Support normalization of $SRC_DIR

[jebrosen]

Rocket's CI has been broken for a while because of UI test diffs like this:

 error[E0277]: the trait bound `usize: rocket::response::Responder<'_>` is not satisfied
-  --> $DIR/responder-types.rs:38:13
-   |
-38 | fn foo() -> usize { 0 }
-   |             ^^^^^ the trait `rocket::response::Responder<'_>` is not implemented for `usize`
-   |
-   = note: required by `rocket::handler::<impl rocket::Outcome<rocket::Response<'r>, rocket::http::Status, rocket::Data>>::from`
+   --> $DIR/responder-types.rs:38:13
+    |
+38  | fn foo() -> usize { 0 }
+    |             ^^^^^ the trait `rocket::response::Responder<'_>` is not implemented for `usize`
+    | 
+   ::: /Users/runner/runners/2.159.2/work/1/s/core/lib/src/handler.rs:202:20
+    |
+202 |     pub fn from<T: Responder<'r>>(req: &Request<'_>, responder: T) -> Outcome<'r> {
+    |                    ------------- required by this bound in `rocket::handler::<impl rocket::Outcome<rocket::Response<'r>, rocket::http::Status, rocket::Data>>::from`

The new annotations appear to be introduced by rust-lang/rust#64151, in which $SRC_DIR has been used to normalize similarly added paths in the output (e.g. https://github.com/rust-lang/rust/pull/64151/files#diff-4b63aaabf76aa70969c04a1a4185c421R7).

$SRC_DIR normalization was added to rustc in rust-lang/rust#50943 but it doesn't appear to be supported in compiletest - this means that it is not currently possible for these errors to be properly tested both in CI and locally, as each run ends up with files in a different path.

If the same change from rust-lang/rust#50943 is likely to be usable (and accepted) here, I'd be happy to make that pull request.

[Manishearth]

Yeah, we'd accept that PR

…

On Tue, Nov 5, 2019, 8:15 PM Jeb Rosen ***@***.***> wrote: Rocket's CI has been broken for a while because of UI test diffs like this: error[E0277]: the trait bound `usize: rocket::response::Responder<'_>` is not satisfied - --> $DIR/responder-types.rs:38:13 - | -38 | fn foo() -> usize { 0 } - | ^^^^^ the trait `rocket::response::Responder<'_>` is not implemented for `usize` - | - = note: required by `rocket::handler::<impl rocket::Outcome<rocket::Response<'r>, rocket::http::Status, rocket::Data>>::from` + --> $DIR/responder-types.rs:38:13 + | +38 | fn foo() -> usize { 0 } + | ^^^^^ the trait `rocket::response::Responder<'_>` is not implemented for `usize` + | + ::: /Users/runner/runners/2.159.2/work/1/s/core/lib/src/handler.rs:202:20 + | +202 | pub fn from<T: Responder<'r>>(req: &Request<'_>, responder: T) -> Outcome<'r> { + | ------------- required by this bound in `rocket::handler::<impl rocket::Outcome<rocket::Response<'r>, rocket::http::Status, rocket::Data>>::from` The new annotations appear to be introduced by rust-lang/rust#64151 <rust-lang/rust#64151>, in which $SRC_DIR has been used to normalize similarly added paths in the output (e.g. https://github.com/rust-lang/rust/pull/64151/files#diff-4b63aaabf76aa70969c04a1a4185c421R7 ). $SRC_DIR normalization was added to rustc in rust-lang/rust#50943 <rust-lang/rust#50943> but it doesn't appear to be supported in compiletest - this means that it is not currently possible for these errors to be properly tested both in CI and locally, as each run ends up with files in a different path. If the same change from rust-lang/rust#50943 <rust-lang/rust#50943> is likely to be usable (and accepted) here, I'd be happy to make that pull request. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#198>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAMK6SH2Y4LYORYQYZOF3T3QSJAEVANCNFSM4JJPKBEQ> .

[jebrosen]

It turns out it's more complicated than that. Copying the code used in rustc's version of compiletest doesn't work for me for two reasons:

• We pass a relative path for src_base. This is in principle easy to fix by converting to an absolute path somewhere, but I'm wary of canonicalize for Windows adding \\?\ when it doesn't appear in error messages.
• The parent of the parent of src_base is a suitable root in rustc, because it contains everything relevant. In rocket, the "root" ends up being another directory or two up. Using parent-of-parent would require projects using compiletest to make sure their directory layout fits.

I've made the change in the https://github.com/jebrosen/compiletest-rs/tree/normalize-srcdir in case it's useful to someone, but I think this is the wrong approach for me to pursue here.