Read non-ASCII chars from unibyte string sources as raw bytes

Previously, latin-1 was incorrectly assumed (bug#70988).

* src/lread.c (readchar): Convert to raw byte.
* test/src/lread-tests.el (lread-unibyte-string-source): New test.

1 files changed, 6 insertions, 0 deletions

diff --git a/test/src/lread-tests.el b/test/src/lread-tests.el
index d832cc9aa4e..d9b31a6c438 100644
--- a/test/src/lread-tests.el
+++ b/test/src/lread-tests.el
@@ -392,4 +392,10 @@ literals (Bug#20852)."
          (val (read (lambda () (pop s)))))
     (should (equal (symbol-name val) "A∪ÿ"))))
 
+(ert-deftest lread-unibyte-string-source ()
+  (let* ((src "\"a\xff\"")
+         (val (read src)))
+    (should (equal val "a\xff"))        ; not "aÿ"
+    (should-not (multibyte-string-p val))))
+
 ;;; lread-tests.el ends here