ohmayr

This commit implements a **temporary bypass for C-extension tests** within the **Kokoro presubmit pipeline** for the `google-crc32c` package. It updates the presubmit configurations for Linux, OSX, and Windows to execute dummy `bypass.sh` or `bypass.bat` scripts, which generate placeholder XML test logs instead of running the actual C-extension test suites. This **chore** effectively disables these specific tests during presubmit checks, likely to address a temporary issue or speed up CI. The change impacts the **CI/CD validation process**, ensuring presubmits can complete without running the `google-crc32c` C-extension tests.

Merge branch 'main' into migration.gapic-generator-python.migration.2026-03-26_09-14-27.migrate

Trigger CI

This commit performs **maintenance** on the **`gapic-generator` CI/CD pipeline** by updating its **GitHub Actions workflow**. Specifically, it modifies `.github/workflows/gapic-generator-tests.yml` to change the Nox session used for running **integration tests** from `core_prerelease_deps` to `core_deps_from_source`. This **presubmit fix** ensures that the `gapic-generator`'s integration tests execute with the correct and intended dependency configuration, improving the reliability of automated checks. The change primarily affects the **developer workflow** and **test stability** for the `gapic-generator` project.

This commit **fixes** issues preventing the correct execution of **prerelease golden tests** within the continuous integration pipeline. It updates the `.github/workflows/gapic-generator-tests.yml` workflow to include a necessary step for installing the `pandoc` system dependency. Additionally, the `nox` command arguments are adjusted to ensure these critical tests run as expected. This **maintenance** work improves the reliability of the **CI pipeline** by ensuring that prerelease versions of the `gapic-generator` are properly validated.

This commit **removes the Owlbot staging process** from the project's build and release pipeline. It discontinues the temporary environment or steps previously used by Owlbot for pre-release validation of generated client libraries. This is a **maintenance** task, likely simplifying the **CI/CD workflow** or transitioning to an updated release strategy. The change primarily impacts internal **development and release automation**, with no direct effect on the functionality or behavior of the client libraries themselves.

This commit performs a **maintenance chore** by refining the **CI workflow** for `gapic-generator-tests`. It **removes unused Python version environment variables** from the `.github/workflows/gapic-generator-tests.yml` configuration. Additionally, it **updates Python version references** within the workflow to leverage job outputs, improving consistency and reducing redundancy. This change streamlines the **GitHub Actions setup**, making the CI pipeline more maintainable and robust without altering any product features.

This commit **enhances the CI/CD pipeline** for the **`gapic-generator`** by **adding new test jobs** and refining existing ones within the `.github/workflows/gapic-generator-tests.yml` workflow. Specifically, it introduces the `showcase-mypy` and `goldens-prerelease` jobs, alongside updates to dependencies and conditions for other tests. This **maintenance and feature enhancement** improves the robustness and coverage of `gapic-generator` testing, ensuring higher quality for generated code and pre-release golden files. The changes directly address feedback from a pull request, strengthening the overall testing infrastructure.

This commit introduces a **conditional execution mechanism** for **GitHub Actions workflows** within `.github/workflows/gapic-generator-tests.yml`. It adds a new job to intelligently determine if **generator tests** are relevant based on recent file changes, and updates existing jobs to depend on this condition. This **chore** significantly **optimizes CI/CD pipelines** by **avoiding unnecessary test runs**. The change improves overall efficiency and reduces resource consumption for the **generator tests**, ensuring they only execute when truly impacted by code modifications.

This commit addresses a **typographical error** within the **`gapic-generator` package**, specifically in its `noxfile.py` configuration. It **removes a trailing backslash** from a string literal found in the `session.skip` message of the `core_deps_from_source` function. This is a **minor style fix** and **maintenance** task, ensuring the correct formatting of messages displayed when `nox` test sessions are skipped. The change improves the readability of `nox` output for the **`gapic-generator`** without impacting any functional behavior or core logic.

This commit **introduces a new `system` Nox session** within the **`gapic-generator`** package's `noxfile.py`. This session acts as a **placeholder for future system tests**, currently configured to skip execution. It represents an **infrastructure growth** effort, laying the groundwork for more comprehensive, end-to-end testing of the `gapic-generator`'s functionality in subsequent development.

This commit **updates the Librarian configuration** by introducing new options for the `django-google-spanner` library. It adds `preserve_regex`, `remove_regex`, and `tag_format` parameters to the `.librarian/state.yaml` file. This **maintenance work** provides more granular control over how the Librarian tool manages and processes this specific dependency. The change primarily affects the **dependency management workflow** for `django-google-spanner`, enabling more precise control over its tagging and pattern handling within the project.

This commit introduces a **new Nox session**, `lint_setup_py`, to the **`gapic-generator`** package's development environment configuration in `noxfile.py`. This **preparatory feature** adds a placeholder for future linting of `setup.py` files. Currently, the session is explicitly **skipped**, ensuring it has no immediate functional impact on the CI/CD pipeline or local development workflows. This change lays the groundwork for enhanced code quality checks for `setup.py` files within the `gapic-generator` module in an upcoming release.

This commit **disables the `lint` Nox session** within the **`gapic-generator`** package by modifying `noxfile.py`. This is a **maintenance chore** to temporarily skip linting execution, citing an ongoing migration effort and a related issue for context. The change ensures that the `lint` session will not run for this package, streamlining development workflows during the migration period.

This commit performs **maintenance** on the **`gapic-generator` tests workflow** by updating the configuration in `.github/workflows/gapic-generator-tests.yml`. The changes ensure that essential **system dependencies**, specifically `pandoc` and `protoc`, are reliably installed within the CI environment. Furthermore, it optimizes the execution of **snippet generation tests** by restricting them to run only on the latest stable Python version. This update enhances the stability and efficiency of the **`gapic-generator` CI pipeline**, ensuring more consistent and faster test runs.

This commit performs a **maintenance chore** by updating the `issue_tracker` URL within the **`gapic-generator`** package's `.repo-metadata.json` file. This ensures that the `issue_tracker` field for the **`gapic-generator`** module points to the current and accurate issue reporting system. The change provides correct links for users reporting issues or seeking support, improving the discoverability of the appropriate **issue tracking system** for the package.

This commit performs a **repository cleanup** by **removing several unwanted files** that were either temporary, outdated, or inadvertently committed. The primary impact is a **cleaner codebase** and a **reduced repository footprint**, improving maintainability. This **maintenance task** ensures that only necessary and relevant assets are part of the project, with no functional changes to the application's features or behavior.

This commit performs a **maintenance chore** by updating the `repo` field within the `.repo-metadata.json` file for the **`gapic-generator` package**. This change corrects the repository URL, ensuring that the metadata accurately reflects the project's location. The update is crucial for **tooling and automation** that relies on this configuration to correctly identify and interact with the **`gapic-generator` module's** source repository.

This commit introduces **presubmit tests** for the **`gapic-generator`** by adding a new **GitHub Actions workflow**. This **maintenance** effort enhances the project's CI/CD pipeline to ensure the generator's stability and correctness. The workflow, defined in `.github/workflows/gapic-generator-tests.yml`, executes specialized tests including **showcase unit tests, goldens, and fragment/snippet tests** across multiple Python versions. This significantly improves the **automated quality assurance** for the code generation process, preventing regressions and ensuring consistent output.

This commit introduces **placeholder Nox sessions** for `prerelease_deps` and `core_deps_from_source` within the `packages/gapic-generator/noxfile.py`. This **enhances the testing infrastructure** by preparing the environment to support future testing against pre-release dependencies and core dependencies installed directly from source. The change is a **maintenance improvement** that lays the groundwork for more comprehensive and robust dependency validation for the **GAPIC generator**, ensuring better compatibility and stability in its future releases.