[ruby-dev:22605] Re: marshaling a nameerror.

なかだです。

At Sat, 17 Jan 2004 14:19:30 +0900,
Tanaka Akira wrote:
> 次のように、とある例外オブジェクトが marshal 出来ないことに気がつきました。
> 
> % ruby -ve '
> begin
> eval("x")
> rescue Exception
> p Marshal.dump($!)
> end'
> ruby 1.9.0 (2004-01-16) [i686-linux]
> -e:5:in `dump': singleton can't be dumped (TypeError)
>         from -e:5
> 
> なぜか、p $! を入れただけで marshal 出来るようになるのが不思議なところ
> です。

メッセージをon-demandで作るために、レシーバ(この場合singletonで
あるmain )を持ってるからですね。to_sの中でメッセージを作って、
レシーバをインスタンス変数から削除しているので、その後はエラー
にならなくなります。

既存のデータと互換性がなくていいなら、marshal_dumpですかねぇ。


Index: error.c
===================================================================
RCS file: /cvs/ruby/src/ruby/error.c,v
retrieving revision 1.87
diff -u -2 -p -d -r1.87 error.c
--- error.c	30 Dec 2003 16:36:05 -0000	1.87
+++ error.c	17 Jan 2004 07:48:52 -0000
@@ -606,9 +606,15 @@ name_err_initialize(argc, argv, self)
     VALUE self;
 {
-    VALUE name;
+    static VALUE name_err_mdump _((VALUE));
+    VALUE recv, name;
 
-    name = (argc > 1) ? argv[--argc] : Qnil;
+    name = (argc > 2) ? argv[--argc] : Qnil;
+    recv = (argc > 1) ? argv[--argc] : Qnil;
     exc_initialize(argc, argv, self);
+    rb_iv_set(self, "recv", recv);
     rb_iv_set(self, "name", name);
+    if (!NIL_P(recv)) {
+	rb_define_singleton_method(self, "marshal_dump", name_err_mdump, 0);
+    }
     return self;
 }
@@ -630,4 +636,73 @@ name_err_name(self)
 /*
  * call-seq:
+ *  name_error.to_s   => string
+ *
+ * Produce a nicely-formated string representing the +NameError+.
+ */
+
+static VALUE
+name_err_to_s(exc)
+    VALUE exc;
+{
+    VALUE mesg = rb_attr_get(exc, rb_intern("mesg"));
+    ID id_recv = rb_intern("recv");
+
+    if (NIL_P(mesg)) return rb_class_path(CLASS_OF(exc));
+    if (rb_ivar_defined(exc, id_recv)) {
+	char buf[BUFSIZ];
+	char *desc = "";
+	VALUE d;
+	int noclass;
+	VALUE obj = rb_ivar_get(exc, id_recv);
+	int state;
+
+	switch (TYPE(obj)) {
+	  case T_NIL:
+	    desc = "nil";
+	    break;
+	  case T_TRUE:
+	    desc = "true";
+	    break;
+	  case T_FALSE:
+	    desc = "false";
+	    break;
+	  default:
+	    d = rb_protect(rb_inspect, obj, 0);
+	    if (!NIL_P(d) || RSTRING(d)->len > 65) {
+		d = rb_any_to_s(obj);
+	    }
+	    break;
+	}
+	if (d) {
+	    desc = RSTRING(d)->ptr;
+	}
+	noclass = (!desc || desc[0]=='#');
+	snprintf(buf, BUFSIZ, RSTRING(mesg)->ptr, desc,
+		 noclass ? "" : ":",
+		 noclass ? "" : rb_obj_classname(obj));
+	mesg = rb_str_new2(buf);
+	rb_iv_set(exc, "mesg", mesg);
+	st_delete(ROBJECT(exc)->iv_tbl, (st_data_t*)&id_recv, 0);
+    }
+    if (OBJ_TAINTED(exc)) OBJ_TAINT(mesg);
+    return mesg;
+}
+
+static VALUE
+name_err_mdump(exc)
+    VALUE exc;
+{
+    VALUE klass;
+
+    name_err_to_s(exc);
+    klass = RBASIC(exc)->klass;
+    if (RBASIC(klass)->flags & FL_SINGLETON) {
+	rb_remove_method(klass, "marshal_dump");
+    }
+    return rb_obj_dup(exc);
+}
+
+/*
+ * call-seq:
  *   NoMethodError.new(msg, name [, args])  => no_method_error
  *
@@ -644,5 +719,5 @@ nometh_err_initialize(argc, argv, self)
     VALUE self;
 {
-    VALUE args = (argc > 2) ? argv[--argc] : Qnil;
+    VALUE args = (argc > 3) ? argv[--argc] : Qnil;
     name_err_initialize(argc, argv, self);
     rb_iv_set(self, "args", args);
@@ -885,4 +960,5 @@ Init_Exception()
     rb_define_method(rb_eNameError, "initialize", name_err_initialize, -1);
     rb_define_method(rb_eNameError, "name", name_err_name, 0);
+    rb_define_method(rb_eNameError, "to_s", name_err_to_s, 0);
     rb_eNoMethodError = rb_define_class("NoMethodError", rb_eNameError);
     rb_define_method(rb_eNoMethodError, "initialize", nometh_err_initialize, -1);
Index: eval.c
===================================================================
RCS file: /cvs/ruby/src/ruby/eval.c,v
retrieving revision 1.629
diff -u -2 -p -d -r1.629 eval.c
--- eval.c	16 Jan 2004 14:53:10 -0000	1.629
+++ eval.c	17 Jan 2004 07:23:46 -0000
@@ -5161,63 +5161,4 @@ static int last_call_status;
 
 /*
- * call-seq:
- *  name_error.to_s   => string
- *
- * Produce a nicely-formated string representing the +NameError+.
- */
-
-static VALUE
-name_err_to_s(exc)
-    VALUE exc;
-{
-    VALUE mesg = rb_attr_get(exc, rb_intern("mesg"));
-    ID id_recv = rb_intern("recv");
-
-    if (NIL_P(mesg)) return rb_class_path(CLASS_OF(exc));
-    if (rb_ivar_defined(exc, id_recv)) {
-	char buf[BUFSIZ];
-	char *desc = "";
-	volatile VALUE d = 0;
-	int noclass;
-	VALUE obj = rb_ivar_get(exc, id_recv);
-	int state;
-
-	switch (TYPE(obj)) {
-	  case T_NIL:
-	    desc = "nil";
-	    break;
-	  case T_TRUE:
-	    desc = "true";
-	    break;
-	  case T_FALSE:
-	    desc = "false";
-	    break;
-	  default:
-	    PUSH_TAG(PROT_NONE);
-	    if ((state = EXEC_TAG()) == 0) {
-		d = rb_inspect(obj);
-	    }
-	    POP_TAG();
-	    if (!d || RSTRING(d)->len > 65) {
-		d = rb_any_to_s(obj);
-	    }
-	    break;
-	}
-	if (d) {
-	    desc = RSTRING(d)->ptr;
-	}
-	noclass = (!desc || desc[0]=='#');
-	snprintf(buf, BUFSIZ, RSTRING(mesg)->ptr, desc,
-		 noclass ? "" : ":",
-		 noclass ? "" : rb_obj_classname(obj));
-	mesg = rb_str_new2(buf);
-	rb_iv_set(exc, "mesg", mesg);
-	st_delete(ROBJECT(exc)->iv_tbl, (st_data_t*)&id_recv, 0);
-    }
-    if (OBJ_TAINTED(exc)) OBJ_TAINT(mesg);
-    return mesg;
-}
-
-/*
  *  call-seq:
  *     obj.method_missing(symbol [, *args] )   => result
@@ -5293,4 +5234,5 @@ rb_method_missing(argc, argv, obj)
 	snprintf(buf, BUFSIZ, format, rb_id2name(id));
 	args[n++] = rb_str_new2(buf);
+	args[n++] = obj;
 	args[n++] = argv[0];
 	if (exc == rb_eNoMethodError) {
@@ -5298,5 +5240,4 @@ rb_method_missing(argc, argv, obj)
 	}
 	exc = rb_class_new_instance(n, args, exc);
-	rb_iv_set(exc, "recv", obj);
 	ruby_frame = ruby_frame->prev; /* pop frame for "method_missing" */
 	rb_exc_raise(exc);
@@ -7662,7 +7603,4 @@ Init_load()
     ruby_dln_librefs = rb_ary_new();
     rb_global_variable(&ruby_dln_librefs);
-
-    /* not really a right place */
-    rb_define_method(rb_eNameError, "to_s", name_err_to_s, 0);
 }
 
Index: marshal.c
===================================================================
RCS file: /cvs/ruby/src/ruby/marshal.c,v
retrieving revision 1.112
diff -u -2 -p -d -r1.112 marshal.c
--- marshal.c	16 Jan 2004 05:36:54 -0000	1.112
+++ marshal.c	17 Jan 2004 07:37:51 -0000
@@ -105,6 +105,10 @@ class2path(klass)
     VALUE path = rb_class_path(klass);
     char *n = RSTRING(path)->ptr;
+    VALUE c = rb_path2class(n);
 
-    if (rb_path2class(n) != klass) {
+    if (c == klass) return path;
+    if (!(RBASIC(klass)->flags & FL_SINGLETON) ||
+	RCLASS(klass)->m_tbl->num_entries ||
+	RCLASS(klass)->super != c) {
 	rb_raise(rb_eArgError, "%s cannot be referred", n);
     }


-- 
--- 僕の前にBugはない。
--- 僕の後ろにBugはできる。
    中田 伸悦