fix(markdown): restore the live preview (rename, guard, dead setq)

F2 ran markdown-mode's own markdown-preview instead of the custom one, so the impatient-mode strapdown preview was dead. I renamed the custom command to cj/markdown-preview and rebound F2 so markdown-mode no longer shadows it. The server guard now uses httpd-running-p (httpd-process isn't a variable), and a dead (setq imp-set-user-filter 'markdown-html) that named neither a real variable nor a real filter is gone.

2 files changed, 14 insertions, 6 deletions

diff --git a/modules/markdown-config.el b/modules/markdown-config.el
index 4faa4474e..16935425d 100644
--- a/modules/markdown-config.el
+++ b/modules/markdown-config.el
@@ -21,7 +21,7 @@
 		 ("\\.md\\'"       . markdown-mode)
          ("\\.markdown\\'" . markdown-mode))
   :bind (:map markdown-mode-map
-			  ("<f2>" . markdown-preview)) ;; use same key as compile for consistency
+			  ("<f2>" . cj/markdown-preview)) ;; use same key as compile for consistency
   :init (setq markdown-command "multimarkdown"))
 
 ;; Register markdown as a known org-src-block language so `org-lint'
@@ -36,9 +36,7 @@
 ;; allows for live previews of your html
 ;; see: https://github.com/skeeto/impatient-mode
 (use-package impatient-mode
-  :defer t
-  :config
-  (setq imp-set-user-filter 'markdown-html))
+  :defer t)
 
 ;;;; --------------------- WIP: Markdown-Preview ---------------------
 
@@ -51,14 +49,14 @@ Idempotent: re-running while the server is already up is a no-op."
   (message "markdown preview server running on http://localhost:8080/imp"))
 
 ;; the filter to apply to markdown before impatient-mode pushes it to the server
-(defun markdown-preview ()
+(defun cj/markdown-preview ()
   "Open the current buffer as a live HTML preview at http://localhost:8080/imp.
 The simple-httpd listener must already be running -- see
 `cj/markdown-preview-server-start'.  Starting a network listener as a
 side effect of opening a preview is surprising, so the server start
 lives in a separate command."
   (interactive)
-  (unless (and (boundp 'httpd-process) httpd-process)
+  (unless (httpd-running-p)
     (user-error "markdown preview server not running; run `M-x cj/markdown-preview-server-start' first"))
   (impatient-mode 1)
   (setq imp-user-filter #'cj/markdown-html)
diff --git a/tests/test-markdown-config.el b/tests/test-markdown-config.el
index 45e1a6018..edb20d357 100644
--- a/tests/test-markdown-config.el
+++ b/tests/test-markdown-config.el
@@ -9,6 +9,7 @@
 ;;; Code:
 
 (require 'ert)
+(require 'cl-lib)
 
 (add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
 
@@ -50,5 +51,14 @@
           (should (string-match-p "<xmp" (buffer-string))))
       (kill-buffer src))))
 
+;;; cj/markdown-preview (guard: refuse when the httpd listener is down)
+
+(ert-deftest test-markdown-preview-errors-when-server-down ()
+  "Error: `cj/markdown-preview' signals a user-error when the simple-httpd
+listener is not running, rather than opening a preview against a dead server.
+Also pins the rename off the bare `markdown-preview' that markdown-mode shadows."
+  (cl-letf (((symbol-function 'httpd-running-p) (lambda () nil)))
+    (should-error (cj/markdown-preview) :type 'user-error)))
+
 (provide 'test-markdown-config)
 ;;; test-markdown-config.el ends here