make query generation reference fields with a dollar sign by default

Author: timgraham

django_mongodb/expressions.py

@@ -2,7 +2,7 @@
 
 
 def col(self, compiler, connection):  # noqa: ARG001
-    return self.target.column
+    return f"${self.target.column}"
 
 
 def register_expressions():

django_mongodb/functions.py

@@ -1,5 +1,4 @@
 from django.db import NotSupportedError
-from django.db.models.expressions import Col
 from django.db.models.functions.datetime import Extract
 
 from .query_utils import process_lhs
@@ -15,8 +14,6 @@ def extract(self, compiler, connection):
         operator = "$year"
     else:
         raise NotSupportedError("%s is not supported." % self.__class__.__name__)
-    if isinstance(self.lhs, Col):
-        lhs_mql = f"${lhs_mql}"
     return {operator: lhs_mql}
 
 

django_mongodb/lookups.py

@@ -1,13 +1,12 @@
 from django.db import NotSupportedError
-from django.db.models.expressions import Col
 from django.db.models.fields.related_lookups import In, MultiColSource, RelatedIn
 from django.db.models.lookups import BuiltinLookup, Exact, IsNull, UUIDTextMixin
 
 from .query_utils import process_lhs, process_rhs
 
 
 def builtin_lookup(self, compiler, connection):
-    lhs_mql = process_lhs(self, compiler, connection)
+    lhs_mql = process_lhs(self, compiler, connection, bare_column_ref=True)
     value = process_rhs(self, compiler, connection)
     rhs_mql = connection.operators[self.lookup_name](value)
     return {lhs_mql: rhs_mql}
@@ -16,8 +15,6 @@ def builtin_lookup(self, compiler, connection):
 def exact(self, compiler, connection):
     lhs_mql = process_lhs(self, compiler, connection)
     value = process_rhs(self, compiler, connection)
-    if isinstance(self.lhs, Col):
-        lhs_mql = f"${lhs_mql}"
     return {"$expr": {"$eq": [lhs_mql, value]}}
 
 
@@ -30,7 +27,7 @@ def in_(self, compiler, connection):
 def is_null(self, compiler, connection):
     if not isinstance(self.rhs, bool):
         raise ValueError("The QuerySet value for an isnull lookup must be True or False.")
-    lhs_mql = process_lhs(self, compiler, connection)
+    lhs_mql = process_lhs(self, compiler, connection, bare_column_ref=True)
     rhs_mql = connection.operators["isnull"](self.rhs)
     return {lhs_mql: rhs_mql}
 

django_mongodb/query_utils.py

@@ -5,10 +5,14 @@ def is_direct_value(node):
     return not hasattr(node, "as_sql")
 
 
-def process_lhs(node, compiler, connection):
+def process_lhs(node, compiler, connection, bare_column_ref=False):
     if is_direct_value(node.lhs):
         return node
-    return node.lhs.as_mql(compiler, connection)
+    mql = node.lhs.as_mql(compiler, connection)
+    # Remove the unneeded $ from column references.
+    if bare_column_ref and mql.startswith("$"):
+        mql = mql[1:]
+    return mql
 
 
 def process_rhs(node, compiler, connection):