71656bdfaa gui: crash fix, disconnect numBlocksChanged() signal during shutdown (furszy)
Pull request description:
Aiming to fixbitcoin-core/gui#862.
The crash stems from the order of the shutdown procedure:
We first unset the client model, then destroy the wallet controller—but we leave
the internal wallet models (`m_wallets`) untouched for a brief period. As a result,
there’s a point in time where views still have connected signals and access to
wallet models that are not connected to any wallet controller.
Now.. since the `clientModel` is only replaced with nullptr locally and not destroyed
yet, signals like `numBlocksChanged` can still emit. Thus, when wallet views receive
them, they see a non-null wallet model ptr, and proceed to call backend functions
from a model that is being torn down.
As the shutdown procedure begins by unsetting `clientModel` from all views. It’s safe
to ignore events when `clientModel` is nullptr.
ACKs for top commit:
maflcko:
lgtm ACK 71656bdfaa
pablomartin4btc:
re-ACK 71656bdfaa
hebasto:
ACK 71656bdfaa, I have reviewed the code and it looks OK.
Tree-SHA512: e6a369c40aad8a5a3da64e92daa10250006f60c53feef353a5580e1bdb17fe8e1ad102abf5419ddeff1caa703b69ab634265ef3b9cfef87e9304f97bfdd2c4aa
d2ac748e9e