linux: fix invalid cross-device link error

[sjet47]

This PR fix the "invalid cross-device link" error occurred in linux when trying to write the settings file atomically, like when click the "Enable vim mode" checkbox at first start.

[2024-02-26T22:59:25+08:00 ERROR util] .../zed/crates/settings/src/settings_file.rs:135: Failed to write settings to file "/home/$USER/.config/zed/settings.json"

Caused by:
0: failed to persist temporary file: Invalid cross-device link (os error 18)
1: Invalid cross-device link (os error 18)

Currently the fs::RealFs::atomic_write() method write to a temp file created with NamedTempFile::new() and then call persist() method to write to the config file path, which actually do a rename syscall under the hood. As the issue said

NamedTempFile::new() will create a temporary file in your system's temporary file directory. You need NamedTempFile::new_in().

The temporary file directory in linux is in /tmp, which is mounted to tmpfs filesystem, and in most case(all case I guess) $HOME/.config/zed is mounted to a different filesystem. And the rename syscall between different filesystems will return a EXDEV errno, as described in the man page rename(2):

       EXDEV  oldpath and newpath are not on the same mounted
              filesystem.  (Linux permits a filesystem to be mounted at
              multiple points, but rename() does not work across
              different mount points, even if the same filesystem is
              mounted on both.)

And as the issue above said, use a different temp dir with NamedTempFile::new_in() for linux platform might be a solution, since the rename syscall provides atomicity.

Release Notes:

• Fix settings.json save failed with invalid cross-device link error in linux

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[sjet47]

@cla-bot check

[cla-bot]

The cla-bot has been summoned, and re-checked this pull request!

[mikayla-maki]

Thank you!

[mikayla-maki]

Thank you!

[mikayla-maki]

Could we remove this comment?

[sjet47]

Sure!

[mikayla-maki]

It also looks like this needs a cargo fmt :)