Fix #6089: Widen litellm dependency constraint to >=1.84.0,<2

The litellm extra was pinned to >=1.83.7,<1.84, but all versions in
that range have transitive dependency conflicts with crewAI's core
requirements:
- litellm 1.83.7 pins python-dotenv==1.0.1 (crewAI needs >=1.2.2)
- litellm 1.83.8 pins openai==2.24.0 (crewAI needs >=2.30.0)
- litellm 1.83.14 pins openai==2.24.0

litellm 1.84.0+ relaxes these to openai>=2.20.0,<3 and
python-dotenv>=1.0.0,<2, which are compatible with crewAI's bounds.

Adds regression tests verifying the dependency bounds stay compatible.

Co-Authored-By: João <joao@crewai.com>

lib/crewai/pyproject.toml

@@ -87,7 +87,7 @@ voyageai = [
     "voyageai~=0.3.5",
 ]
 litellm = [
-    "litellm>=1.83.7,<1.84",
+    "litellm>=1.84.0,<2",
 ]
 bedrock = [
     "boto3~=1.42.79",

lib/crewai/tests/test_litellm_dependency_compat.py

@@ -0,0 +1,142 @@
+"""Tests for litellm optional dependency compatibility with crewAI core deps.
+
+Regression tests for https://github.com/crewAIInc/crewAI/issues/6089:
+the litellm extra must not pin versions whose transitive dependencies
+conflict with crewAI's own requirements (openai, python-dotenv, etc.).
+"""
+
+import sys
+import tomllib
+from pathlib import Path
+
+import pytest
+from packaging.specifiers import SpecifierSet
+from packaging.version import Version
+
+PYPROJECT_PATH = Path(__file__).resolve().parents[1] / "pyproject.toml"
+
+
+@pytest.fixture(scope="module")
+def pyproject():
+    """Load lib/crewai/pyproject.toml as a dict."""
+    with open(PYPROJECT_PATH, "rb") as f:
+        return tomllib.load(f)
+
+
+def _parse_specifier(dep_string: str) -> tuple[str, SpecifierSet]:
+    """Split 'pkg>=1.2,<3' into ('pkg', SpecifierSet('>=1.2,<3'))."""
+    for op in (">=", "<=", "~=", "==", "!=", ">", "<"):
+        idx = dep_string.find(op)
+        if idx != -1:
+            name = dep_string[:idx].strip()
+            spec = dep_string[idx:].split(";")[0].strip()
+            return name, SpecifierSet(spec)
+    return dep_string.strip(), SpecifierSet()
+
+
+class TestLitellmDependencyBounds:
+    """Verify the litellm optional-dependency range is resolvable."""
+
+    def test_litellm_extra_exists(self, pyproject):
+        """The litellm optional dependency group must be defined."""
+        opt_deps = pyproject["project"]["optional-dependencies"]
+        assert "litellm" in opt_deps, "Missing 'litellm' optional-dependency group"
+
+    def test_litellm_lower_bound_at_least_1_84(self, pyproject):
+        """litellm lower bound must be >= 1.84.0 to avoid transitive conflicts.
+
+        Versions < 1.84 pin openai and python-dotenv to ranges that are
+        incompatible with crewAI's core requirements.
+        """
+        opt_deps = pyproject["project"]["optional-dependencies"]
+        litellm_deps = opt_deps["litellm"]
+        litellm_dep = [d for d in litellm_deps if d.startswith("litellm")]
+        assert litellm_dep, "No litellm dependency found in litellm extras"
+
+        _, spec = _parse_specifier(litellm_dep[0])
+
+        # 1.83.x versions have conflicting transitive deps; must be excluded
+        assert not spec.contains(Version("1.83.7")), (
+            "litellm 1.83.7 must be excluded (pins python-dotenv==1.0.1)"
+        )
+        assert not spec.contains(Version("1.83.8")), (
+            "litellm 1.83.8 must be excluded (pins openai==2.24.0)"
+        )
+        assert not spec.contains(Version("1.83.14")), (
+            "litellm 1.83.14 must be excluded (pins openai==2.24.0)"
+        )
+
+        # 1.84.0+ relaxes transitive pins to compatible bounds
+        assert spec.contains(Version("1.84.0")), (
+            "litellm 1.84.0 should be allowed (compatible transitive deps)"
+        )
+
+    def test_litellm_upper_bound_allows_recent_versions(self, pyproject):
+        """litellm range must accept recent 1.x releases."""
+        opt_deps = pyproject["project"]["optional-dependencies"]
+        litellm_deps = opt_deps["litellm"]
+        litellm_dep = [d for d in litellm_deps if d.startswith("litellm")]
+
+        _, spec = _parse_specifier(litellm_dep[0])
+
+        # Ensure reasonable recent versions are included
+        assert spec.contains(Version("1.87.0")), (
+            "litellm 1.87.x should be allowed"
+        )
+        assert spec.contains(Version("1.90.0")), (
+            "litellm 1.90.x should be allowed"
+        )
+
+    def test_litellm_range_excludes_v2(self, pyproject):
+        """litellm range must not include v2 (potential breaking changes)."""
+        opt_deps = pyproject["project"]["optional-dependencies"]
+        litellm_deps = opt_deps["litellm"]
+        litellm_dep = [d for d in litellm_deps if d.startswith("litellm")]
+
+        _, spec = _parse_specifier(litellm_dep[0])
+
+        assert not spec.contains(Version("2.0.0")), (
+            "litellm 2.x should be excluded to avoid breaking changes"
+        )
+
+    def test_core_openai_dep_compatible_with_litellm_range(self, pyproject):
+        """crewAI's openai requirement must be satisfiable alongside litellm>=1.84.
+
+        litellm>=1.84.0 requires openai>=2.20.0,<3.0.0, which overlaps
+        with crewAI's openai>=2.30.0,<3.
+        """
+        deps = pyproject["project"]["dependencies"]
+        openai_deps = [d for d in deps if d.startswith("openai")]
+        assert openai_deps, "openai must be a core dependency"
+
+        _, crewai_openai_spec = _parse_specifier(openai_deps[0])
+
+        # litellm>=1.84 allows openai>=2.20.0,<3.0.0
+        # crewAI requires openai>=2.30.0,<3
+        # The intersection should be non-empty
+        test_version = Version("2.30.0")
+        litellm_openai_spec = SpecifierSet(">=2.20.0,<3.0.0")
+        assert crewai_openai_spec.contains(test_version) and litellm_openai_spec.contains(test_version), (
+            "openai 2.30.0 must satisfy both crewAI and litellm>=1.84 requirements"
+        )
+
+    def test_core_python_dotenv_dep_compatible_with_litellm_range(self, pyproject):
+        """crewAI's python-dotenv requirement must be satisfiable alongside litellm>=1.84.
+
+        litellm>=1.84.0 requires python-dotenv>=1.0.0,<2.0, which overlaps
+        with crewAI's python-dotenv>=1.2.2,<2.
+        """
+        deps = pyproject["project"]["dependencies"]
+        dotenv_deps = [d for d in deps if d.startswith("python-dotenv")]
+        assert dotenv_deps, "python-dotenv must be a core dependency"
+
+        _, crewai_dotenv_spec = _parse_specifier(dotenv_deps[0])
+
+        # litellm>=1.84 allows python-dotenv>=1.0.0,<2.0
+        # crewAI requires python-dotenv>=1.2.2,<2
+        # The intersection should be non-empty
+        test_version = Version("1.2.2")
+        litellm_dotenv_spec = SpecifierSet(">=1.0.0,<2.0")
+        assert crewai_dotenv_spec.contains(test_version) and litellm_dotenv_spec.contains(test_version), (
+            "python-dotenv 1.2.2 must satisfy both crewAI and litellm>=1.84 requirements"
+        )