Fix reporting of read error line/columns in the init file

* src/lread.c (invalid_syntax_lisp): The comments here said that
we were supposed to be called with point in the readcharfun
buffer.  This was not the case (at least) when reading the Emacs
init file, so the reported line/column was always wrong (1 and 0,
respectively) (bug#54550).

1 files changed, 14 insertions, 6 deletions

diff --git a/src/lread.c b/src/lread.c
index d7b56c5087e..6130300b0a2 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -550,13 +550,21 @@ invalid_syntax_lisp (Lisp_Object s, Lisp_Object readcharfun)
 {
   if (BUFFERP (readcharfun))
     {
+      ptrdiff_t line, column;
+
+      /* Get the line/column in the readcharfun buffer.  */
+      {
+        specpdl_ref count = SPECPDL_INDEX ();
+
+        record_unwind_protect_excursion ();
+        set_buffer_internal (XBUFFER (readcharfun));
+        line = count_lines (BEGV_BYTE, PT_BYTE) + 1;
+        column = current_column ();
+        unbind_to (count, Qnil);
+      }
+
       xsignal (Qinvalid_read_syntax,
-               list3 (s,
-                      /* We should already be in the readcharfun
-                         buffer when this error is called, so no need
-                         to switch to it first. */
-                      make_fixnum (count_lines (BEGV_BYTE, PT_BYTE) + 1),
-                      make_fixnum (current_column ())));
+               list3 (s, make_fixnum (line), make_fixnum (column)));
     }
   else
     xsignal1 (Qinvalid_read_syntax, s);