bug#67002: 30.0.50; gnus-article-browse-html-save-cid-content could handle duplicate filenames better

[Dirk-Jan C. Binnema]

Dear Gnus,

This came up in a mu4e bug:
  https://github.com/djcb/mu/issues/2460

(for reference: mu4e is /another/ Emacs MUA, which re-uses a lot of Gnus code)

Basically, in the attached html-email there are _two_ CIDs with the same
filename (but with different content-ids)

When doing a view-in-browser, gnus-article-browse-html-save-cid-content
uses the filename in favor of the cid, and the first file will be
overwritten by the second.

Admittedly, a corner-case. But, it can be fixed.
This fixes it for me:

--8<---------------cut here---------------start------------->8---
@@ -2871,11 +2871,14 @@ gnus-article-browse-html-save-cid-content
                              cid handle directory))
              (throw 'found file)))
           ((equal (concat "<" cid ">") (mm-handle-id handle))
-           (setq file (or (mm-handle-filename handle)
-                          (concat
-                           (make-temp-name "cid")
-                           (car (rassoc (car (mm-handle-type handle))
-                                        mailcap-mime-extensions))))
+           ;; Files are randomized since declared filenames may not be unique.
+           (setq file (format "cid-%d-%s"
+                              (random 99)
+                              (or (mm-handle-filename handle)
+                                  (concat
+                                   (make-temp-name "cid")
+                                   (car (rassoc (car (mm-handle-type handle))
+                                                mailcap-mime-extensions)))))
                  afile (expand-file-name file directory))
--8<---------------cut here---------------end--------------->8---

Kind regards,
Dirk.

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