Composition.Builder.build() drops builder/composable options and generated identifiers when launching a Specification

[shaaravraghu]

Type
Bug

Severity
High

Modules

• spawn-application-composition

Evidence

• spawn-application-composition/src/main/java/build/spawn/application/composition/Composition.java:762-782
• The method merges builder options, composable options, ApplicationIdentifier, and SystemProperty into launchOptions.
• If composable.specification != null, the code ignores launchOptions and calls platform.launch(composable.specification) instead.

Why this matters

• Composition-level defaults and per-composable overrides do not apply consistently.
• Generated composition metadata such as ApplicationIdentifier can be skipped entirely for specification-backed entries.
• This breaks the mental model that the builder controls launch policy uniformly.

Expected behavior

• Specification-backed composables should still receive builder defaults, composable overrides, and generated composition identifiers.

Actual behavior

• Those merged options are applied only for applicationClass launches, not Specification launches.

Suggested reproduction

1. Create a Composition.Builder with a default option such as a diagnostic naming provider or system property.
2. Add one composable with add(applicationClass) and another with add(specification).
3. Build the composition.
4. Compare resulting application configurations and observe that only the class-based launch receives the builder-generated options.

Suggested fix

• Build a new launchable specification or configuration from the original specification plus the merged builder/composable options.
• Ensure generated composition identifiers are applied to both paths.

Suggested tests

• Add a test verifying that ApplicationIdentifier is present for add(specification).
• Add a test proving builder defaults and Composable.with(...) overrides apply equally to both launch paths.

Issue body ready to paste
Composition.Builder.build() merges defaults and generated identifiers into launchOptions, but that merged configuration is only used when launching from applicationClass. The Specification path bypasses launchOptions entirely via platform.launch(composable.specification), so specification-backed entries miss composition-level defaults and generated metadata.`