Do call debugger on failed cl-assert

"Don't call debug on failed cl-assert..." removed the call to `debug' in
cl--assertion-failed because `debug' calls `kill-emacs' in batch mode,
thus messing up ert test runs.  However, calling the debugger is useful
because it allows catching failed assertions even inside
`condition-case' calls.  The problem with ert can be avoided by calling
`debugger' instead of `debug' directly, since ert installs its own
debugger while running tests.

* lisp/emacs-lisp/cl-preloaded.el (cl--assertion-failed): Call
`debugger' if `debug-on-error' is non-nil.

1 files changed, 5 insertions, 3 deletions

diff --git a/lisp/emacs-lisp/cl-preloaded.el b/lisp/emacs-lisp/cl-preloaded.el
index 639ffa64b8c..2b022c49053 100644
--- a/lisp/emacs-lisp/cl-preloaded.el
+++ b/lisp/emacs-lisp/cl-preloaded.el
@@ -44,9 +44,11 @@
 (define-error 'cl-assertion-failed (purecopy "Assertion failed"))
 
 (defun cl--assertion-failed (form &optional string sargs args)
-  (if string
-      (apply #'error string (append sargs args))
-    (signal 'cl-assertion-failed `(,form ,@sargs))))
+  (if debug-on-error
+      (funcall debugger `(cl-assertion-failed ,form ,string ,@sargs))
+    (if string
+        (apply #'error string (append sargs args))
+      (signal 'cl-assertion-failed `(,form ,@sargs)))))
 
 ;; When we load this (compiled) file during pre-loading, the cl--struct-class
 ;; code below will need to access the `cl-struct' info, since it's considered