Index creation silently dropped when referencing relation

[Former user]

(original reporter: rbu) SQLAlchemy (0.7.2 here) silently ignores Index() declarations when they do not reference a proper column when it should at least issue a warning (if not even find out the related column).

For example, with a declarative model such as this:

class Fnord(Base):
    __tablename__ = 'fnord'
    id = Column(Integer, primary_key=True)
    other_id = Column(Integer, ForeignKey(Other.id))
    other = relationship(Other)

this will create an index:

Index("ix_fnord_other", Fnord.other_id)

but this will not:

Index("ix_fnord_other", Fnord.other)

Even nonsensical statements such as

Index("ix_fnord_other")

do not create at least a warning.

[Mike Bayer]

here's a patch:

diff -r 8c05a3bf6599f92bbf8d2246123597e8966f3a52 lib/sqlalchemy/schema.py
--- a/lib/sqlalchemy/schema.py  Wed Jan 18 12:42:54 2012 -0500
+++ b/lib/sqlalchemy/schema.py  Fri Jan 20 11:17:48 2012 -0500
@@ -2172,6 +2172,8 @@
         self.table = None
         # will call _set_parent() if table-bound column
         # objects are present
+        if not columns:
+            raise exc.ArgumentError("No column names or expressions given.")
         ColumnCollectionMixin.__init__(self, *columns)
         self.name = name
         self.unique = kw.pop('unique', False)
@@ -2984,9 +2986,11 @@
    return element

 def _to_schema_column_or_string(element):
-  if hasattr(element, '__clause_element__'):
-      element = element.__clause_element__()
-  return element
+    if hasattr(element, '__clause_element__'):
+        element = element.__clause_element__()
+    if not isinstance(element, (basestring, expression.ColumnElement)):
+        raise exc.ArgumentError("Element %r is not a string name or column element" % element)
+    return element

 class _CreateDropBase(DDLElement):
     """Base class for DDL constucts that represent CREATE and DROP or
diff -r 8c05a3bf6599f92bbf8d2246123597e8966f3a52 test/sql/test_metadata.py
--- a/test/sql/test_metadata.py Wed Jan 18 12:42:54 2012 -0500
+++ b/test/sql/test_metadata.py Fri Jan 20 11:17:48 2012 -0500
@@ -644,7 +644,7 @@
                 "Column('x', String(), table=<bar>), schema=None)"),
             (schema.DefaultGenerator(for_update=True), 
                 "DefaultGenerator(for_update=True)"),
-            (schema.Index("bar"), "Index('bar')"),
+            (schema.Index("bar", "c"), "Index('bar')"),
             (i1, "Index('bar', Column('x', Integer(), table=<foo>))"),
             (schema.FetchedValue(), "FetchedValue()"),
             (ck,

tests to add are:

from sqlalchemy import *

m = MetaData()

# raises (this is an existing raise, might already have a test for this)
t1 = Table('t', m, Column('x', Integer), Index("foo", "q"))

# raises
Index("foo", 5)

# raises
Index("foo")

# raises
t2 = Table('t2', m, Column('x', Integer))
class SomethingLikeARelationship(object):
    def __clause_element__(self):
        return t2

Index("foo", SomethingLikeARelationship())

}}}

[Mike Bayer]

d50ea3eabf49a8f881a4a21dbafd471bd6510ba8

[Mike Bayer]

Removing milestone: 0.7.6 (automated comment)