fix: memory-leak due to unbound type-parameter recursion - #112
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pfitzseb merged 2 commits intoJul 6, 2026
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FakeTypeName expanded a type's parameters recursively with no size bound. A few types explode into enormous trees: type-domain packages whose types recurse into themselves (e.g. TypeDomainNaturalNumbers — naturals as nested types, rationals as continued fractions), and even some Base/LinearAlgebra signatures whose `where`-bounded `Union`s reach tens of thousands of nodes. This produced multi-gigabyte cache files (2.2 GB for TypeDomainNaturalNumbers) that exhausted memory — OOMing the machine — when read back into the store. Cap expansion with a per-type budget of expanded DataTypes (MAX_EXPANDED_TYPES = 128): once it is spent, a type's remaining parameters are dropped and only its name is kept. The budget bounds any shape of explosion (depth, width, or indirect recursion through variable bounds), while ordinary types stay far below it and are unaffected. Add a regression test. Ported from julia-vscode/SymbolServer.jl#320 (SymbolServer.jl is deprecated; the code now lives here under shared/symbolserver/).
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## main #112 +/- ##
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Lines 682 7382 +6700
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Is this still required with #108? If yes, would be nice to also emit a Re |
…ntinel
Instead of silently dropping all parameters when the ExpandBudget is
spent, keep the type's name and a single Unserializable() parameter, so
truncated types render as Foo{…} instead of a misleadingly bare Foo.
Budget is now only spent on types that actually have parameters, and
bumped to 256 to clear the p99 of Base/stdlib signature slots (~160
expanded DataTypes) with some margin.
The sentinel needs a writer method to roundtrip: without one, a
parameters vector containing it would MethodError during the cache
write and degrade the whole module binding to Unserializable.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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FakeTypeNameexpanded a type's parameters recursively with no size bound. A few types explode into enormous trees: type-domain packages whose types recurse into themselves (e.g.TypeDomainNaturalNumbers— naturals as nested types, rationals as continued fractions), and even someBase/LinearAlgebrasignatures whosewhere-boundedUnions reach tens of thousands of nodes. This produced multi-gigabyte cache files (2.2 GB forTypeDomainNaturalNumbers) that exhausted memory — OOMing the machine — when read back into the store.Cap expansion with a per-type budget of expanded
DataTypes (MAX_EXPANDED_TYPES = 128): once it is spent, a type's remaining parameters are dropped and only its name is kept. The budget bounds any shape of explosion (depth, width, or indirect recursion through variable bounds), while ordinary types stay far below it and are unaffected.Ported from julia-vscode/SymbolServer.jl#320 (SymbolServer.jl is deprecated; the code now lives here under shared/symbolserver/).