From ebe0bdae9ded4eab974faefb54a6ba5260523489 Mon Sep 17 00:00:00 2001
From: Philipp Stephani <phst@google.com>
Date: Sat, 27 May 2017 14:39:01 +0200
Subject: [PATCH] Don't attempt to recover from undefined behavior in some
 cases

These functions can only be run in batch mode and exit Emacs on
return, so nothing can be recovered.  Disable unsafe recover
mechanisms so that we get real failures and good stack traces on
fatal signals.

* lisp/emacs-lisp/bytecomp.el (batch-byte-compile)
(batch-byte-recompile-directory):
* lisp/emacs-lisp/ert.el (ert-run-tests-batch-and-exit)
(ert-summarize-tests-batch-and-exit): Don't attempt to recover
from undefined behavior.
---
 lisp/emacs-lisp/bytecomp.el |  8 ++++++++
 lisp/emacs-lisp/ert.el      | 10 ++++++++++
 2 files changed, 18 insertions(+)

diff --git a/lisp/emacs-lisp/bytecomp.el b/lisp/emacs-lisp/bytecomp.el
index 6c12e5d8e25..12a7d4afc2a 100644
--- a/lisp/emacs-lisp/bytecomp.el
+++ b/lisp/emacs-lisp/bytecomp.el
@@ -4960,6 +4960,10 @@ already up-to-date."
   (defvar command-line-args-left)	;Avoid 'free variable' warning
   (if (not noninteractive)
       (error "`batch-byte-compile' is to be used only with -batch"))
+  ;; Better crash loudly than attempting to recover from undefined
+  ;; behavior.
+  (setq attempt-stack-overflow-recovery nil
+        attempt-orderly-shutdown-on-fatal-signal nil)
   (let ((error nil))
     (while command-line-args-left
       (if (file-directory-p (expand-file-name (car command-line-args-left)))
@@ -5052,6 +5056,10 @@ and corresponding effects."
   (defvar command-line-args-left)	;Avoid 'free variable' warning
   (if (not noninteractive)
       (error "batch-byte-recompile-directory is to be used only with -batch"))
+  ;; Better crash loudly than attempting to recover from undefined
+  ;; behavior.
+  (setq attempt-stack-overflow-recovery nil
+        attempt-orderly-shutdown-on-fatal-signal nil)
   (or command-line-args-left
       (setq command-line-args-left '(".")))
   (while command-line-args-left
diff --git a/lisp/emacs-lisp/ert.el b/lisp/emacs-lisp/ert.el
index 280b76acfe4..2c49a634e35 100644
--- a/lisp/emacs-lisp/ert.el
+++ b/lisp/emacs-lisp/ert.el
@@ -1458,6 +1458,12 @@ The exit status will be 0 if all test results were as expected, 1
 on unexpected results, or 2 if the tool detected an error outside
 of the tests (e.g. invalid SELECTOR or bug in the code that runs
 the tests)."
+  (or noninteractive
+      (user-error "This function is only for use in batch mode"))
+  ;; Better crash loudly than attempting to recover from undefined
+  ;; behavior.
+  (setq attempt-stack-overflow-recovery nil
+        attempt-orderly-shutdown-on-fatal-signal nil)
   (unwind-protect
       (let ((stats (ert-run-tests-batch selector)))
         (kill-emacs (if (zerop (ert-stats-completed-unexpected stats)) 0 1)))
@@ -1475,6 +1481,10 @@ The logfiles should have the `ert-run-tests-batch' format.  When finished,
 this exits Emacs, with status as per `ert-run-tests-batch-and-exit'."
   (or noninteractive
       (user-error "This function is only for use in batch mode"))
+  ;; Better crash loudly than attempting to recover from undefined
+  ;; behavior.
+  (setq attempt-stack-overflow-recovery nil
+        attempt-orderly-shutdown-on-fatal-signal nil)
   (let ((nlogs (length command-line-args-left))
         (ntests 0) (nrun 0) (nexpected 0) (nunexpected 0) (nskipped 0)
         nnotrun logfile notests badtests unexpected skipped)
-- 
2.39.2