diff --git a/lisp/erk.el b/lisp/erk.el
index de07c84..8252eab 100644
--- a/lisp/erk.el
+++ b/lisp/erk.el
@@ -273,12 +273,13 @@ Only understands project root or root/lisp."
 ;; TODO quite redundant
 (defun erk--project-root-feature-file ()
   "Return the path of the root feature for the project."
-  (let* ((project-elisp-dir (erk--project-elisp-dir))
-         (package-files (directory-files project-elisp-dir nil (rx ".el" string-end)))
-         (package-files (->> package-files
-                             (--reject (string-match-p (rx "autoloads.el" string-end) it))))
-         (root-feature-file (car (sort package-files #'string<))))
-    (concat project-elisp-dir "/" root-feature-file)))
+  (if-let* ((project-elisp-dir (erk--project-elisp-dir))
+            (package-files (directory-files project-elisp-dir nil (rx ".el" string-end)))
+            (package-files (->> package-files
+                                (--reject (string-match-p (rx "autoloads.el" string-end) it))))
+            (root-feature-file (car (sort package-files #'string<))))
+      (concat project-elisp-dir "/" root-feature-file)
+    (user-error "%s doesn't seem to be an elisp project" (erk--project-root))))
 
 ;; Note, these functions are kind of redundant, but just want to consume
 ;; consistent interfaces internally.
@@ -340,17 +341,20 @@ for development, and being lenient for degenerate cases is fine."
 (defun erk-jump-features ()
   "Jump between the corresponding package and test features."
   (interactive)
-  (let ((file (file-name-nondirectory (buffer-file-name (current-buffer)))))
-    (if (string-match-p ".*\\.el" file)
-        (find-file (if (string-match "\\(.*\\)-tests?\\.el" file)
+  (let* ((filepath (buffer-file-name (current-buffer)))
+         (filename (when filepath
+                     (file-name-nondirectory filepath))))
+    (if (and filename
+             (string-match-p ".*\\.el" filename))
+        (find-file (if (string-match "\\(.*\\)-tests?\\.el" filename)
                        (concat (erk--lisp-directory)
                                (match-string 1 file) ".el")
                      (concat (erk--test-directory)
-                             (and (string-match "\\(.*\\)\\.el" file)
-                                  (match-string 1 file))
+                             (and (string-match "\\(.*\\)\\.el" filename)
+                                  (match-string 1 filename))
                              "-test.el")))
-      ;; fallback, go to root feature, convenient shortcut
-      ;; back into elisp files
+          ;; fallback, go to root feature, convenient shortcut
+          ;; back into elisp files
       (find-file (erk--project-root-feature-file)))))
 
 (defun erk--insert-test (fun buffer)