opentui: fatal: null is not an object (evaluating 's().tailHygiene')

Description

Description

Switching sessions via ctrl+x l crashes the TUI sidebar. setSnapshot(null) fires on session switch and s() returns null until async refresh completes.

Root cause

In packages/plugin/src/tui/slots/sidebar-content.tsx:

• Line 698: setSnapshot(null) fires on session switch (createEffect(on(props.sessionID, ...))).
• Line 720: const s = createMemo(() => snapshot()) — s() returns null after the switch, until refresh() completes its async loadSidebarSnapshot call.
• Line 809: {s()!.tailHygiene !== undefined && ( — uses the TypeScript non-null assertion !, which is compile-time only. At runtime, s() is null, so s().tailHygiene throws.

The SolidJS compiled nested memo at line 866 (_$memo(() => s().tailHygiene !== undefined)) can re-evaluate after s() has already become null but before the outer guard's effect unmounts the inner content. Every other s() access in the file uses s()?. or is wrapped in a s() && ... guard. The tail-hygiene block is the only unguarded access.

Potential fix

- {s()!.tailHygiene !== undefined && (
+ {s()?.tailHygiene !== undefined && (

Lines 813–814 (s()!.tailHygiene!) are inside that guard so ! is safe once the condition is fixed.

Environment

• Plugin: v0.41.4
• OS: darwin arm64
• Node: v24.2.0
• OpenCode: 1.15.6

Configuration

Config from ~/.config/cortexkit/magic-context.jsonc:

{
  "$schema": "https://raw.githubusercontent.com/cortexkit/magic-context/master/assets/magic-context.schema.json",
  "historian": {
    "opencode": {
      "model": "corti/corti-s1-mini"
    }
  },
  "dreamer": {
    "opencode": {
      "model": "corti/corti-s1"
    }
  },
  "sidekick": {
    "model": "corti/corti-s1-mini"
  }
}

Error trace

Error: null is not an object (evaluating 's().tailHygiene')
    at <anonymous> (/Users/jdh/.cache/opencode/packages/@cortexkit/opencode-magic-context@latest/node_modules/@cortexkit/opencode-magic-context/src/tui-compiled/slots/sidebar-content.tsx:866:37)
    at sd (/$bunfs/root/chunk-fcdn7z64.js:2:11235)
    at oa (/$bunfs/root/chunk-fcdn7z64.js:2:11016)
    at qa (/$bunfs/root/chunk-fcdn7z64.js:2:12814)
    at Wd (/$bunfs/root/chunk-fcdn7z64.js:2:13729)
    at Vg (/$bunfs/root/chunk-fcdn7z64.js:2:13091)
    at j (/$bunfs/root/chunk-fcdn7z64.js:2:12995)
    at Vg (/$bunfs/root/chunk-fcdn7z64.js:2:13623)
    at j (/$bunfs/root/chunk-fcdn7z64.js:2:12995)
    at l (/$bunfs/root/chunk-fcdn7z64.js:3:160394)
    at navigate (/$bunfs/root/chunk-cdy7d0x6.js:466:7799)
    at onSelect (/$bunfs/root/chunk-cdy7d0x6.js:489:36199)
    at I (/$bunfs/root/chunk-cdy7d0x6.js:470:10316)
    at j (/$bunfs/root/chunk-yhqshqbk.js:2:32046)
    at runBinding (/$bunfs/root/chunk-yhqshqbk.js:2:34471)
    at _J (/$bunfs/root/chunk-yhqshqbk.js:2:54932)
    at VJ (/$bunfs/root/chunk-yhqshqbk.js:2:49037)
    at TJ (/$bunfs/root/chunk-yhqshqbk.js:2:47585)
    at wJ (/$bunfs/root/chunk-yhqshqbk.js:2:46755)
    at <anonymous> (/$bunfs/root/chunk-yhqshqbk.js:2:68234)
    at emitWithPriority (/$bunfs/root/chunk-vtv1c1d6.js:3:32592)
    at processParsedKey (/$bunfs/root/chunk-vtv1c1d6.js:3:32061)
    at handleStdinEvent (/$bunfs/root/chunk-vtv1c1d6.js:62:5000)
    at <anonymous> (/$bunfs/root/chunk-vtv1c1d6.js:62:4869)
    at drain (/$bunfs/root/chunk-vtv1c1d6.js:33:7440)
    at drainStdinParser (/$bunfs/root/chunk-vtv1c1d6.js:62:4841)
    at <anonymous> (/$bunfs/root/chunk-vtv1c1d6.js:62:2698)
    at emit (node:events:95:22)
    at addChunk (internal:streams/readable:264:47)
    at readableAddChunkPushByteMode (internal:streams/readable:242:18)
    at internalRead (native)
    at processTicksAndRejections (native)...

Plugins

magic-context, aft

OpenCode version

1.15.6

Steps to reproduce

1. Run Opencode
2. Have multiple active sessions
3. Change between sessions with ctrl+x l
4. Repeat 3 until failure (usually less than five session switches)

Screenshot and/or share link

Operating System

macos 26.6.2

Terminal

iTerm2