Cannot have nix 0.20 and 0.23 in same package due to conflicting bitflags requirement

[aDotInTheVoid]

In Cargo.toml

[dependencies]
nix = "0.23.0"
zbus = "1.9.2"

This leads to

error: failed to select a version for `bitflags`.
    ... required by package `nix v0.20.2`
    ... which is depended on by `zbus v1.9.2`
    ... which is depended on by `whyyy v0.1.0 (/private/tmp/whyyy)`
versions that meet the requirements `>=1.1.0, <1.3.0` are: 1.2.1, 1.2.0, 1.1.0

all possible versions conflict with previously selected packages.

  previously selected package `bitflags v1.3.1`
    ... which is depended on by `nix v0.23.0`
    ... which is depended on by `whyyy v0.1.0 (/private/tmp/whyyy)`

failed to select a version for `bitflags` which could resolve this conflict

Because v0.23 needs bitflags > 1.3 but v0.20 need bitflags < 1.3

[aDotInTheVoid]

Also if you could release 0.23.1 with this, that would be super helpfull for fixing the starship issue.

[m-ou-se]

See also #1548

[asomers]

Here's my proposed solution:

• vendor the bitflags crate, so there won't be any external dependencies on it. Vendor the bitflags crate #1560
• Set the rust-version field in Cargo.toml, which will prevent future problems like this from ever happening again, once the MSRV is 1.56.0 or newer. Declare the MSRV in Cargo.toml #1561
• Create a TODO issue to de-vendor bitflags after the MSRV is eventually raised to 1.56.0. MSRV 1.56.0 TODO #1562

@aDotInTheVoid what do you think?

[asomers]

@aDotInTheVoid are you able to review the linked PR?

[aDotInTheVoid]

I think this would solve the problem I'm facing with starship, I'll try in a couple of hours when I'm back at a keyboard

[aDotInTheVoid]

I dont know how to test this actually. Sorry

[asomers]

Aleksey Kladov came up with a different solution, which we merged as #1593 .