hash literal deduplicates like Hash#[]=

From: Eric Wong <e@80x24.org>

* hash.c (rb_hash_key_str): new function
  (hash_aset_str): use rb_hash_key_str
* internal.h: add rb_hash_key_str
* st.c (st_stringify): use rb_hash_key_str
* test/ruby/test_hash.rb (test_NEWHASH_fstring_key): dynamic key
  [ruby-core:84554] [Feature #14258]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61514 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

4 files changed, 21 insertions, 11 deletions

diff --git a/hash.c b/hash.c
index 4452eeed34..b4e86bdfb1 100644
--- a/hash.c
+++ b/hash.c
@@ -1582,19 +1582,25 @@ fstring_existing_str(VALUE str)
     }
 }
 
+VALUE
+rb_hash_key_str(VALUE key)
+{
+    VALUE k;
+
+    if (!RB_OBJ_TAINTED(key) &&
+	(k = fstring_existing_str(key)) != Qnil) {
+	return k;
+    }
+    else {
+	return rb_str_new_frozen(key);
+    }
+}
+
 static int
 hash_aset_str(st_data_t *key, st_data_t *val, struct update_arg *arg, int existing)
 {
     if (!existing && !RB_OBJ_FROZEN(*key)) {
-	VALUE k;
-
-	if (!RB_OBJ_TAINTED(*key) &&
-	    (k = fstring_existing_str(*key)) != Qnil) {
-	    *key = k;
-	}
-	else {
-	    *key = rb_str_new_frozen(*key);
-	}
+	*key = rb_hash_key_str(*key);
     }
     return hash_aset(key, val, arg, existing);
 }
diff --git a/internal.h b/internal.h
index 4ccf3218c6..5fe888cd04 100644
--- a/internal.h
+++ b/internal.h
@@ -1284,6 +1284,7 @@ st_table *rb_init_identtable(void);
 st_table *rb_init_identtable_with_size(st_index_t size);
 VALUE rb_hash_compare_by_id_p(VALUE hash);
 VALUE rb_to_hash_type(VALUE obj);
+VALUE rb_hash_key_str(VALUE);
 
 #define RHASH_TBL_RAW(h) rb_hash_tbl_raw(h)
 VALUE rb_hash_keys(VALUE hash);
diff --git a/st.c b/st.c
index 048e8a22dc..5ca6263db0 100644
--- a/st.c
+++ b/st.c
@@ -2114,8 +2114,8 @@ st_rehash(st_table *tab)
 static st_data_t
 st_stringify(VALUE key)
 {
-    return (rb_obj_class(key) == rb_cString) ?
-        rb_str_new_frozen(key) : key;
+    return (rb_obj_class(key) == rb_cString && !RB_OBJ_FROZEN(key)) ?
+        rb_hash_key_str(key) : key;
 }
 
 static void
diff --git a/test/ruby/test_hash.rb b/test/ruby/test_hash.rb
index 7162f9d01f..313c2fd9de 100644
--- a/test/ruby/test_hash.rb
+++ b/test/ruby/test_hash.rb
@@ -298,6 +298,9 @@ class TestHash < Test::Unit::TestCase
     b = {"ABC" => :t}
     assert_same a.keys[0], b.keys[0]
     assert_same "ABC".freeze, a.keys[0]
+    var = +'ABC'
+    c = { var => :t }
+    assert_same "ABC".freeze, c.keys[0]
   end
 
   def test_tainted_string_key