Add toggle to load of existing deployment values (#7218)

src/prefect/deployments.py

@@ -650,21 +650,21 @@ async def build_from_flow(
         output: str = None,
         skip_upload: bool = False,
         apply: bool = False,
+        load_existing: bool = True,
         **kwargs,
     ) -> "Deployment":
         """
         Configure a deployment for a given flow.
 
-        Note that this method loads any settings that may already be configured for the named deployment
-        server-side (e.g., schedules, default parameter values, etc.).
-
         Args:
             flow: A flow function to deploy
             name: A name for the deployment
             output (optional): if provided, the full deployment specification will be written as a YAML
                 file in the location specified by `output`
             skip_upload: if True, deployment files are not automatically uploaded to remote storage
             apply: if True, the deployment is automatically registered with the API
+            load_existing: if True, load any settings that may already be configured for the named deployment
+                server-side (e.g., schedules, default parameter values, etc.)
             **kwargs: other keyword arguments to pass to the constructor for the `Deployment` class
         """
         if not name:
@@ -691,7 +691,8 @@ async def build_from_flow(
             entry_path = Path(flow_file).absolute().relative_to(Path(".").absolute())
             deployment.entrypoint = f"{entry_path}:{flow.fn.__name__}"
 
-        await deployment.load()
+        if load_existing:
+            await deployment.load()
 
         # set a few attributes for this flow object
         deployment.parameter_openapi_schema = parameter_schema(flow)

tests/test_deployments.py

@@ -354,6 +354,32 @@ async def test_build_from_flow_sets_provided_attrs(self, flow_function):
         assert d.tags == ["A", "B"]
         assert d.version == "12"
 
+    async def test_build_from_flow_doesnt_load_existing(self, flow_function):
+        d = await Deployment.build_from_flow(
+            flow_function,
+            name="foo",
+            tags=["A", "B"],
+            description="foobar",
+            version="12",
+        )
+        assert d.flow_name == flow_function.name
+        assert d.name == "foo"
+        assert d.description == "foobar"
+        assert d.tags == ["A", "B"]
+        assert d.version == "12"
+
+        d = await Deployment.build_from_flow(
+            flow_function,
+            name="foo",
+            version="12",
+            load_existing=False,
+        )
+        assert d.flow_name == flow_function.name
+        assert d.name == "foo"
+        assert d.description != "foobar"
+        assert d.tags != ["A", "B"]
+        assert d.version == "12"
+
 
 class TestYAML:
     def test_deployment_yaml_roundtrip(self, tmp_path):