filetime pin is outdated

[kpcyrd]

I've noticed I can't update to the latest tar release because it depends on filetime 0.2.6, while notify has an explicit pin on filetime 0.2.5, preventing the update.

Please consider pushing an update.

[passcod]

We can't. Filetime has pushed their minimum rustc version to 1.32 as of 0.2.6, while notify guarantees to be compatible down to 1.26.1 without a major version bump.

[passcod]

See #201

[matklad]

Hm, pin dependencies in Cargo.toml are usually not a good idea.

If a project depends on notify 0.4 and on some other library A that has filetime = "0.2.6", than Cargo will just refuse to build that project, and the only solution would be to get rid of either notify or A.

Note that you don't have to pin filetime to 0.2.5 to make sure that notify works with older Rusts. If you specify filetime = "0.2.5" in the Cargo.toml, Cargo can still use 0.2.5, even if 0.2.6 is already published. By default, it will pull 0.2.6 unless there's an existing lockfile, but you can override this with cargo update --package filetime --vers 0.2.5 --precise.

That is, clients of notify will still be able to use notify with old Rust, but it's the client responsibility to make sure they have filetime 0.2.5 in the lockfile.

The practical problem here is building the crate on CI: without lockfile, Cargo will pull the newest filetime, and it will break CI for old Rust. The work around here is to actually use a lockfile when testing with older rusts. See how Cargo.lock.min is used to test once_cell against an old Rust: https://github.com/matklad/once_cell/blob/c62ee6629513d948bce53130ca168d2f856276ab/.travis.yml#L19-L26