2 files changed, 4 insertions, 0 deletions

diff --git a/lisp/gnus/nnimap.el b/lisp/gnus/nnimap.el
index a38d35444a3..b11a0b083d3 100644
--- a/lisp/gnus/nnimap.el
+++ b/lisp/gnus/nnimap.el
@@ -620,6 +620,7 @@ If EXAMINE is non-nil the group is selected read-only."
        ;; to make it more clear.
        (mm-with-unibyte-buffer
          (buffer-disable-undo)
+         ;; headers can be nil if article is write-only
          (when headers (insert headers))
          (let ((head (nnheader-parse-naked-head uid)))
            (mail-header-set-number head uid)
@@ -950,6 +951,7 @@ function is generally only called when Gnus is shutting down."
               (erase-buffer)
               (let ((data (imap-fetch article part prop nil
                                       nnimap-server-buffer)))
+                ;; data can be nil if article is write-only
                 (when data
                   (insert (nnimap-demule (if detail
                                              (nth 2 (car data))
diff --git a/lisp/net/imap.el b/lisp/net/imap.el
index 85afffc100b..8cb248aa513 100644
--- a/lisp/net/imap.el
+++ b/lisp/net/imap.el
@@ -2493,6 +2493,8 @@ Return nil if no complete line has arrived."
   (when (eq (char-after) ?\()
     (let (uid flags envelope internaldate rfc822 rfc822header rfc822text
               rfc822size body bodydetail bodystructure flags-empty)
+      ;; Courier can insert spurious blank characters which will
+      ;; confuse `read', so skip past them.
       (while (let ((moved (skip-chars-forward " \t")))
                (prog1 (not (eq (char-after) ?\)))
                  (unless (= moved 0) (backward-char))))