fix(skill): Detect stacked PR context from branch

[adinauer]

📜 Description

Improve the local create-java-pr skill so it determines whether to run in standalone or stacked PR mode from git context.

The skill now checks the current branch and existing PR relationships to infer stack context, instead of relying on manual prompting.

💡 Motivation and Context

When the workflow starts on main, it should default to a normal PR against main and not accidentally assume stacked PR behavior.

This change makes that default explicit and still allows stacked mode when the user asks for it.

💚 How did you test it?

• Ran ./gradlew spotlessApply apiDump successfully (using JDK 17 locally)
• Verified the updated skill content and git diff

📝 Checklist

• I added GH Issue ID & Linear ID
• I added tests to verify the changes.
• No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled.
• I updated the docs if needed.
• I updated the wizard if needed.
• Review from the native team if needed.
• No breaking change or entry added to the changelog.
• No breaking change for hybrid SDKs or communicated to hybrid SDKs.

🔮 Next steps

• Use the updated skill in future PR prep flows and refine heuristics if new branch patterns appear.

#skip-changelog

[github-actions]

Semver Impact of This PR

🟢 Patch (bug fixes)

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[sentry]

Sentry Build Distribution

App Name	App ID	Version	Configuration	Install Page
SDK Size	io.sentry.tests.size	8.36.0 (1)	release	Install Build

[cursor]

Cursor Bugbot has reviewed your changes and found 2 potential issues.

^{Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.}

[cursor]

Collection branch misclassified as standalone PR context

Medium Severity

The decision tree classifies any branch whose PR targets main/master as standalone, then only checks for downstream PRs when no PR exists for the current branch. A stacked-PR collection branch has a PR targeting main and has downstream stack PRs — but the downstream check is never reached, so the collection branch is incorrectly treated as standalone. The downstream-PR check needs to also run when a PR exists with baseRefName equal to main/master to correctly detect a stack base.

 

[cursor]

Undefined "stack base context" PR type mapping

Low Severity

The downstream-PR check concludes with "treat this as a stack base context," but the three defined PR types below (standalone, first PR of new stack, next PR in existing stack) don't include a "stack base context" option. The classification result doesn't map to any actionable PR workflow, leaving behavior ambiguous.

Additional Locations (1)

• .claude/skills/create-java-pr/SKILL.md#L41-L45