Fix for issue #1240.

[kwmsmith]

Calling _str() on a tuple of expressions triggers a __repr__ call on
each element, resulting in unnecessary computation.

This fix detects when stringifying a tuple of exprs, and calls _str()
recursively in that case.

[llllllllll]

Sort of unrelated, but the else clause is just return pformat(s).rstrip()

[llllllllll]

awesome find

[cpcloud]

@kwmsmith Nice job! Can you add a test? Something like this:

def test_str_does_not_repr():
    d = Data([('aa', 1), ('b', 2)], dshape='2 * {a: string, b: int64}')
    expr = transform(d, c=d.a.strlen() + d.b)
    assert str(expr) == 'make sure this does not contain the repr of the underlying data'

[cpcloud]

i'd put that in tests/test_interactive.py

[kwmsmith]

@cpcloud done. Pls take a look at the test -- I have a feeling there's a better way to do the assert.

[cpcloud]

small nitpick can you keep the re.sub call style?

i also think that even though the name of the expression is an implementation detail it should be consistently numbered and therefore it'd be okay to not do the replace and just keep _1 or whatever it happens to be

[kwmsmith]

I thought of doing that, but my concern is that the _149 (I think that's the symbol) is not necessarily reproducible run-to-run, especially with py.test running things in parallel. Is it reproducible? If so, then I'll make the replacement and remove the re.sub call.

[kwmsmith]

The generated symbol name appears to be test order dependent. When I run the standard testsuite command (py.test --doctest-modules --pyargs blaze) it's assigned _179, and when I run py.test -x --pyargs blaze, it's assigned _177:

$ py.test --doctest-modules --pyargs blaze

[...]
=============================================================== FAILURES ===============================================================
________________________________________________________ test_str_does_not_repr ________________________________________________________

    def test_str_does_not_repr():
        # see GH issue #1240.
        d = Data([('aa', 1), ('b', 2)], dshape='2 * {a: string, b: int64}')
        expr = transform(d, c=d.a.strlen() + d.b)
>       assert str(expr) == "Merge(_child=_149, children=(_149, label(strlen(_child=_149.a) + _149.b, 'c')))"
E       assert "Merge(_child...179.b, 'c')))" == "Merge(_child=...149.b, 'c')))"
E         - Merge(_child=_179, children=(_179, label(strlen(_child=_179.a) + _179.b, 'c')))
E         ?                ^               ^                         ^         ^
E         + Merge(_child=_149, children=(_149, label(strlen(_child=_149.a) + _149.b, 'c')))
E         ?                ^               ^                         ^         ^

blaze/tests/test_interactive.py:102: AssertionError
========================== 1 failed, 1014 passed, 44 skipped, 27 xfailed, 3 xpassed, 2 error in 12.33 seconds ==========================

And:

$ py.test -x --pyargs blaze
[...]
=============================================================== FAILURES ===============================================================
________________________________________________________ test_str_does_not_repr ________________________________________________________

    def test_str_does_not_repr():
        # see GH issue #1240.
        d = Data([('aa', 1), ('b', 2)], dshape='2 * {a: string, b: int64}')
        expr = transform(d, c=d.a.strlen() + d.b)
>       assert str(expr) == "Merge(_child=_149, children=(_149, label(strlen(_child=_149.a) + _149.b, 'c')))"
E       assert "Merge(_child...177.b, 'c')))" == "Merge(_child=...149.b, 'c')))"
E         - Merge(_child=_177, children=(_177, label(strlen(_child=_177.a) + _177.b, 'c')))
E         ?                ^^              ^^                        ^^        ^^
E         + Merge(_child=_149, children=(_149, label(strlen(_child=_149.a) + _149.b, 'c')))
E         ?                ^^              ^^                        ^^        ^^

blaze/tests/test_interactive.py:102: AssertionError
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Interrupted: stopping after 1 failures !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
=============================== 1 failed, 819 passed, 41 skipped, 26 xfailed, 2 xpassed in 11.44 seconds ===============================

[llllllllll]

Can you explicitly name the interactive symbol? Does the name argument appear as the name in the str?

[kwmsmith]

@llllllllll thanks for pointing that out, it works great.

[cpcloud]

@kwmsmith Thanks for finding and fixing this!

[kwmsmith]

@cpcloud @llllllllll I'm glad we got it fixed and that the fix itself was straightforward. Thanks for your help!