
with wrap1:
    print('context manager', dummy.getstack())
    with wrap0:
        print('context manager', dummy.getstack())
        # Bad programmer forgets to unwrap the function, but the context
        # managers still unwrap their wrappings.
        extensions.wrapfunction(dummy, 'getstack', wrappers[2])
        print('context manager', dummy.getstack())
    print('context manager', dummy.getstack())
print('context manager', dummy.getstack())

# Wrap callable object which has no __name__
class callableobj(object):
    def __call__(self):
        return ['orig']


dummy.cobj = callableobj()
extensions.wrapfunction(dummy, 'cobj', wrappers[0])
print('wrap callable object', dummy.cobj())