[pacman-dev] [WIP] Fix for overzealous package removal with unmet dependencies

[Allan McRae]

Here goes a WIP patch for FS#30649.  It fixes one the sync140.py
testcase just sent to the mailing list, but not sync141.py - it works
only when the root cause of the excess dependency removal is first in
the upgraded package list.

If anyone has an idea for how to get it fully fixed, I would appreciate
the help.

Allan


diff --git a/lib/libalpm/sync.c b/lib/libalpm/sync.c
index 841e5d6..65a8f52 100644
--- a/lib/libalpm/sync.c
+++ b/lib/libalpm/sync.c
@@ -406,14 +406,29 @@ int _alpm_sync_prepare(alpm_handle_t *handle,
alpm_list_t **data)

                /* Resolve packages in the transaction one at a time, in 
addition
                   building up a list of packages which could not be resolved. 
*/
-               for(i = trans->add; i; i = i->next) {
+
+               i = trans->add;
+               while(i != NULL) {
                        alpm_pkg_t *pkg = i->data;
                        if(_alpm_resolvedeps(handle, localpkgs, pkg, trans->add,
                                                &resolved, remove, data) == -1) 
{
                                unresolvable = alpm_list_add(unresolvable, pkg);
+
+                               /* remove the unresolvable package from the 
upgrade
+                                  list and recalculate localpkgs to allow the 
a local
+                                  version to satisfy future deps */
+               
+                               i = i->next;
+                               trans->add = alpm_list_remove(trans->add, pkg,
+                                               _alpm_pkg_cmp, NULL);
+                               localpkgs = alpm_list_diff(
+                                               
_alpm_db_get_pkgcache(handle->db_local),        
+                                               trans->add, _alpm_pkg_cmp);
+                       } else {
+                               /* [resolved] now additionally contains [pkg] 
and all of its
+                                  dependencies not already on the list */      
+                               i = i->next;
                        }
-                       /* Else, [resolved] now additionally contains [pkg] and 
all of its
-                          dependencies not already on the list */
                }
                alpm_list_free(localpkgs);
                alpm_list_free(remove);