* transcode.c (enc_arg): must take pointer argument to avoid GC

  problem.  StringValueCStr modifies the argument and it should be
  preserved while the string StringValueCStr returns is used.
  Since the string is used by caller, the modified argument should be
  hold by caller.  Actually
    GC.stress = true
    def (o=Object.new).to_str()
      "universal"+"_newline"
    end                         
    "\u3042".encode(o, "")' 
  causes curious warning:
    rb_define_const: invalid name `' for constant



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@19408 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 9 insertions, 8 deletions

diff --git a/transcode.c b/transcode.c
index cd77ddbacd..b82729cb5b 100644
--- a/transcode.c
+++ b/transcode.c
@@ -2387,16 +2387,17 @@ rb_econv_open_opts(const char *source_encoding, const char *destination_encoding
 }
 
 static int
-enc_arg(VALUE arg, const char **name_p, rb_encoding **enc_p)
+enc_arg(volatile VALUE *arg, const char **name_p, rb_encoding **enc_p)
 {
     rb_encoding *enc;
     const char *n;
     int encidx;
+    VALUE encval;
 
-    if ((encidx = rb_to_encoding_index(arg)) < 0) {
+    if ((encidx = rb_to_encoding_index(encval = *arg)) < 0) {
 	enc = NULL;
 	encidx = 0;
-	n = StringValueCStr(arg);
+	n = StringValueCStr(*arg);
     }
     else {
 	enc = rb_enc_from_index(encidx);
@@ -2418,7 +2419,7 @@ str_transcode_enc_args(VALUE str, volatile VALUE *arg1, volatile VALUE *arg2,
     const char *sname, *dname;
     int sencidx, dencidx;
 
-    dencidx = enc_arg(*arg1, &dname, &denc);
+    dencidx = enc_arg(arg1, &dname, &denc);
 
     if (NIL_P(*arg2)) {
 	sencidx = rb_enc_get_index(str);
@@ -2426,7 +2427,7 @@ str_transcode_enc_args(VALUE str, volatile VALUE *arg1, volatile VALUE *arg2,
 	sname = rb_enc_name(senc);
     }
     else {
-        sencidx = enc_arg(*arg2, &sname, &senc);
+        sencidx = enc_arg(arg2, &sname, &senc);
     }
 
     *sname_p = sname;
@@ -2670,7 +2671,7 @@ econv_s_asciicompat_encoding(VALUE klass, VALUE arg)
     const char *arg_name, *result_name;
     rb_encoding *arg_enc, *result_enc;
 
-    enc_arg(arg, &arg_name, &arg_enc);
+    enc_arg(&arg, &arg_name, &arg_enc);
 
     result_name = rb_econv_asciicompat_encoding(arg_name);
 
@@ -2881,9 +2882,9 @@ rb_econv_init_by_convpath(VALUE self, VALUE convpath,
             if (RARRAY_LEN(pair) != 2)
                 rb_raise(rb_eArgError, "not a 2-element array in convpath");
             snamev = rb_ary_entry(pair, 0);
-            enc_arg(snamev, &sname, &senc);
+            enc_arg(&snamev, &sname, &senc);
             dnamev = rb_ary_entry(pair, 1);
-            enc_arg(dnamev, &dname, &denc);
+            enc_arg(&dnamev, &dname, &denc);
         }
         else {
             sname = "";