RPM spec parser mis-attributes %trigger* -- <trigger> sections to a sub-package

[reubeno]

Drafted by GitHub Copilot CLI while reviewing PR #132.

In RPM trigger syntax, -- separates the trigger's owning sub-package (or no sub-package, meaning the main package) from the trigger condition (the package whose state change fires the scriptlet). For example:

• %triggerin -- foo — owned by main package, fires when foo changes
• %triggerin -n test-devel -- foo — owned by test-devel sub-package, fires when foo changes
• %triggerin devel -- foo — owned by devel sub-package (suffix form), fires when foo changes

GetPackageNameFromSectionHeader (in internal/rpm/spec/spec.go) does not recognize --. It falls through default: index++, leaving the trigger condition to be picked up as the package name suffix.

Reproduction

GetPackageNameFromSectionHeader([]string{"%triggerin", "--", "devel"})
// returns: "devel"
// expected: ""  (main package; trigger condition "devel" is not the owner)

Impact

Affects spec-remove-section and spec-remove-subpackage. For a spec with %triggerin -- devel declared on the main package, RemoveSubpackage("devel") will incorrectly remove the main-package trigger.

This is not net-new behavior introduced by PR #132; it was latent and surfaced by the new overlay.

Proposed fix

Treat -- as a terminator in GetPackageNameFromSectionHeader: stop scanning for the package suffix once -- is encountered. Anything after -- is the trigger condition, not the owning sub-package.

Add fixture tests for %triggerin -- devel, %triggerin devel -- foo, and %triggerin -n test-devel -- foo.