fix for doctest-xcompile stabilization

Author: RalfJung

src/tools/miri/cargo-miri/src/main.rs

@@ -63,27 +63,37 @@ fn main() {
         return;
     }
 
+    let Some(first) = args.next() else {
+        show_error!(
+            "`cargo-miri` called without first argument; please only invoke this binary through `cargo miri`"
+        )
+    };
+
     // The way rustdoc invokes rustc is indistinguishable from the way cargo invokes rustdoc by the
     // arguments alone. `phase_cargo_rustdoc` sets this environment variable to let us disambiguate.
     if env::var_os("MIRI_CALLED_FROM_RUSTDOC").is_some() {
         // ...however, we then also see this variable when rustdoc invokes us as the testrunner!
-        // The runner is invoked as `$runtool ($runtool-arg)* output_file`;
-        // since we don't specify any runtool-args, and rustdoc supplies multiple arguments to
-        // the test-builder unconditionally, we can just check the number of remaining arguments:
-        if args.len() == 1 {
-            phase_runner(args, RunnerPhase::Rustdoc);
-        } else {
-            phase_rustc(args, RustcPhase::Rustdoc);
+        // In that case the first argument is `runner` and there are no more arguments.
+        match first.as_str() {
+            "runner" => phase_runner(args, RunnerPhase::Rustdoc),
+            flag if flag.starts_with("--") || flag.starts_with("@") => {
+                // This is probably rustdoc invoking us to build the test. But we need to get `first`
+                // "back onto the iterator", it is some part of the rustc invocation.
+                phase_rustc(iter::once(first).chain(args), RustcPhase::Rustdoc);
+            }
+            _ => {
+                show_error!(
+                    "`cargo-miri` failed to recognize which phase of the build process this is, please report a bug.\n\
+                    We are inside MIRI_CALLED_FROM_RUSTDOC.\n\
+                    The command-line arguments were: {:#?}",
+                    Vec::from_iter(env::args()),
+                );
+            }
         }
 
         return;
     }
 
-    let Some(first) = args.next() else {
-        show_error!(
-            "`cargo-miri` called without first argument; please only invoke this binary through `cargo miri`"
-        )
-    };
     match first.as_str() {
         "miri" => phase_cargo_miri(args),
         "runner" => phase_runner(args, RunnerPhase::Cargo),

src/tools/miri/cargo-miri/src/phases.rs

@@ -666,11 +666,6 @@ pub fn phase_rustdoc(mut args: impl Iterator<Item = String>) {
         if arg == "--extern" {
             // Patch --extern arguments to use *.rmeta files, since phase_cargo_rustc only creates stub *.rlib files.
             forward_patched_extern_arg(&mut args, &mut cmd);
-        } else if arg == "--test-runtool" {
-            // An existing --test-runtool flag indicates cargo is running in cross-target mode, which we don't support.
-            // Note that this is only passed when cargo is run with the unstable -Zdoctest-xcompile flag;
-            // otherwise, we won't be called as rustdoc at all.
-            show_error!("cross-interpreting doctests is not currently supported by Miri.");
         } else {
             cmd.arg(arg);
         }
@@ -702,10 +697,10 @@ pub fn phase_rustdoc(mut args: impl Iterator<Item = String>) {
     // make sure the 'miri' flag is set for rustdoc
     cmd.arg("--cfg").arg("miri");
 
-    // Make rustdoc call us back.
+    // Make rustdoc call us back for the build.
+    // (cargo already sets `--test-runtool` to us since we are the cargo test runner.)
     let cargo_miri_path = env::current_exe().expect("current executable path invalid");
     cmd.arg("--test-builder").arg(&cargo_miri_path); // invoked by forwarding most arguments
-    cmd.arg("--test-runtool").arg(&cargo_miri_path); // invoked with just a single path argument
 
     debug_cmd("[cargo-miri rustdoc]", verbose, &cmd);
     exec(cmd)

src/tools/miri/test-cargo-miri/run-test.py

@@ -142,24 +142,19 @@ def test_cargo_miri_run():
     )
 
 def test_cargo_miri_test():
-    # rustdoc is not run on foreign targets
-    is_foreign = ARGS.target is not None
-    default_ref = "test.cross-target.stdout.ref" if is_foreign else "test.default.stdout.ref"
-    filter_ref = "test.filter.cross-target.stdout.ref" if is_foreign else "test.filter.stdout.ref"
-
     test("`cargo miri test`",
         cargo_miri("test"),
-        default_ref, "test.empty.ref",
+        "test.default.stdout.ref", "test.empty.ref",
         env={'MIRIFLAGS': "-Zmiri-seed=4242"},
     )
     test("`cargo miri test` (no isolation, no doctests)",
         cargo_miri("test") + ["--bins", "--tests"], # no `--lib`, we disabled that in `Cargo.toml`
-        "test.cross-target.stdout.ref", "test.empty.ref",
+        "test.no-doc.stdout.ref", "test.empty.ref",
         env={'MIRIFLAGS': "-Zmiri-disable-isolation"},
     )
     test("`cargo miri test` (with filter)",
         cargo_miri("test") + ["--", "--format=pretty", "pl"],
-        filter_ref, "test.empty.ref",
+        "test.filter.stdout.ref", "test.empty.ref",
     )
     test("`cargo miri test` (test target)",
         cargo_miri("test") + ["--test", "test", "--", "--format=pretty"],
@@ -171,7 +166,7 @@ def test_cargo_miri_test():
     )
     test("`cargo miri t` (subcrate, no isolation)",
         cargo_miri("t") + ["-p", "subcrate"],
-        "test.subcrate.cross-target.stdout.ref" if is_foreign else "test.subcrate.stdout.ref",
+        "test.subcrate.stdout.ref",
         "test.empty.ref",
         env={'MIRIFLAGS': "-Zmiri-disable-isolation"},
     )
@@ -181,12 +176,12 @@ def test_cargo_miri_test():
     )
     test("`cargo miri test` (custom target dir)",
         cargo_miri("test") + ["--target-dir=custom-test"],
-        default_ref, "test.empty.ref",
+        "test.default.stdout.ref", "test.empty.ref",
     )
     del os.environ["CARGO_TARGET_DIR"] # this overrides `build.target-dir` passed by `--config`, so unset it
     test("`cargo miri test` (config-cli)",
         cargo_miri("test") + ["--config=build.target-dir=\"config-cli\""],
-        default_ref, "test.empty.ref",
+        "test.default.stdout.ref", "test.empty.ref",
     )
     if ARGS.multi_target:
         test_cargo_miri_multi_target()

src/tools/miri/test-cargo-miri/test.filter.cross-target.stdout.ref

@@ -20,3 +20,13 @@ running 6 tests
 ...i..
 test result: ok. 5 passed; 0 failed; 1 ignored; 0 measured; 0 filtered out; finished in $TIME
 
+
+running 5 tests
+.....
+test result: ok. 5 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in $TIME
+
+
+running 5 tests
+.....
+test result: ok. 5 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in $TIME
+