master 4230674: Fix error in 'call-process-region' when START is nil (Bug#40576)

[Philipp Stephani]

branch: master
commit 42306747d8dece897805e89c36c3741bfb8d5e7c
Author: Philipp Stephani <address@hidden>
Commit: Philipp Stephani <address@hidden>

    Fix error in 'call-process-region' when START is nil (Bug#40576)
    
    * src/callproc.c (Fcall_process_region): Fix behavior when START is
    nil and DELETE is non-nil.
    
    * test/src/callproc-tests.el
    (call-process-region-entire-buffer-with-delete): New unit test.
---
 src/callproc.c             | 12 +++++++++++-
 test/src/callproc-tests.el | 10 ++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/callproc.c b/src/callproc.c
index 8883415..65c8583 100644
--- a/src/callproc.c
+++ b/src/callproc.c
@@ -1099,7 +1099,17 @@ usage: (call-process-region START END PROGRAM &optional 
DELETE BUFFER DISPLAY &r
     }
 
   if (nargs > 3 && !NILP (args[3]))
-    Fdelete_region (start, end);
+    {
+      if (NILP (start))
+        {
+          /* No need to save restrictions since we delete everything
+             anyway.  */
+          Fwiden ();
+          del_range (BEG, Z);
+        }
+      else
+        Fdelete_region (start, end);
+    }
 
   if (nargs > 3)
     {
diff --git a/test/src/callproc-tests.el b/test/src/callproc-tests.el
index bf7d47b..1617d5e 100644
--- a/test/src/callproc-tests.el
+++ b/test/src/callproc-tests.el
@@ -66,4 +66,14 @@
                   (error :got-error))))
     (should have-called-debugger)))
 
+(ert-deftest call-process-region-entire-buffer-with-delete ()
+  "Check that Bug#40576 is fixed."
+  (let ((emacs (expand-file-name invocation-name invocation-directory)))
+    (skip-unless (file-executable-p emacs))
+    (with-temp-buffer
+      (insert "Buffer contents\n")
+      (should
+       (eq (call-process-region nil nil emacs :delete nil nil "--version") 0))
+      (should (eq (buffer-size) 0)))))
+
 ;;; callproc-tests.el ends here