Migrate run-make/rustdoc-io-error to rmake.rs

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -189,7 +189,6 @@ run-make/rlib-format-packed-bundled-libs-3/Makefile
 run-make/rlib-format-packed-bundled-libs/Makefile
 run-make/rmeta-preferred/Makefile
 run-make/rustc-macro-dep-files/Makefile
-run-make/rustdoc-io-error/Makefile
 run-make/sanitizer-cdylib-link/Makefile
 run-make/sanitizer-dylib-link/Makefile
 run-make/sanitizer-staticlib-link/Makefile

tests/run-make/rustdoc-io-error/rmake.rs

@@ -0,0 +1,31 @@
+// This test verifies that rustdoc doesn't ICE when it encounters an IO error
+// while generating files. Ideally this would be a rustdoc-ui test, so we could
+// verify the error message as well.
+//
+// It operates by creating a temporary directory and modifying its
+// permissions so that it is not writable. We have to take special care to set
+// the permissions back to normal so that it's able to be deleted later.
+
+//@ ignore-windows - the `set_readonly` functions doesn't work on folders.
+//@ ignore-arm - weird file perms on armhf-gnu
+
+use run_make_support::{path, rustdoc};
+use std::fs;
+
+fn main() {
+    let out_dir = path("rustdoc-io-error");
+    let output = fs::create_dir(&out_dir).unwrap();
+    let mut permissions = fs::metadata(&out_dir).unwrap().permissions();
+    let original_permissions = permissions.clone();
+
+    permissions.set_readonly(true);
+    fs::set_permissions(&out_dir, permissions).unwrap();
+
+    let output = rustdoc().input("foo.rs").output(&out_dir).env("RUST_BACKTRACE", "1").run_fail();
+
+    fs::set_permissions(&out_dir, original_permissions).unwrap();
+
+    output
+        .assert_exit_code(1)
+        .assert_stderr_contains("error: couldn't generate documentation: Permission denied");
+}