for agate, use the "Urb" mode on python 2, handle BOM fiddling

core/dbt/clients/agate_helper.py

@@ -1,11 +1,7 @@
-from codecs import BOM_UTF8
-
 import dbt.compat
 
 import agate
 
-BOM = BOM_UTF8.decode('utf-8')  # '\ufeff'
-
 DEFAULT_TYPE_TESTER = agate.TypeTester(types=[
     agate.data_types.Number(null_values=('null', '')),
     agate.data_types.TimeDelta(null_values=('null', '')),
@@ -46,9 +42,7 @@ def as_matrix(table):
 
 
 def from_csv(abspath):
-    with dbt.compat.open_file(abspath) as fp:
-        if fp.read(1) != BOM:
+    with dbt.compat.open_seed_file(abspath) as fp:
+        if fp.read(len(dbt.compat.BOM_UTF8)) != dbt.compat.BOM_UTF8:
             fp.seek(0)
-
-        file_buf = dbt.compat.read_into_buffer(fp)
-        return agate.Table.from_csv(file_buf, column_types=DEFAULT_TYPE_TESTER)
+        return agate.Table.from_csv(fp, column_types=DEFAULT_TYPE_TESTER)

core/dbt/compat.py

@@ -100,16 +100,18 @@ def open_file(path):
     return open(path, encoding='utf-8')
 
 
-def read_into_buffer(fp):
-    buf = StringIO()
+if WHICH_PYTHON == 2:
+    BOM_UTF8 = codecs.BOM_UTF8
+else:
+    BOM_UTF8 = codecs.BOM_UTF8.decode('utf-8')
 
+
+def open_seed_file(path):
     if WHICH_PYTHON == 2:
-        buf.write(fp.read().encode('utf-8'))
+        fp = open(path, 'Urb')
     else:
-        buf.write(fp.read())
-
-    buf.seek(0)
-    return buf
+        fp = open(path, encoding='utf-8')
+    return fp
 
 
 if WHICH_PYTHON == 2: