Lots of Error::description() deprecation warnings with 1.42

[sdroege]

We should either move to thiserror like in cairo for our errors, or at least just not implement that function.

[sdroege]

@GuillaumeGomez Any objections against using thiserror?

[GuillaumeGomez]

I'll complain but you can go forward with it.

[gdesmott]

Just build glib master with 1.42 and didn't get any warning. Do I have to use specific flags?

[GuillaumeGomez]

@gdesmott You're sure you didn't allow all warnings in your environment variables by any chance? Also, try rustc --version just to be sure. :)

[EPashkin]

Just glib or gtk/examples?

[gdesmott]

Just glib, don't have any warning building https://github.com/gtk-rs/examples either.

$ rustc --version
rustc 1.42.0 (b8cedc004 2020-03-09)

[EPashkin]

Then issue fixed without linking it in PRs. Ex. my cairo PR about this was before this issue.

[sdroege]

It's not fixed, see for example the two Error impls in glib/src/error.rs. We need to go through all Error impls in our crates.

[gdesmott]

ah, I get the warnings when running cargo test!

[gdesmott]

Not sure how we'd like to change the test with this change. I suppose hardcoding source code line numbers in tests isn't ideal.

---- subclass::object::test::test_set_properties stdout ----
thread 'subclass::object::test::test_set_properties' panicked at 'assertion failed: `(left == right)`
  left: `"Error \"property not found\" in \"glib::object\" at src/object.rs:1365"`,
 right: `"property not found"`', src/subclass/object.rs:605:9

[sdroege]

CC @fengalin who added this test

[sdroege]

The same will be needed in other repositories.

[fengalin]

I'll see what I can do, but I'd like to focus on completing https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/merge_requests/298

[sdroege]

@gdesmott actually was looking into that (Error::description) before you took over :)

[fengalin]

Ok :) Let's synchronize here if someone starts updating another repo for this.

[gdesmott]

Which repos need to be fixed as well? I don't have a full checkout so can't easily grep them.

[sdroege]

No others apparently. cairo and gstreamer are already done, the others don't have custom error implementations