[code-review] hooks ExtractFilePath returns garbage for non-string JSON values

[topcheer]

File and Lines

internal/hooks/runner.go:375-396

Problem Description

ExtractFilePath performs manual JSON parsing without validating that the value after a file-path key is actually a string. For non-string JSON values (null, numbers, booleans), the function returns garbage substrings.

For input {"file_path": null, "other": "value"}, the function returns null, as the file path.

Trigger Scenario

1. LLM generates a tool call with "file_path": null (happens when optional parameter is omitted but LLM explicitly includes the key with null)
2. ExtractFilePath returns null, as the file path
3. Garbage flows into HookEnv.FilePath (agent_tool.go:334) and TUI display (tool_labels.go:42)

Expected vs Actual Behavior

• Expected: Return empty string for non-string values
• Actual: Returns garbage substring from other JSON fields

Fix Suggestion

After extracting the value, check that it starts with a quote before processing. If not, skip to the next key.

Severity

Low-Medium - LLM-generated JSON occasionally includes null for optional keys. Garbage flows into hook env vars and TUI display.

Verification

Independently verified by subagent sa-8. Confirmed garbage output for null, number, and boolean types. Two production call sites confirmed.

[topcheer]

已修复 (commit 827ccb2)。

修改内容：
ExtractFilePath 现在在处理值之前检查 JSON 值是否以引号开头。非字符串值（null、数字、布尔值）会被跳过，不再返回垃圾子字符串。