daemon runJSInCurrentTab: js command fails with -1728 when front window has zero tabs (sister concern from #85)

[kiki830621]

Problem

daemon 的 runJSInCurrentTab template（PreCompiledScripts.swift:105-115）：

tell application "Safari"
    do JavaScript "{{JS_SOURCE}}" in current tab of front window
end tell

— Source: PreCompiledScripts.swift:111-115

current tab of front window 在 front window 為 0-tab 時不存在 → AppleScript raise -1728，js（及走 daemon JS path 的命令）失敗。此 template 沒有 try guard。

Type

bug

Reproduction

1. Safari front window 為 0-tab（剛開的 profile 空視窗 / Cmd+N 空白視窗）
2. safari-browser js "document.title"（走 daemon JS path）
3. line 113 current tab of front window raise -1728 → 命令失敗

Expected

front window 為 0-tab 時，JS 命令應給出可理解的錯誤（例如 "front window has no tabs — open a tab or use --url/--window"），或 fallback 到有 tab 的 window，而非吐 raw -1728。

Actual

raw AppleScript -1728。

Root Cause

in current tab of front window 假設 front window 有 current tab。0-tab front window 無 current tab，且此 daemon template 沒有 try guard。

Suggested fix

• 明確指定有 tab 的 target，或在 front window 0-tab 時給明確錯誤訊息
• 兩條 path 應一致：in-process 的 front-window current tab 存取（SafariBridge.swift:2962-2965）已包 try；daemon 這條（PreCompiledScripts.swift:113）沒有

Relation to #85

同根（0-tab / current tab 缺 guard），本 issue 是 daemon JS path 的版本。#85 修 in-process listAllWindows 枚舉路徑；本 issue 修 daemon JS template 的 front-window 假設。

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Source: surfaced during /idd-diagnose #85 sister concern surfacing (Step 3.6)

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Current Status

• Phase: implemented
• Updated: 2026-07-04
• Implemented in cluster PR cluster: guard 0-tab Safari windows (#85 #86 #87) #88 (branch idd/cluster-zerotab-guard, isolated worktree); regression tests green, full suite no-regression.
• Next: /idd-verify

[kiki830621]

Implementation Complete

Checklist (synced from TaskList)

• PreCompiledScripts.swift runJSInCurrentTab template — explicit error for a 0-tab front window before do JavaScript ... in current tab → commit 2753259
• Regression test (ZeroTabWindowGuardTests) → commit b317052

Changes

• 2753259: guard if (count of tabs of front window) = 0 then error ... — actionable error instead of raw -1728; mirrors the try-guard the in-process front-window path already had
• b317052: string-assertion regression test (template contains front-window tab-count guard)

Cluster

Part of cluster PR #88 (#85 #86 #87).

Sister Bugs Filed (mid-impl, Step 5.7)

(none surfaced)

Scope Compliance

Only the runJSInCurrentTab daemon template touched. No scope creep.

Next: verification pending — /idd-verify #87

[kiki830621]

Verify (via PR #88) — cluster #85 #86 #87

Result: FAIL — 2 blockers before merge:

• 🔴 HIGH (merge-safety): winID 7th field dropped vs post-fix: multi-roundtrip 指令的 positional (window,tab) reference 在 z-order 變動時懸空 — 跨分頁 JS 注入（non-interference 違反，sister bug from #76 verify） #79 main → would reopen fix: multi-roundtrip 指令的 positional (window,tab) reference 在 z-order 變動時懸空 — 跨分頁 JS 注入（non-interference 違反，sister bug from #76 verify） #79's z-order injection on merge
• 🟡 MEDIUM (daemon runJSInCurrentTab: js command fails with -1728 when front window has zero tabs (sister concern from #85) #87 in-scope): guard still leaks raw -1728 when Safari has 0 windows

Core guard logic for all three issues verified correct against live Safari. Fix in progress.

Full report: #88 (comment)