* src/fileio.c: Fix bug#36431

(decide_coding_unwind): Re-introduce.  Move text back to the gap.
Return the new `inserted` via the unwind_data.
(Finsert_file_contents): Use it.
Make sure `inserted` is always 0 when we jump straight to `notfound`.
Don't insert the text in the buffer until we know it's properly decoded
for the byteness of the buffer.

* test/src/fileio-tests.el (fileio-tests--insert-file-interrupt):
Allow insert-file-contents to return an empty buffer in case of
non-local exit in set-auto-coding-function.

1 files changed, 6 insertions, 5 deletions

diff --git a/test/src/fileio-tests.el b/test/src/fileio-tests.el
index 8788c830c94..0e0230a145d 100644
--- a/test/src/fileio-tests.el
+++ b/test/src/fileio-tests.el
@@ -120,11 +120,12 @@ Also check that an encoding error can appear in a symlink."
               (let ((set-auto-coding-function (lambda (&rest _) (throw 'toto nil))))
                 (insert-file-contents f)))
             (goto-char (point-min))
-            (forward-line 1)
-            (let ((c1 (char-after)))
-              (forward-char 1)
-              (should (equal c1 (char-before)))
-              (should (equal c1 (char-after))))))
+            (unless (eobp)
+              (forward-line 1)
+              (let ((c1 (char-after)))
+                (forward-char 1)
+                (should (equal c1 (char-before)))
+                (should (equal c1 (char-after)))))))
       (if f (delete-file f)))))
 
 (ert-deftest fileio-tests--relative-default-directory ()