From 6708ef1bdfea27c9ad3ce933ceec2fc73a8da9ac Mon Sep 17 00:00:00 2001
From: Joe Jevnik <joe@quantopian.com>
Date: Wed, 27 Jul 2016 23:28:02 -0400
Subject: [PATCH] ENH: update assets-db-error-msg

---
 tests/test_assets.py           | 16 ++++++++++-----
 zipline/assets/asset_writer.py | 36 ++++++++++++++++++++++++++--------
 zipline/utils/range.py         | 10 ++++++++++
 3 files changed, 49 insertions(+), 13 deletions(-)

diff --git a/tests/test_assets.py b/tests/test_assets.py
index ac725649..b81fac57 100644
--- a/tests/test_assets.py
+++ b/tests/test_assets.py
@@ -642,10 +642,16 @@ class AssetFinderTestCase(WithTradingCalendar, ZiplineTestCase):
 
         self.assertEqual(
             str(e.exception),
-            "Ambiguous ownership of 'MULTIPLE', multiple companies held this"
-            " ticker over the following ranges:\n"
-            "[('2010-01-01 00:00:00', '2012-01-01 00:00:00'),"
-            " ('2011-01-01 00:00:00', '2012-01-01 00:00:00')]",
+            "Ambiguous ownership for 1 symbol, multiple assets held the"
+            " following symbols:\n"
+            "MULTIPLE:\n"
+            "  intersections: (('2010-01-01 00:00:00', '2012-01-01 00:00:00'),"
+            " ('2011-01-01 00:00:00', '2012-01-01 00:00:00'))\n"
+            "      start_date   end_date\n"
+            "  sid                      \n"
+            "  1   2010-01-01 2012-01-01\n"
+            "  2   2010-01-01 2013-01-01\n"
+            "  3   2011-01-01 2012-01-01"
         )
 
     def test_lookup_generic(self):
@@ -1381,7 +1387,7 @@ class TestAssetDBVersioning(ZiplineTestCase):
         downgrade(self.engine, 3)
         metadata = sa.MetaData(conn)
         metadata.reflect(bind=self.engine)
-        check_version_info(metadata.tables['version_info'], 3)
+        check_version_info(conn, metadata.tables['version_info'], 3)
         self.assertFalse('exchange_full' in metadata.tables)
 
         # now go all the way to v0
diff --git a/zipline/assets/asset_writer.py b/zipline/assets/asset_writer.py
index ecf4d7b3..35084e6c 100644
--- a/zipline/assets/asset_writer.py
+++ b/zipline/assets/asset_writer.py
@@ -226,19 +226,39 @@ def _split_symbol_mappings(df):
         end_date.
     """
     mappings = df[list(mapping_columns)]
+    ambigious = {}
     for symbol in mappings.symbol.unique():
         persymbol = mappings[mappings.symbol == symbol]
-        intersections = list(intersecting_ranges(
-            map(from_tuple, zip(persymbol.start_date, persymbol.end_date)),
-        ))
+        intersections = list(intersecting_ranges(map(
+            from_tuple,
+            zip(persymbol.start_date, persymbol.end_date),
+        )))
         if intersections:
-            raise ValueError(
-                'Ambiguous ownership of %r, multiple companies held this'
-                ' ticker over the following ranges:\n%s' % (
-                    symbol,
-                    list(map(_format_range, intersections)),
+            ambigious[symbol] = (
+                intersections,
+                persymbol[['start_date', 'end_date']].astype('datetime64[ns]'),
+            )
+
+    if ambigious:
+        raise ValueError(
+            'Ambiguous ownership for %d symbol%s, multiple assets held the'
+            ' following symbols:\n%s' % (
+                len(ambigious),
+                '' if len(ambigious) == 1 else 's',
+                '\n'.join(
+                    '%s:\n  intersections: %s\n  %s' % (
+                        symbol,
+                        tuple(map(_format_range, intersections)),
+                        # indent the dataframe string
+                        '\n  '.join(str(df).splitlines()),
+                    )
+                    for symbol, (intersections, df) in sorted(
+                        ambigious.items(),
+                        key=first,
+                    ),
                 ),
             )
+        )
     return (
         df.groupby(level=0).apply(_check_asset_group),
         df[list(mapping_columns)],
diff --git a/zipline/utils/range.py b/zipline/utils/range.py
index 45d44b37..0e2f46e1 100644
--- a/zipline/utils/range.py
+++ b/zipline/utils/range.py
@@ -1,3 +1,4 @@
+from functools import reduce
 import operator as op
 
 from six import PY2
@@ -64,6 +65,15 @@ if PY2:
                 self.stop,
                 (', ' + str(self.step)) if self.step != 1 else '',
             )
+
+        def __hash__(self):
+            return hash((type(self), self.start, self.stop, self.step))
+
+        def __eq__(self, other):
+            return reduce(
+                getattr(self, attr) == getattr(other, attr)
+                for attr in self.__slots__
+            )
 else:
     range = range