chore: build through mbx's Cargo shim, toward a warm gate

driver/justfile

@@ -6,7 +6,9 @@
 
 set shell := ["bash", "-euo", "pipefail", "-c"]
 
-export PATH := if env("RUST2_TS_TOOLCHAIN", "") == "" { env("PATH") } else { env("RUST2_TS_TOOLCHAIN") / "bin:" + env("PATH") }
+# mbx's Cargo shim, which the dev shell exports, stays ahead of the nightly so cargo still builds through it.
+cargo_shim := if env("RUST2_CARGO_SHIM", "") == "" { "" } else { env("RUST2_CARGO_SHIM") + ":" }
+export PATH := if env("RUST2_TS_TOOLCHAIN", "") == "" { env("PATH") } else { cargo_shim + env("RUST2_TS_TOOLCHAIN") / "bin:" + env("PATH") }
 
 default:
     @just --list

ffi/justfile

@@ -6,7 +6,9 @@
 
 set shell := ["bash", "-euo", "pipefail", "-c"]
 
-export PATH := if env("RUST2_TS_TOOLCHAIN", "") == "" { env("PATH") } else { env("RUST2_TS_TOOLCHAIN") / "bin:" + env("PATH") }
+# mbx's Cargo shim, which the dev shell exports, stays ahead of the nightly so cargo still builds through it.
+cargo_shim := if env("RUST2_CARGO_SHIM", "") == "" { "" } else { env("RUST2_CARGO_SHIM") + ":" }
+export PATH := if env("RUST2_TS_TOOLCHAIN", "") == "" { env("PATH") } else { cargo_shim + env("RUST2_TS_TOOLCHAIN") / "bin:" + env("PATH") }
 
 # The moq revision these recipes export by default: `just ts`'s, so both follow one moq.
 # just's own path is quoted wherever bash runs it: on Windows, its backslashes are escapes.

flake.nix

@@ -316,6 +316,21 @@
             RUST2_TS_TOOLCHAIN = tsToolchain;
             RUST2_TS_SYSROOT = rust2-ts-std;
             KOTLINX_COROUTINES = "${kotlinx-coroutines}";
+            # The pinned toolchain goes on PATH ahead of everything the host had, which
+            # shadows the Cargo shim `mbx setup` installs. Put it back in front, as moq's dev
+            # shell does, so cargo builds through mbx's cache wherever the host set one up,
+            # the land gate included. The nightly projects' justfiles keep it ahead of their
+            # toolchain through RUST2_CARGO_SHIM. `setup --status` names the shim on its first
+            # line even when it is missing, and its exit code also fails over unrelated setup,
+            # so only the shim existing decides.
+            shellHook = ''
+              shim=$(mbx setup --status 2>/dev/null | sed -n '1s/.*: //p' || true)
+              if [ -x "$shim" ]; then
+                export RUST2_CARGO_SHIM=''${shim%/*}
+                export PATH="$RUST2_CARGO_SHIM:$PATH"
+              fi
+              unset shim
+            '';
           };
           # `just ts bench` adds Chrome and Firefox as engines. Apart for their size.
           devShells.bench = self.devShells.${system}.default.overrideAttrs (old: {

go/justfile

@@ -6,7 +6,9 @@
 
 set shell := ["bash", "-euo", "pipefail", "-c"]
 
-export PATH := if env("RUST2_TS_TOOLCHAIN", "") == "" { env("PATH") } else { env("RUST2_TS_TOOLCHAIN") / "bin:" + env("PATH") }
+# mbx's Cargo shim, which the dev shell exports, stays ahead of the nightly so cargo still builds through it.
+cargo_shim := if env("RUST2_CARGO_SHIM", "") == "" { "" } else { env("RUST2_CARGO_SHIM") + ":" }
+export PATH := if env("RUST2_TS_TOOLCHAIN", "") == "" { env("PATH") } else { cargo_shim + env("RUST2_TS_TOOLCHAIN") / "bin:" + env("PATH") }
 
 default:
     @just --list

quest/m0/checks/cache.md

@@ -13,4 +13,12 @@ gate has. PR code can write to it, a risk moq already accepts; mbx keys each com
 its compiler, target, and inputs. Local worktrees share it too, where the dev shell already
 can.
 
-Public API: none.
+Public API: `uniffi_macros`' `generate_and_include_scaffolding!` with the `trybuild` feature
+resolves a relative path from the calling file, not from rustc's working directory. This is
+breaking and has no `MIGRATE.md` entry yet.
+
+## Waiting
+
+- Maintainer: move the land host's mbx pin from 1.28.0 to 1.29.2 or later, then rerun `mbx setup` wherever a shim exists, since a shim runs the mbx its `mbx-target` file names. Check: `mbx --version` on the land host prints 1.29.2 or later, and the shim's `mbx-target` names that store path. 1.28.0 prints no real paths for files in a build script's `OUT_DIR` ([jdx/mr-boxington#896](https://github.com/jdx/mr-boxington/issues/896)).
+- Maintainer: give rust2's land instance moq's per-repository mbx profile, `id = 9`, `command = "just ci"`, `cpuQuota = 800`, `memoryHigh = "8G"`, `memorySwapMax = "1G"`, with `enable = lib.mkDefault false` until the next item. Check: the host config's `rust2` entry has these values.
+- Maintainer: enable that profile once [#426](https://github.com/moq-dev/rust2/pull/426) has merged. Check: a gate run's log shows `mbx[cache]: object cache: ...`.

ts/justfile

@@ -6,7 +6,9 @@
 
 set shell := ["bash", "-euo", "pipefail", "-c"]
 
-export PATH := if env("RUST2_TS_TOOLCHAIN", "") == "" { env("PATH") } else { env("RUST2_TS_TOOLCHAIN") / "bin:" + env("PATH") }
+# mbx's Cargo shim, which the dev shell exports, stays ahead of the nightly so cargo still builds through it.
+cargo_shim := if env("RUST2_CARGO_SHIM", "") == "" { "" } else { env("RUST2_CARGO_SHIM") + ":" }
+export PATH := if env("RUST2_TS_TOOLCHAIN", "") == "" { env("PATH") } else { cargo_shim + env("RUST2_TS_TOOLCHAIN") / "bin:" + env("PATH") }
 
 # The model fixture, its own workspace, which builds moq-net at the moq pin.
 model := "fixtures/model/Cargo.toml"

uniffi/README.md

@@ -88,6 +88,9 @@ uniffi-rs:
 - Scaffolding is written to a temporary file and renamed into place. Two trybuild cases
   expanding `generate_and_include_scaffolding!` on one UDL write it concurrently, and the
   in-place truncate let one include a partial file.
+- `generate_and_include_scaffolding!` takes a path relative to the calling file, not to
+  rustc's working directory: trybuild compiles from inside the target directory, which a
+  build cache such as mbx moves out of the checkout.
 - The bindgen tests generate into a directory per test instead of one per language, so they
   run under nextest, which runs each test in its own process.
 - `uniffi_bindgen` has no `askama.toml`: its templates move from `src/**/templates` to

uniffi/fixtures/uitests/tests/ui/fieldless_errors_used_in_callbacks_cant_have_fields.rs

@@ -1,5 +1,5 @@
-// Unfortunately, path is relative to a temporary build directory :-/
-uniffi_macros::generate_and_include_scaffolding!("../../../../uniffi/fixtures/uitests/src/errors.udl");
+// The path is relative to this file.
+uniffi_macros::generate_and_include_scaffolding!("../../src/errors.udl");
 
 fn main() { /* empty main required by `trybuild` */}
 

uniffi/fixtures/uitests/tests/ui/interface_cannot_use_mut_self.rs

@@ -1,6 +1,6 @@
 
-// Unfortunately, path is relative to a temporary build directory :-/
-uniffi_macros::generate_and_include_scaffolding!("../../../../uniffi/fixtures/uitests/src/counter.udl");
+// The path is relative to this file.
+uniffi_macros::generate_and_include_scaffolding!("../../src/counter.udl");
 
 fn main() { /* empty main required by `trybuild` */}
 

uniffi/fixtures/uitests/tests/ui/interface_not_sync_and_send.rs

@@ -1,8 +1,8 @@
 
 use std::cell::Cell;
 
-// Unfortunately, path is relative to a temporary build directory :-/
-uniffi_macros::generate_and_include_scaffolding!("../../../../uniffi/fixtures/uitests/src/counter.udl");
+// The path is relative to this file.
+uniffi_macros::generate_and_include_scaffolding!("../../src/counter.udl");
 
 fn main() { /* empty main required by `trybuild` */}
 

uniffi/fixtures/uitests/tests/ui/interface_trait_not_sync_and_send.rs

@@ -1,5 +1,5 @@
-// Unfortunately, path is relative to a temporary build directory :-/
-uniffi_macros::generate_and_include_scaffolding!("../../../../uniffi/fixtures/uitests/src/trait.udl");
+// The path is relative to this file.
+uniffi_macros::generate_and_include_scaffolding!("../../src/trait.udl");
 
 fn main() { /* empty main required by `trybuild` */}
 

uniffi/fixtures/uitests/tests/ui/non_hashable_record_key.rs

@@ -1,4 +1,4 @@
-// Unfortunately, path is relative to a temporary build directory :-/
-uniffi_macros::generate_and_include_scaffolding!("../../../../uniffi/fixtures/uitests/src/records.udl");
+// The path is relative to this file.
+uniffi_macros::generate_and_include_scaffolding!("../../src/records.udl");
 
 fn main() { /* empty main required by `trybuild` */}

uniffi/fixtures/uitests/tests/ui/trait_methods_no_trait.rs

@@ -1,5 +1,5 @@
-// Unfortunately, path is relative to a temporary build directory :-/
-uniffi_macros::generate_and_include_scaffolding!("../../../../uniffi/fixtures/trait-methods/src/trait_methods.udl");
+// The path is relative to this file.
+uniffi_macros::generate_and_include_scaffolding!("../../../trait-methods/src/trait_methods.udl");
 
 fn main() { /* empty main required by `trybuild` */}
 

uniffi/fixtures/uitests/tests/ui/trait_methods_unknown_trait.rs

@@ -1,5 +1,5 @@
-// Unfortunately, path is relative to a temporary build directory :-/
-uniffi_macros::generate_and_include_scaffolding!("../../../../uniffi/fixtures/uitests/src/trait_methods_unknown_trait.udl");
+// The path is relative to this file.
+uniffi_macros::generate_and_include_scaffolding!("../../src/trait_methods_unknown_trait.udl");
 
 fn main() { /* empty main required by `trybuild` */}
 

uniffi/fixtures/uitests/tests/ui/trait_methods_unknown_trait.stderr

@@ -1,7 +1,7 @@
-error: Failed to generate scaffolding from UDL file at ../../../../uniffi/fixtures/uitests/src/trait_methods_unknown_trait.udl: parsing udl file ../../../../uniffi/fixtures/uitests/src/trait_methods_unknown_trait.udl: Invalid trait name: PartialEq
+error: Failed to generate scaffolding from UDL file at ../../src/trait_methods_unknown_trait.udl: parsing udl file $DIR/tests/ui/../../src/trait_methods_unknown_trait.udl: Invalid trait name: PartialEq
  --> tests/ui/trait_methods_unknown_trait.rs:2:1
   |
-2 | uniffi_macros::generate_and_include_scaffolding!("../../../../uniffi/fixtures/uitests/src/trait_methods_unknown_trait.udl");
-  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+2 | uniffi_macros::generate_and_include_scaffolding!("../../src/trait_methods_unknown_trait.udl");
+  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: this error originates in the macro `uniffi_macros::generate_and_include_scaffolding` (in Nightly builds, run with -Z macro-backtrace for more info)

uniffi/fixtures/uitests/tests/ui/typedef_extern.rs

@@ -1,4 +1,4 @@
-// Unfortunately, path is relative to a temporary build directory :-/
-uniffi_macros::generate_and_include_scaffolding!("../../../../uniffi/fixtures/uitests/src/typedef_extern.udl");
+// The path is relative to this file.
+uniffi_macros::generate_and_include_scaffolding!("../../src/typedef_extern.udl");
 
 fn main() { /* empty main required by `trybuild` */}

uniffi/fixtures/uitests/tests/ui/typedef_extern.stderr

@@ -1,4 +1,4 @@
-error: Failed to generate scaffolding from UDL file at ../../../../uniffi/fixtures/uitests/src/typedef_extern.udl: parsing udl file ../../../../uniffi/fixtures/uitests/src/typedef_extern.udl: `typedef extern` is no longer supported.
+error: Failed to generate scaffolding from UDL file at ../../src/typedef_extern.udl: parsing udl file $DIR/tests/ui/../../src/typedef_extern.udl: `typedef extern` is no longer supported.
        You must replace `extern` with the type of the object:
        * "enum" for Enums.
        * "record", "dictionary" or "struct" for Records.
@@ -24,7 +24,7 @@ error: Failed to generate scaffolding from UDL file at ../../../../uniffi/fixtur
        See https://mozilla.github.io/uniffi-rs/next/types/custom_types.html for more.
  --> tests/ui/typedef_extern.rs:2:1
   |
-2 | uniffi_macros::generate_and_include_scaffolding!("../../../../uniffi/fixtures/uitests/src/typedef_extern.udl");
-  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+2 | uniffi_macros::generate_and_include_scaffolding!("../../src/typedef_extern.udl");
+  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: this error originates in the macro `uniffi_macros::generate_and_include_scaffolding` (in Nightly builds, run with -Z macro-backtrace for more info)

uniffi/uniffi_macros/src/lib.rs

@@ -10,7 +10,7 @@
 //! Macros for `uniffi`.
 
 #[cfg(feature = "trybuild")]
-use camino::Utf8Path;
+use camino::Utf8PathBuf;
 use proc_macro::TokenStream;
 use quote::quote;
 use syn::{parse_macro_input, LitStr};
@@ -275,8 +275,9 @@ pub fn use_remote_type(tokens: TokenStream) -> TokenStream {
 ///
 /// This is a convenience macro designed for writing `trybuild`-style tests and
 /// probably shouldn't be used for production code. Given the path to a `.udl` file,
-/// if will run `uniffi-bindgen` to produce the corresponding Rust scaffolding and then
-/// include it directly into the calling file. Like so:
+/// relative to the calling file as `include_str!`'s is, it will run `uniffi-bindgen` to
+/// produce the corresponding Rust scaffolding and then include it directly into the calling
+/// file. Like so:
 ///
 /// ```rs
 /// uniffi_macros::generate_and_include_scaffolding!("path/to/my/interface.udl");
@@ -285,8 +286,19 @@ pub fn use_remote_type(tokens: TokenStream) -> TokenStream {
 #[cfg(feature = "trybuild")]
 pub fn generate_and_include_scaffolding(udl_file: TokenStream) -> TokenStream {
     let udl_file = syn::parse_macro_input!(udl_file as LitStr);
-    let udl_file_string = udl_file.value();
-    let udl_file_path = Utf8Path::new(&udl_file_string);
+    // Not relative to rustc's working directory, which is trybuild's project inside the target
+    // directory, and that need not sit in the checkout.
+    let Some(udl_file_path) = proc_macro::Span::call_site()
+        .local_file()
+        .and_then(|file| Utf8PathBuf::from_path_buf(file).ok())
+        .and_then(|file| Some(file.parent()?.join(udl_file.value())))
+    else {
+        return quote! {
+            compile_error!("generate_and_include_scaffolding! needs a UTF-8 path to the invoking file");
+        }
+        .into();
+    };
+    let udl_file_path = udl_file_path.as_path();
     if std::env::var("OUT_DIR").is_err() {
         quote! {
             compile_error!("This macro assumes the crate has a build.rs script, but $OUT_DIR is not present");