Add work-around for nnmaildir encoding problem

* lisp/gnus/mm-decode.el (mm-with-part): Fix problem with multipart 8bit encoded posts from nnmaildir (bug#44307).
flatwhatson · Jan 7, 2021 · 23a887e · 23a887e
1 parent 7e80aec
commit 23a887e
Show file tree

Hide file tree

Showing 2 changed files with 31 additions and 6 deletions.
diff --git a/lisp/gnus/mm-decode.el b/lisp/gnus/mm-decode.el
@@ -1264,11 +1264,20 @@ in HANDLE."
      (when (and (mm-handle-buffer handle)
 		(buffer-name (mm-handle-buffer handle)))
        (with-temp-buffer
-	 (mm-disable-multibyte)
-	 (insert-buffer-substring (mm-handle-buffer handle))
-	 (mm-decode-content-transfer-encoding
-	  (mm-handle-encoding handle)
-	  (mm-handle-media-type handle))
+	 (if (and (eq (mm-handle-encoding handle) '8bit)
+		  (with-current-buffer (mm-handle-buffer handle)
+		    enable-multibyte-characters))
+	     ;; Due to unfortunate historical reasons, we may have a
+	     ;; multibyte buffer here, but if it's using an 8bit
+	     ;; Content-Transfer-Encoding, then work around that by
+	     ;; just ignoring the situation.
+	     (insert-buffer-substring (mm-handle-buffer handle))
+	   ;; Do the decoding.
+	   (mm-disable-multibyte)
+	   (insert-buffer-substring (mm-handle-buffer handle))
+	   (mm-decode-content-transfer-encoding
+	    (mm-handle-encoding handle)
+	    (mm-handle-media-type handle)))
 	 ,@forms))))
 (put 'mm-with-part 'lisp-indent-function 1)
 (put 'mm-with-part 'edebug-form-spec '(body))

diff --git a/test/lisp/gnus/mm-decode-tests.el b/test/lisp/gnus/mm-decode-tests.el
@@ -54,7 +54,7 @@
                                                          'charset)))
                          "<!doctype html><html><head><meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\"></head><body>ääää</body></html>\n")))))))
 
-(ert-deftest test-mm-with-part ()
+(ert-deftest test-mm-with-part-unibyte ()
   (with-temp-buffer
     (set-buffer-multibyte nil)
     (insert-file-contents-literally (ert-resource-file "8bit-multipart.bin"))
@@ -70,4 +70,20 @@
                                                        'charset)))
                        "ääää\n"))))))
 
+(ert-deftest test-mm-with-part-multibyte ()
+  (with-temp-buffer
+    (set-buffer-multibyte t)
+    (nnheader-insert-file-contents (ert-resource-file "8bit-multipart.bin"))
+    (while (search-forward "\r\n" nil t)
+      (replace-match "\n"))
+    (let ((handle (mm-dissect-buffer)))
+      (pop handle)
+      (let ((part (pop handle)))
+        (should (equal (decode-coding-string
+                        (mm-with-part part
+                          (buffer-string))
+                        (intern (mail-content-type-get (mm-handle-type part)
+                                                       'charset)))
+                       "ääää\n"))))))
+
 ;;; mm-decode-tests.el ends here