Restore check for Emacs 20.2 bytecodes

* src/eval.c (Ffetch_bytecode): Check for multibyte bytecodes
here too.  Problem reported by Stefan Monnier in:
https://lists.gnu.org/r/emacs-devel/2020-05/msg02876.html

1 files changed, 13 insertions, 1 deletions

diff --git a/src/eval.c b/src/eval.c
index be2af2d041b..959adea6467 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -3202,7 +3202,19 @@ DEFUN ("fetch-bytecode", Ffetch_bytecode, Sfetch_bytecode,
               else
                 error ("Invalid byte code");
             }
-          ASET (object, COMPILED_BYTECODE, XCAR (tem));
+
+          Lisp_Object bytecode = XCAR (tem);
+          if (STRING_MULTIBYTE (bytecode))
+            {
+              /* BYTECODE must have been produced by Emacs 20.2 or earlier
+                 because it produced a raw 8-bit string for byte-code and now
+                 such a byte-code string is loaded as multibyte with raw 8-bit
+                 characters converted to multibyte form.  Convert them back to
+                 the original unibyte form.  */
+              bytecode = Fstring_as_unibyte (bytecode);
+            }
+
+          ASET (object, COMPILED_BYTECODE, bytecode);
           ASET (object, COMPILED_CONSTANTS, XCDR (tem));
         }
     }