Gracefully handle in case we cannot run the compiler in doctests

Author: GuillaumeGomez

src/librustdoc/doctest.rs

@@ -671,7 +671,13 @@ fn run_test(
 
     debug!("compiler invocation for doctest: {compiler:?}");
 
-    let mut child = compiler.spawn().expect("Failed to spawn rustc process");
+    let mut child = match compiler.spawn() {
+        Ok(child) => child,
+        Err(error) => {
+            eprintln!("Failed to run compiler: {error:?}");
+            return (Duration::default(), Err(TestFailure::CompileError));
+        }
+    };
     let output = if let Some(merged_test_code) = &doctest.merged_test_code {
         // compile-fail tests never get merged, so this should always pass
         let status = child.wait().expect("Failed to wait");
@@ -733,7 +739,13 @@ fn run_test(
         let status = if !status.success() {
             status
         } else {
-            let mut child_runner = runner_compiler.spawn().expect("Failed to spawn rustc process");
+            let mut child_runner = match runner_compiler.spawn() {
+                Ok(child) => child,
+                Err(error) => {
+                    eprintln!("Failed to spawn rustc process: {error:?}");
+                    return (Duration::default(), Err(TestFailure::CompileError));
+                }
+            };
             child_runner.wait().expect("Failed to wait")
         };