selector: prefer obsoletes (Related:RhBug:1096506)

when searching by provides the packages that contain the same name as provide or contain obsoletes with the same name as their provide will be picked first

Closes: #189
Approved by: j-mracek

data/tests/hawkey/greedy.repo

@@ -5,5 +5,7 @@
 =Pkg: B 1 0 noarch
 =Rec: C
 =Prv: somereq
+=Obs: somereq
 =Pkg: C 1 0 noarch
 =Prv: somereq
+=Pkg: somereq 1 0 noarch

libdnf/hy-goal.c

@@ -523,6 +523,36 @@ filter_name2job(DnfSack *sack, const struct _Filter *f, Queue *job)
     return 0;
 }
 
+/**
+ * add_preferred_provide:
+ * when searching by provides the packages that contain the same
+ * name as provide or contain obsoletes with the same name as their
+ * provide will be picked first
+ */
+static void
+add_preferred_provide(DnfSack *sack, Queue *job, Id id)
+{
+    g_autoptr(GPtrArray) plist = g_ptr_array_new_with_free_func(
+        (GDestroyNotify) g_object_unref);
+    Pool *pool = dnf_sack_get_pool(sack);
+    const char *name = pool_dep2str(pool, id);
+    HyQuery q = hy_query_create(sack);
+    hy_query_filter(q, HY_PKG_NAME, HY_NEQ, name);
+    DnfPackageSet *pset = hy_query_run_set(q);
+    hy_query_filter(q, HY_PKG_PROVIDES, HY_EQ, name);
+    hy_query_filter_package_in(q, HY_PKG_OBSOLETES, HY_NEQ, pset);
+    DnfPackage *pkg;
+    plist = hy_query_run(q);
+    for (guint i = 0; i < plist->len; i++) {
+        pkg = g_ptr_array_index(plist, i);
+        queue_push2(job, SOLVER_DISFAVOR|SOLVER_SOLVABLE,
+                    dnf_package_get_id(pkg));
+    }
+    queue_push2(job, SOLVER_SOLVABLE_PROVIDES, id);
+    hy_query_free(q);
+    g_object_unref(pset);
+}
+
 static int
 filter_provides2job(DnfSack *sack, const struct _Filter *f, Queue *job)
 {
@@ -538,7 +568,7 @@ filter_provides2job(DnfSack *sack, const struct _Filter *f, Queue *job)
     switch (f->cmp_type) {
     case HY_EQ:
         id = dnf_reldep_get_id (f->matches[0].reldep);
-        queue_push2(job, SOLVER_SOLVABLE_PROVIDES, id);
+        add_preferred_provide(sack, job, id);
         break;
     case HY_GLOB:
         dataiterator_init(&di, pool, 0, 0, SOLVABLE_PROVIDES, name, SEARCH_GLOB);
@@ -549,7 +579,7 @@ filter_provides2job(DnfSack *sack, const struct _Filter *f, Queue *job)
         assert(di.idp);
         id = *di.idp;
         if (!job_has(job, SOLVABLE_PROVIDES, id))
-            queue_push2(job, SOLVER_SOLVABLE_PROVIDES, id);
+            add_preferred_provide(sack, job, id);
         dataiterator_free(&di);
         break;
     default:

tests/hawkey/test_goal.c

@@ -230,6 +230,28 @@ START_TEST(test_goal_install_selector)
 }
 END_TEST
 
+START_TEST(test_goal_install_selector_obsoletes_first)
+{
+    HySelector sltr;
+    HyGoal goal = hy_goal_create(test_globals.sack);
+
+    sltr = hy_selector_create(test_globals.sack);
+    hy_selector_set(sltr, HY_PKG_PROVIDES, HY_EQ, "somereq");
+    fail_if(!hy_goal_install_selector(goal, sltr, NULL));
+    hy_selector_free(sltr);
+
+    fail_if(hy_goal_run(goal));
+    assert_iueo(goal, 1, 0, 0, 0);
+
+    GPtrArray *plist = hy_goal_list_installs(goal, NULL);
+    char *nvra = dnf_package_get_nevra(g_ptr_array_index(plist, 0));
+    ck_assert_str_eq(nvra, "B-1-0.noarch");
+    g_free(nvra);
+    g_ptr_array_unref(plist);
+    hy_goal_free(goal);
+}
+END_TEST
+
 START_TEST(test_goal_install_selector_err)
 {
     int rc;
@@ -1437,6 +1459,7 @@ goal_suite(void)
     tc = tcase_create("Greedy");
     tcase_add_unchecked_fixture(tc, fixture_greedy_only, teardown);
     tcase_add_test(tc, test_goal_run_all);
+    tcase_add_test(tc, test_goal_install_selector_obsoletes_first);
     tcase_add_test(tc, test_goal_install_weak_deps);
     suite_add_tcase(s, tc);