[Azure.AI.ContentUnderstanding] UpdateAnalyzer/UpdateAnalyzerAsync docs should clarify which properties are updatable

[chienyuanchang]

Description

The UpdateAnalyzer and UpdateAnalyzerAsync methods (and their protocol overloads) currently have XML doc summaries that say only "Update analyzer properties" without specifying which properties can actually be updated.

The underlying REST API uses PATCH with application/merge-patch+json, and only description and tags are accepted by the service. All other properties (models, fieldSchema, config, baseAnalyzerId, dynamicFieldSchema, processingLocation, knowledgeSources) are create-only — they are silently ignored by the server even though it returns HTTP 200.

This has caused customer confusion — see #57215.

Requested Improvements

1. API doc (<summary> / <remarks>): Add a <remarks> section to UpdateAnalyzer/UpdateAnalyzerAsync listing the updatable properties and noting that other properties require CreateAnalyzerAsync with allowReplace: true.

2. Sample doc (Sample08_UpdateAnalyzer.md): Add a note in the "About updating analyzers" section explaining that only description and tags are updatable via this method, and reference CreateAnalyzerAsync with allowReplace: true for changing models, fieldSchema, etc.

Updatable Properties

Property	Updatable via UpdateAnalyzer (PATCH)?
description	Yes
tags	Yes
models	No — silently ignored
fieldSchema	No — silently ignored
config	No — silently ignored
baseAnalyzerId	No — silently ignored
dynamicFieldSchema	No — silently ignored
processingLocation	No — silently ignored
knowledgeSources	No — silently ignored

Workaround

To change create-only properties on an existing analyzer, use CreateAnalyzerAsync with allowReplace: true. This calls PUT (full resource replacement) instead of PATCH.

Related

• [BUG][Azure.AI.ContentUnderstanding] Update of analyzer is not working properly #57215 — customer report of UpdateAnalyzerAsync not updating models