Merge changes made in Gnus trunk.

gnus-group.el (gnus-group-read-ephemeral-group): Make sure we don't enter invalid buffer configurations into the quit form (bug#9107).
 (gnus-group-tool-bar-gnome): Replace connect/disconnect with unplugged/plugged.
gnus-sum.el (gnus-summary-refer-thread): When inserting new headers, keep track of which ones are unread (bug#9061).
gnus.el (gnus-refer-article-method): Allow entering any sexp (bug#9055).
gnus-art.el (gnus-article-show-images): Allow working if using w3m (bug#9041).
gnus-html.el (mm-util): Require (bug#9073).
gnus-sum.el (gnus-delete-duplicate-headers): New function.
 (gnus-summary-refer-thread): Use it to remove duplicates in the un-threaded view (bug#9053).
 (gnus-summary-insert-subject): Document USE-OLD-HEADER (bug#9070).
nnir.el (nnir-read-server-parm): Use default value from global variable.  Without this the default search engine parameters aren't used at all.
message.el (message-unique-id): Don't use the undocumented return value from (random t) (bug#9118).

1 files changed, 48 insertions, 23 deletions

diff --git a/lisp/gnus/gnus-sum.el b/lisp/gnus/gnus-sum.el
index 5a817e12104..86ff0180f55 100644
--- a/lisp/gnus/gnus-sum.el
+++ b/lisp/gnus/gnus-sum.el
@@ -6562,7 +6562,10 @@ This is meant to be called in `gnus-article-internal-prepare-hook'."
 (defun gnus-summary-insert-subject (id &optional old-header use-old-header)
   "Find article ID and insert the summary line for that article.
 OLD-HEADER can either be a header or a line number to insert
-the subject line on."
+the subject line on.
+If USE-OLD-HEADER is non-nil, then OLD-HEADER should be a header,
+and OLD-HEADER will be used when the summary line is inserted,
+too, instead of trying to fetch new headers."
   (let* ((line (and (numberp old-header) old-header))
 	 (old-header (and (vectorp old-header) old-header))
 	 (header (cond ((and old-header use-old-header)
@@ -8950,6 +8953,21 @@ Return the number of articles fetched."
       (gnus-summary-position-point)
       n)))
 
+(defun gnus-delete-duplicate-headers (headers)
+  ;; First remove leading duplicates.
+  (while (and (> (length headers) 1)
+	      (= (mail-header-number (car headers))
+		 (mail-header-number (cadr headers))))
+    (pop headers))
+  ;; Then the rest.
+  (let ((result headers))
+    (while (> (length headers) 1)
+      (if (= (mail-header-number (car headers))
+	     (mail-header-number (cadr headers)))
+	  (setcdr headers (cddr headers))
+	(pop headers)))
+    result))
+
 (defun gnus-summary-refer-thread (&optional limit)
   "Fetch all articles in the current thread.
 If no backend-specific 'request-thread function is available
@@ -8964,29 +8982,36 @@ variable."
 	 (gnus-summary-ignore-duplicates t)
 	 (gnus-read-all-available-headers t)
 	 (limit (if limit (prefix-numeric-value limit)
-		  gnus-refer-thread-limit)))
+		  gnus-refer-thread-limit))
+	 (new-headers
+	  (if (gnus-check-backend-function
+	       'request-thread gnus-newsgroup-name)
+	      (gnus-request-thread header gnus-newsgroup-name)
+	    (let* ((last (if (numberp limit)
+			     (min (+ (mail-header-number header)
+				     limit)
+				  gnus-newsgroup-highest)
+			   gnus-newsgroup-highest))
+		   (subject (gnus-simplify-subject
+			     (mail-header-subject header)))
+		   (refs (split-string (or (mail-header-references header)
+					   "")))
+		   (gnus-parse-headers-hook
+		    (lambda () (goto-char (point-min))
+		      (keep-lines
+		       (regexp-opt (append refs (list id subject)))))))
+	      (gnus-fetch-headers (list last) (if (numberp limit)
+						  (* 2 limit) limit) t)))))
+    (dolist (header new-headers)
+      (when (member (mail-header-number header) gnus-newsgroup-unselected)
+	(push (mail-header-number header) gnus-newsgroup-unreads)
+	(setq gnus-newsgroup-unselected
+	      (delete (mail-header-number header) gnus-newsgroup-unselected))))
     (setq gnus-newsgroup-headers
-	  (gnus-merge
-	   'list gnus-newsgroup-headers
-	   (if (gnus-check-backend-function
-		'request-thread gnus-newsgroup-name)
-	       (gnus-request-thread header gnus-newsgroup-name)
-	     (let* ((last (if (numberp limit)
-			      (min (+ (mail-header-number header)
-				      limit)
-				   gnus-newsgroup-highest)
-			    gnus-newsgroup-highest))
-		    (subject (gnus-simplify-subject
-			      (mail-header-subject header)))
-		    (refs (split-string (or (mail-header-references header)
-					    "")))
-		    (gnus-parse-headers-hook
-		     (lambda () (goto-char (point-min))
-		       (keep-lines
-			(regexp-opt (append refs (list id subject)))))))
-	       (gnus-fetch-headers (list last) (if (numberp limit)
-						   (* 2 limit) limit) t)))
-	   'gnus-article-sort-by-number))
+	  (gnus-delete-duplicate-headers
+	   (gnus-merge
+	    'list gnus-newsgroup-headers new-headers
+	    'gnus-article-sort-by-number)))
     (gnus-summary-limit-include-thread id)))
 
 (defun gnus-summary-refer-article (message-id)