Description

youknowone

opened on Jun 14, 2022

Issue body actions

Bug report

itertools.chain.from_iterable is safe to use with infinite iterable, but no test exists.

example:

chain.from_iterable(repeat(range(5)))

Your environment

• CPython versions tested on:
  3.10.4 and current main branch

• Operating system and architecture:
  N/A

Activity

1. youknowone

   added

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   on Jun 14, 2022
2. AlexWaygood

   added

   testsTests in the Lib/test dirTests in the Lib/test dir

   on Jun 14, 2022
3. AlexWaygood

   assigned

   rhettinger

   on Jun 14, 2022
4. rhettinger commented on Jun 14, 2022

   

   rhettinger

   on Jun 14, 2022

   Contributor

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   ISTM there is no point in adding another test for this. Infinite iterators a just a special case of "bigger than you can reasonably consume".

   From a consumers point of view, there is no way to differentiate an infinite iterator from a huge iterator (c.f. the halting problem).
5. youknowone commented on Jun 14, 2022

   

   youknowone

   on Jun 14, 2022

   ContributorAuthor

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   The test will prevent a potential regression to evaluate given iterable before consuming.

   Please let me know if there is a test already covers a huge iterator.
   I found test_long_chain_of_empty_iterables is a similar one, but it doesn't fully prevent it.

   ref: RustPython/RustPython#3787
6. miss-islington

   closed this as completedin #93815on Jun 14, 2022
7. miss-islington

   added a commit that references this issue on Jun 14, 2022

   gh-93814: Add infinite test for itertools.chain.from_iterable (GH-93815)

   274769c
8. serhiy-storchaka

   added a commit that references this issue on Jun 26, 2022

   Revert 30935 defer bpo45162 to 312 (#94285)

   1ffde3e

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