Fix --fail-graph when there is indirect cycles

src/rez/tests/test_utils_resolve_graph.py

@@ -0,0 +1,45 @@
+"""
+unit tests for 'utils.resolve_graph' module
+"""
+from rez.tests.util import TestBase
+from rez.utils import resolve_graph
+import rez.utils.graph_utils
+import unittest
+
+
+class TestResolveGraph(TestBase):
+    def test_conflict_graph_with_cycle(self):
+        """ Tests creating a test digraph which contains a cycle foo-1.0.0 => bar-0.0.1 => !foo-1.0.0
+            Note that the solver doesn't detect this as a cycle. See #1568
+        """
+
+        g = '''
+        digraph g {
+            _1 [label="foo-1", fontsize="10", fillcolor="#FFFFAA", style="filled,dashed"];
+            _2 [label="bar", fontsize="10", fillcolor="#FFFFAA", style="filled,dashed"];
+            _6 [label="foo-1.0.0[]", fontsize="10", fillcolor="#AAFFAA", style="filled"];
+            _7 [label="bar-0.0.1[]", fontsize="10", fillcolor="#AAFFAA", style="filled"];
+            _8 [label="!foo-1.0.0", fontsize="10", fillcolor="#F6F6F6", style="filled,dashed"];
+            _1 -> _6 [arrowsize="0.5"];
+            _2 -> _7 [arrowsize="0.5"];
+            _6 -> _2 [arrowsize="0.5"];
+            _7 -> _8 [arrowsize="0.5"];
+            _8 -> _6 [arrowsize="1", style="bold", color="red", fontcolor="red", label=CONFLICT];
+        }
+        '''
+        graph = rez.utils.graph_utils.read_graph_from_string(g)
+        # strip extra quoting from fill color
+        for k, v in graph.node_attr.items():
+            for index, a in enumerate(v):
+                if a[0] == "fillcolor":
+                    stripped_color = a[1].strip("'").strip('"')
+                    v[index] = ("fillcolor", stripped_color)
+
+        # attempt to graph result
+        result = resolve_graph.failure_detail_from_graph(graph)
+        self.assertTrue("foo-1 --> foo-1.0.0 --> bar-0.0.1 --> !foo-1.0.0" in result)
+        self.assertTrue("bar --> bar-0.0.1 --> !foo-1.0.0" in result)
+
+
+if __name__ == '__main__':
+    unittest.main()

src/rez/utils/resolve_graph.py

@@ -53,7 +53,7 @@ def _cycled_detail_from_graph(graph, cycled_edge):
         visited = list()
         while True:
             visited.append(node)
-            down = next((ne for ne in graph.node_neighbors[node]), None)
+            down = next((ne for ne in graph.node_neighbors[node] if ne not in visited), None)
             if down in cycled_edge:
                 visited.append(down)
                 break
@@ -83,7 +83,7 @@ def _conflicted_detail_from_graph(graph, conflicted_edge):
         visited = list()
         while True:
             visited.append(node)
-            down = next((ne for ne in graph.node_neighbors[node]), None)
+            down = next((ne for ne in graph.node_neighbors[node] if ne not in visited), None)
             if down is None:
                 break