Fix string enum serialization (#654)

* Add failing test for RelType serialization

* Fix serialization of string Enum classes

* Add CHANGELOG entry for 654

* Use assertEqual instead of assert + ==

* Use StringEnum in remaining classes inheriting from str, Enum

Author: Jon Duckworth

CHANGELOG.md

@@ -26,6 +26,7 @@
 - `generate_subcatalogs` can include multiple template values in a single subfolder layer 
   ([#595](https://github.com/stac-utils/pystac/pull/595))
 - Avoid implicit re-exports ([#591](https://github.com/stac-utils/pystac/pull/591))
+- Regression where string `Enum` values were not serialized properly in methods like `Link.to_dict` ([#654](https://github.com/stac-utils/pystac/pull/654))
 
 ### Deprecated
 

pystac/catalog.py

@@ -1,6 +1,5 @@
 import os
 from copy import deepcopy
-from enum import Enum
 from pystac.errors import STACTypeError
 from typing import (
     Any,
@@ -29,15 +28,20 @@
     identify_stac_object,
     migrate_to_latest,
 )
-from pystac.utils import is_absolute_href, make_absolute_href, make_relative_href
+from pystac.utils import (
+    StringEnum,
+    is_absolute_href,
+    make_absolute_href,
+    make_relative_href,
+)
 
 if TYPE_CHECKING:
     from pystac.asset import Asset as Asset_Type
     from pystac.item import Item as Item_Type
     from pystac.collection import Collection as Collection_Type
 
 
-class CatalogType(str, Enum):
+class CatalogType(StringEnum):
     SELF_CONTAINED = "SELF_CONTAINED"
     """A 'self-contained catalog' is one that is designed for portability.
     Users may want to download an online catalog from and be able to use it on their

pystac/extensions/datacube.py

@@ -4,7 +4,6 @@
 """
 
 from abc import ABC
-from enum import Enum
 from typing import Any, Dict, Generic, List, Optional, TypeVar, Union, cast
 
 import pystac
@@ -13,7 +12,7 @@
     PropertiesExtension,
 )
 from pystac.extensions.hooks import ExtensionHooks
-from pystac.utils import get_required
+from pystac.utils import StringEnum, get_required
 
 T = TypeVar("T", pystac.Collection, pystac.Item, pystac.Asset)
 
@@ -42,22 +41,22 @@
 VAR_UNIT_PROP = "unit"
 
 
-class DimensionType(str, Enum):
+class DimensionType(StringEnum):
     """Dimension object types for spatial and temporal Dimension Objects."""
 
     SPATIAL = "spatial"
     TEMPORAL = "temporal"
 
 
-class HorizontalSpatialDimensionAxis(str, Enum):
+class HorizontalSpatialDimensionAxis(StringEnum):
     """Allowed values for ``axis`` field of :class:`HorizontalSpatialDimension`
     object."""
 
     X = "x"
     Y = "y"
 
 
-class VerticalSpatialDimensionAxis(str, Enum):
+class VerticalSpatialDimensionAxis(StringEnum):
     """Allowed values for ``axis`` field of :class:`VerticalSpatialDimension`
     object."""
 
@@ -407,7 +406,7 @@ def reference_system(self, v: Optional[Union[str, float, Dict[str, Any]]]) -> No
             self.properties[DIM_REF_SYS_PROP] = v
 
 
-class VariableType(str, Enum):
+class VariableType(StringEnum):
     """Variable object types"""
 
     DATA = "data"

pystac/extensions/file.py

@@ -3,7 +3,6 @@
 https://github.com/stac-extensions/file
 """
 
-from enum import Enum
 from typing import Any, Dict, List, Optional, Union
 
 import pystac
@@ -14,7 +13,7 @@
     STACJSONDescription,
     STACVersionID,
 )
-from pystac.utils import get_required
+from pystac.utils import StringEnum, get_required
 
 SCHEMA_URI = "https://stac-extensions.github.io/file/v2.0.0/schema.json"
 
@@ -26,7 +25,7 @@
 VALUES_PROP = PREFIX + "values"
 
 
-class ByteOrder(str, Enum):
+class ByteOrder(StringEnum):
     """List of allows values for the ``"file:byte_order"`` field defined by the
     :stac-ext:`File Info Extension <file>`."""
 

pystac/extensions/label.py

@@ -3,14 +3,13 @@
 https://github.com/stac-extensions/label
 """
 
-from enum import Enum
 from pystac.extensions.base import ExtensionManagementMixin, SummariesExtension
 from typing import Any, Dict, Iterable, List, Optional, Sequence, Union, cast
 
 import pystac
 from pystac.serialization.identify import STACJSONDescription, STACVersionID
 from pystac.extensions.hooks import ExtensionHooks
-from pystac.utils import get_required, map_opt
+from pystac.utils import StringEnum, get_required, map_opt
 
 SCHEMA_URI = "https://stac-extensions.github.io/label/v1.0.0/schema.json"
 
@@ -25,7 +24,7 @@
 OVERVIEWS_PROP = PREFIX + "overviews"
 
 
-class LabelRelType(str, Enum):
+class LabelRelType(StringEnum):
     """A list of rel types defined in the Label Extension.
 
     See the :stac-ext:`Label Extension Links <label#links-source-imagery>`
@@ -36,7 +35,7 @@ class LabelRelType(str, Enum):
     """Used to indicate a link to the source item to which a label item applies."""
 
 
-class LabelType(str, Enum):
+class LabelType(StringEnum):
     """Enumerates valid label types ("raster" or "vector")."""
 
     VECTOR = "vector"
@@ -46,7 +45,7 @@ class LabelType(str, Enum):
     """Convenience attribute for checking if values are valid label types"""
 
 
-class LabelTask(str, Enum):
+class LabelTask(StringEnum):
     """Enumerates recommended values for "label:tasks" field."""
 
     REGRESSION = "regression"
@@ -55,7 +54,7 @@ class LabelTask(str, Enum):
     SEGMENTATION = "segmentation"
 
 
-class LabelMethod(str, Enum):
+class LabelMethod(StringEnum):
     """Enumerates recommended values for "label:methods" field."""
 
     AUTOMATED = "automated"

pystac/extensions/pointcloud.py

@@ -2,7 +2,6 @@
 
 https://github.com/stac-extensions/pointcloud
 """
-from enum import Enum
 from typing import Any, Dict, Generic, List, Optional, TypeVar, cast, Union
 
 import pystac
@@ -13,7 +12,7 @@
 )
 from pystac.extensions.hooks import ExtensionHooks
 from pystac.summaries import RangeSummary
-from pystac.utils import map_opt, get_required
+from pystac.utils import StringEnum, map_opt, get_required
 
 T = TypeVar("T", pystac.Item, pystac.Asset)
 
@@ -28,7 +27,7 @@
 STATISTICS_PROP = PREFIX + "statistics"
 
 
-class PhenomenologyType(str, Enum):
+class PhenomenologyType(StringEnum):
     """Valid values for the ``pc:type`` field in the :stac-ext:`Pointcloud Item
     Properties <pointcloud#item-properties>`."""
 
@@ -39,7 +38,7 @@ class PhenomenologyType(str, Enum):
     OTHER = "other"
 
 
-class SchemaType(str, Enum):
+class SchemaType(StringEnum):
     """Valid values for the ``type`` field in a :stac-ext:`Schema Object
     <pointcloud#schema-object>`."""
 

pystac/extensions/raster.py

@@ -3,7 +3,6 @@
 https://github.com/stac-extensions/raster
 """
 
-import enum
 from typing import Any, Dict, Iterable, List, Optional, Union
 
 import pystac
@@ -12,19 +11,19 @@
     PropertiesExtension,
     SummariesExtension,
 )
-from pystac.utils import get_opt, get_required, map_opt
+from pystac.utils import StringEnum, get_opt, get_required, map_opt
 
 SCHEMA_URI = "https://stac-extensions.github.io/raster/v1.0.0/schema.json"
 
 BANDS_PROP = "raster:bands"
 
 
-class Sampling(str, enum.Enum):
+class Sampling(StringEnum):
     AREA = "area"
     POINT = "point"
 
 
-class DataType(str, enum.Enum):
+class DataType(StringEnum):
     INT8 = "int8"
     INT16 = "int16"
     INT32 = "int32"

pystac/extensions/sar.py

@@ -3,7 +3,6 @@
 https://github.com/stac-extensions/sar
 """
 
-import enum
 from typing import Any, Dict, Generic, Iterable, List, Optional, TypeVar, cast, Union
 
 import pystac
@@ -15,7 +14,7 @@
     SummariesExtension,
 )
 from pystac.extensions.hooks import ExtensionHooks
-from pystac.utils import get_required, map_opt
+from pystac.utils import StringEnum, get_required, map_opt
 
 T = TypeVar("T", pystac.Item, pystac.Asset)
 
@@ -40,7 +39,7 @@
 OBSERVATION_DIRECTION_PROP: str = PREFIX + "observation_direction"
 
 
-class FrequencyBand(str, enum.Enum):
+class FrequencyBand(StringEnum):
     P = "P"
     L = "L"
     S = "S"
@@ -51,14 +50,14 @@ class FrequencyBand(str, enum.Enum):
     KA = "Ka"
 
 
-class Polarization(str, enum.Enum):
+class Polarization(StringEnum):
     HH = "HH"
     VV = "VV"
     HV = "HV"
     VH = "VH"
 
 
-class ObservationDirection(str, enum.Enum):
+class ObservationDirection(StringEnum):
     LEFT = "left"
     RIGHT = "right"
 

pystac/extensions/sat.py

@@ -3,7 +3,6 @@
 https://github.com/stac-extensions/sat
 """
 
-import enum
 from datetime import datetime as Datetime
 from pystac.summaries import RangeSummary
 from typing import Dict, Any, List, Iterable, Generic, Optional, TypeVar, Union, cast
@@ -15,7 +14,7 @@
     SummariesExtension,
 )
 from pystac.extensions.hooks import ExtensionHooks
-from pystac.utils import str_to_datetime, datetime_to_str, map_opt
+from pystac.utils import StringEnum, str_to_datetime, datetime_to_str, map_opt
 
 T = TypeVar("T", pystac.Item, pystac.Asset)
 
@@ -31,7 +30,7 @@
 ANX_DATETIME_PROP: str = PREFIX + "anx_datetime"
 
 
-class OrbitState(str, enum.Enum):
+class OrbitState(StringEnum):
     ASCENDING = "ascending"
     DESCENDING = "descending"
     GEOSTATIONARY = "geostationary"

pystac/extensions/scientific.py

@@ -8,7 +8,6 @@
 """
 
 import copy
-from enum import Enum
 from typing import Any, Dict, Generic, List, Optional, TypeVar, Union, cast
 from urllib import parse
 
@@ -19,7 +18,7 @@
     SummariesExtension,
 )
 from pystac.extensions.hooks import ExtensionHooks
-from pystac.utils import map_opt
+from pystac.utils import StringEnum, map_opt
 
 T = TypeVar("T", pystac.Collection, pystac.Item)
 
@@ -35,7 +34,7 @@
 
 
 # Link rel type.
-class ScientificRelType(str, Enum):
+class ScientificRelType(StringEnum):
     """A list of rel types defined in the Scientific Citation Extension.
 
     See the :stac-ext:`Scientific Citation Extension Relation types

pystac/extensions/version.py

@@ -2,11 +2,11 @@
 
 https://github.com/stac-extensions/version
 """
-from enum import Enum
 from pystac.utils import get_required, map_opt
 from typing import Generic, List, Optional, TypeVar, Union, cast
 
 import pystac
+from pystac.utils import StringEnum
 from pystac.extensions.base import (
     ExtensionManagementMixin,
     PropertiesExtension,
@@ -23,7 +23,7 @@
 DEPRECATED: str = "deprecated"
 
 
-class VersionRelType(str, Enum):
+class VersionRelType(StringEnum):
     """A list of rel types defined in the Version Extension.
 
     See the `Version Extension Relation types

pystac/media_type.py

@@ -1,7 +1,7 @@
-from enum import Enum
+from pystac.utils import StringEnum
 
 
-class MediaType(str, Enum):
+class MediaType(StringEnum):
     """A list of common media types that can be used in STAC Asset and Link metadata."""
 
     COG = "image/tiff; application=geotiff; profile=cloud-optimized"

pystac/provider.py

@@ -1,8 +1,9 @@
-from enum import Enum
 from typing import Any, Dict, List, Optional
 
+from pystac.utils import StringEnum
 
-class ProviderRole(str, Enum):
+
+class ProviderRole(StringEnum):
     """Enumerates the allows values of the Provider "role" field."""
 
     LICENSOR = "licensor"

pystac/rel_type.py

@@ -1,7 +1,7 @@
-from enum import Enum
+from pystac.utils import StringEnum
 
 
-class RelType(str, Enum):
+class RelType(StringEnum):
     """A list of common rel types that can be used in STAC Link metadata.
     See :stac-spec:`"Using Relation Types <best-practices.md#using-relation-types>`
     in the STAC Best Practices for guidelines on using relation types. You may also want