Speed up make_simplified_union for Literal[string]s (issue #9169) #9192
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travis has actually passed, it just doesn't show up like that on github for whatever reason |
JukkaL
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Jul 31, 2020
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Thanks for the performance fix!
This looks like a reasonable workaround for the immediate issue. A more general fix could split the items into literal and non-literal types, and manipulate the literal items using the more efficient algorithm, but also efficiently support unions containing non-literal types.
Changing mypy so that the simplification happens less often would definitely be nice, but it will be non-trivial to implement.
mypy used to be like that, but 25b1c4d broke it |
huguesb
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In PR python#9192 a fast path was created to address the slowness reported in issue python#9169 wherein large Union or literal types would dramatically slow down typechecking. It is desirable to extend this fast path to cover Enum types, as these can also leverage the O(n) set-based fast path instead of the O(n**2) fallback. This is seen to bring down the typechecking of a single fairly simple chain of `if` statements operating on a large enum (~3k members) from ~40min to 12s in real-world code! Note that the timing is taken from a pure-python run of mypy, as opposed to a compiled version.
huguesb
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Sep 1, 2020
In PR python#9192 a fast path was created to address the slowness reported in issue python#9169 wherein large Union or literal types would dramatically slow down typechecking. It is desirable to extend this fast path to cover Enum types, as these can also leverage the O(n) set-based fast path instead of the O(n**2) fallback. This is seen to bring down the typechecking of a single fairly simple chain of `if` statements operating on a large enum (~3k members) from ~40min to 12s in real-world code! Note that the timing is taken from a pure-python run of mypy, as opposed to a compiled version.
huguesb
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Sep 2, 2020
In PR python#9192 a fast path was created to address the slowness reported in issue python#9169 wherein large Union or literal types would dramatically slow down typechecking. It is desirable to extend this fast path to cover Enum types, as these can also leverage the O(n) set-based fast path instead of the O(n**2) fallback. This is seen to bring down the typechecking of a single fairly simple chain of `if` statements operating on a large enum (~3k members) from ~40min to 12s in real-world code! Note that the timing is taken from a pure-python run of mypy, as opposed to a compiled version.
huguesb
added a commit
to huguesb/mypy
that referenced
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Sep 2, 2020
In PR python#9192 a fast path was created to address the slowness reported in issue python#9169 wherein large Union or literal types would dramatically slow down typechecking. It is desirable to extend this fast path to cover Enum types, as these can also leverage the O(n) set-based fast path instead of the O(n**2) fallback. This is seen to bring down the typechecking of a single fairly simple chain of `if` statements operating on a large enum (~3k members) from ~40min to 12s in real-world code! Note that the timing is taken from a pure-python run of mypy, as opposed to a compiled version.
huguesb
added a commit
to huguesb/mypy
that referenced
this pull request
Sep 2, 2020
In PR python#9192 a fast path was created to address the slowness reported in issue python#9169 wherein large Union or literal types would dramatically slow down typechecking. It is desirable to extend this fast path to cover Enum types, as these can also leverage the O(n) set-based fast path instead of the O(n**2) fallback. This is seen to bring down the typechecking of a single fairly simple chain of `if` statements operating on a large enum (~3k members) from ~40min to 12s in real-world code! Note that the timing is taken from a pure-python run of mypy, as opposed to a compiled version.
huguesb
added a commit
to huguesb/mypy
that referenced
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Sep 3, 2020
In PR python#9192 a fast path was created to address the slowness reported in issue python#9169 wherein large Union or literal types would dramatically slow down typechecking. It is desirable to extend this fast path to cover Enum types, as these can also leverage the O(n) set-based fast path instead of the O(n**2) fallback. This is seen to bring down the typechecking of a single fairly simple chain of `if` statements operating on a large enum (~3k members) from ~40min to 12s in real-world code! Note that the timing is taken from a pure-python run of mypy, as opposed to a compiled version.
huguesb
added a commit
to huguesb/mypy
that referenced
this pull request
Sep 3, 2020
In PR python#9192 a fast path was created to address the slowness reported in issue python#9169 wherein large Union or literal types would dramatically slow down typechecking. It is desirable to extend this fast path to cover Enum types, as these can also leverage the O(n) set-based fast path instead of the O(n**2) fallback. This is seen to bring down the typechecking of a single fairly simple chain of `if` statements operating on a large enum (~3k members) from ~40min to 12s in real-world code! Note that the timing is taken from a pure-python run of mypy, as opposed to a compiled version.
msullivan
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Jul 7, 2021
In PR #9192 a fast path was created to address the slowness reported in issue #9169 wherein large Union or literal types would dramatically slow down typechecking. It is desirable to extend this fast path to cover Enum types, as these can also leverage the O(n) set-based fast path instead of the O(n**2) fallback. This is seen to bring down the typechecking of a single fairly simple chain of `if` statements operating on a large enum (~3k members) from ~40min to 12s in real-world code! Note that the timing is taken from a pure-python run of mypy, as opposed to a compiled version.
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make_simplified_unionno longer runs for 0.5 seconds every time it's called with a Union containing 270 literals of strings.like I explained in #9169, this only fixes half of the problem and I'm not capable of fixing the other half. This function is still called 1098 times for the "reduced" example code, and IMO it should be called only once.