fix(cli): disable Bun code-splitting to fix baseline release crash

[catrielmuller]

Issue

Follow-up to #10955, #10956, #10957. Despite the morphsdk CJS redirect, the build-cli job still fails — now at the cli-linux-x64-baseline smoke test:

Smoke test failed for @kilocode/cli-linux-x64-baseline:
  SyntaxError: Exported binding 'G9' needs to refer to a top-level declared variable.
  Bun v1.3.14 (Linux x64 baseline)

See https://github.com/Kilo-Org/kilocode/actions/runs/27035450876/job/79798417163.

Root cause — it was never morphsdk

The previous fixes targeted @morphllm/morphsdk on the theory that its pre-split ESM barrel was feeding bad chunks to Bun's splitter. Inspecting the compiled binary disproves that:

• The morphsdk redirect works — client.cjs content is embedded, no morphsdk chunk-*.js imports remain.
• The SyntaxError is a runtime crash at binary startup, not a build-time error.
• The offending code is import{vn as G9}from"/$bunfs/root/chunk-*.js" — a cross-chunk re-export Bun itself generates under splitting: true, where the exported binding isn't top-level.

This is a known Bun 1.3.14 code-splitting bug (oven-sh/bun#25621, #5344, #7265; also hit by opencode#23349), fixed upstream in Bun#26089 (post-1.3.14). It only crashes on the baseline target, whose stricter runtime rejects the invalid binding.

Fix

Set splitting: false in script/build.ts. Splitting only deduplicated shared code between the 5 entrypoints (index + 4 workers); disabling it inlines per entrypoint and produces a valid binary. The morphsdk redirect is kept (harmless, simplifies the bundle) but its comments are corrected to note it is not the actual fix.

Verification

Built locally from packages/opencode/ with the real script/build.ts and inspected the compiled binary:

splitting	build	as G9 in binary
true (before)	ok	present → baseline crashes
false (after)	ok	gone

• bun run typecheck passes.
• bun run script/check-opencode-annotations.ts passes.

The local smoke test exits 139 on my Nix host — a pre-existing environment segfault in Bun's compiled-binary bootstrap (crashes right after execve, before any JS), unrelated to this change and not present on CI's Ubuntu runners.

No changeset — CI-only build fix.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Files Reviewed (3 files)

• packages/opencode/script/build.ts — removed morphsdkCjsPlugin, added splitting: false with explanation comment
• packages/opencode/src/kilocode/compat/morphsdk.ts — deleted (compat shim no longer needed)
• packages/opencode/src/tool/warpgrep.ts — reverted to direct import from @morphllm/morphsdk/tools/warp-grep/client

lgtm — the root cause analysis is sound, the fix is minimal and correct. splitting: false directly addresses the Bun 1.3.14 codegen bug without introducing side effects. The compat shim and its plugin were the wrong workaround and are cleanly removed. kilocode_change markers are properly placed.

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_{Reviewed by claude-4.6-sonnet-20260217 · 294,858 tokens}

_{Review guidance: REVIEW.md from base branch main}