diff-against-workshop-branch

name	diff-against-workshop-branch
description	Compare the current asset-manager workspace against one of the workshop reference branches (workshop/java-upgrade, workshop/expected, workshop/deployment-expected) so users can self-check migration progress. Use when the user asks "how far am I", "what should I have changed", "what does the expected state look like", or wants a checkpoint diff during the GitHub Copilot app modernization workshop.
argument-hint	Branch name (java-upgrade | expected | deployment-expected) and optional path filter

Diff Against Workshop Branch

Compare the user's current working tree to one of the canonical workshop branches and surface the meaningful migration deltas.

When to use

• The user is partway through the workshop and wants to know how their code compares to the reference.
• The user got stuck on a migration step and asks what the expected outcome looks like.
• The user wants a focused diff (e.g., "just the pom files", "just the RabbitMQ config") against a checkpoint.

Do not use this skill to merge or cherry-pick the reference branch into the user's branch — its only purpose is read-only inspection.

Reference branches

Argument	Reference branch	What it represents
java-upgrade	workshop/java-upgrade	After "Upgrade Runtime & Frameworks" (Java 8 → 21, Spring Boot 2.7 → 3.x).
expected	workshop/expected	After all migration tasks (PostgreSQL, Blob, Service Bus, health endpoints).
deployment-expected	workshop/deployment-expected	After containerization + deployment (includes .azure/, Dockerfiles).

All three live in Azure-Samples/java-migration-copilot-samples. The local repo may not have them fetched yet — the helper script handles that.

Procedure

1. Parse arguments. Required first argument: the branch nickname (java-upgrade, expected, deployment-expected). Optional second argument: a path filter (e.g. web/, pom.xml, worker/src/main/java/**). If the first argument is missing or not in the table above, ask the user — do not guess.

2. Run the helper script. Execute scripts/diff.sh with the resolved branch and optional path filter:

   ./.github/skills/diff-against-workshop-branch/scripts/diff.sh <branch-nickname> [path-filter]
   

   The script:

   • Adds the upstream remote workshop-upstream (idempotent) pointing at https://github.com/Azure-Samples/java-migration-copilot-samples.git if not already present.
   • Fetches just the requested branch (shallow).
   • Runs git diff --stat followed by git diff between the current HEAD and workshop-upstream/workshop/<branch> for the optional path filter.
   • Skips any files under .azure/, logs/, pids/, and target/ to keep output focused on source changes.

3. Summarize the diff for the user. Group changes by category:

   • Build (pom.xml, mvnw*, application.properties)
   • Code (java/kt source under web/, worker/)
   • Infra/Deploy (Dockerfile*, .azure/, scripts/deploy-to-azure.*)
   • Docs / templates

   For each category, list the top files changed and one-sentence summary of the migration intent (e.g. "RabbitMQ → Service Bus: removed spring-boot-starter-amqp, added spring-cloud-azure-starter-servicebus-jms"). Link each file with markdown links using the workspace-relative path so the user can open them in VS Code.

4. Offer next actions. Never apply changes automatically. Suggest options:

   • "Open file X side-by-side with the workshop version"
   • "Run the migration task that produces this delta via the GitHub Copilot app modernization extension (point to the matching README section)"
   • "Re-run with a narrower path filter"

Constraints

• Read-only. Do not check out, merge, rebase onto, or cherry-pick from the reference branch. The script only fetches into a separate remote.
• Don't pollute the user's git config. The remote is named workshop-upstream; if it already exists with a different URL, surface that and ask the user before changing it.
• Stay focused on source diffs. Skip target/, logs/, pids/, IDE state files; these are workshop side effects, not migration changes.