release: --split-debug-info under build/ is wiped by inter-ABI flutter clean (obfuscated releases silently lose arm64 symbols)

[kennedyowusu]

What

On a multi-ABI koolbase release with --obfuscate --split-debug-info=<dir under build/>, the flutter clean run between ABIs deletes build/, taking the first ABI's symbol map with it. The release ships with only the last ABI's map → arm64 crash symbolication is silently broken.

Trigger (needs all three)

• Obfuscation on (--obfuscate)
• Multi-ABI release (the default)
• --split-debug-info resolves under build/

Why it matters

Silent, and fails late — only surfaces when symbolicating a real production arm64 crash. Bad look for a platform that sells crash handling.

Not affected

• Shipped engines / patches (orthogonal)
• Non-obfuscated releases
• Symbol dirs outside build/

Fix (remove the footgun, don't just document it)

release already preserves each ABI's libapp.so across the inter-ABI clean — route the symbol map through that same preserve step. Or default --split-debug-info to a koolbase-managed dir outside build/ when the dev doesn't set one. Keep a guard that warns/relocates if it resolves under build/.

Do NOT

Rip out the inter-ABI flutter clean to "solve" this — it's likely load-bearing for clean per-ABI artifacts. Preserve-the-map is the safe fix; removing the clean is a separate investigation.

Priority

Low. Belongs in the release.go pass but must not expand chunk 1.

Stopgap today: put --split-debug-info outside build/ (the kb_symbols workaround already in use).

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⚠️ Unverified: confirm release actually runs flutter clean between ABIs against the source before treating this as fact.