Fixes [Bug #22883] eval isolation in Ractors for Prism

amuta · amuta · commit 445bb45ea006 · 2025-10-24T15:04:04.000-03:00
Add helper functions to compute isolation depth for eval contexts.
Both Prism and parse.y parsers now use the same isolation detection,
ensuring consistent behavior when accessing outer locals in Ractors.
diff --git a/bootstraptest/test_ractor.rb b/bootstraptest/test_ractor.rb
@@ -754,6 +754,37 @@ def ractor_local_globals
   end
 }
 
+# eval with outer locals in a Ractor raises SyntaxError
+# [Bug #22883]
+assert_equal 'SyntaxError', %q{
+  outer = 42
+  r = Ractor.new do
+    eval("outer")
+  end
+  begin
+    r.value
+  rescue Ractor::RemoteError => e
+    e.cause.class
+  end
+}
+
+# eval of an undefined name in a Ractor raises NameError
+assert_equal 'NameError', %q{
+  r = Ractor.new do
+    eval("totally_undefined_name")
+  end
+  begin
+    r.value
+  rescue Ractor::RemoteError => e
+    e.cause.class
+  end
+}
+
+# eval of a local defined inside the Ractor works
+assert_equal '99', %q{
+  Ractor.new { inner = 99; eval("inner").to_s }.value
+}
+
 # ivar in shareable-objects are not allowed to access from non-main Ractor
 assert_equal "can not get unshareable values from instance variables of classes/modules from non-main Ractors", <<~'RUBY', frozen_string_literal: false
   class C
diff --git a/vm_eval.c b/vm_eval.c
@@ -1669,6 +1669,24 @@ get_eval_default_path(void)
     return eval_default_path;
 }
 
+static inline int
+compute_isolated_depth_from_ep(const VALUE *ep)
+{
+    int depth = 1;
+    while (1) {
+        if (VM_ENV_FLAGS(ep, VM_ENV_FLAG_ISOLATED)) return depth;
+        if (VM_ENV_LOCAL_P(ep)) return 0;
+        ep = VM_ENV_PREV_EP(ep);
+        depth++;
+    }
+}
+
+static inline int
+compute_isolated_depth_from_block(const struct rb_block *blk)
+{
+    return compute_isolated_depth_from_ep(vm_block_ep(blk));
+}
+
 static const rb_iseq_t *
 pm_eval_make_iseq(VALUE src, VALUE fname, int line,
         const struct rb_block *base_block)
@@ -1677,8 +1695,8 @@ pm_eval_make_iseq(VALUE src, VALUE fname, int line,
     const rb_iseq_t *iseq = parent;
     VALUE name = rb_fstring_lit("<compiled>");
 
-    // Conditionally enable coverage depending on the current mode:
     int coverage_enabled = ((rb_get_coverage_mode() & COVERAGE_TARGET_EVAL) != 0) ? 1 : 0;
+    int isolated_depth = compute_isolated_depth_from_block(base_block);
 
     if (!fname) {
         fname = rb_source_location(&line);
@@ -1872,7 +1890,7 @@ pm_eval_make_iseq(VALUE src, VALUE fname, int line,
 #undef FORWARDING_ALL_STR
 
     int error_state;
-    iseq = pm_iseq_new_eval(&result.node, name, fname, Qnil, line, parent, 0, &error_state);
+    iseq = pm_iseq_new_eval(&result.node, name, fname, Qnil, line, parent, isolated_depth, &error_state);
 
     pm_scope_node_t *prev = result.node.previous;
     while (prev) {
@@ -1908,27 +1926,9 @@ eval_make_iseq(VALUE src, VALUE fname, int line,
     rb_iseq_t *iseq = NULL;
     VALUE ast_value;
     rb_ast_t *ast;
-    int isolated_depth = 0;
 
-    // Conditionally enable coverage depending on the current mode:
     int coverage_enabled = (rb_get_coverage_mode() & COVERAGE_TARGET_EVAL) != 0;
-
-    {
-        int depth = 1;
-        const VALUE *ep = vm_block_ep(base_block);
-
-        while (1) {
-            if (VM_ENV_FLAGS(ep, VM_ENV_FLAG_ISOLATED)) {
-                isolated_depth = depth;
-                break;
-            }
-            else if (VM_ENV_LOCAL_P(ep)) {
-                break;
-            }
-            ep = VM_ENV_PREV_EP(ep);
-            depth++;
-        }
-    }
+    int isolated_depth = compute_isolated_depth_from_block(base_block);
 
     if (!fname) {
         fname = rb_source_location(&line);
