[go] Auto-detect bundler package name

[qmuntal]

Summary

• auto-detect the destination Go package by parsing package declarations
• ignore test files and previously generated bundler sources during detection
• fall back to main with a warning when package detection fails

This supports use cases where the Copilot integration happens in a non-main package, ensuring the generated embed sources use that package name.

Testing

• go test ./cmd/bundler

[Copilot]

Copilot review overview

🟡 Changes recommended

Detection must respect target-specific filenames and build constraints to avoid generating an invalid package declaration.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Review tier: Balanced
Findings: 1

New issues introduced by this change (1)

Severity	Finding
	go/​cmd/​bundler/​main.go — Package detection currently parses every .go file, including files excluded for the requested…

What changed in this PR

Adds destination package auto-detection for generated Go bundler sources.

Changes:

• Parses package declarations while excluding tests and generated files.
• Falls back to main with a warning.
• Adds detection tests.

File	Description
go/​cmd/​bundler/​main.go	Implements package detection and uses it during generation.
go/​cmd/​bundler/​main_test.go	Tests detection and fallback behavior.

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[qmuntal]

@copilot rebase

[SteveSandersonMS]

Thanks for this improvement — I validated the non-main package scenario end-to-end and it works as intended. Scope is appropriately Go-specific, and this looks good to merge. The remaining issue was only the rebase conflict with main, which now appears resolved.

[SteveSandersonMS]

Approved. I validated the Go bundler non-main package scenario end-to-end, and the rebased branch is mergeable with passing checks.