Deploy, Upgrade, and the Buffer Account Pattern
This is Part 4 of the Solana Program Lifecycle series. In Part 3 we saw that a program is two accounts: a 36-byte Program Account that points to a ProgramData Account holding the actual bytecode. Now we look at how those two accounts get created and replaced. The short version: there is a third account involved. A temporary one. It exists only during the deploy or upgrade, and if anything goes wrong, it can sit on chain holding your SOL until you reclaim it. ...