From: Mark Oteiza <mvoteiza@udel.edu>
Date: Mon, 18 Sep 2017 13:00:45 +0000 (-0400)
Subject: Fix gensym
X-Git-Tag: emacs-26.0.90~138
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=331d0e520f;p=emacs.git

Fix gensym

* lisp/subr.el (gensym): Actually implement the default prefix.
* test/lisp/subr-tests.el (subr-tests--gensym): New test.
---

diff --git a/lisp/subr.el b/lisp/subr.el
index 79ae1f4830d..96b1ac19b4b 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -289,7 +289,7 @@ The name is made by appending `gensym-counter' to PREFIX.
 PREFIX is a string, and defaults to \"g\"."
   (let ((num (prog1 gensym-counter
                (setq gensym-counter (1+ gensym-counter)))))
-    (make-symbol (format "%s%d" prefix num))))
+    (make-symbol (format "%s%d" (or prefix "g") num))))
 
 (defun ignore (&rest _ignore)
   "Do nothing and return nil.
diff --git a/test/lisp/subr-tests.el b/test/lisp/subr-tests.el
index ac9e2df603c..a68688eba7a 100644
--- a/test/lisp/subr-tests.el
+++ b/test/lisp/subr-tests.el
@@ -300,6 +300,12 @@ cf. Bug#25477."
       (setq res (read-passwd "pass: " 'confirm (mapconcat #'string default "")))
       (should (string= default res)))))
 
+(ert-deftest subr-tests--gensym ()
+  "Test `gensym' behavior."
+  (should (equal (symbol-name (let ((gensym-counter 0)) (gensym)))
+                 "g0"))
+  (should (eq (string-to-char (symbol-name (gensym))) ?g))
+  (should (eq (string-to-char (symbol-name (gensym "X"))) ?X)))
 
 (provide 'subr-tests)
 ;;; subr-tests.el ends here