dpkg: Properly mark obsolete conffiles on package replaces

This ensures that when taking over conffiles from another package
the obsolete conffiles are marked as such on the other package.

debian/changelog

@@ -35,6 +35,7 @@ dpkg (1.16.9) UNRELEASED; urgency=low
     This ensures conffile entries are not misshandled nor mixed up when
     configuring packages owning the non-obsolete conffiles. Closes: #689836
     Based on a patch by Andreas Beckmann <debian@abeckmann.de>.
+  * Properly mark in the database obsolete conffiles on package replaces.
 
   [ Updated programs translations ]
   * Czech (Miroslav Kure).

src/archives.c

@@ -962,6 +962,8 @@ tarobject(void *ctx, struct tar_entry *ti)
   }
 
   if (keepexisting) {
+    if (nifd->namenode->flags & fnnf_new_conff)
+      nifd->namenode->flags |= fnnf_obs_conff;
     remove_file_from_list(tc, ti, oldnifd, nifd);
     tarobject_skip_entry(tc, ti);
     return 0;

src/help.c

@@ -291,6 +291,27 @@ dir_is_used_by_pkg(struct filenamenode *file, struct pkginfo *pkg,
   return false;
 }
 
+/**
+ * Mark a conffile as obsolete.
+ *
+ * @param pkg		The package owning the conffile.
+ * @param namenode	The namenode for the obsolete conffile.
+ */
+void
+conffile_mark_obsolete(struct pkginfo *pkg, struct filenamenode *namenode)
+{
+  struct conffile *conff;
+
+  for (conff = pkg->installed.conffiles; conff; conff = conff->next) {
+    if (strcmp(conff->name, namenode->name) == 0) {
+      debug(dbg_conff, "marking %s conffile %s as obsolete",
+            pkg_name(pkg, pnaw_always), conff->name);
+      conff->obsolete = true;
+      return;
+    }
+  }
+}
+
 void oldconffsetflags(const struct conffile *searchconff) {
   struct filenamenode *namenode;
 

src/main.h

@@ -210,6 +210,7 @@ bool ignore_depends(struct pkginfo *pkg);
 bool force_breaks(struct deppossi *possi);
 bool force_depends(struct deppossi *possi);
 bool force_conflicts(struct deppossi *possi);
+void conffile_mark_obsolete(struct pkginfo *pkg, struct filenamenode *namenode);
 void oldconffsetflags(const struct conffile *searchconff);
 void ensure_pathname_nonexisting(const char *pathname);
 int secure_unlink(const char *pathname);

src/processarc.c

@@ -1351,6 +1351,9 @@ void process_archive(const char *filename) {
         continue;
       }
 
+      if (cfile->namenode->flags & fnnf_new_conff)
+        conffile_mark_obsolete(otherpkg, cfile->namenode);
+
       /* If !fileslistvalid then it's one of the disappeared packages above
        * or we have already updated the files list file, and we don't bother
        * with it here, clearly. */