Fix Marshal.dump(closed_io) to raise TypeError and allow encoding on closed IO

Mashalling a closed IO object raised "closed stream (IOError)" before instead of TypeError.
This changes IO#(in|ex)ternal_encoding to still return the encoding even if the underlying FD is closed.

Fixes bug #18077

2 files changed, 8 insertions, 4 deletions

diff --git a/spec/ruby/core/io/external_encoding_spec.rb b/spec/ruby/core/io/external_encoding_spec.rb
index c1b727d930..25af11f686 100644
--- a/spec/ruby/core/io/external_encoding_spec.rb
+++ b/spec/ruby/core/io/external_encoding_spec.rb
@@ -94,8 +94,10 @@ describe "IO#external_encoding" do
     rm_r @name
   end
 
-  it "raises an IOError on closed stream" do
-    -> { IOSpecs.closed_io.external_encoding }.should raise_error(IOError)
+  ruby_version_is '3.1' do
+    it "can be retrieved from a closed stream" do
+      IOSpecs.closed_io.external_encoding.should equal(Encoding.default_external)
+    end
   end
 
   describe "with 'r' mode" do
diff --git a/spec/ruby/core/io/internal_encoding_spec.rb b/spec/ruby/core/io/internal_encoding_spec.rb
index 210e969c7b..c76c9c8508 100644
--- a/spec/ruby/core/io/internal_encoding_spec.rb
+++ b/spec/ruby/core/io/internal_encoding_spec.rb
@@ -113,8 +113,10 @@ describe "IO#internal_encoding" do
     Encoding.default_internal = @internal
   end
 
-  it "raises an IOError on closed stream" do
-    -> { IOSpecs.closed_io.internal_encoding }.should raise_error(IOError)
+  ruby_version_is '3.1' do
+    it "can be retrieved from a closed stream" do
+      IOSpecs.closed_io.internal_encoding.should equal(Encoding.default_internal)
+    end
   end
 
   describe "with 'r' mode" do