Fix concurrency issue of Terraform provider cache #21805
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The worst concurrency bug with the Terraform provider cache is when nonatomic moves result in incorrect hashes in the lockfile which gets pulled into the Pants cache and then poisons it. So we just don't use the provider cache in that case. I think there's still the possibility that the nonatomic move triggers a problem with a module with a lockfile when the cache is being populated, but at least that won't enter the cache. I think that risk is lower since the files are fetched during `init` but used later (ex during `validate`), by which time the copy operation has completed.
lilatomic
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category:bugfix
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The Terraform provider cache is not concurrency safe.
The worst concurrency bug with the Terraform provider cache is when nonatomic moves result in incorrect hashes in the lockfile which gets pulled into the Pants cache and then poisons it. So we just don't use the provider cache in that case.
I think there's still the possibility that the nonatomic move triggers a problem with a module with a lockfile when the cache is being populated, but at least that won't enter the cache. I think that risk is lower since the files are fetched during
initbut used later (ex duringvalidate), by which time the copy operation has completed.TODO:
fixes #21804