Riccardo trying to fix bugs #1475 and #1477 properly

# Execution Plan: Resolving PRs 1477 and 1475 ## Background - **PRs:** [1477 (Postgres)](https://github.com/GoogleCloudPlatform/ruby-docs-samples/pull/1477) and [1475 (MySQL)](https://github.com/GoogleCloudPlatform/ruby-docs-samples/pull/1475) - **Goal:** Update the `app.yaml` files for the GAE Flex Rails 7 tutorials to use modern Ruby versions (e.g., 3.2 or 3.3) on `ubuntu22`, fixing the "end of support" error described in Issue #1476. - **Current Proposed Fix in PRs:** Added `runtime_config: operating_system: "ubuntu22"` to `app.yaml`. ## Current Roadblocks / Comments 1. **CI Pipeline Failures:** `glasnt` identified that the oldest tested Ruby version is failing due to issues with built-in Gemfile config versions. They suggested updating the repository's oldest supported testing ruby version. 2. **Deployment Errors:** `bipashant` tested the PR and still received an error: `runtime ruby32 is not selectable with operating system ubuntu22`. This suggests the current patch in the PR is incomplete or incorrectly specifies the GAE Flex environment for newer Rubies. ## Recommended Execution Steps ### Step 1: Fix CI Matrix (Address glasnt's feedback) - Investigate the central CI configurations (likely in `.kokoro/` or `.github/workflows/`). - Update the Ruby version matrix to drop unsupported EOL Rubies (like 2.6/2.7/3.0) and include modern versions (3.2 and 3.3). - Update the oldest tested Ruby to at least 3.1 or 3.2. ### Step 2: Validate GAE Flex Configuration (Address bipashant's feedback) - Research the exact `app.yaml` syntax required to run Ruby 3.2+ on `ubuntu22` in GAE Flex. - It likely requires either: 1. Adding a `.ruby-version` file to the directories specifying `3.2.3` (or similar) AND keeping the `operating_system: "ubuntu22"` in `app.yaml`. 2. Specifying `runtime_version` under `runtime_config` within `app.yaml`. - Deploy locally using `gcloud app deploy` (or dry-run) to a test project to ensure the `INVALID_ARGUMENT` error resolves. ### Step 3: Implement Changes in PRs - For both `appengine/rails-cloudsql-postgres` and `appengine/rails-cloudsql-mysql`: - Adjust `app.yaml` based on the successful syntax from Step 2. - Adding `.ruby-version` if necessary. - Update `Gemfile`/`Gemfile.lock` to reflect changes if bounded by bundler requirements. - Commit these changes directly to the respective branches for PR 1477 (`palladius-patch-2`) and PR 1475 (`palladius-patch-1`), or create a new consolidated PR linking both. ### Step 4: Finalize - Confirm CI passes after adjusting the ruby matrix. - Reply to reviewers `glasnt` and `bipashant`, requesting re-review. - Merge the PRs.