Improve check disk space in bitcoind #16265

Addressing: #15813.

Instead of requiring constant 50MB of space, this checks chainparams.AssumedBlockchainSize() and chainparams.AssumedChainStateSize() for a more accurate calculation.

This is my first time touching C++ code in Bitcoin, so some questions:

• I adapted this code from the gui: https://github.com/bitcoin/bitcoin/blob/master/src/qt/intro.cpp#L133. From what I can tell, -prune=1 in bitcoind means manual pruning but gui treats that as a valid 1MB pruning limit? Clarification on that would be helpful.
• Do I need to add a test?
• I added the same check for datadir and blocksdir. Is that right (and necessary)?

Feedback welcome.

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Conflicts

No conflicts as of last run.

This would prevent the node from starting when the blockchain is already downloaded fully?

This would prevent the node from starting when the blockchain is already downloaded fully?

I'm not sure to be honest. I was mostly copying what happens in the GUI intro.

https://github.com/bitcoin/bitcoin/blob/a54a12046e98c57512715041d30ecf2f0ab8f6dd/src/qt/intro.cpp#L133-L146

It's possible that the GUI intro only happens at the first run, rather than on every start?

It's possible that the GUI intro only happens at the first run, rather than on every start?

Yes, unless you do a -resetguisettings.

This PR seems to have been based on a misunderstanding of the GUI code and gone inactive, so closing it for now. Let me know when you intend to work on this again.