[mypyc] Support explicit acyclic native classes that avoid gc#20795
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[mypyc] Support explicit acyclic native classes that avoid gc#20795
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Use `@mypyc_attr(acyclic=True)` so that instances of the class don't participate in cyclic gc. This sped up a microbenchmark that just allocates lots of temporary objects by ~60%. Acyclic instances also use less memory, since there is no GC header. I did some manual testing beyond the added tests to ensure acyclic classes work as expected. This was created using Claude Code.
p-sawicki
approved these changes
Feb 13, 2026
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Use
@mypyc_attr(acyclic=True)so that instances of the class don'tparticipate in cyclic gc. This sped up a microbenchmark that just
allocates lots of temporary objects by ~60%. Acyclic instances also
use less memory, since there is no GC header.
I did some manual testing beyond the added tests to ensure acyclic
classes work as expected.
We can later add support for inferring acyclicity automatically in some
cases, but usually it will have to be explicitly declared.
This was created using Claude Code.