From 9d1fe2ba165721db0e75be72b3bde7d1209edb5a Mon Sep 17 00:00:00 2001
From: Andy Fingerhut <andy_fingerhut@alum.wustl.edu>
Date: Fri, 26 Jul 2019 01:16:36 -0700
Subject: [PATCH] Fix issue 46 by adding metadata g to all returned edge
 objects

If we modify find-edges-impl, it will also cause all of the functions
listed below to return edges with metadata g, since they all end up
calling find-edges-impl:

* find-edge-impl
* find-edges
* find-edge
* get-edge
---
 src/ubergraph/core.clj       | 14 +++++++-----
 test/ubergraph/core_test.clj | 43 ++++++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+), 6 deletions(-)

diff --git a/src/ubergraph/core.clj b/src/ubergraph/core.clj
index 5ab6a17..7768f10 100644
--- a/src/ubergraph/core.clj
+++ b/src/ubergraph/core.clj
@@ -344,7 +344,8 @@ will `upgrade' the directed edge to undirected and merge attributes."
 
 (defn- find-edges-impl
   ([g src dest]
-    (get-in g [:node-map src :out-edges dest]))
+   (map #(with-meta % g)
+        (get-in g [:node-map src :out-edges dest])))
   ([g {src :src dest :dest :as attributes}]
     (let [edges
           (cond
@@ -353,11 +354,12 @@ will `upgrade' the directed edge to undirected and merge attributes."
             dest (in-edges g dest)
             :else (edges g))
           attributes (dissoc attributes :src :dest)]
-      (if (pos? (count attributes))
-        (for [edge edges
-              :when (submap? attributes (get-in g [:attrs (:id edge)]))]
-          edge)
-        edges))))
+      (map #(with-meta % g)
+           (if (pos? (count attributes))
+             (for [edge edges
+                   :when (submap? attributes (get-in g [:attrs (:id edge)]))]
+               edge)
+             edges)))))
 
 (defn- find-edge-impl [& args]
   (first (apply find-edges-impl args)))
diff --git a/test/ubergraph/core_test.clj b/test/ubergraph/core_test.clj
index 7ce5172..526d0f5 100644
--- a/test/ubergraph/core_test.clj
+++ b/test/ubergraph/core_test.clj
@@ -353,3 +353,46 @@
     ;; This will use calculated hashes during =, but should still be
     ;; true.
     (is (= g2 g1))))
+
+
+(defn all-edges-with-meta-g [g edges]
+  (every? (fn [e]
+            (and (edge? e)
+                 (= g (meta e))))
+          edges))
+
+
+(defn check-all-edge-returning-fns [g]
+  (let [es1 (edges g)
+        es2 (out-edges g 1)
+        es3 (in-edges g 3)
+        es4 (find-edges g 2 3)
+        es5 (find-edges g {:src 2 :dest 3})
+        es6 (find-edge g 2 3)
+        es7 (find-edge g {:src 2 :dest 3})]
+    (is (> (count es1) 0))
+    (is (= true (all-edges-with-meta-g g es1)))
+    (is (> (count es2) 0))
+    (is (= true (all-edges-with-meta-g g es2)))
+    (is (> (count es3) 0))
+    (is (= true (all-edges-with-meta-g g es3)))
+    (is (> (count es4) 0))
+    (is (= true (all-edges-with-meta-g g es4)))
+    (is (> (count es5) 0))
+    (is (= true (all-edges-with-meta-g g es5)))
+
+    (is (not (nil? es6)))
+    (is (= true (all-edges-with-meta-g g [es6])))
+    (is (not (nil? es7)))
+    (is (= true (all-edges-with-meta-g g [es7])))))
+
+
+(deftest returned-edge-objects-contain-g-in-metadata
+  (let [g1 (graph [1 2] [1 3] [2 3] 4)
+        g2 (digraph [1 2] [1 3] [2 3] 4)
+        g3 (multigraph [1 2] [1 2] [2 1] [1 3] [2 3] [2 3] 4)
+        g4 (multidigraph [1 2] [1 2] [1 2] [2 1] [1 3] [2 3] [2 3] 4)]
+    (check-all-edge-returning-fns g1)
+    (check-all-edge-returning-fns g2)
+    (check-all-edge-returning-fns g3)
+    (check-all-edge-returning-fns g4)))