added regex constraint for mlm:framework to migration

Author: jonas-hurst

pystac/extensions/mlm.py

@@ -8,6 +8,7 @@
 
 from __future__ import annotations
 
+import warnings
 from abc import ABC
 from collections.abc import Iterable
 from typing import Any, Generic, Literal, TypeVar, cast
@@ -2055,10 +2056,39 @@ class MLMExtensionHooks(ExtensionHooks):
     @staticmethod
     def _migrate_1_0_to_1_1(obj: dict[str, Any]) -> None:
         if "mlm:framework" in obj["properties"]:
+            framework = obj["properties"]["mlm:framework"]
+            # remove invalid characters at beginning and end
+            forbidden_chars = [".", "_", "-", " ", "\t", "\n", "\r", "\f", "\v"]
+            if framework[0] in forbidden_chars or framework[-1] in forbidden_chars:
+                warnings.warn(
+                    "Value for mlm:framework is invalid in mlm>=1.1, as it must"
+                    "not start or end with one of the following characters: "
+                    "._- and whitespace. These characters are therefore removed while"
+                    "migrating the STAC object to v1.1.",
+                    SyntaxWarning,
+                )
+                while obj["properties"]["mlm:framework"][0] in forbidden_chars:
+                    new_str = obj["properties"]["mlm:framework"][1:]
+                    obj["properties"]["mlm:framework"] = new_str
+                while obj["properties"]["mlm:framework"][-1] in forbidden_chars:
+                    new_str = obj["properties"]["mlm:framework"][:-1]
+                    obj["properties"]["mlm:framework"] = new_str
+
+            # rename frameworks
             if obj["properties"]["mlm:framework"] == "Scikit-learn":
                 obj["properties"]["mlm:framework"] = "scikit-learn"
+                warnings.warn(
+                    "mlm:framework value Scikit-learn is no longer valid in mlm>=1.1. "
+                    "Renaming it to scikit-learn",
+                    SyntaxWarning,
+                )
             if obj["properties"]["mlm:framework"] == "Huggingface":
                 obj["properties"]["mlm:framework"] = "Hugging Face"
+                warnings.warn(
+                    "mlm:framework value Huggingface is no longer valid in mlm>=1.1. "
+                    "Renaming it to Hugging Face",
+                    SyntaxWarning,
+                )
 
     @staticmethod
     def _migrate_1_1_to_1_2(obj: dict[str, Any]) -> None:

tests/extensions/test_mlm.py

@@ -1,5 +1,6 @@
 import json
 import logging
+import re
 from copy import deepcopy
 from typing import Any, cast
 
@@ -1075,20 +1076,35 @@ def test_raise_exception_on_mlm_extension_and_asset() -> None:
 
 
 @pytest.mark.parametrize(
-    "framework_old, framework_new",
-    ((None, None), ("Scikit-learn", "scikit-learn"), ("Huggingface", "Hugging Face")),
+    "framework_old, framework_new, valid",
+    (
+        ("Scikit-learn", "scikit-learn", False),
+        ("Huggingface", "Hugging Face", False),
+        ("-_ .asdf", "asdf", False),
+        ("asdf-_ .", "asdf", False),
+        ("-._   asdf-.", "asdf", False),
+        ("test_framework", "test_framework", True),
+    ),
 )
 def test_migration_1_0_to_1_1(
-    framework_old: None | str, framework_new: None | str
+    framework_old: None | str, framework_new: None | str, valid: bool
 ) -> None:
     data: dict[str, Any] = {"properties": {}}
 
     MLMExtensionHooks._migrate_1_0_to_1_1(data)
     assert "mlm:framework" not in data["properties"]
 
+    pattern = r"^(?=[^\s._\-]).*[^\s._\-]$"
     data["properties"]["mlm:framework"] = framework_old
-    MLMExtensionHooks._migrate_1_0_to_1_1(data)
+
+    if valid:
+        MLMExtensionHooks._migrate_1_0_to_1_1(data)
+    else:
+        with pytest.warns(SyntaxWarning):
+            MLMExtensionHooks._migrate_1_0_to_1_1(data)
+
     assert data["properties"]["mlm:framework"] == framework_new
+    assert bool(re.match(pattern, data["properties"]["mlm:framework"]))
 
 
 @pytest.mark.parametrize(