Fix wrong usage of iter_utils.unique_seen

This wasn't actually using the right data to derive
uniqueness, so fix it to actually use the right entry
to determine what to skip or what not to skip.

Closes-Bug: #1525379

Change-Id: Ic23b6d03877f7714f6a3fb74adac0ba58cd97f0d

1 files changed, 9 insertions, 8 deletions

diff --git a/taskflow/utils/iter_utils.py b/taskflow/utils/iter_utils.py
index 413b36f..959f666 100644
--- a/taskflow/utils/iter_utils.py
+++ b/taskflow/utils/iter_utils.py
@@ -91,7 +91,7 @@ def generate_delays(delay, max_delay, multiplier=2):
     return _gen_it()
 
 
-def unique_seen(it, *its):
+def unique_seen(its, seen_selector=None):
     """Yields unique values from iterator(s) (and retains order)."""
 
     def _gen_it(all_its):
@@ -99,16 +99,17 @@ def unique_seen(it, *its):
         # can happen before generation/iteration... (instead of
         # during generation/iteration)
         seen = set()
-        while all_its:
-            it = all_its.popleft()
+        for it in all_its:
             for value in it:
-                if value not in seen:
+                if seen_selector is not None:
+                    maybe_seen_value = seen_selector(value)
+                else:
+                    maybe_seen_value = value
+                if maybe_seen_value not in seen:
                     yield value
-                    seen.add(value)
+                    seen.add(maybe_seen_value)
 
-    all_its = collections.deque([it])
-    if its:
-        all_its.extend(its)
+    all_its = list(its)
     for it in all_its:
         if not isinstance(it, collections.Iterable):
             raise ValueError("Iterable expected, but '%s' is"