Marks MutTxId as !Send#3972
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Shubham8287 merged 3 commits intoshub/fix-procedures-deadlockfrom Jan 14, 2026
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| #[derive(Clone, Default)] | ||
| pub struct TxSlot { | ||
| // Wrapped in Mutex for interior mutability. |
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I don't see this comment as particularly helpful. Obviously the mutex is for interior mutability, that's what mutexes do. A more useful comment would describe why interior mutability is necessary: do we hold multiple & shared references to a single TxSlot, or do we clone the inner Arc? Who holds these pointers, and when do they access them?
| pub timer: Instant, | ||
| pub ctx: ExecutionContext, | ||
| pub metrics: ExecutionMetrics, | ||
| // Marks `MutTxId` as `!Send` by embedding a non-`Send` type. |
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| // Marks `MutTxId` as `!Send` by embedding a non-`Send` type. | |
| /// Marks `MutTxId` as `!Send` by embedding a non-`Send` type. | |
| /// | |
| /// We want `MutTxId` to be `!Send` to prevent holding it across `await` points, | |
| /// which would lead to deadlocks. | |
| /// It is not possible to invoke Undefined Behavior by improperly sending a `MutTxId`, | |
| /// but it will likely deadlock and cause SpacetimeDB to become unresponsive. |
Co-authored-by: Phoebe Goldman <phoebe@clockworklabs.io> Signed-off-by: Shubham Mishra <shivam828787@gmail.com>
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# Description of Changes Same as #3972. Merged the original PR into wrong branch instead of mater :) --------- Signed-off-by: Shubham Mishra <shivam828787@gmail.com> Co-authored-by: Phoebe Goldman <phoebe@clockworklabs.io>
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Description of Changes
Depends on #3968.
Makes
MutTxId,!Sendto avoid being deadlocked by holding it acrossawaitpointsafter taking learnings from #3938 and #3968.
API and ABI breaking changes
NA
Expected complexity level and risk
1, It only increases the compile time safety.
Testing
Existing should be enough.