From a144c29831a39ed303d6ea8d2ae91e1c36d64c84 Mon Sep 17 00:00:00 2001
Message-Id: <a144c29831a39ed303d6ea8d2ae91e1c36d64c84.1559799452.git.pmatilai@redhat.com>
From: Panu Matilainen <pmatilai@redhat.com>
Date: Wed, 15 May 2019 13:51:19 +0300
Subject: [PATCH] Fix packages getting erased on failed update with dnf
 (RhBug:1620275)

When adding update elements, we set the erase element to depend on the
install element, but if an API user adds the same erasure manually
after adding the update, we know its a duplicate erasure and filter
it out, BUT we zero out the dependent element in the process. And
if installing the update now fails, we end up removing the whole package
due to that missing dependent element.

This never happens with rpm itself so we can't easily test it, but is
100% reproducable with dnf (at least dnf 3-4). Apparently it adds all
erasures by itself (which is kind of understandable I guess, perhaps
we should better allow this in the API)
---
 lib/depends.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/depends.c b/lib/depends.c
index 6e9866eae..f8a6084ab 100644
--- a/lib/depends.c
+++ b/lib/depends.c
@@ -121,7 +121,8 @@ static int removePackage(rpmts ts, Header h, rpmte depends)
 
     /* Filter out duplicate erasures. */
     if (packageHashGetEntry(tsmem->removedPackages, dboffset, &pp, NULL, NULL)) {
-	rpmteSetDependsOn(pp[0], depends);
+	if (depends)
+	    rpmteSetDependsOn(pp[0], depends);
 	return 0;
     }
 
-- 
2.21.0