Alex Hong

This commit prepares for the **release of `pubsub` module version `v1.50.2`** within the `google-cloud-go` repository. It performs **maintenance updates** by incrementing the version number in `.librarian/state.yaml` and `pubsub/internal/version.go`. This release specifically incorporates a **bug fix** that addresses nil concurrency control spans, improving the robustness of the **`pubsub` client library**. Merging this pull request will trigger the official release process for the **`pubsub` client library**, making the `v1.50.2` version available.

This commit **releases version 2.5.1 of the `pubsub/v2` client library**, primarily to **address a critical bug fix** in the **Google Cloud Pub/Sub client**. The update resolves a potential `nil` span panic within the `Subscriber.Receive` method, significantly enhancing the stability of message consumption. This **maintenance release** updates the internal version constant in `pubsub/v2/internal/version.go` and the librarian state, ensuring users receive a more robust and reliable client library.

This commit delivers a crucial **bug fix** to the **Pub/Sub** client library, specifically addressing an issue within the `pubsub/subscription.go` file. It introduces a **nil check** for the concurrency control span within the `Receive` method, preventing potential panics that could arise if the span was unexpectedly null before being ended. This enhancement significantly improves the **stability** and **robustness** of message reception, safeguarding applications from crashes related to concurrency control.

This commit **updates the golden test data** for the **`internal/godocfx` tool**, specifically affecting the expected documentation output for the `cloud.google.com/go/storage` package. This **test maintenance** task adjusts the `internal/godocfx/testdata/golden/cloud.google.com/go/storage@v1.33.0/index.yml` file. The update reflects a change in the **HTML link format** for `Query.StartOffset` and `Query.EndOffset` within the generated documentation. This ensures the `godocfx` tool's tests remain accurate and consistent with the current expected output for these specific elements, validating the documentation generation process.

This commit **adjusts test limits** within the **Pub/Sub client library's flow controller tests** to ensure compatibility with 32-bit systems. It **reduces the byte acquisition limit** from 4GB to 2GB in the `TestFlowControllerUnboundedBytes` test cases found in both `pubsub/flow_controller_test.go` and `pubsub/v2/flow_controller_test.go`. This is a **test maintenance** change that prevents test failures on architectures where 4GB would overflow an `int32`. The adjustment retains the test's intent while broadening its execution environment, without altering the underlying `flow_controller`'s functional behavior.

This commit performs a **maintenance chore** by **configuring Renovate** to exclude the `go.einride.tech/aip` package from its automated dependency update process. Specifically, it modifies `.github/renovate.json` to add this package to the `disabled matchPackagePatterns`. This change affects the **dependency management automation**, preventing Renovate from proposing updates for a dependency that is slated for future removal. This streamlines development efforts and aligns with the project's deprecation plans for the `go.einride.tech` dependency.

This commit **initializes the release process** for the **`auth` library**, updating its version from `v0.18.2` to `v0.19.0`. This **maintenance chore**, orchestrated by the Librarian CLI, prepares for the official release of new **OpenTelemetry gRPC and HTTP wrappers for T4 tracing** within the `auth` module. The changes include updating the internal `Version` constant in `auth/internal/version.go` and modifying the `.librarian/state.yaml` configuration. Merging this pull request will **automatically trigger the release** of the `auth` module, making these new tracing capabilities available to consumers.

This commit provides a **bug fix** to the **`godocfx` internal tool** by making the `friendlyAPIName` function more tolerant of missing package metadata. It **reverts `friendlyAPIName` to its prior behavior** of returning an empty string instead of an error when a package's description or metadata is not found, as implemented in **`internal/godocfx/parse.go`**. This change is crucial for preventing build and test failures for packages like `alloydbconn` and `cloudqlconn`, which do not have `repo-metadata.json` files, and also resolves issues with `auth` library generation. The **`internal/godocfx/godocfx_test.go`** file is updated to reflect this new tolerance, ensuring the tool can process packages without complete metadata without erroring out.

This commit **releases version `v2.5.0`** of the **Google Cloud Pub/Sub Go client library** (`pubsub/v2`), a **feature update** that introduces several new capabilities. Key enhancements include the addition of a `BigtableConfig` type, the introduction of per-stream flow control, and support for keep-alive mechanisms. This release process, orchestrated by the Librarian CLI, updates internal versioning in files like `.librarian/state.yaml` and `pubsub/v2/internal/version.go`. Merging this pull request will trigger the official release, making these new features available to users of the `pubsub/v2` module.

This commit **fixes a race condition** in the **Pub/Sub v2 client library's message iterator** that could occur during stream shutdown. Previously, concurrent access to the `serverTimeout` value, particularly when `pingStream` and `checkServer` ran as goroutines, led to instability in the keep-alive mechanism. The **bug fix** introduces a dedicated `serverTimeout` field to the `messageIterator` struct, which is initialized once in `newMessageIterator` and then accessed synchronously by `checkServer`. This change significantly improves the **stability and reliability** of Pub/Sub message consumption by preventing unexpected stream terminations.

This commit implements a **new stream keep-alive mechanism** for the **`pubsub/v2` client library's streaming pull**, significantly enhancing connection **robustness and reliability**. A dedicated background goroutine now monitors for periodic pings from the server and manages client-side ping sending, ensuring that inactive or broken streams are automatically detected and re-established. This **new feature** prevents silent connection failures, improving message delivery guarantees for long-lived streaming pull operations. The `iterator` and `pullstream` components are updated to support this, and the `pstest` fake server now handles the new protocol version.

This commit performs a **maintenance update** within the **dependency management system**. Specifically, it updates the `last_generated_commit` hash for the `auditmanager` library in the `.librarian/state.yaml` configuration file. This **chore** ensures that the `librarian` tool correctly tracks the current state or version of the `auditmanager` dependency, reflecting a routine update to its configuration. The change is purely administrative, with no functional code modifications, primarily affecting the **build and dependency management infrastructure**.

This commit **fixes** an issue with the **Audit Manager API's Go proto code generation**, which incorrectly placed `*.pb.go` files in `apiv1main/`. It **refactors** the build process to correctly generate these files within the `auditmanager/apiv1/` directory. This is a **breaking change** that necessitates updating import paths in the **Audit Manager Go client**, auxiliary functions, tests, and generated snippets to reflect the new, correct location of the proto definitions. The `librarian` configuration is also updated to reflect this change, ensuring proper library management.

This commit performs a **maintenance chore** by adding **repository metadata** for the **Pub/Sub API v2** veneer. A new `.repo-metadata.json` file is introduced within the `pubsub/v2` directory, specifying essential details such as the shortname, documentation links, and library type for the v2 client. This metadata improves the discoverability and integration of the Pub/Sub v2 library within the project's ecosystem, without altering its functional behavior or introducing new features.

This commit **fixes** a metadata discovery issue within the **`internal/godocfx` tool**, specifically for packages where `.repo-metadata.json` files are located in subdirectories. The `friendlyAPIName` function in `parse.go` was updated to recursively search subdirectories, ensuring that **API documentation generation** correctly identifies metadata for client libraries like `cloud.google.com/go/translate`. This **bug fix** prevents failures during documentation processing for nested package structures and is validated by new test cases in `godocfx_test.go`.

This commit **refactors** the `internal/godocfx` tool to adapt its API metadata resolution process. It now supports a new, decentralized metadata structure by reading API descriptions from individual `.repo-metadata.json` files located within package directories, rather than a single centralized file. The update introduces a new search mechanism in `parse.go` that traverses upwards from package directories, includes caching, and provides a **fallback mechanism** for older module versions, ensuring correct API naming and improved symbol linking in generated documentation. This **enhancement** also includes **test updates** to reflect these changes and removes hardcoded remote metadata URLs from `main.go`.

This commit **updates the deprecation timeline** for the **`cloud.google.com/go/pubsub` v1 module**, extending its end-of-support date to December 31st, 2026. It **enhances the visibility of this deprecation notice** by adding it to the module-level documentation in `pubsub/doc.go` and updating the `pubsub/MIGRATING.md` guide. This **maintenance update** provides users with a longer migration window to `pubsub/v2` and ensures the deprecation is clearly communicated across more official channels.

This commit introduces a **new client library** for the **Audit Manager API**, specifically within the `auditmanager/apiv1` module. It provides a comprehensive **new capability** for developers to programmatically interact with the Audit Manager service, offering methods for **resource enrollment**, **audit report generation**, and **status retrieval**. The addition includes the core client (`audit_manager_client.go`), auxiliary types for long-running operations and iterators, and extensive documentation. This significantly expands the project's integration capabilities by providing a dedicated Go client for the Audit Manager service, complete with example usage snippets.

This commit introduces a **new capability** for **per-stream flow control** within the **Cloud Pub/Sub client library (v2)**. It enhances the `pubsub/v2/subscriber.go` module by adding an `EnablePerStreamFlowControl` field to `ReceiveSettings`, allowing the `Receive` function to apply flow control either globally or on a per-stream basis. This addresses a critical limitation where client-wide flow control could cause messages to be pulled but not processed efficiently across multiple concurrent streams, potentially leading to message timeouts. Users can now enable this setting to significantly improve message delivery and throughput when utilizing `ReceiveSettings.NumGoroutines` for multiple streams, with new tests in `pubsub/v2/subscriber_test.go` validating this behavior.

This commit implements a **Renovate configuration change** to **disable major version upgrades** for the **`cloud.google.com/go/pubsub`** client library. This **maintenance chore** specifically prevents the automatic update from `pubsub` v1 to v2, overriding a previous proposal to upgrade. By modifying `.github/renovate.json`, the project temporarily avoids potential breaking changes or migration efforts associated with the `pubsub` v2 release. This ensures continued stability for the **`pubsub` integration** by keeping it on its current major version.