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authorBenoit Daloze <eregontp@gmail.com>2019-09-08 11:53:27 +0200
committerBenoit Daloze <eregontp@gmail.com>2019-09-26 10:23:02 +0200
commit6ffc045a817fbdf04a6945d3c260b55b0fa1fd1e (patch)
treee830df0ad8e9d5ad4413d1008115699b703e215b
parent4a4c5028258e53f3395af29655a66bcef796fd73 (diff)
[EXPERIMENTAL] Make Symbol#to_s return a frozen String
* Always the same frozen String for a given Symbol. * Avoids extra allocations whenever calling Symbol#to_s. * See [Feature #16150]
Notes
Notes: Merged: https://github.com/ruby/ruby/pull/2437
-rw-r--r--NEWS8
-rw-r--r--spec/ruby/core/symbol/shared/id2name.rb17
-rw-r--r--string.c5
-rw-r--r--test/-ext-/string/test_capacity.rb4
4 files changed, 31 insertions, 3 deletions
diff --git a/NEWS b/NEWS
index 70c5ff6bdff..4e168518cad 100644
--- a/NEWS
+++ b/NEWS
@@ -197,6 +197,14 @@ RubyVM::
* RubyVM.resolve_feature_path moved to
$LOAD_PATH.resolve_feature_path. [Feature #15903] [Feature #15230]
+Symbol::
+
+ Modified method::
+
+ * Symbol#to_s now always returns a frozen String. The returned String is
+ always the same for a given Symbol. This change is experimental.
+ [Feature #16150]
+
Time::
New methods::
diff --git a/spec/ruby/core/symbol/shared/id2name.rb b/spec/ruby/core/symbol/shared/id2name.rb
index 47f97bd3320..a0e190a6807 100644
--- a/spec/ruby/core/symbol/shared/id2name.rb
+++ b/spec/ruby/core/symbol/shared/id2name.rb
@@ -6,4 +6,21 @@ describe :symbol_id2name, shared: true do
:@ruby.send(@method).should == "@ruby"
:@@ruby.send(@method).should == "@@ruby"
end
+
+ ruby_version_is "2.7" do
+ it "returns a frozen String" do
+ :my_symbol.to_s.frozen?.should == true
+ :"dynamic symbol #{6 * 7}".to_s.frozen?.should == true
+ end
+
+ it "always returns the same String for a given Symbol" do
+ s1 = :my_symbol.to_s
+ s2 = :my_symbol.to_s
+ s1.should equal(s2)
+
+ s1 = :"dynamic symbol #{6 * 7}".to_s
+ s2 = :"dynamic symbol #{2 * 3 * 7}".to_s
+ s1.should equal(s2)
+ end
+ end
end
diff --git a/string.c b/string.c
index 367773f0f50..3f0e69689c0 100644
--- a/string.c
+++ b/string.c
@@ -10869,7 +10869,8 @@ sym_inspect(VALUE sym)
* sym.id2name -> string
* sym.to_s -> string
*
- * Returns the name or string corresponding to <i>sym</i>.
+ * Returns a frozen string corresponding to <i>sym</i>.
+ * The returned String is always the same String instance for a given Symbol.
*
* :fred.id2name #=> "fred"
* :ginger.to_s #=> "ginger"
@@ -10879,7 +10880,7 @@ sym_inspect(VALUE sym)
VALUE
rb_sym_to_s(VALUE sym)
{
- return str_new_shared(rb_cString, rb_sym2str(sym));
+ return rb_sym2str(sym);
}
diff --git a/test/-ext-/string/test_capacity.rb b/test/-ext-/string/test_capacity.rb
index df59e767781..f5830a033b8 100644
--- a/test/-ext-/string/test_capacity.rb
+++ b/test/-ext-/string/test_capacity.rb
@@ -14,7 +14,9 @@ class Test_StringCapacity < Test::Unit::TestCase
end
def test_capacity_shared
- assert_equal 0, capa(:abcdefghijklmnopqrstuvwxyz.to_s)
+ str = :abcdefghijklmnopqrstuvwxyz.to_s.dup
+ assert Bug::String.shared_string? str
+ assert_equal 0, capa(str)
end
def test_capacity_normal