Search: join tables when necessary

Some searches (eg, "owner:foo" or "project:bar") were performing
an implicit join on the primary key that joins them with the
change table in a 1:1 relationship.  If a user negated those,
then the result would be "not (a.key=b.key and a.value=foo)"
which is equal to "a.key!=b.key or a.value!=foo".  The partial
negation of the join criteria is definitely not what we want.

Instead, for the known 1:1 relationships that can be produced,
add the join criteria outside of the main expression iff those
tables are referenced.  Then the remaining part of the
condition (a.value == foo) can be optionally negated as normal.
Expressions for relationships other than 1:1 are handled by
subselects and so should not be impacted by this.

Also, I'm leaving a simple bit of debug code in the search
module for future use.

Change-Id: I92bb0a01f1768cb4f7cc9b3b28d54ebd309fa406

gertty/search/__init__.py

@@ -13,6 +13,7 @@
 # under the License.
 
 import sqlalchemy.sql.expression
+from sqlalchemy.sql.expression import and_
 
 from gertty.search import tokenizer, parser
 import gertty.db
@@ -28,6 +29,42 @@ class SearchCompiler(object):
         self.lexer = tokenizer.SearchTokenizer()
         self.parser = parser.SearchParser()
 
+    def findTables(self, expression):
+        tables = set()
+        stack = [expression]
+        while stack:
+            x = stack.pop()
+            if hasattr(x, 'table'):
+                if (x.table != gertty.db.change_table
+                    and hasattr(x.table, 'name')):
+                    tables.add(x.table)
+            for child in x.get_children():
+                if not isinstance(child, sqlalchemy.sql.selectable.Select):
+                    stack.append(child)
+        return tables
+
     def parse(self, data):
         self.parser.username = self.app.config.username
-        return self.parser.parse(data, lexer=self.lexer)
+        result = self.parser.parse(data, lexer=self.lexer)
+        tables = self.findTables(result)
+        if gertty.db.project_table in tables:
+            result = and_(gertty.db.change_table.c.project_key == gertty.db.project_table.c.key,
+                          result)
+            tables.remove(gertty.db.project_table)
+        if gertty.db.account_table in tables:
+            result = and_(gertty.db.change_table.c.account_key == gertty.db.account_table.c.key,
+                          result)
+            tables.remove(gertty.db.account_table)
+        if tables:
+            raise Exception("Unknown table in search: %s" % tables)
+        return result
+
+if __name__ == '__main__':
+    class Dummy(object):
+        pass
+    app = Dummy()
+    app.config = Dummy()
+    app.config.username = 'bob'
+    search = SearchCompiler(app)
+    x = search.parse('owner:self')
+    print x

gertty/search/parser.py

@@ -122,13 +122,11 @@ def SearchParser():
         '''owner_term : OP_OWNER string'''
         if p[2] == 'self':
             username = p.parser.username
-            p[0] = and_(gertty.db.change_table.c.account_key == gertty.db.account_table.c.key,
-                        gertty.db.account_table.c.username == username)
+            p[0] = gertty.db.account_table.c.username == username
         else:
-            p[0] = and_(gertty.db.change_table.c.account_key == gertty.db.account_table.c.key,
-                        or_(gertty.db.account_table.c.username == p[2],
-                            gertty.db.account_table.c.email == p[2],
-                            gertty.db.account_table.c.name == p[2]))
+            p[0] = or_(gertty.db.account_table.c.username == p[2],
+                       gertty.db.account_table.c.email == p[2],
+                       gertty.db.account_table.c.name == p[2])
 
     def p_reviewer_term(p):
         '''reviewer_term : OP_REVIEWER string'''
@@ -266,8 +264,7 @@ def SearchParser():
         elif p[2] == 'abandoned':
             p[0] = gertty.db.change_table.c.status == 'ABANDONED'
         elif p[2] == 'owner':
-            p[0] = and_(gertty.db.change_table.c.account_key == gertty.db.account_table.c.key,
-                        gertty.db.account_table.c.username == username)
+            p[0] = gertty.db.account_table.c.username == username
         elif p[2] == 'reviewer':
             filters = []
             filters.append(gertty.db.approval_table.c.change_key == gertty.db.change_table.c.key)