05117e6e17 rpc: clarify longpoll behavior (Sjors Provoost)
5315278e7c Have createNewBlock() wait for a tip (Sjors Provoost)
64a2795fd4 rpc: handle shutdown during long poll and wait methods (Sjors Provoost)
a3bf43343f rpc: drop unneeded IsRPCRunning() guards (Sjors Provoost)
f9cf8bd0ab Handle negative timeout for waitTipChanged() (Sjors Provoost)
Pull request description:
This PR prevents Mining interface methods from sometimes crashing when called during startup before a tip is connected. It also makes other improvements like making more RPC methods usable from the GUI. Specifically this PR:
- Adds an `Assume` check to disallow passing negative timeout values to `Mining::waitTipChanged`
- Makes `waitfornewblock`, `waitforblock` and `waitforblockheight` RPC methods usable from the GUI when `-server=1` is not set.
- Changes `Mining::waitTipChanged` to return `optional<BlockRef>` instead of `BlockRef` and return `nullopt` instead of crashing if there is a timeout or if the node is shut down before a tip is connected.
- Changes `Mining::waitTipChanged` to not time out before a tip is connected, so it is convenient and safe to call during startup, and only returns `nullopt` on early shutdowns.
- Changes `Mining::createNewBlock` to block and wait for a tip to be connected if it is called on startup instead of crashing. Also documents that it will return null on early shutdowns.
This allows `waitNext()` (added in https://github.com/bitcoin/bitcoin/pull/31283) to safely assume `TipBlock()` isn't `null`, not even during a scenario of early shutdown.
Finally this PR clarifies long poll behaviour, mostly by adding code comments, but also through an early `break`.
ACKs for top commit:
achow101:
ACK 05117e6e17
ryanofsky:
Code review ACK 05117e6e17, just updated a commit message since last review
TheCharlatan:
ACK 05117e6e17
vasild:
ACK 05117e6e17
Tree-SHA512: 277c285a6e73dfff88fd379298190b264254996f98b93c91c062986ab35c2aa5e1fbfec4cd71d7b29dc2d68e33f252b5cfc501345f54939d6bd78599b71fec04
99a4ddf5ab