chore(generator): centralize mypy configuration and regenerate google-cloud-datastore POC (#17408)

> [!note]
> This is step one of a multi-step process. The work done here is
outlined below.
Additional steps (to be completed in other PRs) include:
> * generate the remaining **generated packages**
> * generate and/or post process **hybrid packages**

This work:
* Adds a centralized `mypy.ini` file at the root of the repository.
* Updates GAPIC generator templates to omit local `mypy.ini` and
dynamically resolve the root config via a `MYPY_CONFIG_FILE` constant.
* Removes `mypy.ini` replacements from `datastore-integration.yaml`
post-processing.
* Regenerates `google-cloud-datastore` using the updated generator
configurations to serve as a proof of concept.

> [!note]
> Work on strictly handwritten libraries is outside the scope of this PR
and can be found here:
#17409

Author: chalmerlowe

.librarian/generator-input/client-post-processing/datastore-integration.yaml

@@ -39,42 +39,6 @@ replacements:
           "google-cloud-core >= 2.0.0, <3.0.0",
           "grpcio >= 1.59.0, < 2.0.0",
     count: 1
-  - paths: [
-      "packages/google-cloud-datastore/mypy.ini",
-    ]
-    before: |-
-      # Performance: reuse results from previous runs to speed up 'nox'
-      incremental = True
-    after: |-
-      # Performance: reuse results from previous runs to speed up "nox"
-      incremental = True
-
-      [mypy-google.cloud.datastore._app_engine_key_pb2]
-      ignore_errors = True
-
-      # TODO(https://github.com/googleapis/gapic-generator-python/issues/2410):
-      # Remove once this generator bug is fixed
-      [mypy-google.cloud.datastore_v1.services.datastore.async_client]
-      ignore_errors = True
-
-      # TODO(https://github.com/googleapis/gapic-generator-python/issues/2410):
-      # Remove once this generator bug is fixed
-      [mypy-google.cloud.datastore_v1.services.datastore.client]
-      ignore_errors = True
-    count: 1
-  - paths: [
-      "packages/google-cloud-datastore/mypy.ini",
-    ]
-    before: |
-      ignore_missing_imports = False
-
-      # TODO\(https://github.com/googleapis/gapic-generator-python/issues/2563\):
-      # Dependencies that historically lacks py.typed markers
-      \[mypy-google\.iam\.\*\]
-      ignore_missing_imports = True
-    after: |
-      ignore_missing_imports = True
-    count: 1
   - paths: [
       "packages/google-cloud-datastore/docs/index.rst",
     ]

mypy.ini

@@ -9,77 +9,94 @@ explicit_package_bases = True
 incremental = True
 
 exclude = (?x)(
-    ^third_party/
-  | tests/unit/resources/
-  | tests/unit/gapic/
+    (^|/)third_party/
+  | (^|/)tests/unit/resources/
+  | (^|/)tests/unit/gapic/
   )
 
-# TODO(https://github.com/googleapis/gapic-generator-python/issues/2563):
-# Dependencies that historically lacks py.typed markers
-[mypy-google.iam.*]
-ignore_missing_imports = True
-
-[mypy-google.type.*]
-ignore_missing_imports = True
-
 
 # ==============================================================================
-# PACKAGE-SPECIFIC OVERRIDES
+# GLOBAL THIRD-PARTY & SHARED LIBRARY IGNORES
 # ==============================================================================
 
-# --- google-cloud-core ---
-[mypy-google.protobuf.*]
+[mypy-anywidget]
 ignore_missing_imports = True
 
-# --- bigframes ---
 [mypy-cloudpickle.*]
 ignore_missing_imports = True
+
 [mypy-flask]
 ignore_missing_imports = True
-[mypy-pydata_google_auth]
-ignore_missing_imports = True
-[mypy-google.colab]
+
+[mypy-google.auth.*]
 ignore_missing_imports = True
-[mypy-pytz]
+
+[mypy-google.cloud.bigtable]
 ignore_missing_imports = True
-[mypy-pyarrow.*]
+
+[mypy-google.cloud.pubsub]
 ignore_missing_imports = True
-[mypy-ibis.*]
+
+[mypy-google.colab]
 ignore_missing_imports = True
-[mypy-ipywidgets]
+
+[mypy-google.iam.*]
 ignore_missing_imports = True
-[mypy-google.cloud.pubsub]
+
+[mypy-google.longrunning.*]
 ignore_missing_imports = True
-[mypy-google.cloud.bigtable]
+
+[mypy-google.oauth2.*]
 ignore_missing_imports = True
-[mypy-anywidget]
+
+[mypy-google.protobuf.*]
 ignore_missing_imports = True
 
-# --- google-cloud-bigtable ---
-[mypy-google.cloud.bigtable.*]
-check_untyped_defs = True
-warn_unreachable = True
-disallow_any_generics = True
-ignore_errors = True
+[mypy-google.rpc.*]
+ignore_missing_imports = True
 
-[mypy-google.cloud.bigtable.data.*]
-ignore_errors = False
+[mypy-google.type.*]
+ignore_missing_imports = True
 
 [mypy-grpc.*]
 ignore_missing_imports = True
-[mypy-google.auth.*]
+
+[mypy-ibis.*]
 ignore_missing_imports = True
-[mypy-google.longrunning.*]
+
+[mypy-ipywidgets]
 ignore_missing_imports = True
-[mypy-google.oauth2.*]
+
+[mypy-proto.*]
 ignore_missing_imports = True
-[mypy-google.rpc.*]
+
+[mypy-pyarrow.*]
 ignore_missing_imports = True
-[mypy-proto.*]
+
+[mypy-pydata_google_auth]
 ignore_missing_imports = True
+
 [mypy-pytest]
 ignore_missing_imports = True
 
+[mypy-pytz]
+ignore_missing_imports = True
+
+
+# ==============================================================================
+# PACKAGE-SPECIFIC OVERRIDES & EXCEPTIONS
+# ==============================================================================
+
+# --- google-cloud-bigtable ---
+[mypy-google.cloud.bigtable.*]
+ignore_errors = True
+
+[mypy-google.cloud.bigtable.data.*]
+check_untyped_defs = True
+warn_unreachable = True
+disallow_any_generics = True
+ignore_errors = False
+
 # --- google-cloud-datastore ---
 [mypy-google.cloud.datastore._app_engine_key_pb2]
 ignore_errors = True

packages/gapic-generator/gapic/ads-templates/mypy.ini.j2

@@ -3,10 +3,16 @@
 {% block content %}
 
 import os
+import pathlib
 
 import nox  # type: ignore
 
 
+CURRENT_DIRECTORY = pathlib.Path(__file__).parent.absolute()
+# Path to the centralized mypy configuration file at the repository root.
+MYPY_CONFIG_FILE = str(CURRENT_DIRECTORY.parent.parent / "mypy.ini")
+
+
 # TODO(https://github.com/googleapis/gapic-generator-python/issues/2450):
 # Add tests for Python 3.15 alpha1
 # https://peps.python.org/pep-0790/
@@ -44,6 +50,7 @@ def mypy(session):
     session.install('.')
     session.run(
         'mypy',
+        f"--config-file={MYPY_CONFIG_FILE}",
         {% if api.naming.module_namespace %}
         '{{ api.naming.module_namespace[0] }}',
         {% else %}

packages/gapic-generator/gapic/ads-templates/noxfile.py.j2

@@ -40,6 +40,8 @@ DEFAULT_PYTHON_VERSION = "3.14"
 PREVIEW_PYTHON_VERSION = "3.14"
 
 CURRENT_DIRECTORY = pathlib.Path(__file__).parent.absolute()
+# Path to the centralized mypy configuration file at the repository root.
+MYPY_CONFIG_FILE = str(CURRENT_DIRECTORY.parent.parent / "mypy.ini")
 
 if (CURRENT_DIRECTORY / "testing").exists():
     LOWER_BOUND_CONSTRAINTS_FILE = (
@@ -101,6 +103,7 @@ def mypy(session):
     session.install(".")
     session.run(
         "mypy",
+        f"--config-file={MYPY_CONFIG_FILE}",
         "-p",
         {% if api.naming.module_namespace %}
         "{{ api.naming.module_namespace[0] }}",

packages/gapic-generator/gapic/templates/mypy.ini.j2

@@ -47,6 +47,8 @@
 PREVIEW_PYTHON_VERSION = "3.14"
 
 CURRENT_DIRECTORY = pathlib.Path(__file__).parent.absolute()
+# Path to the centralized mypy configuration file at the repository root.
+MYPY_CONFIG_FILE = str(CURRENT_DIRECTORY.parent.parent / "mypy.ini")
 
 if (CURRENT_DIRECTORY / "testing").exists():
     LOWER_BOUND_CONSTRAINTS_FILE = (
@@ -108,6 +110,7 @@ def mypy(session):
     session.install(".")
     session.run(
         "mypy",
+        f"--config-file={MYPY_CONFIG_FILE}",
         "-p",
         "google",
         "--check-untyped-defs",

packages/gapic-generator/gapic/templates/noxfile.py.j2

@@ -47,6 +47,8 @@
 PREVIEW_PYTHON_VERSION = "3.14"
 
 CURRENT_DIRECTORY = pathlib.Path(__file__).parent.absolute()
+# Path to the centralized mypy configuration file at the repository root.
+MYPY_CONFIG_FILE = str(CURRENT_DIRECTORY.parent.parent / "mypy.ini")
 
 if (CURRENT_DIRECTORY / "testing").exists():
     LOWER_BOUND_CONSTRAINTS_FILE = (
@@ -108,6 +110,7 @@ def mypy(session):
     session.install(".")
     session.run(
         "mypy",
+        f"--config-file={MYPY_CONFIG_FILE}",
         "-p",
         "google",
         "--check-untyped-defs",