feat: bypass request copying in method calls (#557)

If a proto-plus message is passed in, do not copy it.

gapic/ads-templates/%namespace/%name/%version/%sub/services/%service/client.py.j2

@@ -287,24 +287,28 @@ class {{ service.client_name }}(metaclass={{ service.client_name }}Meta):
             request = {{ method.input.ident }}()
         {% endif -%}{# Cross-package req and flattened fields #}
         {%- else %}
-        request = {{ method.input.ident }}(request)
+        # Minor optimization to avoid making a copy if the user passes
+        # in a {{ method.input.ident }}.
+        # There's no risk of modifying the input as we've already verified
+        # there are no flattened fields.
+        if not isinstance(request, {{ method.input.ident }}):
+            request = {{ method.input.ident }}(request)
         {% endif %} {# different request package #}
-
         {#- Vanilla python protobuf wrapper types cannot _set_ repeated fields #}
-        {% if method.flattened_fields -%}
-        # If we have keyword arguments corresponding to fields on the
-        # request, apply these.
-        {% endif -%}
-        {%- for key, field in method.flattened_fields.items() if not(field.repeated and method.input.ident.package != method.ident.package) %}
-        if {{ field.name }} is not None:
-            request.{{ key }} = {{ field.name }}
-        {%- endfor %}
-        {# They can be _extended_, however -#}
-        {%- for key, field in method.flattened_fields.items() if (field.repeated and method.input.ident.package != method.ident.package) %}
-        if {{ field.name }}:
-            request.{{ key }}.extend({{ field.name }})
-        {%- endfor %}
-        {%- endif %}
+            {% if method.flattened_fields -%}
+            # If we have keyword arguments corresponding to fields on the
+            # request, apply these.
+            {% endif -%}
+            {%- for key, field in method.flattened_fields.items() if not(field.repeated and method.input.ident.package != method.ident.package) %}
+            if {{ field.name }} is not None:
+                request.{{ key }} = {{ field.name }}
+            {%- endfor %}
+            {# They can be _extended_, however -#}
+            {%- for key, field in method.flattened_fields.items() if (field.repeated and method.input.ident.package != method.ident.package) %}
+            if {{ field.name }}:
+                request.{{ key }}.extend({{ field.name }})
+            {%- endfor %}
+            {%- endif %}
 
         # Wrap the RPC method; this adds retry and timeout information,
         # and friendly error handling.

gapic/ads-templates/tests/unit/gapic/%name_%version/%sub/test_%service.py.j2

@@ -201,15 +201,15 @@ def test_{{ service.client_name|snake_case }}_client_options_from_dict():
 
 
 {% for method in service.methods.values() -%}
-def test_{{ method.name|snake_case }}(transport: str = 'grpc'):
+def test_{{ method.name|snake_case }}(transport: str = 'grpc', request_type={{ method.input.ident }}):
     client = {{ service.client_name }}(
         credentials=credentials.AnonymousCredentials(),
         transport=transport,
     )
 
     # Everything is optional in proto3 as far as the runtime is concerned,
     # and we are mocking out the actual API, so just send an empty request.
-    request = {{ method.input.ident }}()
+    request = request_type()
     {% if method.client_streaming %}
     requests = [request]
     {% endif %}
@@ -250,7 +250,7 @@ def test_{{ method.name|snake_case }}(transport: str = 'grpc'):
         {% if method.client_streaming %}
         assert next(args[0]) == request
         {% else %}
-        assert args[0] == request
+        assert args[0] == {{ method.input.ident }}()
         {% endif %}
 
     # Establish that the response is the type that we expect.
@@ -275,6 +275,11 @@ def test_{{ method.name|snake_case }}(transport: str = 'grpc'):
     {% endfor %}
     {% endif %}
 
+
+def test_{{ method.name|snake_case }}_from_dict():
+    test_{{ method.name|snake_case }}(request_type=dict)
+
+
 {% if method.field_headers and not method.client_streaming %}
 def test_{{ method.name|snake_case }}_field_headers():
     client = {{ service.client_name }}(

gapic/templates/%namespace/%name_%version/%sub/services/%service/client.py.j2

@@ -282,7 +282,8 @@ class {{ service.client_name }}(metaclass={{ service.client_name }}Meta):
         {% if method.flattened_fields -%}
         # Sanity check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
-        if request is not None and any([{{ method.flattened_fields.values()|join(', ', attribute='name') }}]):
+        has_flattened_params = any([{{ method.flattened_fields.values()|join(', ', attribute='name') }}])
+        if request is not None and has_flattened_params:
             raise ValueError('If the `request` argument is set, then none of '
                              'the individual field arguments should be set.')
 
@@ -297,24 +298,29 @@ class {{ service.client_name }}(metaclass={{ service.client_name }}Meta):
             request = {{ method.input.ident }}()
         {% endif -%}{# Cross-package req and flattened fields #}
         {%- else %}
-        request = {{ method.input.ident }}(request)
+        # Minor optimization to avoid making a copy if the user passes
+        # in a {{ method.input.ident }}.
+        # There's no risk of modifying the input as we've already verified
+        # there are no flattened fields.
+        if not isinstance(request, {{ method.input.ident }}):
+            request = {{ method.input.ident }}(request)
         {% endif %} {# different request package #}
 
-        {#- Vanilla python protobuf wrapper types cannot _set_ repeated fields #}
-        {% if method.flattened_fields -%}
-        # If we have keyword arguments corresponding to fields on the
-        # request, apply these.
-        {% endif -%}
-        {%- for key, field in method.flattened_fields.items() if not(field.repeated and method.input.ident.package != method.ident.package) %}
-        if {{ field.name }} is not None:
-            request.{{ key }} = {{ field.name }}
-        {%- endfor %}
-        {# They can be _extended_, however -#}
-        {%- for key, field in method.flattened_fields.items() if (field.repeated and method.input.ident.package != method.ident.package) %}
-        if {{ field.name }}:
-            request.{{ key }}.extend({{ field.name }})
-        {%- endfor %}
-        {%- endif %}
+            {#- Vanilla python protobuf wrapper types cannot _set_ repeated fields #}
+            {% if method.flattened_fields -%}
+            # If we have keyword arguments corresponding to fields on the
+            # request, apply these.
+            {% endif -%}
+            {%- for key, field in method.flattened_fields.items() if not(field.repeated and method.input.ident.package != method.ident.package) %}
+            if {{ field.name }} is not None:
+                request.{{ key }} = {{ field.name }}
+            {%- endfor %}
+            {# They can be _extended_, however -#}
+            {%- for key, field in method.flattened_fields.items() if (field.repeated and method.input.ident.package != method.ident.package) %}
+            if {{ field.name }}:
+                request.{{ key }}.extend({{ field.name }})
+            {%- endfor %}
+            {%- endif %}
 
         # Wrap the RPC method; this adds retry and timeout information,
         # and friendly error handling.

gapic/templates/tests/unit/gapic/%name_%version/%sub/test_%service.py.j2

@@ -299,15 +299,15 @@ def test_{{ service.client_name|snake_case }}_client_options_from_dict():
 
 
 {% for method in service.methods.values() -%}
-def test_{{ method.name|snake_case }}(transport: str = 'grpc'):
+def test_{{ method.name|snake_case }}(transport: str = 'grpc', request_type={{ method.input.ident }}):
     client = {{ service.client_name }}(
         credentials=credentials.AnonymousCredentials(),
         transport=transport,
     )
 
     # Everything is optional in proto3 as far as the runtime is concerned,
     # and we are mocking out the actual API, so just send an empty request.
-    request = {{ method.input.ident }}()
+    request = request_type()
     {% if method.client_streaming %}
     requests = [request]
     {% endif %}
@@ -348,7 +348,7 @@ def test_{{ method.name|snake_case }}(transport: str = 'grpc'):
         {% if method.client_streaming %}
         assert next(args[0]) == request
         {% else %}
-        assert args[0] == request
+        assert args[0] == {{ method.input.ident }}()
         {% endif %}
 
     # Establish that the response is the type that we expect.
@@ -374,6 +374,10 @@ def test_{{ method.name|snake_case }}(transport: str = 'grpc'):
     {% endif %}
 
 
+def test_{{ method.name|snake_case }}_from_dict():
+    test_{{ method.name|snake_case }}(request_type=dict)
+
+
 @pytest.mark.asyncio
 async def test_{{ method.name|snake_case }}_async(transport: str = 'grpc_asyncio'):
     client = {{ service.async_client_name }}(