edgedb branch switch fails with "Invalid cross-device link" or "The system cannot move the file to a different disk drive" if the project directory is on a different filesystem than the user's home directory

[zackelan]

• EdgeDB Version: 5.2 (it probably doesn't matter, other than a 5.x instance being necessary in order to attempt edgedb branch switch)
• EdgeDB CLI Version: 5.2.0-dev (19c2cf33ff915cac2729139d66ba622e33124540, master as of 2024-05-22)
• OS Version: NixOS 23.11.6827.383ffe076d9b

Steps to Reproduce:

• create a cloud instance (this likely happens with local instances as well, but I haven't tested it): edgedb instance create --region aws-us-west-2 --tier free --version =5.2 zackelan/cross-filesystem-52-us-west-2

• mount a USB flash drive, or some other way of getting onto a separate filesystem

• initialize a project on that separate filesystem:

/mnt/test $ edgedb project init --server-instance zackelan/cross-filesystem-52-us-west-2
No `edgedb.toml` found in `/mnt/test` or above
Do you want to initialize a new project? [Y/n]
> Y
Specify the name of EdgeDB instance to use with this project [default: zackelan/cross-filesystem-52-us-west-2]:
> zackelan/cross-filesystem-52-us-west-2
Do you want to use existing instance "zackelan/cross-filesystem-52-us-west-2" for the project? [y/n]
> y
Specify branch name: [default: main]:
> main
Applying migrations...
Everything is up to date. Revision initial
Project linked
To connect to zackelan/cross-filesystem-52-us-west-2, run `edgedb`

create a branch:

/mnt/test $ edgedb branch create test
Creating branch 'test'...
OK: CREATE BRANCH

attempt to switch to the branch:

/mnt/test $ edgedb branch switch test
Switching from 'main' to 'test'
edgedb error: Invalid cross-device link (os error 18)

excerpt from straceing this command shows we're attempting rename(2) of a temp file from /mnt/test to my home directory:

readlink("/mnt", 0x7513e1afe800, 1023)  = -1 EINVAL (Invalid argument)
readlink("/mnt/test", 0x7513e1afe800, 1023) = -1 EINVAL (Invalid argument)
openat(AT_FDCWD, ".~database.tmp", O_WRONLY|O_CREAT|O_TRUNC|O_CLOEXEC, 0666) = 11
write(11, "test", 4)                    = 4
close(11)                               = 0
rename(".~database.tmp", "/home/zack/.config/edgedb/projects/test-da7755e901263282076d1c7457a40a9f3eef74ab/database") = -1 EXDEV (Invalid cross-device link)
futex(0x6340dc68b070, FUTEX_WAKE_PRIVATE, 2147483647) = 0
close(5)                                = 0
close(10)                               = 0
futex(0x6e905213658, FUTEX_WAKE_PRIVATE, 2147483647) = 1
futex(0x6e9050e9430, FUTEX_WAIT_BITSET_PRIVATE, 0, NULL, FUTEX_BITSET_MATCH_ANY) = -1 EAGAIN (Resource temporarily unavailable)
futex(0x6340d7fff990, FUTEX_WAIT_BITSET|FUTEX_CLOCK_REALTIME, 263635, NULL, FUTEX_BITSET_MATCH_ANY) = 0
write(2, "\33[38;5;9;1medgedb error:\33[0m \33[3"..., 85edgedb error: Invalid cross-device link (os error 18)
) = 85
sigaltstack({ss_sp=NULL, ss_flags=SS_DISABLE, ss_size=8192}, NULL) = 0
munmap(0x6340dc39d000, 12288)           = 0
exit_group(1)                           = ?
+++ exited with 1 +++

https://man7.org/linux/man-pages/man2/rename.2.html

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.)