dsh tui: every slash command via commands.execute fails - signal passed in the images slot (TypeError reading 'aborted')

[tommy2lion]

Describe the bug

In the TUI, every slash command routed through the command registry fails immediately with:

Command failed: TypeError: Cannot read properties of undefined (reading 'aborted')

The TUI calls commands.execute(...) with the wrong argument order — the AbortSignal is passed in the images slot, leaving signal undefined.

Environment

• dsh 0.1.1-rc.2, dsh-tui-plugin 0.3.0, Windows (Git Bash)

Root cause

@deepseek-ai/dsh-commands execute signature is (agent, line, images, signal):

// @deepseek-ai/dsh-commands/lib/index.js:300
async execute(agent, line, images, signal) {
    ...
    if (signal.aborted) throw abortError(signal);   // line 305 — TypeError when signal is undefined

dsh-tui-plugin@0.3.0 calls it with 3 arguments (no images placeholder), so the signal lands in the images slot:

// lib/tui/app.js:722  (compactCurrent, the "context low → run /compact" prompt path)
const execution = await commands.execute(agent, '/compact', controller.signal);
// lib/tui/app.js:828  (send — any `/command` typed in the composer)
const execution = await commands.execute(agent, line, controller.signal);

→ images = controller.signal, signal = undefined → signal.aborted at line 305 throws the reported TypeError. Because this happens inside execute() before the command handler runs, all registered slash commands (not just /compact) fail this way. Local TUI commands like /sessions still work because they are handled in-app and never reach commands.execute.

Repro

1. dsh --profile tui
2. Type any non-local slash command, e.g. /compact
3. Immediately: Command failed: TypeError: Cannot read properties of undefined (reading 'aborted')

Expected

The command runs; /compact should perform a manual compaction (it is actively suggested by the TUI's context-low banner).

Suggested fix

Pass undefined (or []) in the images slot at both call sites:

commands.execute(agent, '/compact', undefined, controller.signal);  // app.js:722
commands.execute(agent, line, undefined, controller.signal);       // app.js:828

[liyangbing]

这个定位是对的。我用官方 alpha.1 cd5ef814 的 commands runtime、README 和测试交叉确认了：公开契约是 execute(agent, line, images, signal)，而且 signal.aborted 在 handler 执行前读取；官方 text-only 调用和 /compact 测试都明确传 [] 作为第三个参数。因此三参数调用会让所有已解析的 registry command 在同一个边界失败，而不是 /compact 自身的故障。

建议两处都统一改成：

await commands.execute(agent, line, [], controller.signal)

其中 context-low /compact 路径也要单独覆盖，否则普通 composer 修好后，低上下文提示仍会失败。不建议通过把 runtime 的 signal 改成 optional 来兜底：这既掩盖 adapter ABI 错误，也没有把误传的 AbortSignal 变成合法 images 数组，还会破坏 UI request 的取消所有权。

修复后的验证不应只看异常消失，至少要覆盖：

• /compact 和另一条 registry command 都进入 handler 并正常 settle；
• /sessions 等本地命令仍走 TUI local path；
• unknown slash command 不会退化成 model prompt；
• already-aborted signal 在 command/run 之前拒绝；
• clean reinstall 后加载的是修复 bundle，不是旧的 global/link 副本；
• 直接断言两个调用点都收到 (agent, line, [], controller.signal)。

我把版本/加载路径取证、两调用点修复、失败分流和 8 项 adapter 回归契约整理成了完整 runbook：
https://sandbaseai.github.io/deepseek-harness-handbook/tui-slash-command-signal.html

英文 canonical 文档：
https://github.com/sandbaseai/deepseek-harness-handbook/blob/main/docs/en/troubleshooting/tui-slash-command-signal-images-slot.md

[Jstn-1g]

Fixed and regression-tested in Jstn-1g/dsh-tui-plugin PR #1. Both commands.execute call sites now pass [] in the images slot and the live AbortSignal in the fourth slot, including the context-low /compact path. The plugin dependencies are aligned to the Harness 0.1.1-rc.2 package set and the plugin version is bumped to 0.3.1. Verification: clean install, 397 tests across 15 files against the exact rc.2 base patch, build, package dry-run, and zero production audit findings.