solana-cli transfer subcommand naively tries to pay even if unfunded

[ryoqun]

Problem

Failed system transfers (due to insufficient funds) charges a transaction fee on the payer account. And even if solana-cli can check whether the tx will fail or not because of that in advance, it naive submits the transfer transaction naively.

This is a bit unhelpful. Small, but it causes spending a tx fee and looks silly from the user's viewpoint.

For example, user must again manually calculate the reduced all remaining fund when doing manually this unimplemented thing: #9862

Proposed Solution

Fail by deafult by doing account's fund balance check and introduce --force? But then this will introduce false-positives due to toctou vulnerability. Maybe #8971 is the ultimate fix?

context

https://discord.com/channels/428295358100013066/439194979856809985/707339402250158210

[t-nelson]

See also: #9406 😉