Various improvements about subqueries.

doc/source/advanced_query_operations.rst

@@ -60,7 +60,7 @@ As discussed in the note above, this is for example useful when you need to orde
 
 Options for `intermediate_transform` *variables* are:
 
-- `source`: `string`or `Resolver` - the variable to use as source for the transformation. Works with resolvers (see below).
+- `source`: `string` or `Resolver` - the variable to use as source for the transformation. Works with resolvers (see below).
 - `source_prop`: `string` - optionally, a property of the source variable to use as source for the transformation.
 - `include_in_return`: `bool` - whether to include the variable in the return statement. Defaults to False.
 
@@ -95,7 +95,7 @@ Subqueries
 The `subquery` method allows you to perform a `Cypher subquery <https://neo4j.com/docs/cypher-manual/current/subqueries/call-subquery/>`_ inside your query. This allows you to perform operations in isolation to the rest of your query::
 
     from neomodel.sync_match import Collect, Last
-    
+
     # This will create a CALL{} subquery
     # And return a variable named supps usable in the rest of your query
     Coffee.nodes.filter(name="Espresso")
@@ -106,12 +106,18 @@ The `subquery` method allows you to perform a `Cypher subquery <https://neo4j.co
         )
         .annotate(supps=Last(Collect("suppliers"))),
         ["supps"],
+        [NodeNameResolver("self")]
     )
 
+Options for `subquery` calls are:
+
+- `return_set`: list of `string` - the subquery variables that should be included in the outer query result
+- `initial_context`: optional list of `string` or `Resolver` - the outer query variables that will be injected at the begining of the subquery
+
 .. note::
-    Notice the subquery starts with Coffee.nodes ; neomodel will use this to know it needs to inject the source "coffee" variable generated by the outer query into the subquery. This means only Espresso coffee nodes will be considered in the subquery.
+   In the example above, we reference `self` to be included in the initial context. It will actually inject the outer variable corresponding to `Coffee` node.
 
-    We know this is confusing to read, but have not found a better wat to do this yet. If you have any suggestions, please let us know.
+   We know this is confusing to read, but have not found a better wat to do this yet. If you have any suggestions, please let us know.
 
 Helpers
 -------

neomodel/async_/match.py

@@ -1,7 +1,6 @@
 import inspect
 import re
 import string
-import warnings
 from dataclasses import dataclass
 from typing import Any, Dict, List
 from typing import Optional as TOptional
@@ -13,7 +12,7 @@
 from neomodel.exceptions import MultipleNodesReturned
 from neomodel.match_q import Q, QBase
 from neomodel.properties import AliasProperty, ArrayProperty, Property
-from neomodel.typing import Transformation
+from neomodel.typing import Subquery, Transformation
 from neomodel.util import INCOMING, OUTGOING
 
 CYPHER_ACTIONS_WITH_SIDE_EFFECT_EXPR = re.compile(r"(?i:MERGE|CREATE|DELETE|DETACH)")
@@ -414,13 +413,13 @@ def __init__(
 
 
 class AsyncQueryBuilder:
-    def __init__(self, node_set, subquery_context: bool = False) -> None:
+    def __init__(self, node_set, subquery_namespace: TOptional[str] = None) -> None:
         self.node_set = node_set
         self._ast = QueryAST()
         self._query_params: Dict = {}
         self._place_holder_registry: Dict = {}
         self._ident_count: int = 0
-        self._subquery_context: bool = subquery_context
+        self._subquery_namespace: TOptional[str] = subquery_namespace
 
     async def build_ast(self) -> "AsyncQueryBuilder":
         if hasattr(self.node_set, "relations_to_fetch"):
@@ -558,7 +557,7 @@ def build_traversal_from_path(
                     # contains the primary node so _contains() works
                     # as usual
                     self._ast.return_clause = lhs_name
-                    if self._subquery_context:
+                    if self._subquery_namespace:
                         # Don't include label in identifier if we are in a subquery
                         lhs_ident = lhs_name
                 elif relation["include_in_return"]:
@@ -672,7 +671,10 @@ def _register_place_holder(self, key: str) -> str:
             self._place_holder_registry[key] += 1
         else:
             self._place_holder_registry[key] = 1
-        return key + "_" + str(self._place_holder_registry[key])
+        place_holder = f"{key}_{self._place_holder_registry[key]}"
+        if self._subquery_namespace:
+            place_holder = f"{self._subquery_namespace}_{place_holder}"
+        return place_holder
 
     def _parse_path(self, source_class, prop: str) -> Tuple[str, str, str, Any]:
         is_rel_filter = "|" in prop
@@ -879,10 +881,21 @@ def build_query(self) -> str:
                 query += ",".join(ordering)
 
         if hasattr(self.node_set, "_subqueries"):
-            for subquery, return_set in self.node_set._subqueries:
-                outer_primary_var = self._ast.return_clause
-                query += f" CALL {{ WITH {outer_primary_var} {subquery} }} "
-                for varname in return_set:
+            for subquery in self.node_set._subqueries:
+                query += " CALL {"
+                if subquery["initial_context"]:
+                    query += " WITH "
+                    context: List[str] = []
+                    for var in subquery["initial_context"]:
+                        if isinstance(var, (NodeNameResolver, RelationNameResolver)):
+                            context.append(var.resolve(self))
+                        else:
+                            context.append(var)
+                    query += ",".join(context)
+
+                query += f"{subquery['query']} }} "
+                self._query_params.update(subquery["query_params"])
+                for varname in subquery["return_set"]:
                     # We declare the returned variables as "virtual" relations of the
                     # root node class to make sure they will be translated by a call to
                     # resolve_subgraph() (otherwise, they will be lost).
@@ -893,10 +906,10 @@ def build_query(self) -> str:
                         "variable_name": varname,
                         "rel_variable_name": varname,
                     }
-                returned_items += return_set
+                returned_items += subquery["return_set"]
 
         query += " RETURN "
-        if self._ast.return_clause and not self._subquery_context:
+        if self._ast.return_clause and not self._subquery_namespace:
             returned_items.append(self._ast.return_clause)
         if self._ast.additional_return:
             returned_items += self._ast.additional_return
@@ -1120,6 +1133,8 @@ class NodeNameResolver:
     node: str
 
     def resolve(self, qbuilder: AsyncQueryBuilder) -> str:
+        if self.node == "self" and qbuilder._ast.return_clause:
+            return qbuilder._ast.return_clause
         result = qbuilder.lookup_query_variable(self.node)
         if result is None:
             raise ValueError(f"Unable to resolve variable name for node {self.node}")
@@ -1238,7 +1253,7 @@ def __init__(self, source) -> None:
 
         self.relations_to_fetch: List = []
         self._extra_results: List = []
-        self._subqueries: list[Tuple[str, list[str]]] = []
+        self._subqueries: list[Subquery] = []
         self._intermediate_transforms: list = []
 
     def __await__(self):
@@ -1525,7 +1540,10 @@ async def resolve_subgraph(self) -> list:
         return results
 
     async def subquery(
-        self, nodeset: "AsyncNodeSet", return_set: List[str]
+        self,
+        nodeset: "AsyncNodeSet",
+        return_set: List[str],
+        initial_context: TOptional[List[str]] = None,
     ) -> "AsyncNodeSet":
         """Add a subquery to this node set.
 
@@ -1534,16 +1552,41 @@ async def subquery(
         declared inside return_set variable in order to be included in the final RETURN
         statement.
         """
-        qbuilder = await nodeset.query_cls(nodeset, subquery_context=True).build_ast()
+        namespace = f"sq{len(self._subqueries) + 1}"
+        qbuilder = await nodeset.query_cls(
+            nodeset, subquery_namespace=namespace
+        ).build_ast()
         for var in return_set:
             if (
                 var != qbuilder._ast.return_clause
                 and var not in qbuilder._ast.additional_return
                 and var
                 not in [res["alias"] for res in nodeset._extra_results if res["alias"]]
+                and var
+                not in [
+                    varname
+                    for tr in nodeset._intermediate_transforms
+                    for varname, vardef in tr["vars"].items()
+                    if vardef.get("include_in_return")
+                ]
             ):
                 raise RuntimeError(f"Variable '{var}' is not returned by subquery.")
-        self._subqueries.append((qbuilder.build_query(), return_set))
+        if initial_context:
+            for var in initial_context:
+                if type(var) is not str and not isinstance(
+                    var, (NodeNameResolver, RelationNameResolver, RawCypher)
+                ):
+                    raise ValueError(
+                        f"Wrong variable specified in initial context, should be a string or an instance of NodeNameResolver or RelationNameResolver"
+                    )
+        self._subqueries.append(
+            {
+                "query": qbuilder.build_query(),
+                "query_params": qbuilder._query_params,
+                "return_set": return_set,
+                "initial_context": initial_context,
+            }
+        )
         return self
 
     def intermediate_transform(

neomodel/sync_/match.py

@@ -1,7 +1,6 @@
 import inspect
 import re
 import string
-import warnings
 from dataclasses import dataclass
 from typing import Any, Dict, List
 from typing import Optional as TOptional
@@ -13,7 +12,7 @@
 from neomodel.sync_ import relationship_manager
 from neomodel.sync_.core import StructuredNode, db
 from neomodel.sync_.relationship import StructuredRel
-from neomodel.typing import Transformation
+from neomodel.typing import Subquery, Transformation
 from neomodel.util import INCOMING, OUTGOING
 
 CYPHER_ACTIONS_WITH_SIDE_EFFECT_EXPR = re.compile(r"(?i:MERGE|CREATE|DELETE|DETACH)")
@@ -414,13 +413,13 @@ def __init__(
 
 
 class QueryBuilder:
-    def __init__(self, node_set, subquery_context: bool = False) -> None:
+    def __init__(self, node_set, subquery_namespace: TOptional[str] = None) -> None:
         self.node_set = node_set
         self._ast = QueryAST()
         self._query_params: Dict = {}
         self._place_holder_registry: Dict = {}
         self._ident_count: int = 0
-        self._subquery_context: bool = subquery_context
+        self._subquery_namespace: TOptional[str] = subquery_namespace
 
     def build_ast(self) -> "QueryBuilder":
         if hasattr(self.node_set, "relations_to_fetch"):
@@ -558,7 +557,7 @@ def build_traversal_from_path(
                     # contains the primary node so _contains() works
                     # as usual
                     self._ast.return_clause = lhs_name
-                    if self._subquery_context:
+                    if self._subquery_namespace:
                         # Don't include label in identifier if we are in a subquery
                         lhs_ident = lhs_name
                 elif relation["include_in_return"]:
@@ -672,7 +671,10 @@ def _register_place_holder(self, key: str) -> str:
             self._place_holder_registry[key] += 1
         else:
             self._place_holder_registry[key] = 1
-        return key + "_" + str(self._place_holder_registry[key])
+        place_holder = f"{key}_{self._place_holder_registry[key]}"
+        if self._subquery_namespace:
+            place_holder = f"{self._subquery_namespace}_{place_holder}"
+        return place_holder
 
     def _parse_path(self, source_class, prop: str) -> Tuple[str, str, str, Any]:
         is_rel_filter = "|" in prop
@@ -879,10 +881,21 @@ def build_query(self) -> str:
                 query += ",".join(ordering)
 
         if hasattr(self.node_set, "_subqueries"):
-            for subquery, return_set in self.node_set._subqueries:
-                outer_primary_var = self._ast.return_clause
-                query += f" CALL {{ WITH {outer_primary_var} {subquery} }} "
-                for varname in return_set:
+            for subquery in self.node_set._subqueries:
+                query += " CALL {"
+                if subquery["initial_context"]:
+                    query += " WITH "
+                    context: List[str] = []
+                    for var in subquery["initial_context"]:
+                        if isinstance(var, (NodeNameResolver, RelationNameResolver)):
+                            context.append(var.resolve(self))
+                        else:
+                            context.append(var)
+                    query += ",".join(context)
+
+                query += f"{subquery['query']} }} "
+                self._query_params.update(subquery["query_params"])
+                for varname in subquery["return_set"]:
                     # We declare the returned variables as "virtual" relations of the
                     # root node class to make sure they will be translated by a call to
                     # resolve_subgraph() (otherwise, they will be lost).
@@ -893,10 +906,10 @@ def build_query(self) -> str:
                         "variable_name": varname,
                         "rel_variable_name": varname,
                     }
-                returned_items += return_set
+                returned_items += subquery["return_set"]
 
         query += " RETURN "
-        if self._ast.return_clause and not self._subquery_context:
+        if self._ast.return_clause and not self._subquery_namespace:
             returned_items.append(self._ast.return_clause)
         if self._ast.additional_return:
             returned_items += self._ast.additional_return
@@ -1118,6 +1131,8 @@ class NodeNameResolver:
     node: str
 
     def resolve(self, qbuilder: QueryBuilder) -> str:
+        if self.node == "self" and qbuilder._ast.return_clause:
+            return qbuilder._ast.return_clause
         result = qbuilder.lookup_query_variable(self.node)
         if result is None:
             raise ValueError(f"Unable to resolve variable name for node {self.node}")
@@ -1236,7 +1251,7 @@ def __init__(self, source) -> None:
 
         self.relations_to_fetch: List = []
         self._extra_results: List = []
-        self._subqueries: list[Tuple[str, list[str]]] = []
+        self._subqueries: list[Subquery] = []
         self._intermediate_transforms: list = []
 
     def __await__(self):
@@ -1522,24 +1537,52 @@ def resolve_subgraph(self) -> list:
             )
         return results
 
-    def subquery(self, nodeset: "NodeSet", return_set: List[str]) -> "NodeSet":
+    def subquery(
+        self,
+        nodeset: "NodeSet",
+        return_set: List[str],
+        initial_context: TOptional[List[str]] = None,
+    ) -> "NodeSet":
         """Add a subquery to this node set.
 
         A subquery is a regular cypher query but executed within the context of a CALL
         statement. Such query will generally fetch additional variables which must be
         declared inside return_set variable in order to be included in the final RETURN
         statement.
         """
-        qbuilder = nodeset.query_cls(nodeset, subquery_context=True).build_ast()
+        namespace = f"sq{len(self._subqueries) + 1}"
+        qbuilder = nodeset.query_cls(nodeset, subquery_namespace=namespace).build_ast()
         for var in return_set:
             if (
                 var != qbuilder._ast.return_clause
                 and var not in qbuilder._ast.additional_return
                 and var
                 not in [res["alias"] for res in nodeset._extra_results if res["alias"]]
+                and var
+                not in [
+                    varname
+                    for tr in nodeset._intermediate_transforms
+                    for varname, vardef in tr["vars"].items()
+                    if vardef.get("include_in_return")
+                ]
             ):
                 raise RuntimeError(f"Variable '{var}' is not returned by subquery.")
-        self._subqueries.append((qbuilder.build_query(), return_set))
+        if initial_context:
+            for var in initial_context:
+                if type(var) is not str and not isinstance(
+                    var, (NodeNameResolver, RelationNameResolver, RawCypher)
+                ):
+                    raise ValueError(
+                        f"Wrong variable specified in initial context, should be a string or an instance of NodeNameResolver or RelationNameResolver"
+                    )
+        self._subqueries.append(
+            {
+                "query": qbuilder.build_query(),
+                "query_params": qbuilder._query_params,
+                "return_set": return_set,
+                "initial_context": initial_context,
+            }
+        )
         return self
 
     def intermediate_transform(

neomodel/typing.py

@@ -1,6 +1,6 @@
 """Custom types used for annotations."""
 
-from typing import Any, Optional, TypedDict
+from typing import Any, Dict, List, Optional, TypedDict
 
 Transformation = TypedDict(
     "Transformation",
@@ -10,3 +10,14 @@
         "include_in_return": Optional[bool],
     },
 )
+
+
+Subquery = TypedDict(
+    "Subquery",
+    {
+        "query": str,
+        "query_params": Dict,
+        "return_set": List[str],
+        "initial_context": Optional[List[Any]],
+    },
+)