rahul2393

This commit is a **maintenance** task to prepare for the **release of the `spanner` client library to version v1.89.0**. Initiated by the Librarian CLI, it updates the version metadata across various `spanner` related files, including `spanner/internal/version.go` and generated snippet metadata. The new `spanner` version introduces several **new features**, such as E2E fallback, cache updates, routing hints, and gRPC A66/A94 metrics, alongside **bug fixes** for session management and transaction rollback. Merging this pull request will automatically trigger the official release, making these enhancements and fixes available to users of the **`spanner` module**.

This commit introduces **key-aware routing hints** for `BeginTransaction` and `Commit` requests within the **Spanner client library**, significantly enhancing its `location-aware routing` capabilities. This **new capability** populates `RoutingHint` based on mutation keys for both `BeginTransaction` and `Commit` operations, while also enabling the client to consume and apply **cache updates** from `Transaction` and `CommitResponse` objects. The changes, primarily in `spanner/channel_finder.go`, `spanner/key_recipe_cache.go`, and `spanner/location_router.go`, ensure more intelligent request distribution and proper endpoint authority preservation, ultimately leading to **improved performance and data consistency** for mutation-heavy workloads.

This commit **fixes a critical deadlock** in the **Cloud Spanner client library's session management** by **reworking the multiplexed session initialization logic**. It replaces the previous unbuffered channel request loop, which was susceptible to deadlocks when a cancelled read-only transaction waiter blocked session creation, with a **shared in-flight creation record**. This **refactoring** ensures that concurrent session requests are coordinated through a single background creation process, improving **cancellation handling** and allowing `Client.Close` to properly unblock waiting requests. The change, primarily affecting `spanner/session.go`, includes new test coverage in `spanner/session_test.go` to validate the improved robustness against concurrent cancellations and client shutdowns.

This commit **fixes a panic** in the **Spanner client library's** `ReadWriteTransaction.rollback` function. Previously, if a statement-based transaction commit was aborted and its session handle (`t.sh`) was cleared, a subsequent rollback attempt could dereference a nil handle, leading to a panic. The change introduces a **nil check for the session handle** within `rollback` and returns early if it's already cleared, effectively making rollback a no-op in such scenarios. This **enhances the robustness** of Spanner transaction error handling by preventing crashes during specific retry and cleanup paths.

This commit introduces **location-aware routing** for **Spanner RPCs**, significantly enhancing performance and resource utilization by directing requests to optimal server endpoints. It implements a new `locationAwareSpannerClient` wrapper that intercepts RPCs and routes them using an `endpointClientCache` for efficient gRPC connection management. A crucial **new capability** is the **transaction affinity tracking**, which ensures `Commit` and `Rollback` operations are directed to the same server that handled the transaction, while read-only transactions are routed independently per-request. This involves a substantial **refactoring** of the `spanner` client library, centralizing routing logic and request preparation within the new client wrapper, thereby improving the overall architecture and maintainability.

This commit performs **release preparation** for the **`google-cloud-spanner` client library**, advancing it to version `3.63.0`. This **maintenance** update incorporates a **new feature** that adds request ID information to error exceptions and a **bug fix** preventing thread leaks through improved singleton initialization. It updates version strings across the `spanner_admin_database_v1`, `spanner_admin_instance_v1`, `spanner_dbapi`, and `spanner_v1` modules, along with associated snippet metadata. Merging this pull request will trigger the official release, delivering these enhancements and stability improvements to users of the `google-cloud-spanner` library.

This commit performs a **release update** for the **Cloud Spanner client library**, bumping the `spanner` module from version 1.87.0 to **1.88.0**. This **maintenance** release introduces several **new features**, including support for sending and acknowledging Spanner mutations, additions to `ClientContext`, and `PGNumeric` improvements. It also incorporates **bug fixes** such as improved JSONB array decoding and **performance enhancements** related to session management. This update significantly enhances the functionality, stability, and efficiency of the **Cloud Spanner** client within the `google-cloud-go` project.

This commit introduces a **new capability** to the **`google-cloud-spanner` client library** by augmenting error exceptions with request ID information. It integrates a mechanism to attach a unique `request_id` to `GoogleAPICallError` instances, significantly **enhancing observability and debugging**. This functionality is woven into critical operations across various modules, including `batch`, `database`, `pool`, `session`, `snapshot`, and `transaction` management. The change allows users to easily trace failed operations back to server-side logs, thereby improving the **diagnosability** of issues within the Spanner client.

This commit performs the necessary **release preparation** for **`google-cloud-spanner` version 3.62.0**, updating all internal version identifiers across the library. It specifically bumps the version string in `gapic_version.py` files for `spanner_admin_database_v1`, `spanner_admin_instance_v1`, and `spanner_v1`, as well as the `spanner_dbapi` module. This **maintenance** task also updates snippet metadata and the Librarian state file, enabling the official distribution of new features like **UUID support** and critical **bug fixes** related to transaction tags, dependency resolution, and stream restart handling.

This commit performs a **release update** for the **Cloud Spanner client library** in `google-cloud-go`, bumping its version from 1.86.1 to 1.87.0. This **maintenance** release introduces **new features** including `Send` and `Ack` mutations for Queues, exposure of `AutoscalingConfig` in `InstancePartition`, a Spanner location API, and improved SQL formatting. It also incorporates several **bug fixes**, addressing issues like goroutine leaks, incorrect value mapping in `SelectAll`, and transaction handling. This update ensures users of the `spanner` module benefit from enhanced functionality and increased stability.

This commit prepares for the **release of `google-cloud-spanner` version `3.60.0`**, representing a **minor version upgrade** that bundles numerous **new features** and **bug fixes**. Notable additions include enabling **OpenTelemetry metrics and tracing by default**, exposing `AutoscalingConfig` in `InstancePartition`, and introducing `QueryAdvisorResult` for query plans, along with new Spanner location and queue mutation APIs. The update also addresses issues such as configuring gRPC TCP `keepAlive` times and deprecating the `credentials_file` argument, while providing an option to disable metrics. This **release preparation** ensures that users of the `google-cloud-spanner` library will benefit from enhanced observability, new Spanner capabilities, and improved stability. Merging this pull request will trigger the automated release of the updated library.

This commit delivers a **bug fix** for the **Cloud Spanner client library**, specifically addressing an issue within the `SelectAll` function. It refactors the decoding logic to correctly map Spanner row columns to Go struct fields, ensuring values are assigned accurately even when column order differs or when using embedded structs and `spanner` tags. This resolves a critical data mapping problem, preventing incorrect value assignments for users of the `spanner` module who deserialize Spanner rows into Go structs. New test cases have been added to validate this corrected behavior and prevent regressions.

This commit introduces a **bug fix** by configuring a **120-second keep-alive time** for **gRPC TCP connections** across the **`google-cloud-spanner` client library**. This crucial change impacts the **`database_admin`**, **`instance_admin`**, and **`spanner`** services, ensuring more stable and persistent connections for both synchronous and asynchronous gRPC transports. The primary goal is to **prevent premature connection termination** and enhance the reliability of long-running operations with Google Cloud Spanner. Additionally, the commit includes necessary **test updates** to validate the new configuration and a **maintenance update** to the `owlbot.py` script to automate this setting. A separate **flaky test fix** for `test_session.py` is also incorporated to improve test suite stability.

This commit performs **test maintenance** for the **Spanner client library**, specifically within its transaction test suite. It **increases the context timeout** from 5ms to 50ms in `spanner/transaction_test.go` for a read-write transaction test. This adjustment ensures that the `executeSql` operation within the test has adequate time to complete, preventing premature cancellation and resolving potential **test flakiness**. The change is isolated to the **test environment** and does not impact the runtime behavior or performance of the Spanner client.

This commit introduces a **new capability** to the **Spanner client library**, enabling the parsing and handling of a `spanner:"->"` struct tag. This tag allows users to explicitly mark Go struct fields as read-only, ensuring they are automatically excluded from write mutations. The `spannerTagParser` now correctly identifies these fields, and the `structToMutationParams` function prevents their inclusion in generated mutations, enhancing data integrity. This feature simplifies application development by preventing accidental modification of server-generated or immutable columns, directly addressing issue #8933.

This commit **disables** the `afe_connectivity_error_count` metric within the **Spanner client library**. It achieves this by modifying the `recordAFEError` function in `spanner/metrics.go` to be a no-op, effectively halting its execution and preventing metric increments. This **maintenance fix** addresses an issue or removes an unnecessary metric from the **metrics collection subsystem**, ensuring that the client library no longer reports AFE connectivity errors. Consequently, downstream monitoring systems will cease to receive data for the `afe_connectivity_error_count` counter.

This commit performs a **maintenance update** by **removing support for Python 3.7 and 3.8** across the `google-cloud-spanner` library. It updates **CI/CD workflows**, **documentation**, and **testing configurations** to reflect Python 3.9 as the new minimum supported runtime. Specifically, `presubmit.yaml` and `noxfile.py` are adjusted to remove older Python versions from test matrices, while `CONTRIBUTING.rst` and `README.rst` are updated to guide developers and users accordingly. This change ensures the project aligns with current Python ecosystem standards and focuses development on newer runtime versions.

This commit delivers a **performance improvement** to the **Spanner client library** by **refactoring** the `mutationsProto` function. The changes optimize the internal mutation selection logic, resulting in **reduced memory allocations** and **faster processing** of mutations. A new benchmark, `BenchmarkMutationsProto`, was introduced to validate these performance gains, ensuring a more efficient and resource-friendly experience for users interacting with Spanner.

chore(spanner): release 1.84.1 (#12665)

feat(spanner): release 1.84.1 (#12663)