{
  "id": "python/pip-pep517-requires-build-deps",
  "signature": "ERROR: Some build dependencies for package are missing: 'cython' is required to build the package but is not installed.",
  "signature_zh": "错误：package 的某些构建依赖缺失：构建该包需要 'cython'，但未安装。",
  "regex": "ERROR:\\ Some\\ build\\ dependencies\\ for\\ package\\ are\\ missing:\\ 'cython'\\ is\\ required\\ to\\ build\\ the\\ package\\ but\\ is\\ not\\ installed\\.",
  "domain": "python",
  "category": "install_error",
  "subcategory": null,
  "root_cause": "The project's build-system.requires lists a build dependency that pip cannot fetch or that is not installed when --no-build-isolation is used.",
  "root_cause_type": "generic",
  "root_cause_zh": "项目的 build-system.requires 列出了 pip 无法获取的构建依赖，或在使用 --no-build-isolation 时未安装的依赖。",
  "versions": [
    {
      "version": "3.x",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    }
  ],
  "os_specific": {},
  "dead_ends": [
    {
      "action": "",
      "why_fails": "Installing in the host env does not help when build isolation is enabled; the isolated env still lacks it.",
      "fail_rate": 0.8,
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "why_fails": "The build actually needs Cython; removing it causes a different error (missing .c files).",
      "fail_rate": 0.85,
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "why_fails": "--no-deps affects runtime deps, not build-time deps.",
      "fail_rate": 0.9,
      "condition": "",
      "sources": []
    }
  ],
  "workarounds": [
    {
      "action": "",
      "success_rate": 0.88,
      "how": "Install build deps in the host and disable isolation: pip install cython && pip install --no-build-isolation .",
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "success_rate": 0.92,
      "how": "Ensure build-system.requires is correct: [build-system]\\nrequires = [\"setuptools>=61\", \"cython>=3.0\"]\\nbuild-backend = \"setuptools.build_meta\"",
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "success_rate": 0.85,
      "how": "Check network access to fetch build deps: pip download cython -d /tmp/cython-test",
      "condition": "",
      "sources": []
    }
  ],
  "workarounds_zh": [],
  "transition_graph": {
    "leads_to": [],
    "preceded_by": [],
    "frequently_confused_with": []
  },
  "official_doc_url": null,
  "official_doc_section": null,
  "error_code": null,
  "verification_tier": "ai_generated",
  "confidence": 0.85,
  "fix_success_rate": 0.8,
  "resolvable": "true",
  "first_seen": "2026-01-15",
  "last_confirmed": "2025-01-01",
  "last_updated": "2025-01-01",
  "evidence_count": 0,
  "tags": [],
  "locale": "en",
  "aliases": []
}