Fix resolving symlinks in Eshell history file names

* lisp/eshell/em-dirs.el (eshell-write-last-dir-ring):
* lisp/eshell/em-hist.el (eshell-write-history): Don't call
file-truename with argument of nil.  (Bug#33477)

* test/lisp/eshell/eshell-tests.el (with-temp-eshell): Remove
HISTFILE from the environment, to make sure the Eshell history
file is nil.

3 files changed, 5 insertions, 2 deletions

diff --git a/lisp/eshell/em-dirs.el b/lisp/eshell/em-dirs.el
index c16a5ac6e07..853382888c9 100644
--- a/lisp/eshell/em-dirs.el
+++ b/lisp/eshell/em-dirs.el
@@ -553,7 +553,7 @@ in the minibuffer:
 (defun eshell-write-last-dir-ring ()
   "Write the buffer's `eshell-last-dir-ring' to a history file."
   (let* ((file eshell-last-dir-ring-file-name)
-         (resolved-file (file-truename file)))
+         (resolved-file (if (stringp file) (file-truename file))))
     (cond
      ((or (null file)
           (equal file "")
diff --git a/lisp/eshell/em-hist.el b/lisp/eshell/em-hist.el
index f866dfd7276..1b240c0460f 100644
--- a/lisp/eshell/em-hist.el
+++ b/lisp/eshell/em-hist.el
@@ -467,7 +467,7 @@ Useful within process sentinels.
 
 See also `eshell-read-history'."
   (let* ((file (or filename eshell-history-file-name))
-         (resolved-file (file-truename file)))
+         (resolved-file (if (stringp file) (file-truename file))))
     (cond
      ((or (null file)
           (equal file "")
diff --git a/test/lisp/eshell/eshell-tests.el b/test/lisp/eshell/eshell-tests.el
index b6dbd09a3d6..cefbeef5677 100644
--- a/test/lisp/eshell/eshell-tests.el
+++ b/test/lisp/eshell/eshell-tests.el
@@ -31,6 +31,9 @@
 (defmacro with-temp-eshell (&rest body)
   "Evaluate BODY in a temporary Eshell buffer."
   `(let* ((eshell-directory-name (make-temp-file "eshell" t))
+          ;; We want no history file, so prevent Eshell from falling
+          ;; back on $HISTFILE.
+          (_ (setenv "HISTFILE"))
           (eshell-history-file-name nil)
           (eshell-buffer (eshell t)))
      (unwind-protect