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Fix lambda expression's unexpected UnboundLocalError #4226

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Merged
youknowone merged 2 commits into from
Oct 17, 2022
Merged

Fix lambda expression's unexpected UnboundLocalError #4226

youknowone merged 2 commits into from
Oct 17, 2022

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@jopemachine
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@jopemachine jopemachine commented Oct 16, 2022 •
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This PR trying to fix #3934.

I think the compile context of the lambda expression should be resolved as Function after executing enter_function like in the compile_function_def.

The detailed explanations are in the above issue's comments.

Result

Example code:

>>>>> class X:
.....   v = 999
.....   f = lambda x=v:x
..... 
>>>>>

Example code's bytecodes:

  1           0 LoadGlobal           (0, __name__)
              1 StoreLocal           (1, __module__)
              2 LoadConst            ("X")
              3 StoreLocal           (2, __qualname__)
              4 LoadConst            (None)
              5 StoreLocal           (3, __doc__)

  2           6 LoadConst            (999)
              7 StoreLocal           (4, v)

  3           8 LoadNameAny          (4, v)
              9 BuildTuple           (1, false)
             10 LoadConst            (<code object <lambda> at ??? file "a.py", line 3>)
             11 LoadConst            ("<lambda>")
             12 MakeFunction         (DEFAULTS)
             13 StoreLocal           (5, f)
             14 LoadConst            (None)
             15 ReturnValue

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youknowone commented Oct 16, 2022

awesome, would you add the example code in #3934 under extra_tests/snippets?

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jopemachine commented Oct 17, 2022

awesome, would you add the example code in #3934 under extra_tests/snippets?

Sure, I added the issue's example code directly.
If I should add more extra tests, please let me know for more work.

youknowone
youknowone approved these changes Oct 17, 2022
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because the bug is more like scope bug than lambda itself, I changed the test file name

@youknowone youknowone merged commit 72332c9 into RustPython:main Oct 17, 2022
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member field + lambda results unexpected UnboundLocalError

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