Initial commit: hardened DeerFlow factory

Vendored deer-flow upstream (bytedance/deer-flow) plus prompt-injection
hardening:

- New deerflow.security package: content_delimiter, html_cleaner,
  sanitizer (8 layers — invisible chars, control chars, symbols, NFC,
  PUA, tag chars, horizontal whitespace collapse with newline/tab
  preservation, length cap)
- New deerflow.community.searx package: web_search, web_fetch,
  image_search backed by a private SearX instance, every external
  string sanitized and wrapped in <<<EXTERNAL_UNTRUSTED_CONTENT>>>
  delimiters
- All native community web providers (ddg_search, tavily, exa,
  firecrawl, jina_ai, infoquest, image_search) replaced with hard-fail
  stubs that raise NativeWebToolDisabledError at import time, so a
  misconfigured tool.use path fails loud rather than silently falling
  back to unsanitized output
- Native client back-doors (jina_client.py, infoquest_client.py)
  stubbed too
- Native-tool tests quarantined under tests/_disabled_native/
  (collect_ignore_glob via local conftest.py)
- Sanitizer Layer 7 fix: only collapse horizontal whitespace, preserve
  newlines and tabs so list/table structure survives
- Hardened runtime config.yaml references only the searx-backed tools
- Factory overlay (backend/) kept in sync with deer-flow tree as a
  reference / source

See HARDENING.md for the full audit trail and verification steps.

deer-flow/backend/tests/test_tracing_config.py

@@ -0,0 +1,146 @@
+"""Tests for deerflow.config.tracing_config."""
+
+from __future__ import annotations
+
+import pytest
+
+from deerflow.config import tracing_config as tracing_module
+
+
+def _reset_tracing_cache() -> None:
+    tracing_module._tracing_config = None
+
+
+@pytest.fixture(autouse=True)
+def clear_tracing_env(monkeypatch):
+    for name in (
+        "LANGSMITH_TRACING",
+        "LANGCHAIN_TRACING_V2",
+        "LANGCHAIN_TRACING",
+        "LANGSMITH_API_KEY",
+        "LANGCHAIN_API_KEY",
+        "LANGSMITH_PROJECT",
+        "LANGCHAIN_PROJECT",
+        "LANGSMITH_ENDPOINT",
+        "LANGCHAIN_ENDPOINT",
+        "LANGFUSE_TRACING",
+        "LANGFUSE_PUBLIC_KEY",
+        "LANGFUSE_SECRET_KEY",
+        "LANGFUSE_BASE_URL",
+    ):
+        monkeypatch.delenv(name, raising=False)
+    _reset_tracing_cache()
+    yield
+    _reset_tracing_cache()
+
+
+def test_prefers_langsmith_env_names(monkeypatch):
+    monkeypatch.setenv("LANGSMITH_TRACING", "true")
+    monkeypatch.setenv("LANGSMITH_API_KEY", "lsv2_key")
+    monkeypatch.setenv("LANGSMITH_PROJECT", "smith-project")
+    monkeypatch.setenv("LANGSMITH_ENDPOINT", "https://smith.example.com")
+
+    _reset_tracing_cache()
+    cfg = tracing_module.get_tracing_config()
+
+    assert cfg.langsmith.enabled is True
+    assert cfg.langsmith.api_key == "lsv2_key"
+    assert cfg.langsmith.project == "smith-project"
+    assert cfg.langsmith.endpoint == "https://smith.example.com"
+    assert tracing_module.is_tracing_enabled() is True
+    assert tracing_module.get_enabled_tracing_providers() == ["langsmith"]
+
+
+def test_falls_back_to_langchain_env_names(monkeypatch):
+    monkeypatch.delenv("LANGSMITH_TRACING", raising=False)
+    monkeypatch.delenv("LANGSMITH_API_KEY", raising=False)
+    monkeypatch.delenv("LANGSMITH_PROJECT", raising=False)
+    monkeypatch.delenv("LANGSMITH_ENDPOINT", raising=False)
+
+    monkeypatch.setenv("LANGCHAIN_TRACING_V2", "true")
+    monkeypatch.setenv("LANGCHAIN_API_KEY", "legacy-key")
+    monkeypatch.setenv("LANGCHAIN_PROJECT", "legacy-project")
+    monkeypatch.setenv("LANGCHAIN_ENDPOINT", "https://legacy.example.com")
+
+    _reset_tracing_cache()
+    cfg = tracing_module.get_tracing_config()
+
+    assert cfg.langsmith.enabled is True
+    assert cfg.langsmith.api_key == "legacy-key"
+    assert cfg.langsmith.project == "legacy-project"
+    assert cfg.langsmith.endpoint == "https://legacy.example.com"
+    assert tracing_module.is_tracing_enabled() is True
+    assert tracing_module.get_enabled_tracing_providers() == ["langsmith"]
+
+
+def test_langsmith_tracing_false_overrides_langchain_tracing_v2_true(monkeypatch):
+    """LANGSMITH_TRACING=false must win over LANGCHAIN_TRACING_V2=true."""
+    monkeypatch.setenv("LANGSMITH_TRACING", "false")
+    monkeypatch.setenv("LANGCHAIN_TRACING_V2", "true")
+    monkeypatch.setenv("LANGSMITH_API_KEY", "some-key")
+
+    _reset_tracing_cache()
+    cfg = tracing_module.get_tracing_config()
+
+    assert cfg.langsmith.enabled is False
+    assert tracing_module.is_tracing_enabled() is False
+    assert tracing_module.get_enabled_tracing_providers() == []
+
+
+def test_defaults_when_project_not_set(monkeypatch):
+    monkeypatch.setenv("LANGSMITH_TRACING", "yes")
+    monkeypatch.setenv("LANGSMITH_API_KEY", "key")
+    monkeypatch.delenv("LANGSMITH_PROJECT", raising=False)
+    monkeypatch.delenv("LANGCHAIN_PROJECT", raising=False)
+
+    _reset_tracing_cache()
+    cfg = tracing_module.get_tracing_config()
+
+    assert cfg.langsmith.project == "deer-flow"
+
+
+def test_langfuse_config_is_loaded(monkeypatch):
+    monkeypatch.setenv("LANGFUSE_TRACING", "true")
+    monkeypatch.setenv("LANGFUSE_PUBLIC_KEY", "pk-lf-test")
+    monkeypatch.setenv("LANGFUSE_SECRET_KEY", "sk-lf-test")
+    monkeypatch.setenv("LANGFUSE_BASE_URL", "https://langfuse.example.com")
+
+    _reset_tracing_cache()
+    cfg = tracing_module.get_tracing_config()
+
+    assert cfg.langfuse.enabled is True
+    assert cfg.langfuse.public_key == "pk-lf-test"
+    assert cfg.langfuse.secret_key == "sk-lf-test"
+    assert cfg.langfuse.host == "https://langfuse.example.com"
+    assert tracing_module.get_enabled_tracing_providers() == ["langfuse"]
+
+
+def test_dual_provider_config_is_loaded(monkeypatch):
+    monkeypatch.setenv("LANGSMITH_TRACING", "true")
+    monkeypatch.setenv("LANGSMITH_API_KEY", "lsv2_key")
+    monkeypatch.setenv("LANGFUSE_TRACING", "true")
+    monkeypatch.setenv("LANGFUSE_PUBLIC_KEY", "pk-lf-test")
+    monkeypatch.setenv("LANGFUSE_SECRET_KEY", "sk-lf-test")
+
+    _reset_tracing_cache()
+    cfg = tracing_module.get_tracing_config()
+
+    assert cfg.langsmith.is_configured is True
+    assert cfg.langfuse.is_configured is True
+    assert tracing_module.is_tracing_enabled() is True
+    assert tracing_module.get_enabled_tracing_providers() == ["langsmith", "langfuse"]
+
+
+def test_langfuse_enabled_requires_public_and_secret_keys(monkeypatch):
+    monkeypatch.setenv("LANGFUSE_TRACING", "true")
+    monkeypatch.delenv("LANGFUSE_PUBLIC_KEY", raising=False)
+    monkeypatch.setenv("LANGFUSE_SECRET_KEY", "sk-lf-test")
+
+    _reset_tracing_cache()
+
+    assert tracing_module.get_tracing_config().is_configured is False
+    assert tracing_module.get_enabled_tracing_providers() == []
+    assert tracing_module.get_tracing_config().explicitly_enabled_providers == ["langfuse"]
+
+    with pytest.raises(ValueError, match="LANGFUSE_PUBLIC_KEY"):
+        tracing_module.validate_enabled_tracing_providers()