Correctly reindent previous line in electric-indent-mode

Fixes: bug#35254

Do this even when electric-indent-inhibit is t, except when the
newline insertion is being performed by electric-layout-mode.

* lisp/electric.el (electric-indent-post-self-insert-function):
Reindent previous line unless operating under
electric-layout-mode.
(electric-layout-post-self-insert-function-1): Bind
electric-indent-inhibit to 'electric-layout-mode.

* test/lisp/electric-tests.el
(electric-layout-control-reindentation): New test.

1 files changed, 8 insertions, 5 deletions

diff --git a/lisp/electric.el b/lisp/electric.el
index 53e53bd975c..a14deb71afb 100644
--- a/lisp/electric.el
+++ b/lisp/electric.el
@@ -270,10 +270,13 @@ or comment."
                   (goto-char before)
                   (condition-case-unless-debug ()
                       (indent-according-to-mode)
-                    (error (throw 'indent-error nil)))
-                  ;; The goal here will be to remove the trailing
-                  ;; whitespace after reindentation of the previous line
-                  ;; because that may have (re)introduced it.
+                    (error (throw 'indent-error nil))))
+                (unless (eq electric-indent-inhibit 'electric-layout-mode)
+                  ;; Unless we're operating under
+                  ;; `electric-layout-mode' (Bug#35254), the goal here
+                  ;; will be to remove the trailing whitespace after
+                  ;; reindentation of the previous line because that
+                  ;; may have (re)introduced it.
                   (goto-char before)
                   ;; We were at EOL in marker `before' before the call
                   ;; to `indent-according-to-mode' but after we may
@@ -451,7 +454,7 @@ If multiple rules match, only first one is executed.")
                       ;; really wants to reindent, then
                       ;; `last-command-event' should be in
                       ;; `electric-indent-chars'.
-                      (let ((electric-indent-inhibit t))
+                      (let ((electric-indent-inhibit 'electric-layout-mode))
                         (funcall nl-after)))))))
             (pcase sym
               ('before (funcall nl-before))