[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);