* variable.c (rb_const_get_0): Fix previous change. There were

  possibilities   when   an   autoload-specified   library   lacks
  definition of  the constant  it was bound  to.  Once  after such
  library had  already beed loaded, the autoload  engine shall not
  reload  it.   Instead  the  interpreter have  to  consider  such
  constant nonexistent.  It results in a const_missing situation.

* variable.c (rb_autoload_load): ditto.

* variable.c (autoload_node): ditto.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@31734 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

2 files changed, 51 insertions, 14 deletions

diff --git a/ChangeLog b/ChangeLog
index 7b28323c99..bb4e65ac1f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+Wed May 25 18:40:47 2011  URABE Shyouhei  <shyouhei@ruby-lang.org>
+
+	* variable.c (rb_const_get_0):  Fix  previous change.   There were
+	  possibilities   when   an   autoload-specified   library   lacks
+	  definition of  the constant  it was bound  to.  Once  after such
+	  library had  already beed loaded, the autoload  engine shall not
+	  reload  it.   Instead  the  interpreter have  to  consider  such
+	  constant nonexistent.  It results in a const_missing situation.
+
+	* variable.c (rb_autoload_load): ditto.
+
+	* variable.c (autoload_node): ditto.
+
 Wed May 25 14:35:02 2011  URABE Shyouhei  <shyouhei@ruby-lang.org>
 
 	* variable.c (rb_autoload_load):  There is a  race condition while
diff --git a/variable.c b/variable.c
index 7f5064521f..54bb153e2b 100644
--- a/variable.c
+++ b/variable.c
@@ -1352,16 +1352,29 @@ autoload_node(mod, id)
     ID id;
 {
     st_data_t val, load, n = id;
-    struct st_table *p = RCLASS(mod)->iv_tbl;
+    struct st_table *p, *q;
 
-    if (p && st_lookup(p, autoload, &val)) {
-        st_table *q = check_autoload_table((VALUE)val);
-
-        if (q && st_lookup(q, n, &load)) {
-            return (NODE *)load;
-        }
+    if ((p = RCLASS(mod)->iv_tbl) == 0) {
+        return 0;
+    }
+    else if (!st_lookup(p, n, &val)) {
+        return 0;
+    }
+    else if (val != Qundef) {
+        return 0;
+    }
+    else if (!st_lookup(p, autoload, &val)) {
+        return 0;
+    }
+    else if ((q = check_autoload_table((VALUE)val)) == 0) {
+        return 0;
+    }
+    else if (!st_lookup(q, n, &load)) {
+        return 0;
+    }
+    else {
+        return (NODE *)load;
     }
-    return 0;
 }
 
 VALUE
@@ -1372,12 +1385,16 @@ rb_autoload_load(klass, id)
     NODE *load = 0;
     VALUE ret = 0;
 
-    if ((load = autoload_node(klass, id)) != 0) {
-        if ((ret = rb_require_safe(load->nd_lit, load->nd_nth)) != Qfalse) {
-            (void) autoload_delete(klass, id);
-        }
+    if ((load = autoload_node(klass, id)) == 0) {
+        return 0;
+    }
+    else if ((ret = rb_require_safe(load->nd_lit, load->nd_nth)) == Qfalse) {
+        return 0;
+    }
+    else {
+        (void) autoload_delete(klass, id);
+        return ret;
     }
-    return ret;
 }
 
 static VALUE
@@ -1440,7 +1457,14 @@ rb_const_get_0(klass, id, exclude, recurse)
 	while (RCLASS(tmp)->iv_tbl && st_lookup(RCLASS(tmp)->iv_tbl,id,&value)) {
 	    if (value == Qundef) {
 		rb_autoload_load(tmp, id);
-		continue;
+                st_lookup(RCLASS(tmp)->iv_tbl, id, &value);
+                if (value == Qundef) {
+                    /* the autoload above did not assign a constant */
+                    break;
+                }
+                else {
+                    continue;
+                }
 	    }
 	    if (exclude && tmp == rb_cObject && klass != rb_cObject) {
 		rb_warn("toplevel constant %s referenced by %s::%s",