bug#30870: Error opening HTML mail when mm-text-html-renderer is nil

bug#30870: Error opening HTML mail when mm-text-html-renderer is nil

[Basil L. Contovounesios]

[-- Attachment #1: Backtrace --]
[-- Type: text/plain, Size: 3692 bytes --]

Debugger entered--Lisp error: (void-function nil)
  nil((#<buffer  *mm*-901610> ("text/html" (charset . "us-ascii")) 7bit nil nil nil nil nil))
  apply(nil (#<buffer  *mm*-901610> ("text/html" (charset . "us-ascii")) 7bit nil nil nil nil nil) nil)
  (cond ((functionp func) (funcall func handle)) (t (apply (car func) handle (cdr func))))
  (let* ((func mm-text-html-renderer) (entry (assq func mm-text-html-renderer-alist)) (inhibit-read-only t)) (if entry (setq func (cdr entry))) (cond ((functionp func) (funcall func handle)) (t (apply (car func) handle (cdr func)))))
  (if (stringp (car handle)) (mapcar 'mm-inline-text-html (cdr handle)) (let* ((func mm-text-html-renderer) (entry (assq func mm-text-html-renderer-alist)) (inhibit-read-only t)) (if entry (setq func (cdr entry))) (cond ((functionp func) (funcall func handle)) (t (apply (car func) handle (cdr func))))))
  mm-inline-text-html((#<buffer  *mm*-901610> ("text/html" (charset . "us-ascii")) 7bit nil nil nil nil nil))
  mm-display-inline((#<buffer  *mm*-901610> ("text/html" (charset . "us-ascii")) 7bit nil nil nil nil nil))
  gnus-mime-display-single((#<buffer  *mm*-901610> ("text/html" (charset . "us-ascii")) 7bit nil nil nil nil nil))
  gnus-mime-display-part((#<buffer  *mm*-901610> ("text/html" (charset . "us-ascii")) 7bit nil nil nil nil nil))
  gnus-mime-display-part((#("multipart/related" 0 17 (boundary "----=_Part_3611803_15130720.1521495438553" buffer #<buffer  *mm*-582300> from "foo@bar.com" start nil)) (#<buffer  *mm*-901610> ("text/html" (charset . "us-ascii")) 7bit nil nil nil nil nil) (#<buffer  *mm*-743752> ("image/jpeg" (name . "barcode_2F72GF.jpg")) base64 nil ("attachment" (filename . "barcode_2F72GF.jpg")) nil nil "<barcode_2F72GF.jpg>")))
  gnus-display-mime((#("multipart/related" 0 17 (boundary "----=_Part_3611803_15130720.1521495438553" buffer #<buffer  *mm*-582300> from "foo@bar.com" start nil)) (#<buffer  *mm*-901610> ("text/html" (charset . "us-ascii")) 7bit nil nil nil nil nil) (#<buffer  *mm*-743752> ("image/jpeg" (name . "barcode_2F72GF.jpg")) base64 nil ("attachment" (filename . "barcode_2F72GF.jpg")) nil nil "<barcode_2F72GF.jpg>")))
  gnus-mime-display-alternative(((#<buffer  *mm*-616996> ("text/plain" (charset . "us-ascii")) 7bit nil ("inline") nil nil nil) (#("multipart/related" 0 17 (boundary "----=_Part_3611803_15130720.1521495438553" buffer #<buffer  *mm*-582300> from "foo@bar.com" start nil)) (#<buffer  *mm*-901610> ("text/html" (charset . "us-ascii")) 7bit nil nil nil nil nil) (#<buffer  *mm*-743752> ("image/jpeg" (name . "barcode_2F72GF.jpg")) base64 nil ("attachment" (filename . "barcode_2F72GF.jpg")) nil nil "<barcode_2F72GF.jpg>"))) nil nil 1)
  gnus-mime-display-part((#("multipart/alternative" 0 21 (boundary "----=_Part_3611802_12201241.1521495438553" buffer #<buffer  *mm*-774885> from "foo@bar.com" start nil)) (#<buffer  *mm*-616996> ("text/plain" (charset . "us-ascii")) 7bit nil ("inline") nil nil nil) (#("multipart/related" 0 17 (boundary "----=_Part_3611803_15130720.1521495438553" buffer #<buffer  *mm*-582300> from "foo@bar.com" start nil)) (#<buffer  *mm*-901610> ("text/html" (charset . "us-ascii")) 7bit nil nil nil nil nil) (#<buffer  *mm*-743752> ("image/jpeg" (name . "barcode_2F72GF.jpg")) base64 nil ("attachment" (filename . "barcode_2F72GF.jpg")) nil nil "<barcode_2F72GF.jpg>"))))
  gnus-display-mime()
  gnus-article-prepare-display()
  gnus-article-prepare(62 nil)
  gnus-summary-display-article(62 nil)
  gnus-summary-select-article(nil nil pseudo)
  gnus-summary-scroll-up(1)
  funcall-interactively(gnus-summary-scroll-up 1)
  call-interactively(gnus-summary-scroll-up nil nil)
  command-execute(gnus-summary-scroll-up)

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(Hopefully someone else can reproduce this issue without my having to
 start an uncustomised Gnus.)

1. M-x toggle-debug-on-error RET
2. M-x set-variable RET mm-text-html-renderer RET nil RET
3. Open a HTML article in Gnus, e.g. by typing RET in a summary buffer

This results in the attached backtrace.

I'm quite unfamiliar with the relevant code, but the patch I am
currently using as a workaround follows my signature, as do listings of
my Gnus and Emacs versions.

Thanks,

-- 
Basil

Gnus v5.13
GNU Emacs 27.0.50 (build 16, x86_64-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2018-03-19


[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #3: Workaround --]
[-- Type: text/x-diff, Size: 2972 bytes --]

diff --git a/lisp/gnus/mm-view.el b/lisp/gnus/mm-view.el
index c11af7060b..6cd93c91a4 100644
--- a/lisp/gnus/mm-view.el
+++ b/lisp/gnus/mm-view.el
@@ -311,17 +311,18 @@ mm-inline-render-with-function
 
 (defun mm-inline-text-html (handle)
   (if (stringp (car handle))
-      (mapcar 'mm-inline-text-html (cdr handle))
-    (let* ((func mm-text-html-renderer)
-	   (entry (assq func mm-text-html-renderer-alist))
-	   (inhibit-read-only t))
-      (if entry
-	  (setq func (cdr entry)))
+      (mapcar #'mm-inline-text-html (cdr handle))
+    (let ((func (alist-get mm-text-html-renderer
+                           mm-text-html-renderer-alist
+                           mm-text-html-renderer))
+          (inhibit-read-only t))
       (cond
        ((functionp func)
 	(funcall func handle))
+       ((functionp (car func))
+        (apply (car func) handle (cdr func)))
        (t
-	(apply (car func) handle (cdr func)))))))
+        (mm-interactively-view-part handle))))))
 
 (defun mm-inline-text-vcard (handle)
   (let ((inhibit-read-only t))
diff --git a/lisp/mh-e/mh-gnus.el b/lisp/mh-e/mh-gnus.el
index 3d202890b6..f1256bdef5 100644
--- a/lisp/mh-e/mh-gnus.el
+++ b/lisp/mh-e/mh-gnus.el
@@ -165,8 +165,8 @@ mh-mm-save-part
 
 (defun mh-mm-text-html-renderer ()
   "Find the renderer Gnus is using to display text/html MIME parts."
-  (or (and (boundp 'mm-inline-text-html-renderer) mm-inline-text-html-renderer)
-      (and (boundp 'mm-text-html-renderer) mm-text-html-renderer)))
+  (or (bound-and-true-p mm-inline-text-html-renderer)
+      (bound-and-true-p mm-text-html-renderer)))
 
 (provide 'mh-gnus)
 
diff --git a/lisp/mh-e/mh-mime.el b/lisp/mh-e/mh-mime.el
index e2c682a399..8ad1877327 100644
--- a/lisp/mh-e/mh-mime.el
+++ b/lisp/mh-e/mh-mime.el
@@ -140,9 +140,7 @@ mh-mm-inline-media-tests
     ("text/html"
      ,(if (fboundp 'mm-inline-text-html) 'mm-inline-text-html 'mm-inline-text)
      (lambda (handle)
-       (or (and (boundp 'mm-inline-text-html-renderer)
-                mm-inline-text-html-renderer)
-           (and (boundp 'mm-text-html-renderer) mm-text-html-renderer))))
+       (mh-mm-text-html-renderer)))
     ("text/x-vcard"
      mh-mm-inline-text-vcard
      (lambda (handle)
@@ -781,9 +779,9 @@ mh-small-image-p
         (mm-inline-large-images t))
     (and media-test
          (equal (mm-handle-media-supertype handle) "image")
-         (funcall media-test handle) ; Since mm-inline-large-images is T,
-                                        ; this only tells us if the image is
-                                        ; something that emacs can display
+         (funcall media-test handle) ; Since `mm-inline-large-images' is t,
+                                     ; this only tells us if the image is
+                                     ; something that Emacs can display
          (let* ((image (mm-get-image handle)))
            (or (mh-do-in-xemacs
                  (and (mh-funcall-if-exists glyphp image)

bug#30870: Error opening HTML mail when mm-text-html-renderer is nil

[Lars Ingebrigtsen]

"Basil L. Contovounesios" <contovob@tcd.ie> writes:

> (Hopefully someone else can reproduce this issue without my having to
>  start an uncustomised Gnus.)
>
> 1. M-x toggle-debug-on-error RET
> 2. M-x set-variable RET mm-text-html-renderer RET nil RET
> 3. Open a HTML article in Gnus, e.g. by typing RET in a summary buffer
>
> This results in the attached backtrace.
>
> I'm quite unfamiliar with the relevant code, but the patch I am
> currently using as a workaround follows my signature, as do listings of
> my Gnus and Emacs versions.

As this hasn't been working for quite a while, apparently, and nil is a
nonsensical value (popping up Firefox every time you happen to click on
an email that contains an HTML part sounds unsafe), I've now removed
that option instead of fixing it.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no