support `require` in non-main Ractors

Many libraries should be loaded on the main ractor because of
setting constants with unshareable objects and so on.

This patch allows to call `requore` on non-main Ractors by
asking the main ractor to call `require` on it. The calling ractor
waits for the result of `require` from the main ractor.

If the `require` call failed with some reasons, an exception
objects will be deliverred from the main ractor to the calling ractor
if it is copy-able.

Same on `require_relative` and `require` by `autoload`.

Now `Ractor.new{pp obj}` works well (the first call of `pp` requires
`pp` library implicitly).

[Feature #20627]

1 files changed, 16 insertions, 7 deletions

diff --git a/load.c b/load.c
index c1862c38fa..e4dd1e47ba 100644
--- a/load.c
+++ b/load.c
@@ -18,6 +18,7 @@
 #include "darray.h"
 #include "ruby/encoding.h"
 #include "ruby/util.h"
+#include "ractor_core.h"
 
 static VALUE ruby_dln_libmap;
 
@@ -1383,17 +1384,25 @@ static VALUE
 rb_require_string_internal(VALUE fname, bool resurrect)
 {
     rb_execution_context_t *ec = GET_EC();
-    int result = require_internal(ec, fname, 1, RTEST(ruby_verbose));
 
-    if (result > TAG_RETURN) {
-        EC_JUMP_TAG(ec, result);
-    }
-    if (result < 0) {
+    // main ractor check
+    if (!rb_ractor_main_p()) {
         if (resurrect) fname = rb_str_resurrect(fname);
-        load_failed(fname);
+        return rb_ractor_require(fname);
     }
+    else {
+        int result = require_internal(ec, fname, 1, RTEST(ruby_verbose));
+
+        if (result > TAG_RETURN) {
+            EC_JUMP_TAG(ec, result);
+        }
+        if (result < 0) {
+            if (resurrect) fname = rb_str_resurrect(fname);
+            load_failed(fname);
+        }
 
-    return RBOOL(result);
+        return RBOOL(result);
+    }
 }
 
 VALUE