Check for end-of-file when reading character escapes (bug#79097)

* src/lread.c (read_char_escape): Add check.
* test/src/lread-tests.el (lread-char-escape-eof): New test.

2 files changed, 33 insertions, 0 deletions

diff --git a/src/lread.c b/src/lread.c
index 287528ab32d..54b74b18782 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -3108,6 +3108,8 @@ read_char_escape (source_t *source, int next_char)
       chr = c;
       break;
     }
+  if (chr < 0)
+    end_of_file_error ();
   eassert (chr >= 0 && chr < (1 << CHARACTERBITS));
 
   /* Apply Control modifiers, using the rules:
diff --git a/test/src/lread-tests.el b/test/src/lread-tests.el
index 02e3efcf06c..421c0c0ed4a 100644
--- a/test/src/lread-tests.el
+++ b/test/src/lread-tests.el
@@ -358,6 +358,37 @@ literals (Bug#20852)."
   (should-error (read-from-string "?\\\n x"))
   (should (equal (read-from-string "\"a\\\nb\"") '("ab" . 6))))
 
+(ert-deftest lread-char-escape-eof ()
+  ;; Check that unfinished char escapes signal an error.
+  (should-error (read "?\\"))
+
+  (should-error (read "?\\^"))
+  (should-error (read "?\\C"))
+  (should-error (read "?\\M"))
+  (should-error (read "?\\S"))
+  (should-error (read "?\\H"))
+  (should-error (read "?\\A"))
+
+  (should-error (read "?\\C-"))
+  (should-error (read "?\\M-"))
+  (should-error (read "?\\S-"))
+  (should-error (read "?\\H-"))
+  (should-error (read "?\\A-"))
+  (should-error (read "?\\s-"))
+
+  (should-error (read "?\\C-\\"))
+  (should-error (read "?\\C-\\M"))
+  (should-error (read "?\\C-\\M-"))
+
+  (should-error (read "?\\x"))
+  (should-error (read "?\\u"))
+  (should-error (read "?\\u234"))
+  (should-error (read "?\\U"))
+  (should-error (read "?\\U0010010"))
+  (should-error (read "?\\N"))
+  (should-error (read "?\\N{"))
+  (should-error (read "?\\N{SPACE")))
+
 (ert-deftest lread-force-load-doc-strings ()
   ;; Verify that lazy doc strings are loaded lazily by default,
   ;; but eagerly with `force-load-doc-strings' set.