Clarify prefix check on interned string type

Author: zrax

pyc_module.h

@@ -64,6 +64,11 @@ class PycModule {
         return (m_maj >= 3) || (m_code->flags() & PycCode::CO_FUTURE_UNICODE_LITERALS) != 0;
     }
 
+    bool internIsBytes() const
+    {
+        return (m_maj < 3) && (m_code->flags() & PycCode::CO_FUTURE_UNICODE_LITERALS) != 0;
+    }
+
     PycRef<PycCode> code() const { return m_code; }
 
     void intern(PycRef<PycString> str) { m_interns.emplace_back(std::move(str)); }

pyc_string.cpp

@@ -68,14 +68,14 @@ void PycString::print(std::ostream &pyc_output, PycModule* mod, bool triple,
         prefix = mod->strIsUnicode() ? 0 : 'u';
         break;
     case PycObject::TYPE_INTERNED:
+        prefix = mod->internIsBytes() ? 'b' : 0;
+        break;
     case PycObject::TYPE_ASCII:
     case PycObject::TYPE_ASCII_INTERNED:
     case PycObject::TYPE_SHORT_ASCII:
     case PycObject::TYPE_SHORT_ASCII_INTERNED:
-        if (mod->majorVer() >= 3)
-            prefix = 0;
-        else
-            prefix = mod->strIsUnicode() ? 'b' : 0;
+        // These types don't exist until Python 3.4
+        prefix = 0;
         break;
     default:
         throw std::runtime_error("Invalid string type");