workflows

Junco Legacy Hotfix CI/CD Pipeline

This directory contains the GitHub Actions workflows used to validate hotfixes for legacy versions of the junco package.

Because legacy environments are locked and cannot use modern CRAN packages without breaking, this pipeline uses a "Time Machine" approach combined with dynamic memory injection (hotpatchR) to safely test fixes exactly as they will behave in production.

Architecture Overview

Unlike standard R package CI pipelines, this workflow performs a dual-checkout:

1. It pulls your current hotfix script (hotfix_repo).
2. It pulls the pristine, historical source code of the legacy package (junco_source).

It then installs the legacy package, dynamically injects your hotfix into its locked memory, and runs the legacy test suite.

Key Mechanisms (Do Not Alter Without Review)

1. The CRAN Time Machine (RSPM)

Variable: RSPM: "https://packagemanager.posit.co/cran/2024-04-20" Legacy packages rely on legacy dependencies. If we build junco v0.1.3 using today's CRAN, tests will fail due to deprecated upstream functions. We lock the Posit Public Package Manager (RSPM) to the exact date the legacy container was finalized (e.g., 2024-04-20). This guarantees zero dependency drift.

2. Specific R Version Binding

Variable: matrix.config.r: '4.5.2' This pipeline is hardcoded to run on R 4.5.2 to exactly mirror the 2025q4_r450_1_0_0 production container. Do not upgrade this to release or latest unless the target container's R version is also being upgraded.

3. Memory Injection (hotpatchR)

This pipeline uses hotpatchR to rewrite the package namespace in memory. This provides a 1:1 simulation of how the hotfix script will execute in the end-user's R session.

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How to Create a Pipeline for a New Legacy Version

When you need to support a new legacy version (e.g., v0.1.4), duplicate the existing YAML file and update the following four targets:

Step 1: Update Workflow Name and Triggers

Rename the file (e.g., hotfix-v0.1.4.yml) and update the header name so it is easily identifiable in the GitHub Actions UI.

name: Hotfix Tests v0.1.4 🔥

Step 2: Update the Legacy Branch/Tag Reference

Tell the pipeline which historical version of junco to check out as the baseline.

      - name: Checkout Junco v0.1.4
        uses: actions/checkout@v4
        with:
          ref: refs/heads/v0.1.4  # <-- Update this to the target branch or tag
          path: junco_source

Step 3: Update the Hotfix Target File

Update the R script injection path so it looks for the correct file in your feature/hotfix-* branch.

      - name: Execute tests via hotpatchR
        run: |
          # ...
          apply_hotfix_file("hotfix_repo/dev/junco_hotfix_v0-1-4.R") # <-- Update filename

Step 4: Align the Time Machine Date

Determine when the new legacy version was deployed, and update the RSPM snapshot date to match that era.

    env:
      # e.g., Set to the month v0.1.4 was released
      RSPM: "[https://packagemanager.posit.co/cran/2024-10-15](https://packagemanager.posit.co/cran/2024-10-15)" 

Once these four variables are updated, the pipeline will automatically trigger whenever a developer pushes a branch starting with feature/hotfix-* and will test their script against the newly defined legacy environment.