Implement build sysroot with cargo_metadata

.gitignore

@@ -3,3 +3,4 @@ target
 .liquid
 *.dot
 log
+sysroot/

lib/flux-rs/Cargo.toml

@@ -9,3 +9,6 @@ flux-attrs = { path = "../flux-attrs", version = "0.1.0" }
 
 [lints]
 workspace = true
+
+[package.metadata.flux]
+enabled = true

lib/flux-rs/src/lib.rs

@@ -1 +1,4 @@
 pub use flux_attrs::*;
+
+#[sig(fn(bool[true]) )]
+pub fn assert(_: bool) {}

tests/src/lib.rs

@@ -1,30 +1,7 @@
-#![feature(register_tool)]
-use std::path::PathBuf;
-
 pub const FLUX_SYSROOT: &str = "FLUX_SYSROOT";
 pub const FLUX_FULL_COMPILATION: &str = "FLUX_FULL_COMPILATION";
 
-pub fn find_flux_path() -> PathBuf {
-    let executable_name = if cfg!(windows) { "rustc-flux.exe" } else { "rustc-flux" };
-    find_file_in_target_dir(executable_name)
-}
-
 /// Rustc flags to pass Flux when running tests
 pub fn default_rustc_flags() -> Vec<String> {
     vec!["--crate-type=rlib".to_string(), "--edition=2021".to_string()]
 }
-
-fn find_file_in_target_dir(file: &str) -> PathBuf {
-    let target_directory = if cfg!(debug_assertions) { "debug" } else { "release" };
-    let local_path: PathBuf = ["target", target_directory, file].into_iter().collect();
-    if local_path.exists() {
-        return local_path;
-    }
-    let workspace_path: PathBuf = ["..", "target", target_directory, file]
-        .into_iter()
-        .collect();
-    if workspace_path.exists() {
-        return workspace_path;
-    }
-    panic!("Could not find {file}");
-}

tests/tests/compiletest.rs

@@ -5,19 +5,53 @@ use std::{env, path::PathBuf};
 
 use compiletest_rs::{common::Mode, Config};
 use itertools::Itertools;
-use tests::{default_rustc_flags, find_flux_path, FLUX_FULL_COMPILATION, FLUX_SYSROOT};
-
-fn config() -> Config {
-    let bless = env::args().any(|arg| arg == "--bless");
-    let filters = env::args()
-        .tuple_windows()
-        .filter_map(|(arg, val)| if arg == "--test-args" { Some(val) } else { None })
-        .collect_vec();
-    Config { rustc_path: find_flux_path(), filters, bless, ..Config::default() }
+use tests::{default_rustc_flags, FLUX_FULL_COMPILATION, FLUX_SYSROOT};
+
+#[derive(Debug)]
+struct Args {
+    filters: Vec<String>,
+    flux: PathBuf,
+    sysroot: PathBuf,
+}
+
+impl Args {
+    fn parse() -> Args {
+        let mut filters = vec![];
+        let mut sysroot = None;
+        let mut flux = None;
+        for (arg, val) in env::args().tuple_windows() {
+            match &arg[..] {
+                "--filter" => {
+                    filters.push(val);
+                }
+                "--flux" => {
+                    if flux.is_some() {
+                        panic!("option '--flux' given more than once");
+                    }
+                    flux = Some(val);
+                }
+                "--sysroot" => {
+                    if sysroot.is_some() {
+                        panic!("option '--sysroot' given more than once");
+                    }
+                    sysroot = Some(val);
+                }
+                _ => {}
+            }
+        }
+        let Some(flux) = flux else {
+            panic!("option '--flux' must be provided");
+        };
+        let Some(sysroot) = sysroot else {
+            panic!("option '--sysroot' must be provided");
+        };
+        Args { filters, flux: PathBuf::from(flux), sysroot: PathBuf::from(sysroot) }
+    }
 }
 
 fn test_runner(_: &[&()]) {
-    let mut config = config().tempdir();
+    let args = Args::parse();
+    let mut config = Config { rustc_path: args.flux, filters: args.filters, ..Config::default() };
 
     let mut rustc_flags = default_rustc_flags();
 
@@ -32,7 +66,7 @@ fn test_runner(_: &[&()]) {
 
     // Force full compilation to make sure we generate artifacts when annotating tests with `@aux-build`
     env::set_var(FLUX_FULL_COMPILATION, "1");
-    env::set_var(FLUX_SYSROOT, config.rustc_path.parent().unwrap());
+    env::set_var(FLUX_SYSROOT, &args.sysroot);
 
     let path: PathBuf = ["tests", "pos"].iter().collect();
     if path.exists() {