Fix merging documents with @list elements.

This happens when we find two metadata files each with at least two authors.

swh/indexer/codemeta.py

@@ -186,7 +186,20 @@ def merge_documents(documents):
                         merged_document[SCHEMA_URI + 'sameAs'].append(value)
             else:
                 for value in values:
-                    if value not in merged_document[key]:
+                    if isinstance(value, dict) and set(value) == {'@list'}:
+                        # Value is of the form {'@list': [item1, item2]}
+                        # instead of the usual [item1, item2].
+                        # We need to merge the inner lists (and mostly
+                        # preserve order).
+                        merged_value = merged_document.setdefault(
+                            key, {'@list': []})
+                        for subvalue in value['@list']:
+                            # merged_value must be of the form
+                            # {'@list': [item1, item2]}; as it is the same
+                            # type as value, which is an @list.
+                            if subvalue not in merged_value['@list']:
+                                merged_value['@list'].append(subvalue)
+                    elif value not in merged_document[key]:
                         merged_document[key].append(value)
 
     return compact(merged_document)

swh/indexer/tests/test_codemeta.py

@@ -156,3 +156,128 @@ def test_merge_documents_duplicate_ids():
         "name": ['test_1', 'test_1b', 'test_2']
     }
     assert results == expected_results
+
+
+def test_merge_documents_lists():
+    """Tests merging two @list elements."""
+    # given
+    metadata_list = [{
+        '@context': 'https://doi.org/10.5063/schema/codemeta-2.0',
+        'author': {
+            '@list': [
+                {'name': 'test_1'},
+            ]
+        },
+    }, {
+        '@context': 'https://doi.org/10.5063/schema/codemeta-2.0',
+        'author': {
+            '@list': [
+                {'name': 'test_2'},
+            ]
+        },
+    }]
+
+    # when
+    results = merge_documents(metadata_list)
+
+    # then
+    expected_results = {
+        '@context': 'https://doi.org/10.5063/schema/codemeta-2.0',
+        'author': [
+            {'name': 'test_1'},
+            {'name': 'test_2'},
+        ],
+    }
+    assert results == expected_results
+
+
+def test_merge_documents_lists_duplicates():
+    """Tests merging two @list elements with a duplicate subelement."""
+    # given
+    metadata_list = [{
+        '@context': 'https://doi.org/10.5063/schema/codemeta-2.0',
+        'author': {
+            '@list': [
+                {'name': 'test_1'},
+            ]
+        },
+    }, {
+        '@context': 'https://doi.org/10.5063/schema/codemeta-2.0',
+        'author': {
+            '@list': [
+                {'name': 'test_2'},
+                {'name': 'test_1'},
+            ]
+        },
+    }]
+
+    # when
+    results = merge_documents(metadata_list)
+
+    # then
+    expected_results = {
+        '@context': 'https://doi.org/10.5063/schema/codemeta-2.0',
+        'author': [
+            {'name': 'test_1'},
+            {'name': 'test_2'},
+        ],
+    }
+    assert results == expected_results
+
+
+def test_merge_documents_list_left():
+    """Tests merging a singleton with an @list."""
+    # given
+    metadata_list = [{
+        '@context': 'https://doi.org/10.5063/schema/codemeta-2.0',
+        'author': {'name': 'test_1'},
+    }, {
+        '@context': 'https://doi.org/10.5063/schema/codemeta-2.0',
+        'author': {
+            '@list': [
+                {'name': 'test_2'},
+            ]
+        },
+    }]
+
+    # when
+    results = merge_documents(metadata_list)
+
+    # then
+    expected_results = {
+        '@context': 'https://doi.org/10.5063/schema/codemeta-2.0',
+        'author': [
+            {'name': 'test_1'},
+            {'name': 'test_2'},
+        ],
+    }
+    assert results == expected_results
+
+
+def test_merge_documents_list_right():
+    """Tests merging an @list with a singleton."""
+    # given
+    metadata_list = [{
+        '@context': 'https://doi.org/10.5063/schema/codemeta-2.0',
+        'author': {
+            '@list': [
+                {'name': 'test_1'},
+            ]
+        },
+    }, {
+        '@context': 'https://doi.org/10.5063/schema/codemeta-2.0',
+        'author': {'name': 'test_2'},
+    }]
+
+    # when
+    results = merge_documents(metadata_list)
+
+    # then
+    expected_results = {
+        '@context': 'https://doi.org/10.5063/schema/codemeta-2.0',
+        'author': [
+            {'name': 'test_1'},
+            {'name': 'test_2'},
+        ],
+    }
+    assert results == expected_results