fix(jsonschemagen): avoid duplicate subschemas

Signed-off-by: Silvano Cirujano Cuesta <silvano.cirujano-cuesta@siemens.com>

Author: Silvanoc

packages/linkml/src/linkml/generators/jsonschemagen.py

@@ -57,6 +57,25 @@
 }
 
 
+def _deduplicate_subschemas(subschemas: list["JsonSchema"]) -> list["JsonSchema"]:
+    """Return *subschemas* with duplicate entries removed, preserving order.
+
+    Two subschemas are considered duplicates when their JSON representations are
+    identical.  This can occur, for example, when multiple ``any_of`` branches
+    point to different classes whose identifier slot shares the same scalar type
+    (e.g. both ``Person.id`` and ``Organization.id`` have ``range: string``),
+    producing redundant ``{"type": "string"}`` entries.
+    """
+    seen: set[str] = set()
+    result: list[JsonSchema] = []
+    for schema in subschemas:
+        key = json.dumps(schema, sort_keys=True)
+        if key not in seen:
+            seen.add(key)
+            result.append(schema)
+    return result
+
+
 def _slot_examples_for_json_schema(
     examples: list[Example],
     *,
@@ -857,19 +876,27 @@ def get_subschema_for_slot(
 
         bool_subschema = JsonSchema()
         if slot.any_of is not None and len(slot.any_of) > 0:
-            bool_subschema["anyOf"] = [self.get_subschema_for_slot(s, include_null=False) for s in slot.any_of]
+            bool_subschema["anyOf"] = _deduplicate_subschemas(
+                [self.get_subschema_for_slot(s, include_null=False) for s in slot.any_of]
+            )
             if not slot.required and not prop.is_array and include_null:
                 bool_subschema["anyOf"].append({"type": "null"})
 
         if slot.all_of is not None and len(slot.all_of) > 0:
-            bool_subschema["allOf"] = [self.get_subschema_for_slot(s, include_null=False) for s in slot.all_of]
+            bool_subschema["allOf"] = _deduplicate_subschemas(
+                [self.get_subschema_for_slot(s, include_null=False) for s in slot.all_of]
+            )
 
         if slot.exactly_one_of is not None and len(slot.exactly_one_of) > 0:
-            bool_subschema["oneOf"] = [self.get_subschema_for_slot(s, include_null=False) for s in slot.exactly_one_of]
+            bool_subschema["oneOf"] = _deduplicate_subschemas(
+                [self.get_subschema_for_slot(s, include_null=False) for s in slot.exactly_one_of]
+            )
 
         if slot.none_of is not None and len(slot.none_of) > 0:
             bool_subschema["not"] = {
-                "anyOf": [self.get_subschema_for_slot(s, include_null=False) for s in slot.none_of]
+                "anyOf": _deduplicate_subschemas(
+                    [self.get_subschema_for_slot(s, include_null=False) for s in slot.none_of]
+                )
             }
 
         if bool_subschema:

tests/linkml/test_scripts/__snapshots__/genjsonschema/meta.json

@@ -122,9 +122,6 @@
             "properties": {
                 "attribute2": {
                     "anyOf": [
-                        {
-                            "type": "string"
-                        },
                         {
                             "type": "string"
                         },

tests/linkml/test_scripts/__snapshots__/genjsonschema/meta_inline.json

@@ -122,9 +122,6 @@
             "properties": {
                 "attribute2": {
                     "anyOf": [
-                        {
-                            "type": "string"
-                        },
                         {
                             "type": "string"
                         },