Make stac-pydantic optional

CHANGELOG.md

@@ -8,6 +8,13 @@ The format is (loosely) based on [Keep a Changelog](http://keepachangelog.com/)
 
 ### Changed
 
+- Made `stac-pydantic` an optional dependency ([#129](https://github.com/stac-utils/stac-check/pull/129))
+  - `stac-validator` is now installed without the `[pydantic]` extra by default
+  - Added `stac-check[pydantic]` extra for users who need pydantic validation
+  - Added graceful fallback to JSONSchema validation when pydantic is not available
+  - Updated tests to handle both scenarios (with and without pydantic installed)
+  - Added helpful warning messages when pydantic is requested but not installed
+
 - Migrated documentation from Read the Docs to GitHub Pages ([#128](https://github.com/stac-utils/stac-check/pull/128))
   - Updated documentation build system to use Sphinx with sphinx_rtd_theme
   - Added support for Markdown content in documentation using myst-parser

setup.py

@@ -20,7 +20,7 @@
         "requests>=2.32.3",
         "jsonschema>=4.23.0",
         "click>=8.1.8",
-        "stac-validator[pydantic]>=3.7.0",
+        "stac-validator>=3.7.0",
         "PyYAML",
         "python-dotenv",
     ],
@@ -29,13 +29,15 @@
             "pytest",
             "requests-mock",
             "types-setuptools",
+            "stac-validator[pydantic]",
         ],
         "docs": [
             "sphinx>=4.0.0",
             "sphinx_rtd_theme>=1.0.0",
             "myst-parser>=0.18.0",
             "sphinx-autodoc-typehints>=1.18.0",
         ],
+        "pydantic": ["stac-validator[pydantic]"],
     },
     entry_points={"console_scripts": ["stac-check=stac_check.cli:main"]},
     author="Jonathan Healy",

stac_check/cli.py

@@ -223,12 +223,24 @@ def cli_message(linter: Linter) -> None:
 @click.option(
     "--pydantic",
     is_flag=True,
-    help="Use stac-pydantic for enhanced validation with Pydantic models.",
+    help="Use pydantic validation (requires stac-pydantic to be installed).",
 )
 @click.command()
 @click.argument("file")
 @click.version_option(version=importlib.metadata.distribution("stac-check").version)
 def main(file, recursive, max_depth, assets, links, no_assets_urls, header, pydantic):
+    # Check if pydantic validation is requested but not installed
+    if pydantic:
+        try:
+            importlib.import_module("stac_pydantic")
+        except ImportError:
+            click.secho(
+                "Warning: stac-pydantic is not installed. Pydantic validation will be disabled.\n"
+                "To enable pydantic validation, install it with: pip install stac-check[pydantic]",
+                fg="yellow",
+            )
+            pydantic = False
+
     linter = Linter(
         file,
         assets=assets,

stac_check/lint.py

@@ -141,6 +141,21 @@ def check_summaries(self) -> bool:
     pydantic: bool = False
 
     def __post_init__(self):
+        # Check if pydantic validation is requested but not installed
+        if self.pydantic:
+            try:
+                importlib.import_module("stac_pydantic")
+            except ImportError:
+                import warnings
+
+                warnings.warn(
+                    "stac-pydantic is not installed. Pydantic validation will be disabled. "
+                    "Install it with: pip install stac-check[pydantic]",
+                    UserWarning,
+                    stacklevel=2,
+                )
+                self.pydantic = False
+
         self.data = self.load_data(self.item)
         self.message = self.validate_file(self.item)
         self.config = self.parse_config(self.config_file)

tests/test_lint.py

@@ -923,34 +923,60 @@ def test_bbox_antimeridian():
     assert linter.check_bbox_antimeridian() == True
 
 
+# Check if stac-pydantic is available
+try:
+    import importlib
+
+    importlib.import_module("stac_pydantic")
+    PYDANTIC_AVAILABLE = True
+except ImportError:
+    PYDANTIC_AVAILABLE = False
+
+# Test decorator for pydantic tests
+pytest.mark.pydantic = pytest.mark.skipif(
+    not PYDANTIC_AVAILABLE,
+    reason="stac-pydantic is not installed. Run 'pip install -e .[dev]' to install test dependencies.",
+)
+
+
+@pytest.mark.pydantic
 def test_lint_pydantic_validation_valid():
     """Test pydantic validation with a valid STAC item."""
     file = "sample_files/1.0.0/core-item.json"
     linter = Linter(file, pydantic=True)
 
-    assert linter.valid_stac == True
+    assert linter.valid_stac is True
     assert linter.asset_type == "ITEM"
-    assert "stac-pydantic Item model" in linter.message["schema"]
+    assert any("stac-pydantic" in schema for schema in linter.message["schema"])
     assert linter.message["validation_method"] == "pydantic"
 
 
+@pytest.mark.pydantic
 def test_lint_pydantic_validation_invalid():
     """Test pydantic validation with an invalid STAC item (missing required fields)."""
     file = "sample_files/1.0.0/bad-item.json"
     linter = Linter(file, pydantic=True)
 
-    assert linter.valid_stac == False
+    assert linter.valid_stac is False
     assert "PydanticValidationError" in linter.message["error_type"]
     assert "id: Field required" in linter.message["error_message"]
-    assert linter.message["validation_method"] == "pydantic"
 
 
-def test_lint_pydantic_validation_recursive():
-    """Test pydantic validation with recursive option."""
-    file = "sample_files/1.0.0/collection.json"
-    linter = Linter(file, recursive=True, max_depth=1, pydantic=True)
+def test_pydantic_fallback_without_import(monkeypatch):
+    """Test that pydantic validation falls back to JSONSchema when stac-pydantic is not available."""
+    # Skip this test if stac-pydantic is actually installed
+    if PYDANTIC_AVAILABLE:
+        pytest.skip("stac-pydantic is installed, skipping fallback test")
 
-    assert linter.valid_stac == True
-    assert linter.asset_type == "COLLECTION"
-    assert "stac-pydantic Collection model" in linter.message["schema"]
-    assert linter.message["validation_method"] == "pydantic"
+    # Test that pydantic=False works without stac-pydantic
+    file = "sample_files/1.0.0/core-item.json"
+    linter = Linter(file, pydantic=False)
+    assert linter.valid_stac is True
+    assert linter.asset_type == "ITEM"
+    assert linter.message["validation_method"] == "default"
+
+    # Test that pydantic=True falls back to JSONSchema when stac-pydantic is not available
+    linter = Linter(file, pydantic=True)
+    assert linter.valid_stac is True
+    assert linter.asset_type == "ITEM"
+    assert linter.message["validation_method"] == "default"