Add regression test when unable to run compiler in doctest

Author: GuillaumeGomez

src/librustdoc/doctest.rs

@@ -501,10 +501,7 @@ fn add_exe_suffix(input: String, target: &TargetTuple) -> String {
  input + &exe_suffix
 }
 
-fn wrapped_rustc_command<'a>(
- rustc_wrappers: &'a [PathBuf],
- rustc_binary: &'a Path,
-) -> (Command, &'a Path) {
+fn wrapped_rustc_command<'a>(rustc_wrappers: &'a [PathBuf], rustc_binary: &'a Path) -> Command {
  let mut args = rustc_wrappers.iter().map(PathBuf::as_path).chain([rustc_binary]);
 
  let exe = args.next().expect("unable to create rustc command");
@@ -513,7 +510,7 @@ fn wrapped_rustc_command<'a>(
  command.arg(arg);
  }
 
- (command, rustc_wrappers.first().map(|p| &**p).unwrap_or(rustc_binary))
+ command
 }
 
 /// Information needed for running a bundle of doctests.
@@ -633,8 +630,7 @@ fn run_test(
  .test_builder
  .as_deref()
  .unwrap_or_else(|| rustc_interface::util::rustc_path(sysroot).expect("found rustc"));
- let (mut compiler, binary_path) =
- wrapped_rustc_command(&rustdoc_options.test_builder_wrappers, rustc_binary);
+ let mut compiler = wrapped_rustc_command(&rustdoc_options.test_builder_wrappers, rustc_binary);
 
  compiler.args(&compiler_args);
 
@@ -675,6 +671,7 @@ fn run_test(
 
  debug!("compiler invocation for doctest: {compiler:?}");
 
+ let binary_path = compiler.get_program().to_os_string();
  let mut child = match compiler.spawn() {
  Ok(child) => child,
  Err(error) => {
@@ -690,7 +687,7 @@ fn run_test(
  // build it now
  let runner_input_file = doctest.path_for_merged_doctest_runner();
 
- let (mut runner_compiler, binary_path) =
+ let mut runner_compiler =
  wrapped_rustc_command(&rustdoc_options.test_builder_wrappers, rustc_binary);
  // the test runner does not contain any user-written code, so this doesn't allow
  // the user to exploit nightly-only features on stable
@@ -743,6 +740,7 @@ fn run_test(
  let status = if !status.success() {
  status
  } else {
+ let binary_path = runner_compiler.get_program().to_os_string();
  let mut child_runner = match runner_compiler.spawn() {
  Ok(child) => child,
  Err(error) => {

tests/run-make/rustdoc-test-builder/foo.rs

@@ -0,0 +1,3 @@
+//! ```
+//! let x = 12;
+//! ```

tests/run-make/rustdoc-test-builder/rmake.rs

@@ -0,0 +1,22 @@
+// This test ensures that if the rustdoc test binary is not executable, it will
+// gracefully fail and not panic.
+
+//@ needs-target-std
+
+use run_make_support::{path, rfs, rustdoc};
+
+fn main() {
+ let absolute_path = path("foo.rs").canonicalize().expect("failed to get absolute path");
+ let output = rustdoc()
+ .input("foo.rs")
+ .arg("--test")
+ .arg("-Zunstable-options")
+ .arg("--test-builder")
+ .arg(&absolute_path)
+ .run_fail();
+
+ output.assert_stdout_contains("Failed to spawn ");
+ output.assert_stderr_not_contains("the compiler unexpectedly panicked. this is a bug.");
+ // Just in case...
+ output.assert_stdout_not_contains("the compiler unexpectedly panicked. this is a bug.");
+}