Frozen string cannot change encodingfrozen_string_spec_support

This was shown in specs but surely this will be happening in application
code as well if this method is passes a frozen string.

We were also trying to force_encode a OmniAuth::AuthHash which had the
very confusing behaviour of returning nil when it was sent a method that
it did not define. Fix that by only force_encoding a String.

3 files changed, 8 insertions, 4 deletions

diff --git a/lib/gitlab/auth/o_auth/auth_hash.rb b/lib/gitlab/auth/o_auth/auth_hash.rb
index 72a187377d0..91b9ddc0d00 100644
--- a/lib/gitlab/auth/o_auth/auth_hash.rb
+++ b/lib/gitlab/auth/o_auth/auth_hash.rb
@@ -60,8 +60,7 @@ module Gitlab
 
         def get_info(key)
           value = info[key]
-          Gitlab::Utils.force_utf8(value) if value
-          value
+          value.is_a?(String) ? Gitlab::Utils.force_utf8(value) : value
         end
 
         def username_and_email
diff --git a/lib/gitlab/utils.rb b/lib/gitlab/utils.rb
index 31c9e18c996..c66ce0434a4 100644
--- a/lib/gitlab/utils.rb
+++ b/lib/gitlab/utils.rb
@@ -22,7 +22,7 @@ module Gitlab
     end
 
     def force_utf8(str)
-      str.force_encoding(Encoding::UTF_8)
+      str.dup.force_encoding(Encoding::UTF_8)
     end
 
     def ensure_utf8_size(str, bytes:)
diff --git a/spec/lib/gitlab/auth/o_auth/auth_hash_spec.rb b/spec/lib/gitlab/auth/o_auth/auth_hash_spec.rb
index 40001cea22e..a5436149818 100644
--- a/spec/lib/gitlab/auth/o_auth/auth_hash_spec.rb
+++ b/spec/lib/gitlab/auth/o_auth/auth_hash_spec.rb
@@ -40,7 +40,11 @@ describe Gitlab::Auth::OAuth::AuthHash do
       last_name:  last_name_ascii,
       name:       name_ascii,
       nickname:   nickname_ascii,
-      uid:        uid_ascii
+      uid:        uid_ascii,
+      address: {
+        locality: 'some locality',
+        country: 'some country'
+      }
     }
   end
 
@@ -51,6 +55,7 @@ describe Gitlab::Auth::OAuth::AuthHash do
     it { expect(auth_hash.username).to eql nickname_utf8 }
     it { expect(auth_hash.name).to eql name_utf8 }
     it { expect(auth_hash.password).not_to be_empty }
+    it { expect(auth_hash.location).to eq 'some locality, some country' }
   end
 
   context 'email not provided' do