From: Yusuke ENDOH <mame@...>
Date: 2010-05-20T21:58:42+09:00
Subject: [ruby-dev:41375] Re: [Bug #3316] Kernel#caller returns nil as 	well

遠藤です。

2010年5月20日4:47 Nobuhiro IMAI <nov@yo.rim.or.jp>:
> が、これだと、caller(0) で返る配列のサイズを越える数を引数として渡して
> も空配列が返るようになってしまっているようです。

ぐああ、問題を誤解していました。nil が帰ることがあるのは元からなんですね。
以下のパッチで再挑戦します。それから頂いたパッチは取り込んでおきます。


diff --git a/vm.c b/vm.c
index 084c8c8..ac1d8ed 100644
--- a/vm.c
+++ b/vm.c
@@ -706,19 +706,20 @@ rb_vm_get_sourceline(const rb_control_frame_t *cfp)
 }

 static int
-vm_backtrace_each(rb_thread_t *th, int lev, rb_backtrace_iter_func
*iter, void *arg)
+vm_backtrace_each(rb_thread_t *th, int lev, void (*init)(void *),
rb_backtrace_iter_func *iter, void *arg)
 {
     const rb_control_frame_t *limit_cfp = th->cfp;
     const rb_control_frame_t *cfp = (void *)(th->stack + th->stack_size);
-    VALUE file = Qnil;
+    VALUE file = Qnil, *aryp = arg;
     int line_no = 0;

     cfp -= 2;
     while (lev-- >= 0) {
-	if (++limit_cfp >= cfp) {
+	if (++limit_cfp > cfp) {
 	    return FALSE;
 	}
     }
+    if (init) (*init)(arg);
     limit_cfp = RUBY_VM_NEXT_CONTROL_FRAME(limit_cfp);
     if (th->vm->progname) file = th->vm->progname;
     while (cfp > limit_cfp) {
@@ -747,15 +748,19 @@ vm_backtrace_each(rb_thread_t *th, int lev,
rb_backtrace_iter_func *iter, void *
     return TRUE;
 }

+static void
+vm_backtrace_alloc(void *arg)
+{
+    VALUE *aryp = arg;
+    *aryp = rb_ary_new();
+}
+
 static int
 vm_backtrace_push(void *arg, VALUE file, int line_no, VALUE name)
 {
     VALUE *aryp = arg;
     VALUE bt;

-    if (!*aryp) {
-	*aryp = rb_ary_new();
-    }
     bt = rb_enc_sprintf(rb_enc_compatible(file, name), "%s:%d:in `%s'",
 			RSTRING_PTR(file), line_no, RSTRING_PTR(name));
     rb_ary_push(*aryp, bt);
@@ -770,7 +775,7 @@ vm_backtrace(rb_thread_t *th, int lev)
     if (lev < 0) {
 	ary = rb_ary_new();
     }
-    vm_backtrace_each(th, lev, vm_backtrace_push, &ary);
+    vm_backtrace_each(th, lev, vm_backtrace_alloc, vm_backtrace_push, &ary);
     if (!ary) return Qnil;
     return rb_ary_reverse(ary);
 }
diff --git a/vm_eval.c b/vm_eval.c
index d1e6352..b854efc 100644
--- a/vm_eval.c
+++ b/vm_eval.c
@@ -16,7 +16,7 @@ static inline VALUE rb_vm_set_finish_env(rb_thread_t * th);
 static inline VALUE vm_yield_with_cref(rb_thread_t *th, int argc,
const VALUE *argv, const NODE *cref);
 static inline VALUE vm_yield(rb_thread_t *th, int argc, const VALUE *argv);
 static inline VALUE vm_backtrace(rb_thread_t *th, int lev);
-static int vm_backtrace_each(rb_thread_t *th, int lev,
rb_backtrace_iter_func *iter, void *arg);
+static int vm_backtrace_each(rb_thread_t *th, int lev, void
(*init)(void *), rb_backtrace_iter_func *iter, void *arg);
 static NODE *vm_cref_push(rb_thread_t *th, VALUE klass, int noex,
rb_block_t *blockptr);
 static VALUE vm_exec(rb_thread_t *th);
 static void vm_set_eval_stack(rb_thread_t * th, VALUE iseqval, const
NODE *cref);
@@ -1574,9 +1574,7 @@ rb_f_caller(int argc, VALUE *argv)
     if (lev < 0)
 	rb_raise(rb_eArgError, "negative level (%d)", lev);

-    ary = vm_backtrace(GET_THREAD(), lev);
-    if (NIL_P(ary)) ary = rb_ary_new();
-    return ary;
+    return vm_backtrace(GET_THREAD(), lev);
 }

 static int
@@ -1598,7 +1596,7 @@ print_backtrace(void *arg, VALUE file, int line,
VALUE method)
 void
 rb_backtrace(void)
 {
-    vm_backtrace_each(GET_THREAD(), -1, print_backtrace, stderr);
+    vm_backtrace_each(GET_THREAD(), -1, NULL, print_backtrace, stderr);
 }

 VALUE
@@ -1629,7 +1627,7 @@ rb_thread_backtrace(VALUE thval)
 int
 rb_backtrace_each(rb_backtrace_iter_func *iter, void *arg)
 {
-    return vm_backtrace_each(GET_THREAD(), -1, iter, arg);
+    return vm_backtrace_each(GET_THREAD(), -1, NULL, iter, arg);
 }

 /*

-- 
Yusuke Endoh <mame@tsg.ne.jp>