Simplify conditional encoding in install_scripts and easy_install

Author: abravalheri

setuptools/command/easy_install.py

@@ -874,12 +874,8 @@ def write_script(self, script_name, contents, mode="t", blockers=()):
         if os.path.exists(target):
             os.unlink(target)
 
-        if "b" not in mode and isinstance(contents, str):
-            kw = {"encoding": "utf-8"}
-        else:
-            kw = {}
-
-        with open(target, "w" + mode, **kw) as f:
+        encoding = None if "b" in mode else "utf-8"
+        with open(target, "w" + mode, encoding=encoding) as f:
             f.write(contents)
         chmod(target, 0o777 - mask)
 

setuptools/command/install_scripts.py

@@ -57,14 +57,10 @@ def write_script(self, script_name, contents, mode="t", *ignored):
         target = os.path.join(self.install_dir, script_name)
         self.outfiles.append(target)
 
-        if "b" not in mode and isinstance(contents, str):
-            kw = {"encoding": "utf-8"}
-        else:
-            kw = {}
-
+        encoding = None if "b" in mode else "utf-8"
         mask = current_umask()
         if not self.dry_run:
             ensure_directory(target)
-            with open(target, "w" + mode, **kw) as f:
+            with open(target, "w" + mode, encoding=encoding) as f:
                 f.write(contents)
             chmod(target, 0o777 - mask)