[ER] Fix a soundness hole in parameter access#230
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vswarte merged 4 commits intovswarte:mainfrom Feb 21, 2026
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As discussed on Discord, providing non-`unsafe` access to parameters through `SoloParamRepository` (even immutable access) while also providing mutable access through `FD4ParamRepository` is a soundness hole unless we explicitly require that only one of these singletons be accessed at a time. This fixes the issue by making access via `FD4ParamRepository` require an `unsafe` block with the condition that no other parameters have access. For a detailed account of why we went this direction, see the comment on `FD4ParamRepository`.
vswarte
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Feb 18, 2026
vswarte
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Feb 19, 2026
| .find_index(param_id) | ||
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| // Double-check that the parameter we found is the one we're epxecting. | ||
| if res_cap.matches_param::<P>() { |
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Changed to a debug-only assert
axd1x8a
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Feb 21, 2026
vswarte
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Feb 21, 2026
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As discussed on Discord, providing non-
unsafeaccess to parameters throughSoloParamRepository(even immutable access) while also providing mutable access throughFD4ParamRepositoryis a soundness hole unless we explicitly require that only one of these singletons be accessed at a time.This fixes the issue by making access via
FD4ParamRepositoryrequire anunsafeblock with the condition that no other parameters have access. For a detailed account of why we went this direction, see the comment onFD4ParamRepository.