Remove next() method from Graph (#2440)

Author: Kludex

docs/changelog.md

@@ -12,6 +12,10 @@ Pydantic AI is still pre-version 1, so breaking changes will occur, however:
 !!! note
     Here's a filtered list of the breaking changes for each version to help you upgrade Pydantic AI.
 
+### v0.6.0 (2025-08-06)
+
+See [#2440](https://github.com/pydantic/pydantic-ai/pull/2440) - The `next` method was removed from the `Graph` class. Use `async with graph.iter(...) as run:  run.next()` instead.
+
 ### v0.5.0 (2025-08-04)
 
 See [#2388](https://github.com/pydantic/pydantic-ai/pull/2388) - The `source` field of an `EvaluationResult` is now of type `EvaluatorSpec` rather than the actual source `Evaluator` instance, to help with serialization/deserialization.

pydantic_graph/pydantic_graph/graph.py

@@ -10,7 +10,6 @@
 
 import logfire_api
 import typing_extensions
-from typing_extensions import deprecated
 from typing_inspection import typing_objects
 
 from . import _utils, exceptions, mermaid
@@ -342,43 +341,6 @@ async def initialize(
         persistence.set_graph_types(self)
         await persistence.snapshot_node(state, node)
 
-    @deprecated('`next` is deprecated, use `async with graph.iter(...) as run:  run.next()` instead')
-    async def next(
-        self,
-        node: BaseNode[StateT, DepsT, RunEndT],
-        persistence: BaseStatePersistence[StateT, RunEndT],
-        *,
-        state: StateT = None,
-        deps: DepsT = None,
-        infer_name: bool = True,
-    ) -> BaseNode[StateT, DepsT, Any] | End[RunEndT]:
-        """Run a node in the graph and return the next node to run.
-
-        Args:
-            node: The node to run.
-            persistence: State persistence interface, defaults to
-                [`SimpleStatePersistence`][pydantic_graph.SimpleStatePersistence] if `None`.
-            state: The current state of the graph.
-            deps: The dependencies of the graph.
-            infer_name: Whether to infer the graph name from the calling frame.
-
-        Returns:
-            The next node to run or [`End`][pydantic_graph.nodes.End] if the graph has finished.
-        """
-        if infer_name and self.name is None:
-            self._infer_name(inspect.currentframe())
-
-        persistence.set_graph_types(self)
-        run = GraphRun[StateT, DepsT, RunEndT](
-            graph=self,
-            start_node=node,
-            persistence=persistence,
-            state=state,
-            deps=deps,
-            traceparent=None,
-        )
-        return await run.next(node)
-
     def mermaid_code(
         self,
         *,

tests/graph/test_graph.py

@@ -401,39 +401,6 @@ async def run(self, ctx: GraphRunContext) -> End[None]:
             await run.next()
 
 
-async def test_next(mock_snapshot_id: object):
-    @dataclass
-    class Foo(BaseNode):
-        async def run(self, ctx: GraphRunContext) -> Bar:
-            return Bar()
-
-    @dataclass
-    class Bar(BaseNode):
-        async def run(self, ctx: GraphRunContext) -> Foo:
-            return Foo()  # pragma: no cover
-
-    g = Graph(nodes=(Foo, Bar))
-    assert g.name is None
-    sp = FullStatePersistence()
-    with pytest.warns(DeprecationWarning, match='`next` is deprecated, use `async with graph.iter(...)'):
-        n = await g.next(Foo(), persistence=sp)  # pyright: ignore[reportDeprecated]
-    assert n == Bar()
-    assert g.name == 'g'
-    assert sp.history == snapshot(
-        [
-            NodeSnapshot(
-                state=None,
-                node=Foo(),
-                start_ts=IsNow(tz=timezone.utc),
-                duration=IsFloat(),
-                status='success',
-                id='Foo:1',
-            ),
-            NodeSnapshot(state=None, node=Bar(), id='Bar:2'),
-        ]
-    )
-
-
 async def test_deps(mock_snapshot_id: object):
     @dataclass
     class Deps: