docs: document strand/thread_pool teardown precondition (#348)#354
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mvandeberg merged 1 commit intoJul 2, 2026
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) A strand holds only a non-owning reference to its execution context. Posting or dispatching to a strand concurrently with, or after, that context's destruction is undefined behavior: it races service teardown (the cppalliance#348 null-deref of service_) and, past destroy(), a use-after-free on the freed service state and pool queue. This is a precondition violation, not a bug reachable by correct code: legitimate posts run on pool workers, and join()-before-shutdown() already ensures no worker is active when the service tears down. The safe pattern is to submit work through run/run_async (work-tracked, so join() waits for it) and to join() the context before destroying it. Document the requirement on strand (class + post()/dispatch()) and on the thread_pool destructor. No code change.
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## develop-2 #354 +/- ##
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Coverage 98.29% 98.29%
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Files 77 79 +2
Lines 3984 3986 +2
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+ Hits 3916 3918 +2
Misses 68 68
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A strand holds only a non-owning reference to its execution context. Posting or dispatching to a strand concurrently with, or after, that context's destruction is undefined behavior: it races service teardown (the #348 null-deref of service_) and, past destroy(), a use-after-free on the freed service state and pool queue.
This is a precondition violation, not a bug reachable by correct code: legitimate posts run on pool workers, and join()-before-shutdown() already ensures no worker is active when the service tears down. The safe pattern is to submit work through run/run_async (work-tracked, so join() waits for it) and to join() the context before destroying it.
Document the requirement on strand (class + post()/dispatch()) and on the thread_pool destructor. No code change.