feat: add generation config comparator (#2587)

In this PR:
- Add a generation config comparator to compare the change type and
which libraries are affected by the change.
- Refactor `LibraryConfig`.
- Add unit tests (no integration tests because the comparator has not
been used).

The comparator makes assumptions that the following library level
parameters will not change:
- googleapis commit (no use case)

This is the first step to
[improve](https://docs.google.com/document/d/1JiCcG3X7lnxaJErKe0ES_JkyU7ECb40nf2Xez3gWvuo/edit?tab=t.g3vua2kd06gx#heading=h.pygigzqg78jp)
performance of hermetic code generation.

library_generation/model/library_config.py

@@ -12,6 +12,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+from hashlib import sha1
 
 from typing import List, Optional
 from library_generation.model.gapic_config import GapicConfig
@@ -71,3 +72,70 @@ def __init__(
         self.cloud_api = cloud_api
         self.requires_billing = requires_billing
         self.extra_versioned_modules = extra_versioned_modules
+
+    def get_library_name(self) -> str:
+        """
+        Return the library name of a given LibraryConfig object
+        :return: the library name
+        """
+        return self.library_name if self.library_name else self.api_shortname
+
+    def __eq__(self, other):
+        return (
+            self.api_shortname == other.api_shortname
+            and self.api_description == other.api_description
+            and self.name_pretty == other.name_pretty
+            and self.product_documentation == other.product_documentation
+            and self.gapic_configs == other.gapic_configs
+            and self.library_type == other.library_type
+            and self.release_level == other.release_level
+            and self.api_id == other.api_id
+            and self.api_reference == other.api_reference
+            and self.codeowner_team == other.codeowner_team
+            and self.excluded_dependencies == other.excluded_dependencies
+            and self.excluded_poms == other.excluded_poms
+            and self.client_documentation == other.client_documentation
+            and self.distribution_name == other.distribution_name
+            and self.googleapis_commitish == other.googleapis_commitish
+            and self.group_id == other.group_id
+            and self.issue_tracker == other.issue_tracker
+            and self.library_name == other.library_name
+            and self.rest_documentation == other.rest_documentation
+            and self.rpc_documentation == other.rpc_documentation
+            and self.cloud_api == other.cloud_api
+            and self.requires_billing == other.requires_billing
+            and self.extra_versioned_modules == other.extra_versioned_modules
+        )
+
+    def __hash__(self):
+        m = sha1()
+        m.update(
+            str(
+                [
+                    self.api_shortname,
+                    self.api_description,
+                    self.name_pretty,
+                    self.product_documentation,
+                    self.library_type,
+                    self.release_level,
+                    self.api_id,
+                    self.api_reference,
+                    self.codeowner_team,
+                    self.excluded_dependencies,
+                    self.excluded_poms,
+                    self.client_documentation,
+                    self.distribution_name,
+                    self.googleapis_commitish,
+                    self.group_id,
+                    self.issue_tracker,
+                    self.library_name,
+                    self.rest_documentation,
+                    self.rpc_documentation,
+                    self.cloud_api,
+                    self.requires_billing,
+                    self.extra_versioned_modules,
+                ]
+                + [config.proto_path for config in self.gapic_configs]
+            ).encode("utf-8")
+        )
+        return int(m.hexdigest(), 16)

library_generation/test/integration_tests.py

@@ -29,7 +29,6 @@
 from library_generation.model.generation_config import from_yaml, GenerationConfig
 from library_generation.test.compare_poms import compare_xml
 from library_generation.utilities import (
-    get_library_name,
     sh_util as shell_call,
     run_process_and_print_output,
 )
@@ -214,7 +213,7 @@ def __pull_repo_to(cls, default_dest: Path, repo: str, committish: str) -> str:
     def __get_library_names_from_config(cls, config: GenerationConfig) -> List[str]:
         library_names = []
         for library in config.libraries:
-            library_names.append(f"java-{get_library_name(library)}")
+            library_names.append(f"java-{library.get_library_name()}")
 
         return library_names
 
@@ -248,21 +247,22 @@ def __load_json_to_sorted_list(cls, path: str) -> List[tuple]:
 
     @classmethod
     def __recursive_diff_files(
-        self,
+        cls,
         dcmp: dircmp,
         diff_files: List[str],
         left_only: List[str],
         right_only: List[str],
         dirname: str = "",
     ):
         """
-        recursively compares two subdirectories. The found differences are passed to three expected list references
+        Recursively compares two subdirectories. The found differences are
+        passed to three expected list references.
         """
         append_dirname = lambda d: dirname + d
         diff_files.extend(map(append_dirname, dcmp.diff_files))
         left_only.extend(map(append_dirname, dcmp.left_only))
         right_only.extend(map(append_dirname, dcmp.right_only))
         for sub_dirname, sub_dcmp in dcmp.subdirs.items():
-            self.__recursive_diff_files(
+            cls.__recursive_diff_files(
                 sub_dcmp, diff_files, left_only, right_only, dirname + sub_dirname + "/"
             )

library_generation/test/model/library_config_unit_tests.py

@@ -0,0 +1,39 @@
+# Copyright 2024 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import unittest
+
+from library_generation.model.library_config import LibraryConfig
+
+
+class LibraryConfigTest(unittest.TestCase):
+    def test_get_library_returns_library_name(self):
+        library = LibraryConfig(
+            api_shortname="secret",
+            name_pretty="",
+            product_documentation="",
+            api_description="",
+            gapic_configs=list(),
+            library_name="secretmanager",
+        )
+        self.assertEqual("secretmanager", library.get_library_name())
+
+    def test_get_library_returns_api_shortname(self):
+        library = LibraryConfig(
+            api_shortname="secret",
+            name_pretty="",
+            product_documentation="",
+            api_description="",
+            gapic_configs=list(),
+        )
+        self.assertEqual("secret", library.get_library_name())

library_generation/test/utilities_unit_tests.py

@@ -391,12 +391,6 @@ def test_remove_version_from_returns_self(self):
             "google/cloud/aiplatform", util.remove_version_from(proto_path)
         )
 
-    def test_get_library_returns_library_name(self):
-        self.assertEqual("bare-metal-solution", util.get_library_name(library_1))
-
-    def test_get_library_returns_api_shortname(self):
-        self.assertEqual("secretmanager", util.get_library_name(library_2))
-
     def test_generate_prerequisite_files_non_monorepo_success(self):
         library_path = self.__setup_prerequisite_files(
             num_libraries=1, library_type="GAPIC_COMBO"