feat(search): app/search/skills.py — 技能注册表与 frontmatter 解析

从 TRM4 core/search/skills.py 保真迁移。提供 parse_frontmatter、
strip_frontmatter、SkillRegistry、discover_skills 四个公共 API。
逻辑完全一致，仅调整导入路径并添加中文 docstring。

17 个单元测试全部通过，覆盖正常/异常/边界场景。

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/search/skills.py

@@ -0,0 +1,195 @@
+"""技能注册表与 Markdown frontmatter 解析工具。
+
+提供 Skill 文件的 frontmatter 解析、正文提取、注册表管理和目录扫描功能，
+供搜索 Agent 装配层使用。
+"""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+from loguru import logger
+
+if TYPE_CHECKING:
+    from pathlib import Path
+
+_FRONTMATTER_FIELDS = {"name", "description", "always", "task_type"}
+
+
+def _extract_frontmatter_lines(text: str) -> tuple[list[str], int] | None:
+    """提取 frontmatter 行与正文起始偏移。
+
+    参数:
+        text: 原始 Markdown 文本。
+
+    返回:
+        (frontmatter 行列表, 正文起始字节偏移) 二元组；
+        若不存在完整 frontmatter 则返回 None。
+    """
+    lines = text.splitlines(keepends=True)
+    if not lines or lines[0].strip() != "---":
+        return None
+
+    offset = len(lines[0])
+    frontmatter_lines: list[str] = []
+    for line in lines[1:]:
+        if line.strip() == "---":
+            return frontmatter_lines, offset + len(line)
+        frontmatter_lines.append(line)
+        offset += len(line)
+
+    logger.debug("frontmatter 缺少结束分隔符，按普通正文处理")
+    return None
+
+
+def strip_frontmatter(text: str) -> str:
+    """移除 Markdown 文本开头的 frontmatter，并返回正文。
+
+    参数:
+        text: 原始 Markdown 文本。
+
+    返回:
+        去除 frontmatter 后的正文；若 frontmatter 不完整或不存在，则返回原文。
+    """
+    extracted = _extract_frontmatter_lines(text)
+    if extracted is None:
+        return text
+
+    _, body_start = extracted
+    return text[body_start:]
+
+
+def parse_frontmatter(text: str) -> dict[str, str]:
+    """解析 Markdown frontmatter 中的目标字段。
+
+    仅识别 ``name``、``description``、``always``、``task_type`` 四个字段，
+    其余字段会被忽略。引号包裹的值会自动去除引号。
+
+    参数:
+        text: 原始 Markdown 文本。
+
+    返回:
+        仅包含目标字段的字符串字典。
+        若不存在完整 frontmatter，则返回空字典。
+    """
+    extracted = _extract_frontmatter_lines(text)
+    if extracted is None:
+        return {}
+
+    frontmatter_lines, _ = extracted
+    parsed: dict[str, str] = {}
+    for raw_line in frontmatter_lines:
+        line = raw_line.strip()
+        if not line or ":" not in line:
+            continue
+
+        key, _, raw_value = line.partition(":")
+        normalized_key = key.strip()
+        if normalized_key not in _FRONTMATTER_FIELDS:
+            continue
+
+        value = raw_value.strip()
+        if len(value) >= 2 and (
+            (value.startswith('"') and value.endswith('"'))
+            or (value.startswith("'") and value.endswith("'"))
+        ):
+            value = value[1:-1]
+        parsed[normalized_key] = value
+
+    return parsed
+
+
+class SkillRegistry:
+    """管理技能名称到文件路径映射并读取技能正文。
+
+    通过 ``set_paths`` 注入名称→路径映射后，
+    可用 ``read`` 按名读取技能 Markdown 正文（自动去除 frontmatter）。
+    """
+
+    def __init__(self) -> None:
+        self._paths: dict[str, Path] = {}
+
+    def set_paths(self, mapping: dict[str, Path]) -> None:
+        """注入技能名称到文件路径的映射。
+
+        参数:
+            mapping: 技能名到 Markdown 文件路径的映射。
+        """
+        self._paths = dict(mapping)
+        logger.debug("SkillRegistry 已载入 {} 个技能路径", len(self._paths))
+
+    def read(self, name: str) -> str:
+        """读取指定技能文件，并返回去除 frontmatter 后的正文。
+
+        参数:
+            name: 技能名称。
+
+        返回:
+            技能 Markdown 正文。
+
+        异常:
+            KeyError: 技能名称未注册时抛出。
+        """
+        try:
+            path = self._paths[name]
+        except KeyError:
+            logger.error("技能未注册: {}", name)
+            raise
+
+        logger.debug("读取技能文件: name={}, path={}", name, path)
+        return strip_frontmatter(path.read_text(encoding="utf-8"))
+
+
+def discover_skills(
+    skills_dir: Path,
+) -> tuple[str, dict[str, str], str, SkillRegistry]:
+    """扫描 skills 目录，按 frontmatter 分类返回。
+
+    遍历 ``*.md`` 文件，根据 frontmatter 的 ``always`` / ``task_type`` 字段分类：
+
+    - ``always=true`` 的 skill 拼入 ``always_skills_text``
+    - 有 ``task_type`` 的 skill 加入 ``task_skill_map``
+    - 非 always 的 skill 生成 ``catalog_text`` 并注册到 registry
+
+    参数:
+        skills_dir: Skill 文件目录。
+
+    返回:
+        ``(always_skills_text, task_skill_map, catalog_text, registry)`` 四元组。
+    """
+    if not skills_dir.exists():
+        return "", {}, "", SkillRegistry()
+
+    always_parts: list[str] = []
+    task_skill_map: dict[str, str] = {}
+    catalog_lines: list[str] = []
+    registry_paths: dict[str, Path] = {}
+
+    for path in sorted(skills_dir.glob("*.md")):
+        raw = path.read_text(encoding="utf-8")
+        meta = parse_frontmatter(raw)
+        if "name" not in meta:
+            logger.warning("跳过无 name 的 skill 文件: {}", path)
+            continue
+
+        body = strip_frontmatter(raw)
+        name = meta["name"]
+        desc = meta.get("description", "")
+        task_type = meta.get("task_type", "")
+        is_always = str(meta.get("always", "false")).lower() == "true"
+
+        if is_always:
+            always_parts.append(body)
+        else:
+            if task_type:
+                task_skill_map[task_type] = body
+            catalog_lines.append(f"- **{name}**: {desc}")
+            registry_paths[name] = path
+
+    always_text = "\n\n---\n\n".join(always_parts)
+    catalog_text = "\n".join(catalog_lines)
+
+    registry = SkillRegistry()
+    registry.set_paths(registry_paths)
+
+    return always_text, task_skill_map, catalog_text, registry

tests/unit/test_search_skills.py

@@ -0,0 +1,214 @@
+"""app/search/skills 模块的单元测试。
+
+覆盖 parse_frontmatter、strip_frontmatter、SkillRegistry、discover_skills。
+"""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+import pytest
+
+from app.search.skills import (
+    SkillRegistry,
+    discover_skills,
+    parse_frontmatter,
+    strip_frontmatter,
+)
+
+if TYPE_CHECKING:
+    from pathlib import Path
+
+
+# ── parse_frontmatter ──────────────────────────────────────────────
+
+
+class TestParseFrontmatter:
+    """parse_frontmatter 的测试集。"""
+
+    def test_normal(self) -> None:
+        """正常 frontmatter 应解析出目标字段。"""
+        text = (
+            "---\n"
+            "name: my_skill\n"
+            'description: "A cool skill"\n'
+            "always: true\n"
+            "task_type: qa\n"
+            "---\n"
+            "Body text here.\n"
+        )
+        result = parse_frontmatter(text)
+        assert result == {
+            "name": "my_skill",
+            "description": "A cool skill",
+            "always": "true",
+            "task_type": "qa",
+        }
+
+    def test_missing_closing_delimiter(self) -> None:
+        """缺少结束 --- 应返回空字典。"""
+        text = "---\nname: orphan\ndescription: no end\n"
+        assert parse_frontmatter(text) == {}
+
+    def test_no_frontmatter(self) -> None:
+        """不以 --- 开头的文本应返回空字典。"""
+        text = "Just plain markdown.\n"
+        assert parse_frontmatter(text) == {}
+
+    def test_ignores_unknown_fields(self) -> None:
+        """非目标字段应被忽略。"""
+        text = "---\nname: s1\nauthor: someone\n---\nBody\n"
+        result = parse_frontmatter(text)
+        assert result == {"name": "s1"}
+        assert "author" not in result
+
+    def test_single_quoted_value(self) -> None:
+        """单引号包裹的值应去除引号。"""
+        text = "---\nname: 'quoted_name'\n---\nBody\n"
+        result = parse_frontmatter(text)
+        assert result["name"] == "quoted_name"
+
+
+# ── strip_frontmatter ──────────────────────────────────────────────
+
+
+class TestStripFrontmatter:
+    """strip_frontmatter 的测试集。"""
+
+    def test_strips_frontmatter(self) -> None:
+        """正常情况下应去除 frontmatter，返回正文。"""
+        text = "---\nname: x\n---\nBody content.\n"
+        assert strip_frontmatter(text) == "Body content.\n"
+
+    def test_no_frontmatter_returns_original(self) -> None:
+        """无 frontmatter 时应返回原文。"""
+        text = "No frontmatter here.\n"
+        assert strip_frontmatter(text) == text
+
+    def test_incomplete_frontmatter_returns_original(self) -> None:
+        """不完整 frontmatter（缺结束符）应返回原文。"""
+        text = "---\nname: x\nstill going\n"
+        assert strip_frontmatter(text) == text
+
+
+# ── SkillRegistry ──────────────────────────────────────────────────
+
+
+class TestSkillRegistry:
+    """SkillRegistry 的测试集。"""
+
+    def test_read_normal(self, tmp_path: Path) -> None:
+        """read 应返回去除 frontmatter 后的正文。"""
+        skill_file = tmp_path / "skill_a.md"
+        skill_file.write_text("---\nname: skill_a\n---\nSkill A body.\n", encoding="utf-8")
+
+        registry = SkillRegistry()
+        registry.set_paths({"skill_a": skill_file})
+        assert registry.read("skill_a") == "Skill A body.\n"
+
+    def test_read_unregistered_raises_key_error(self) -> None:
+        """读取未注册的技能应抛出 KeyError。"""
+        registry = SkillRegistry()
+        with pytest.raises(KeyError):
+            registry.read("nonexistent")
+
+
+# ── discover_skills ────────────────────────────────────────────────
+
+
+class TestDiscoverSkills:
+    """discover_skills 的测试集。"""
+
+    def _write_skill(self, path: Path, content: str) -> None:
+        """辅助方法：写入技能文件。"""
+        path.write_text(content, encoding="utf-8")
+
+    def test_always_skill(self, tmp_path: Path) -> None:
+        """always=true 的技能应出现在 always_text 中。"""
+        self._write_skill(
+            tmp_path / "always_skill.md",
+            "---\nname: a1\ndescription: always on\nalways: true\n---\nAlways body.\n",
+        )
+        always_text, task_map, catalog_text, registry = discover_skills(tmp_path)
+
+        assert "Always body." in always_text
+        assert task_map == {}
+        assert "a1" not in catalog_text
+
+    def test_task_type_skill(self, tmp_path: Path) -> None:
+        """有 task_type 的非 always 技能应出现在 task_skill_map 中。"""
+        self._write_skill(
+            tmp_path / "task_skill.md",
+            "---\nname: t1\ndescription: task skill\ntask_type: qa\n---\nTask body.\n",
+        )
+        always_text, task_map, catalog_text, registry = discover_skills(tmp_path)
+
+        assert always_text == ""
+        assert task_map == {"qa": "Task body.\n"}
+        assert "t1" in catalog_text
+
+    def test_catalog_skill(self, tmp_path: Path) -> None:
+        """普通技能应出现在 catalog_text 和 registry 中。"""
+        self._write_skill(
+            tmp_path / "cat_skill.md",
+            "---\nname: c1\ndescription: catalog skill\n---\nCatalog body.\n",
+        )
+        always_text, task_map, catalog_text, registry = discover_skills(tmp_path)
+
+        assert always_text == ""
+        assert task_map == {}
+        assert "**c1**" in catalog_text
+        assert "catalog skill" in catalog_text
+        assert registry.read("c1") == "Catalog body.\n"
+
+    def test_empty_directory(self, tmp_path: Path) -> None:
+        """空目录应返回所有空值。"""
+        always_text, task_map, catalog_text, registry = discover_skills(tmp_path)
+
+        assert always_text == ""
+        assert task_map == {}
+        assert catalog_text == ""
+
+    def test_nonexistent_directory(self, tmp_path: Path) -> None:
+        """不存在的目录应返回所有空值。"""
+        missing = tmp_path / "no_such_dir"
+        always_text, task_map, catalog_text, registry = discover_skills(missing)
+
+        assert always_text == ""
+        assert task_map == {}
+        assert catalog_text == ""
+
+    def test_mixed_skills(self, tmp_path: Path) -> None:
+        """混合 always / task_type / catalog 技能应正确分类。"""
+        self._write_skill(
+            tmp_path / "01_always.md",
+            "---\nname: a1\ndescription: always\nalways: true\n---\nA body.\n",
+        )
+        self._write_skill(
+            tmp_path / "02_task.md",
+            "---\nname: t1\ndescription: task\ntask_type: summary\n---\nT body.\n",
+        )
+        self._write_skill(
+            tmp_path / "03_catalog.md",
+            "---\nname: c1\ndescription: catalog\n---\nC body.\n",
+        )
+        always_text, task_map, catalog_text, registry = discover_skills(tmp_path)
+
+        assert "A body." in always_text
+        assert task_map == {"summary": "T body.\n"}
+        assert "**t1**" in catalog_text
+        assert "**c1**" in catalog_text
+        # always 技能不应出现在 catalog 或 registry 中
+        assert "a1" not in catalog_text
+
+    def test_skip_no_name(self, tmp_path: Path) -> None:
+        """没有 name 字段的技能文件应被跳过。"""
+        self._write_skill(
+            tmp_path / "bad.md",
+            "---\ndescription: no name\n---\nBody.\n",
+        )
+        always_text, task_map, catalog_text, registry = discover_skills(tmp_path)
+
+        assert always_text == ""
+        assert task_map == {}
+        assert catalog_text == ""