Fix bug: news server can return #(0 0 0) as server-info for a news

group, indicating that there are no articles on the server.  News
reader was expecting the last two numbers to be article numbers, but
zero is not a valid article number.

diff --git a/v7/src/edwin/snr.scm b/v7/src/edwin/snr.scm
index 81c5e7af6c86d248498c9c1e7aa6f6f7c9821ec3..1c6bceb40a1b3a60f5da7356a46fba09d1f36306 100644 (file)
--- a/v7/src/edwin/snr.scm
+++ b/v7/src/edwin/snr.scm
@@ -1,6 +1,6 @@
 ;;; -*-Scheme-*-
 ;;;
-;;;    $Id: snr.scm,v 1.32 1997/05/18 07:59:44 cph Exp $
+;;;    $Id: snr.scm,v 1.33 1997/05/27 07:30:31 cph Exp $
 ;;;
 ;;;    Copyright (c) 1995-97 Massachusetts Institute of Technology
 ;;;
@@ -3149,12 +3149,11 @@ C-c C-q  mail-fill-yanked-message (fill what was yanked)."
 (define (valid-group-server-info? server-info)
   (and (vector? server-info)
        (= (vector-length server-info) 3)
-       (or (not (vector-ref server-info 0))
-          (article-number? (vector-ref server-info 0)))
-       (or (not (vector-ref server-info 1))
-          (article-number? (vector-ref server-info 1)))
-       (or (not (vector-ref server-info 2))
-          (article-number? (vector-ref server-info 2)))))
+       (or (equal? '#(#f #f #f) server-info)
+          (equal? '#(0 0 0) server-info)
+          (and (exact-nonnegative-integer? (vector-ref server-info 0))
+               (article-number? (vector-ref server-info 1))
+               (article-number? (vector-ref server-info 2))))))
 \f
 ;;;; Ignored-Subjects File
 
@@ -4032,16 +4031,20 @@ With prefix arg, replaces the file with the list information."
    (add-to-ranges! (news-group:guarantee-ranges-deleted group) number)))
 
 (define (news-group:unread-header-numbers group)
-  (ranges->list
-   (complement-ranges (news-group:guarantee-ranges-deleted group)
-                     (news-group:first-article group)
-                     (news-group:last-article group))))
+  (if (news-group:server-has-articles? group)
+      (ranges->list
+       (complement-ranges (news-group:guarantee-ranges-deleted group)
+                         (news-group:first-article group)
+                         (news-group:last-article group)))
+      '()))
 
 (define (news-group:all-header-numbers group)
-  (ranges->list
-   (complement-ranges '()
-                     (news-group:first-article group)
-                     (news-group:last-article group))))
+  (if (news-group:server-has-articles? group)
+      (ranges->list
+       (complement-ranges '()
+                         (news-group:first-article group)
+                         (news-group:last-article group)))
+      '()))
 
 (define (news-group:update-ranges! group)
   (let ((msg
@@ -4061,13 +4064,17 @@ With prefix arg, replaces the file with the list information."
     (news-group:purge-header-cache group 'ALL)
     (news-group:purge-pre-read-headers group
       (if (ref-variable news-group-keep-seen-headers buffer)
-         (lambda (header)
-           (let ((number (news-header:number header)))
-             (or (< number (news-group:first-article group))
-                 (> number (news-group:last-article group))
-                 (and (not (ref-variable news-group-keep-ignored-headers
-                                         buffer))
-                      (news-header:ignore? header)))))
+         (if (news-group:server-has-articles? group)
+             (lambda (header)
+               (let ((number (news-header:number header)))
+                 (or (< number (news-group:first-article group))
+                     (> number (news-group:last-article group))
+                     (and (not (ref-variable news-group-keep-ignored-headers
+                                             buffer))
+                          (news-header:ignore? header)))))
+             (lambda (header)
+               header
+               #t))
          news-header:article-deleted?))
     (news-group:close-database group)
     (message msg "done")))
@@ -4088,9 +4095,11 @@ With prefix arg, replaces the file with the list information."
 
 (define (news-group:guarantee-ranges-deleted group)
   (let ((ranges
-        (clip-ranges! (news-group:ranges-deleted group)
-                      (news-group:first-article group)
-                      (news-group:last-article group))))
+        (if (news-group:server-has-articles? group)
+            (clip-ranges! (news-group:ranges-deleted group)
+                          (news-group:first-article group)
+                          (news-group:last-article group))
+            '())))
     (set-news-group:ranges-deleted! group ranges)
     ranges))
 \f
@@ -4208,6 +4217,10 @@ With prefix arg, replaces the file with the list information."
                 set-news-group:ranges-browsed!
                 #f
                 add-to-ranges!))
+
+(define (news-group:server-has-articles? group)
+  (and (article-number? (news-group:first-article group))
+       (article-number? (news-group:last-article group))))
 \f
 ;;;; Ignored-Subjects Database