# \#method-invalidation

**URL:** https://discourse.julialang.org/tag/method-invalidation/475.md

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## [Why is v1.12 "more prone to invalidations"?](https://discourse.julialang.org/t/why-is-v1-12-more-prone-to-invalidations/134327)

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**Author:** [@mattsignorelli](https://discourse.julialang.org/u/mattsignorelli)\
**Replies:** 0\
**Last updated:** [December 3, 2025, 12:15pm UTC](https://discourse.julialang.org/t/why-is-v1-12-more-prone-to-invalidations/134327 "2025-12-03T12:15:43Z")

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When v1.12.0 was first released some time ago, my precompile script immediately stopped being effective, even though my code was unchanged. In particular, it was ineffective if IJulia.jl was also loaded. The full details…

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## [Mystery of invalidations in V\>1.10. Even in precompiled code](https://discourse.julialang.org/t/mystery-of-invalidations-in-v-1-10-even-in-precompiled-code/132081)

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**Author:** [@joa-quim](https://discourse.julialang.org/u/joa-quim)\
**Replies:** 10\
**Last updated:** [September 7, 2025, 3:42pm UTC](https://discourse.julialang.org/t/mystery-of-invalidations-in-v-1-10-even-in-precompiled-code/132081 "2025-09-07T15:42:15Z")

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I have reported before the very large degradation in TTFP in GMT for version 1.11 and later. One example as reminder | | |\_| | | | (\_| | | Version 1.10.10 (2025-06-27) \_/ |\\\_\_'\_|\_|\_|\\\_\_'\_| | Official https://juli…

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## [Unexpected allocations after re-including unchanged file in ODE simulation](https://discourse.julialang.org/t/unexpected-allocations-after-re-including-unchanged-file-in-ode-simulation/131445)

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**Author:** [@Vladislav](https://discourse.julialang.org/u/Vladislav)\
**Replies:** 2\
**Last updated:** [August 8, 2025, 4:10am UTC](https://discourse.julialang.org/t/unexpected-allocations-after-re-including-unchanged-file-in-ode-simulation/131445 "2025-08-08T04:10:15Z")

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Hello! I’m running a large number of parallel Monte Carlo simulations, so I’m working to minimize memory allocations in my code. While doing this, I encountered some behavior I don’t fully understand. I’m using Julia V…

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## [How to benefit from package specific @recompile\_invalidations when developing the same package?](https://discourse.julialang.org/t/how-to-benefit-from-package-specific-recompile-invalidations-when-developing-the-same-package/120805)

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**Author:** [@frankier](https://discourse.julialang.org/u/frankier)\
**Replies:** 3\
**Last updated:** [October 27, 2024, 11:41am UTC](https://discourse.julialang.org/t/how-to-benefit-from-package-specific-recompile-invalidations-when-developing-the-same-package/120805 "2024-10-27T11:41:08Z")

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I have a package MyPackage that loads stuff in an order that ends up invalidating a lot of Makie. using DependencyA using Makie Long term I would like to solve it, but for now I would just like to work around it. If I …

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## [How bad is it if x \< y doesn't return a Bool?](https://discourse.julialang.org/t/how-bad-is-it-if-x-y-doesnt-return-a-bool/114611)

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**Author:** [@gdalle](https://discourse.julialang.org/u/gdalle)\
**Replies:** 22\
**Last updated:** [May 24, 2024, 6:30am UTC](https://discourse.julialang.org/t/how-bad-is-it-if-x-y-doesnt-return-a-bool/114611 "2024-05-24T06:30:27Z")

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Suppose I define a number type T for which order comparison is not meaningful: \<(x::T, y::T) doesn’t make any mathematical sense, because T actually contains a set. There are good reasons why I’m doing this, see SparseCo…

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## [Case Study: Method Invalidations caused by Pkg.jl with Julia 1.11](https://discourse.julialang.org/t/case-study-method-invalidations-caused-by-pkg-jl-with-julia-1-11/109038)

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**Author:** [@mkitti](https://discourse.julialang.org/u/mkitti)\
**Replies:** 13\
**Last updated:** [January 23, 2024, 7:26pm UTC](https://discourse.julialang.org/t/case-study-method-invalidations-caused-by-pkg-jl-with-julia-1-11/109038 "2024-01-23T19:26:07Z")

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Introduction When using Julia nightly, to be Julia 1.11, I noticed that loading Pkg.jl causes method invalidations. As of Julia 1.11, Pkg.jl is no longer part of the system image and is thus a normal package. Thus, Pkg.j…

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## [StaticArrays forces recompilation of JLLs on Windows with Julia 1.8.1](https://discourse.julialang.org/t/staticarrays-forces-recompilation-of-jlls-on-windows-with-julia-1-8-1/87725)

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**Author:** [@mkitti](https://discourse.julialang.org/u/mkitti)\
**Replies:** 18\
**Last updated:** [January 9, 2024, 12:59pm UTC](https://discourse.julialang.org/t/staticarrays-forces-recompilation-of-jlls-on-windows-with-julia-1-8-1/87725 "2024-01-09T12:59:40Z")

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Eric Davies, @longemen3000, I and others encountered an unexpected result after looking at @time\_imports and discussed it on Slack. Something was forcing JLL packages to recompile a lot of code. We narrowed it down to th…

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## [Invalidation from extending \`Base.reduce\_first\`](https://discourse.julialang.org/t/invalidation-from-extending-base-reduce-first/103146)

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**Author:** [@jishnub](https://discourse.julialang.org/u/jishnub)\
**Replies:** 1\
**Last updated:** [August 24, 2023, 9:09am UTC](https://discourse.julialang.org/t/invalidation-from-extending-base-reduce-first/103146 "2023-08-24T09:09:37Z")

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FillArrays has recently introduced a specialization Base.reduce\_first(::typeof(+), x::Ones) = Fill(Base.reduce\_first(+, getindex\_value(x)), axes(x)) On v1.10.0-beta2, this seems to introduce invalidations (although not…

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## [Name this method extension technique, piracy evasion](https://discourse.julialang.org/t/name-this-method-extension-technique-piracy-evasion/101099)

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**Author:** [@mkitti](https://discourse.julialang.org/u/mkitti)\
**Replies:** 21\
**Last updated:** [July 4, 2023, 7:42am UTC](https://discourse.julialang.org/t/name-this-method-extension-technique-piracy-evasion/101099 "2023-07-04T07:42:40Z")

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Let’s say I want to change how Base.write works with a Base type, NTuple{N,UInt8} from a package. Currently, writing NTuple via Base.write errors. julia\> iob = IOBuffer() IOBuffer(data=UInt8\[...\], readable=true, writab…

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## [Optional multiple dispatch with Glue Packages?](https://discourse.julialang.org/t/optional-multiple-dispatch-with-glue-packages/93480)

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**Author:** [@mkitti](https://discourse.julialang.org/u/mkitti)\
**Replies:** 8\
**Last updated:** [January 25, 2023, 5:44pm UTC](https://discourse.julialang.org/t/optional-multiple-dispatch-with-glue-packages/93480 "2023-01-25T17:44:54Z")

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Now that built in glue packages are on their way, I wonder if it is worthwhile to consider a new design pattern of optional multiple dispatch. Typically in Julia we tend to take advantage of multiple dispatch rather tha…

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## [How to resolve this method invalidation for \`all\` introduced by loading FillArrays?](https://discourse.julialang.org/t/how-to-resolve-this-method-invalidation-for-all-introduced-by-loading-fillarrays/92417)

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**Author:** [@jishnub](https://discourse.julialang.org/u/jishnub)\
**Replies:** 0\
**Last updated:** [January 2, 2023, 1:39pm UTC](https://discourse.julialang.org/t/how-to-resolve-this-method-invalidation-for-all-introduced-by-loading-fillarrays/92417 "2023-01-02T13:39:11Z")

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julia\> using SnoopCompileCore julia\> invalidations = @snoopr using FillArrays; julia\> using SnoopCompile julia\> trees = invalidation\_trees(invalidations); julia\> trees\[end\] inserting all(f::Function, x::FillArrays.Ab…

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## [CategoricalArrays forces OpenSpecFun\_jll recompilation](https://discourse.julialang.org/t/categoricalarrays-forces-openspecfun-jll-recompilation/87759)

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**Author:** [@mkitti](https://discourse.julialang.org/u/mkitti)\
**Replies:** 25\
**Last updated:** [September 26, 2022, 4:47pm UTC](https://discourse.julialang.org/t/categoricalarrays-forces-openspecfun-jll-recompilation/87759 "2022-09-26T16:47:58Z")

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@tim.holy here’s a fresh invalidation issue. CategoricalArrays seems to invalidate OpenSpecFun\_jll compilation. \_ \_ \_(\_)\_ | Documentation: https://docs.julialang.org (\_) | (\_) (\_) | \_ \_ \_| |\_…

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## [How to define \`promote\_rule\` without including \`Union{}\` as an argument?](https://discourse.julialang.org/t/how-to-define-promote-rule-without-including-union-as-an-argument/85609)

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**Author:** [@jishnub](https://discourse.julialang.org/u/jishnub)\
**Replies:** 0\
**Last updated:** [August 11, 2022, 8:54am UTC](https://discourse.julialang.org/t/how-to-define-promote-rule-without-including-union-as-an-argument/85609 "2022-08-11T08:54:28Z")

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E.g., while using Polynomials.jl, julia\> @which promote\_rule(Polynomial{Int}, Union{}) promote\_rule(::Type{\<:AbstractPolynomial{T}}, ::Type{\<:AbstractPolynomial{S}}) where {T, S} @ Polynomials ~/Dropbox/JuliaPackag…

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## [How are invalidated MethodInstances found, and how well does the process scale?](https://discourse.julialang.org/t/how-are-invalidated-methodinstances-found-and-how-well-does-the-process-scale/83099)

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**Author:** [@Benny](https://discourse.julialang.org/u/Benny)\
**Replies:** 7\
**Last updated:** [June 22, 2022, 7:54am UTC](https://discourse.julialang.org/t/how-are-invalidated-methodinstances-found-and-how-well-does-the-process-scale/83099 "2022-06-22T07:54:52Z")

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From what I understand, compiled methods (for clarity I’ll call them MethodInstances) are invalidated when methods are defined, e.g. f(x) = 1; f(1); f(x::Real) = 2. I imagine the most wasteful algorithm would be to check…

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## [Why don't macros and modules also have backedges to allow "invalidating" dependent code?](https://discourse.julialang.org/t/why-dont-macros-and-modules-also-have-backedges-to-allow-invalidating-dependent-code/81408)

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**Author:** [@Benny](https://discourse.julialang.org/u/Benny)\
**Replies:** 0\
**Last updated:** [May 21, 2022, 10:07am UTC](https://discourse.julialang.org/t/why-dont-macros-and-modules-also-have-backedges-to-allow-invalidating-dependent-code/81408 "2022-05-21T10:07:32Z")

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Something cool that Julia does is method invalidation. When a method is compiled to a MethodInstance upon a call, assumptions like what methods are dispatched to and compile-time constants are baked in. When a function i…

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## [Invalidation checker for packages \[code snippet\]](https://discourse.julialang.org/t/invalidation-checker-for-packages-code-snippet/54976)

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**Author:** [@Marcell\_Havlik](https://discourse.julialang.org/u/Marcell_Havlik)\
**Replies:** 0\
**Last updated:** [February 10, 2021, 10:02am UTC](https://discourse.julialang.org/t/invalidation-checker-for-packages-code-snippet/54976 "2021-02-10T10:02:29Z")

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Hey, I just wanted to share this code snippet which can be helpful to find where the imported invalidation comes from. using SnoopCompileCore using SnoopCompile using SnoopCompile: countchildren using Pkg using Printf …

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## [A couple questions on compiler latency and method invalidation](https://discourse.julialang.org/t/a-couple-questions-on-compiler-latency-and-method-invalidation/48260)

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**Author:** [@Benny](https://discourse.julialang.org/u/Benny)\
**Replies:** 8\
**Last updated:** [October 15, 2020, 8:11am UTC](https://discourse.julialang.org/t/a-couple-questions-on-compiler-latency-and-method-invalidation/48260 "2020-10-15T08:11:38Z")

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I’ve been looking up compiler latency in Julia after reading the blog post on decreasing method invalidation in version 1.6 \[Analyzing sources of compiler latency in Julia: method invalidations\]. I think I sort of got th…

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## [Numerical optimization function does not get cached](https://discourse.julialang.org/t/numerical-optimization-function-does-not-get-cached/46373)

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**Author:** [@xor0110](https://discourse.julialang.org/u/xor0110)\
**Replies:** 4\
**Last updated:** [September 14, 2020, 6:19pm UTC](https://discourse.julialang.org/t/numerical-optimization-function-does-not-get-cached/46373 "2020-09-14T18:19:06Z")

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I have an application with a number of image analysis functions based on LeastSquaresOptim.jl. The application has to be re-started often, unfortunately — maybe a topic for another post. Every time the application is ran…