Prevent race condition in get_with method to avoid evaluating init closure/future multiple times
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`init` closure/future multiple times In the current implementation, there is a small chance that the following methods to evaluate the `init` closure/function more than once in concurrent calls: - `get_with` - `get_with_if` - `optionally_get_with` - `try_get_with` It will happen when a call to one of these methods is made at the time when another call to the same method is about to complete. New test cases in `tests/entry_api_sync.rs` will reproduce the issue. This commit contains the fix by doing a double check if the value still does not exist after the lock is acquired and also extending the lock as needed.
tatsuya6502
changed the title
get_with methods to avoid evaluating init closure/future multiple timesget_with method to avoid evaluating init closure/future multiple times
`init` closure/future multiple times Add async test cases: - `tests/entry_api_actix_rt2.rs` - `tests/entry_api_async_std.rs` - `tests/entry_api_tokio.rs`
init closure/future multiple times Cosmetic changes mostly in source code comments.
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In the current implementation (up to v0.9.5), there is a small chance that the following methods to evaluate the
initclosure/function more than once in concurrent calls:get_withget_with_ifoptionally_get_withtry_get_withIt will happen when a call to one of these methods is made when another call to the same method on the same key is about to complete.
New test cases in he following files will reproduce the issue:
tests/entry_api_sync.rstests/entry_api_tokio.rstests/entry_api_actix_rt2.rstests/entry_api_async_std.rsThis PR fixes the issue by doing a double check if the value still does not exist after the lock is acquired and also extending the lock as needed.