Merge pull request #109970 from vamuzumd/vamuzumd/OutputFieldMappingErrorImprovement

Add details and resolution for output field warnings and a new error message

Author: PRMerger10

articles/search/cognitive-search-common-errors-warnings.md

@@ -72,6 +72,11 @@ Indexer read the document from the data source, but there was an issue convertin
 | Could not apply field mapping to a field | Could not apply mapping function `'functionName'` to field `'fieldName'`. Array cannot be null. Parameter name: bytes | Double check the [field mappings](search-indexer-field-mappings.md) defined on the indexer, and compare with the data of the specified field of the failed document. It may be necessary to modify the field mappings or the document data. |
 | Could not read field value | Could not read the value of column `'fieldName'` at index `'fieldIndex'`. A transport-level error has occurred when receiving results from the server. (provider: TCP Provider, error: 0 - An existing connection was forcibly closed by the remote host.) | These errors are typically due to unexpected connectivity issues with the data source's underlying service. Try running the document through your indexer again later. |
 
+<a name="Could not map output field '`xyz`' to search index due to deserialization problem while applying mapping function '`abc`'"/>
+
+## Error: Could not map output field '`xyz`' to search index due to deserialization problem while applying mapping function '`abc`'
+The output mapping might have failed because the output data is in the wrong format for the mapping function you are using. For example, applying Base64Encode mapping function on binary data would generate this error. To resolve the issue, either rerun indexer without specifying mapping function or ensure that the mapping function is compatible with the output field data type. See [Output field mapping](cognitive-search-output-field-mapping.md) for details.
+
 <a name="could-not-execute-skill"/>
 
 ## Error: Could not execute skill
@@ -307,7 +312,12 @@ For more information, see [Indexer limits](search-limits-quotas-capacity.md#inde
 <a name="could-not-map-output-field-x-to-search-index"/>
 
 ## Warning: Could not map output field 'X' to search index
-Output field mappings that reference non-existent/null data will produce warnings for each document and result in an empty index field. To workaround this issue, double-check your output field-mapping source paths for possible typos, or set a default value using the [Conditional skill](cognitive-search-skill-conditional.md#sample-skill-definition-2-set-a-default-value-for-a-value-that-doesnt-exist).
+Output field mappings that reference non-existent/null data will produce warnings for each document and result in an empty index field. To workaround this issue, double-check your output field-mapping source paths for possible typos, or set a default value using the [Conditional skill](cognitive-search-skill-conditional.md#sample-skill-definition-2-set-a-default-value-for-a-value-that-doesnt-exist). See [Output field mapping](cognitive-search-output-field-mapping.md) for details.
+
+| Reason | Details/Example | Resolution |
+| --- | --- | --- |
+| Cannot iterate over non-array | "Cannot iterate over non-array `/document/normalized_images/0/imageCelebrities/0/detail/celebrities`." | This error occurs when the output is not an array. If you think the output should be an array, check the indicated output source field path for errors. For example, you might have a missing or extra `*` in the source field name. It's also possible that the input to this skill is null, resulting in an empty array. Find similar details in [Skill Input was Invalid](cognitive-search-common-errors-warnings.md#warning-skill-input-was-invalid) section.    |
+| Unable to select `0` in non-array | "Unable to select `0` in non-array `/document/pages`." | This could happen if the skills output does not produce an array and the output source field name has array index or `*` in its path. Please double check the paths provided in the output source field names and the field value for the indicated field name. Find similar details in [Skill Input was Invalid](cognitive-search-common-errors-warnings.md#warning-skill-input-was-invalid) section.  |
 
 <a name="the-data-change-detection-policy-is-configured-to-use-key-column-x"/>