fix mlm:artifact_type check missing in assets and other disallowed MLM fields

CHANGELOG.md

@@ -16,6 +16,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   for the entire input (but still possible).
 
 ### Changed
+- Explicitly disallow `mlm:name`, `mlm:input`, `mlm:output` and `mlm:hyperparameters` at the Asset level.
+  These fields describe the model as a whole and should therefore be defined in Item properties.
 - Moved `norm_type` to `value_scaling` object to better reflect the expected operation, which could be another
   operation than what is typically known as "normalization" or "standardization" techniques in machine learning.
 - Moved `statistics` to `value_scaling` object to better reflect their mutual `type` and additional
@@ -34,6 +36,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   Otherwise, the amount of `value_scaling` objects should match the number of bands or channels involved in the input.
 
 ### Fixed
+- Fix missing `mlm:artifact_type` property check for a Model Asset definition
+  (fixes <https://github.com/stac-extensions/mlm/issues/42>).
+  The `mlm:artifact_type` is now mutually and exclusively required by the corresponding Asset with `mlm:model` role.
 - Fix check of disallowed unknown/undefined `mlm:`-prefixed fields
   (fixes [#41](https://github.com/stac-extensions/mlm/issues/41)).
 

examples/item_bands_expression.json

@@ -150,6 +150,7 @@
         "mlm:model",
         "mlm:weights"
       ],
+      "mlm:artifact_type": "torch.save",
       "$comment": "Following 'eo:bands' is required to fulfil schema validation of 'eo' extension.",
       "eo:bands": [
         {

examples/item_basic.json

@@ -120,7 +120,8 @@
       "type": "text/html",
       "roles": [
         "mlm:model"
-      ]
+      ],
+      "mlm:artifact_type": "torch.save"
     }
   },
   "links": [

examples/item_eo_and_raster_bands.json

@@ -508,6 +508,7 @@
         "mlm:model",
         "mlm:weights"
       ],
+      "mlm:artifact_type": "torch.save",
       "$comment": "Following 'eo:bands' is required to fulfil schema validation of 'eo' extension.",
       "eo:bands": [
         {
@@ -557,7 +558,6 @@
       "description": "Source code to run the model.",
       "type": "text/x-python",
       "roles": [
-        "mlm:model",
         "code",
         "metadata"
       ]

examples/item_eo_bands.json

@@ -285,6 +285,7 @@
         "mlm:model",
         "mlm:weights"
       ],
+      "mlm:artifact_type": "torch.save",
       "$comment": "Following 'eo:bands' is required to fulfil schema validation of 'eo' extension.",
       "eo:bands": [
         {

examples/item_eo_bands_summarized.json

@@ -377,6 +377,7 @@
         "mlm:model",
         "mlm:weights"
       ],
+      "mlm:artifact_type": "torch.save",
       "$comment": "Following 'eo:bands' is required to fulfil schema validation of 'eo' extension.",
       "eo:bands": [
         {
@@ -426,7 +427,6 @@
       "description": "Source code to run the model.",
       "type": "text/x-python",
       "roles": [
-        "mlm:model",
         "code",
         "metadata"
       ]

examples/item_multi_io.json

@@ -227,6 +227,7 @@
         "mlm:model",
         "mlm:weights"
       ],
+      "mlm:artifact_type": "torch.save",
       "raster:bands": [
         {
           "name": "B02 - blue",

examples/item_raster_bands.json

@@ -216,6 +216,7 @@
         "mlm:model",
         "mlm:weights"
       ],
+      "mlm:artifact_type": "torch.save",
       "raster:bands": [
         {
           "name": "B01",