Fix electric-pair-tests by disabling bug#33794's fix with a variable

The variable c--disable-fix-of-bug-33794, which should be removed in
the short term in favor of a permanent solution, is introduced.

It is bound to nil by default.  This means that breakage is still
happening in actual c-mode and c++-mode usage, though the tests no
longer show it.

To get around this breakage, put

   (setq c--disable-fix-of-bug-33794 t)

In your init file.  Evidently, you will lose the fix for bug#33794,
but that only affects a small corner case of c-toggle-auto-newline,
which is not turned on by default.

See https://lists.gnu.org/archive/html/emacs-devel/2019-01/msg00360.html
for more information.

* lisp/progmodes/cc-cmds.el (c--disable-fix-of-bug-33794): New
variable.
(c--with-post-self-insert-hook-maybe): New macro.
(c-electric-pound, c-electric-brace, c-electric-slash)
(c-electric-star, c-electric-semi&comma, c-electric-colon)
(c-electric-lt-gt, c-electric-paren): Use it.
(c-electric-paren, c-electric-brace): Check
c--disable-fix-of-bug-33794.

* test/lisp/electric-tests.el (c--disable-fix-of-bug-33794):
Forward declare.
(electric-pair-test-for)
(electric-layout-int-main-kernel-style)
(electric-modes-in-c-mode-with-self-insert-command): Use it.

1 files changed, 6 insertions, 0 deletions

diff --git a/test/lisp/electric-tests.el b/test/lisp/electric-tests.el
index 5a4b20ed04e..b55d889f0b5 100644
--- a/test/lisp/electric-tests.el
+++ b/test/lisp/electric-tests.el
@@ -47,10 +47,14 @@
   (declare (indent defun) (debug t))
   `(call-with-saved-electric-modes #'(lambda () ,@body)))
 
+;; Defined in lisp/progmodes/cc-cmds.el
+(defvar c--disable-fix-of-bug-33794 t)
+
 (defun electric-pair-test-for (fixture where char expected-string
                                        expected-point mode bindings fixture-fn)
   (with-temp-buffer
     (funcall mode)
+    (setq-local c--disable-fix-of-bug-33794 t)
     (insert fixture)
     (save-electric-modes
       (let ((last-command-event char)
@@ -821,6 +825,7 @@ baz\"\""
     (electric-layout-local-mode 1)
     (electric-pair-local-mode 1)
     (electric-indent-local-mode 1)
+    (setq-local c--disable-fix-of-bug-33794 t)
     (setq-local electric-layout-rules
                 '((?\{ . (after-stay after))))
     (insert "int main () ")
@@ -834,6 +839,7 @@ baz\"\""
     (electric-layout-local-mode 1)
     (electric-pair-local-mode 1)
     (electric-indent-local-mode 1)
+    (setq-local c--disable-fix-of-bug-33794 t)
     (setq-local electric-layout-rules
                 '((?\{ . (before after-stay after))))
     (insert "int main () ")