8 test files and 1 fixture file in packages/opencode/test/ to detect memory leaks and orphan processes in Kilo CLI. These tests target the specific leak sources identified in upstream opencode#3013.

Files Created

File	Lines	Purpose
`test/fixture/mcp/fake-mcp-server.js`	~90	Minimal JSON-RPC 2.0 MCP server over stdio
`test/memory/helper.ts`	~130	Shared utilities for all memory/process tests
`test/memory/orphan-process.test.ts`	~175	Orphan process detection after MCP/LSP lifecycle
`test/memory/heap-growth.test.ts`	~125	Unbounded heap growth across subsystems
`test/memory/disposal.test.ts`	~145	Disposal chain correctness verification
`test/memory/mcp-lifecycle.test.ts`	~130	MCP-specific leak scenarios
`test/memory/lsp-lifecycle.test.ts`	~130	LSP server process lifecycle
`test/memory/state-leak.test.ts`	~175	State/Bus/GlobalBus/subscription leaks
`test/memory/session-heap-growth.test.ts`	~145	Full session DB + event lifecycle

Test Results: 28 tests total

23 PASS — no leaks detected in these areas

Suite	Tests	Key Findings
`disposal.test.ts`	5/5	Disposal chain works: `Instance.dispose` -> `State.dispose`, idempotent `disposeAll`, slow disposal completes
`state-leak.test.ts`	5/5	`recordsByKey` cleared on dispose, Instance cache cleared on `disposeAll`, GlobalBus listeners bounded, Bus subscriptions per-instance and cleared
`lsp-lifecycle.test.ts`	3/3	`LSPClient.shutdown()` correctly kills server process, no orphans after 5 cycles, 0.22 MB growth over 10 cycles
`heap-growth.test.ts`	4/4	Instance provide/dispose: 0.57 MB/20 cycles. Bus subscriptions: 0.50 MB/100 cycles. State entries: -0.40 MB/100 cycles. MCP add/disconnect heap: 0.00 MB/3 cycles
`session-heap-growth.test.ts`	3/3	Session create/remove: 0.32 MB/10 cycles. Message CRUD: 0.15 MB/50 ops. Full lifecycle with events: 0.27 MB/25 sessions
`orphan-process.test.ts`	1/4	LSP shutdown: no orphans
`mcp-lifecycle.test.ts`	1/3	`MCP.tools()` 50x: 0.05 MB growth

5 FAIL — correctly detecting real MCP orphan process bugs

Test	Error
MCP: no orphans after dispose	`Found 1 orphan process: bun fake-mcp-server.js`
MCP: no orphans after disconnect	`Found 1 orphan process: bun fake-mcp-server.js`
disposeAll cleans up all instances	`Found 1 orphan process: bun fake-mcp-server.js`
MCP.add closes existing before overwriting	`Found 1 orphan process: bun fake-mcp-server.js`
MCP.connect closes existing before reconnecting	`Found 1 orphan process: bun fake-mcp-server.js`

Root Cause Confirmed

Every MCP test that spawns a server and then calls client.close() (via StdioClientTransport) leaves the child process alive. The MCP SDK's StdioClientTransport.close() closes the transport pipes but does not kill the spawned child process. This is the exact orphan process bug described in upstream #3013.

In contrast, LSPClient.shutdown() explicitly calls process.kill() on the server process, which is why all LSP tests pass cleanly.

Architecture Decisions

Real processes, mocked nothing for process tests: MCP/LSP servers are real child_process.spawn instances running fake-mcp-server.js / fake-lsp-server.js. This ensures process lifecycle is tested authentically.
pgrep -P for process tree snapshots: Works on macOS and Linux CI. Each test takes a before/after snapshot and asserts no new orphan descendants.
afterEach safety net: Force-kills any orphans to prevent cascading test failures.
Empty config for MCP tests: The MCP state() init connects to ALL configured servers on first access. Putting servers in config doubles connections and causes timeouts. Tests use MCP.add() directly.
Session tests use real DB, no LLM mock: Instead of mocking streamText's complex async iterable, session tests exercise Session.create/updateMessage/updatePart/remove with Bus subscriptions — covering the real Database + Bus + State code paths.
Generous thresholds: < 10 MB for most growth tests, < 5 MB for targeted ones. Multiple GC passes (Bun.gc(true) x 3) with 50ms sleeps for stable measurement.

Running the Tests

cd packages/opencode

# All memory tests (non-MCP-process tests complete in ~150s)
bun test test/memory/disposal.test.ts test/memory/state-leak.test.ts test/memory/lsp-lifecycle.test.ts test/memory/heap-growth.test.ts test/memory/session-heap-growth.test.ts

# MCP process tests (detect real orphan bugs, ~300s)
bun test test/memory/orphan-process.test.ts test/memory/mcp-lifecycle.test.ts

# Individual suites
bun test test/memory/disposal.test.ts
bun test test/memory/session-heap-growth.test.ts

What Happens When The Bug Is Fixed

Once StdioClientTransport.close() is patched to kill the child process (or a wrapper is added in src/mcp/index.ts), all 5 currently-failing orphan tests will pass — providing regression protection.