The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

Conflicts

Reviewers, this pull request conflicts with the following ones:

• #24274 (Introduce GetFileArg and use it where possible by prusnak)
• #24266 (util: Avoid buggy std::filesystem:::create_directories() call by hebasto)
• #24265 (Drop StripRedundantLastElementsOfPath() function by hebasto)

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

I've tested the following scenarios. I run bitcoind from command line for each scenario and see what happens:

• Create a valid symlink with ln -s /home/me/Documents .bitcoin - OK (it read and writes into /home/me/Documents properly)
• Non existing ~/.bitcoin file/folder - OK (create a ~/.bitcoin folder)
• Existing ~/.bitcoin folder - OK (load the content of ~/.bitcoin folder)
• Create a broken symlink with ln -s /1234 .bitcoin - ??? (bitcoind does not start, but seems to crash, see below)

bitcoind: fs.cpp:39: fs::path fsbridge::AbsPathJoin(const fs::path&, const fs::path&): Assertion `base.is_absolute()' failed.
Aborted (core dumped)

• Create a new wallet using bitcoin-cli - OK (create ~/.bitcoin/wallets/xxx folder)
• Moved ~/.bitcoin/wallets/xxx to ~/.bitcoin/xxx - OK (I can load xxx wallet using bitcoin-cli)

@nymkappa

I've tested the following scenarios...

If there are behavior changes comparing to pre-20744 variant, could describe them in the PR description?

@nymkappa

I've tested the following scenarios...

If there are behavior changes comparing to pre-20744 variant, could describe them in the PR description?

This is the only behavior change I've noticed from the previously mentioned scenario between master@04255073bbd2b8ea71ae8a9ff7433be499312758 (before #20744 was merged) and my pull request.

It looks like even though .bitcoin is a symbolic link (pointing to an invalid location), core does not try to follow it and instead tries to create a directory at that location.

• Create a broken symlink with ln -s /1234 .bitcoin - ??? (bitcoind does not start, but seems to crash, see below)

************************
EXCEPTION: N5boost10filesystem16filesystem_errorE       
boost::filesystem::create_directory: File exists: "/home/me/.bitcoin"       
bitcoin in AppInit()       

bitcoind: chainparamsbase.cpp:35: const CBaseChainParams& BaseParams(): Assertion `globalChainBaseParams' failed.
Aborted (core dumped)

This is the only behavior change I've noticed from the previously mentioned scenario between master@04255073bbd2b8ea71ae8a9ff7433be499312758 (before #20744 was merged) and my pull request.

FWIW, #24266 preserves the pre-20744 behavior, and for a broken link bitcoind reports an exception with a meaningful message:

$ src/bitcoind


************************
EXCEPTION: NSt10filesystem7__cxx1116filesystem_errorE       
filesystem error: cannot create directories: File exists [/home/hebasto/.bitcoin/wallets]       
bitcoin in AppInit()       

This is the only behavior change I've noticed from the previously mentioned scenario between master@04255073bbd2b8ea71ae8a9ff7433be499312758 (before #20744 was merged) and my pull request.

FWIW, #24266 preserves the pre-20744 behavior, and for a broken link bitcoind reports an exception with a meaningful message:

$ src/bitcoind


************************
EXCEPTION: NSt10filesystem7__cxx1116filesystem_errorE       
filesystem error: cannot create directories: File exists [/home/hebasto/.bitcoin/wallets]       
bitcoin in AppInit()       

Closing this PR as #24266 provides a better fix. Thank you for your time hebasto 👍🏻