chore: remove retired Azure AI Anomaly Detector components

[ranadeepsingh]

Problem

The Azure AI Anomaly Detector service has been retired by Microsoft. Every
anomalydetector REST endpoint now answers HTTP 410 (Gone), verified from an
external host across paths, API versions and regions:

Region	Path	Status
westus2	/anomalydetector/v1.1/timeseries/entire/detect	410
westus2	/anomalydetector/v1.1/timeseries/last/detect	410
westus2	/anomalydetector/v1.1/timeseries/changepoint/detect	410
westus2	/anomalydetector/v1.1/multivariate/models	410
westus2	/anomalydetector/v1.0/timeseries/entire/detect	410
eastus	/anomalydetector/v1.1/timeseries/entire/detect	410
westus2	/vision/v3.2/analyze (control, same host)	401
westus2	/text/analytics/v3.1/languages (control, same host)	401

Controls on the same hosts still answer 401, which rules out key, region, network
and DNS problems — the API itself is gone. This is what breaks the UnitTests anomaly CI job today: a 410 carries no response body, so the output struct decodes
to null and the all-primitive, non-nullable ADEntireResponse / ADLastResponse
encoders throw Null value appeared in non-nullable field: top level Product or row object.

The six stages were already @deprecated in-repo pointing at IsolationForest.
Microsoft's replacement is the open-source
microsoft/anomaly-detector
library rather than a REST API, so there is nothing to migrate these stages onto.

This removes the components entirely, following the same approach as the Bing Search
v7 removal (#2494).

Changes

Code. Deletes AnomalyDetection.scala, AnomalyDetectorSchemas.scala,
MultivariateAnomalyDetection.scala and MultivariateAnomalyDetectorSchemas.scala,
covering DetectAnomalies, DetectLastAnomaly, SimpleDetectAnomalies,
SimpleFitMultivariateAnomaly, SimpleDetectMultivariateAnomaly and
DetectLastMultivariateAnomaly. Nothing else in the repo referenced them. The
synapse.ml.cognitive.anomaly deprecation shim is updated the same way bing.py
was.

Tests. Deletes AnamolyDetectionSuite.scala and
MultivariateAnamolyDetectionSuite.scala (the latter was 340 lines of entirely
commented-out code), and removes every Anomaly Detector FuzzingTest exemption —
including the stale services.DetectMultivariateAnomaly entry, which pointed at a
pre-reorg class path. Removes the now-unused madTestFile benchmark helper.

CI and secrets. Removes the anomaly test matrix entry from pipeline.yaml,
the Anomaly feature name, and the AnomalyApiKey and MADTestStorageKey secrets.
Drops the now-dead notebook exclusions from DatabricksUtilities and SynapseTests
rather than leaving them behind.

Docs. Deletes _AnomalyDetection.md, _MAD.md and estimators_cognitive.md
(which contained nothing but the MAD entry), the Multivariate Anomaly Detection and
Predictive Maintenance notebooks, and the anomaly cells in the AI Services overview
notebook. Updates transformers_cognitive.md, sidebars.js,
docusaurus.config.js and the docgen manifest. Redirects that pointed at the
deleted pages now point at the Isolation Forests quickstart, so existing inbound
links keep working instead of 404ing.

Bug fix this surfaced. FormRecognizerV3 called
logClass(FeatureNames.AiServices.Anomaly) instead of .Form, so its telemetry was
being misattributed to Anomaly Detector. Fixed while removing the feature name.

Deliberately left alone: CyberML (synapse.ml.cyber.anomaly), Isolation Forest, and
the generic "anomaly detection" capability wording in README.md / docs/Overview.md
— SynapseML still does anomaly detection, just not via this retired service.

Validation

Run locally against Scala 2.12.17 / Spark 3.5.0 on JDK 11:

• compile + Test/compile, all modules — success
• scalastyle + Test/scalastyle, all modules — 0 errors, 0 warnings
• FuzzingTest — 10/10 passed, with the exemptions removed, confirming the
  stages are genuinely gone and no dangling fuzzer-coverage requirement remains
• codegen — success; no services/anomaly wrappers are generated

Related

Fixes the UnitTests anomaly failure seen in ADO build 229662289.

[azure-pipelines]

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[github-actions]

Hey @ranadeepsingh 👋!
Thank you so much for contributing to our repository 🙌.
Someone from SynapseML Team will be reviewing this pull request soon.

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[Copilot]

Pull request overview

This PR retires SynapseML’s Azure AI Anomaly Detector pipeline stages now that the upstream service has shut down and all anomalydetector REST endpoints return HTTP 410 (Gone). The approach keeps existing classes/params/serialization so saved pipelines still load, but makes runtime behavior deterministic by failing fast with an actionable UnsupportedOperationException and updating tests/docs/CI accordingly.

Changes:

• Retire univariate and multivariate anomaly stages by throwing a consistent UnsupportedOperationException (instead of attempting HTTP calls that now always 410).
• Replace live-service test suites with an offline AnomalyDetectionRetirementSuite, and update fuzzing and notebook test exclusions.
• Update docs/notebooks to remove runnable anomaly examples and add retirement guidance; make CI deterministic by removing FLAKY for the anomaly unit test matrix job.

Show a summary per file

File	Description
src/test/scala/com/microsoft/azure/synapse/ml/core/test/fuzzing/FuzzingTest.scala	Exempts retired anomaly stages from fuzzing coverage checks.
pipeline.yaml	Removes FLAKY flag from the anomaly unit-test matrix entry.
docs/Quick Examples/transformers/cognitive/_AnomalyDetection.md	Replaces runnable anomaly examples with a retirement notice and keeps API tables.
docs/Quick Examples/estimators/cognitive/_MAD.md	Adds retirement warning to the multivariate anomaly estimator quick example.
docs/Explore Algorithms/AI Services/Quickstart - Predictive Maintenance.ipynb	Updates notebook to retirement notice and migration guidance.
docs/Explore Algorithms/AI Services/Overview.ipynb	Removes anomaly-detector content so the overview notebook remains runnable.
docs/Explore Algorithms/AI Services/Multivariate Anomaly Detection.ipynb	Updates notebook to retirement notice and migration guidance.
core/src/test/scala/com/microsoft/azure/synapse/ml/nbtest/SynapseTests.scala	Excludes Predictive Maintenance notebook from Synapse notebook runs.
core/src/test/scala/com/microsoft/azure/synapse/ml/nbtest/DatabricksUtilities.scala	Excludes Predictive Maintenance notebook from Databricks notebook runs.
cognitive/src/test/scala/com/microsoft/azure/synapse/ml/services/anomaly/MultivariateAnamolyDetectionSuite.scala	Removes dead (commented-out) live-service multivariate suite.
cognitive/src/test/scala/com/microsoft/azure/synapse/ml/services/anomaly/AnamolyDetectionSuite.scala	Removes live-service univariate suite that cannot pass post-shutdown.
cognitive/src/test/scala/com/microsoft/azure/synapse/ml/services/anomaly/AnomalyDetectionRetirementSuite.scala	Adds offline retirement-contract assertions for all six stages.
cognitive/src/main/scala/com/microsoft/azure/synapse/ml/services/anomaly/MultivariateAnomalyDetection.scala	Makes multivariate fit/transform fail fast via the retirement helper.
cognitive/src/main/scala/com/microsoft/azure/synapse/ml/services/anomaly/AnomalyDetection.scala	Introduces shared retirement notice + makes base transform fail fast for univariate stages.

Review details

Suppressed comments (3)

docs/Quick Examples/transformers/cognitive/_AnomalyDetection.md:36

• The DocTable sourceLink points at a path that doesn't exist in this repo (…/ml/cognitive/AnomalyDetection.scala). This will produce a broken GitHub source link in the docs; please update it to the actual Scala source location under services/anomaly.

<DocTable className="DetectAnomalies"
py="synapse.ml.cognitive.html#module-synapse.ml.cognitive.DetectAnomalies"
scala="com/microsoft/azure/synapse/ml/cognitive/DetectAnomalies.html"
csharp="classSynapse_1_1ML_1_1Cognitive_1_1DetectAnomalies.html"
sourceLink="https://github.com/microsoft/SynapseML/blob/master/cognitive/src/main/scala/com/microsoft/azure/synapse/ml/cognitive/AnomalyDetection.scala" />

docs/Quick Examples/transformers/cognitive/_AnomalyDetection.md:44

• The DocTable sourceLink points at a path that doesn't exist in this repo (…/ml/cognitive/AnomalyDetection.scala). This will produce a broken GitHub source link in the docs; please update it to the actual Scala source location under services/anomaly.

<DocTable className="SimpleDetectAnomalies"
py="synapse.ml.cognitive.html#module-synapse.ml.cognitive.SimpleDetectAnomalies"
scala="com/microsoft/azure/synapse/ml/cognitive/SimpleDetectAnomalies.html"
csharp="classSynapse_1_1ML_1_1Cognitive_1_1SimpleDetectAnomalies.html"
sourceLink="https://github.com/microsoft/SynapseML/blob/master/cognitive/src/main/scala/com/microsoft/azure/synapse/ml/cognitive/AnomalyDetection.scala" />

docs/Quick Examples/transformers/cognitive/_AnomalyDetection.md:28

• The DocTable sourceLink points at a path that doesn't exist in this repo (…/ml/cognitive/AnomalyDetection.scala). This will produce a broken GitHub source link in the docs; please update it to the actual Scala source location under services/anomaly.

This issue also appears in the following locations of the same file:

• line 32
• line 40

<DocTable className="DetectLastAnomaly"
py="synapse.ml.cognitive.html#module-synapse.ml.cognitive.DetectLastAnomaly"
scala="com/microsoft/azure/synapse/ml/cognitive/DetectLastAnomaly.html"
csharp="classSynapse_1_1ML_1_1Cognitive_1_1DetectLastAnomaly.html"
sourceLink="https://github.com/microsoft/SynapseML/blob/master/cognitive/src/main/scala/com/microsoft/azure/synapse/ml/cognitive/AnomalyDetection.scala" />

• Files reviewed: 14/14 changed files
• Comments generated: 0
• Review effort level: Lite

[ranadeepsingh]

/azp run

[azure-pipelines]

Azure Pipelines:
Successfully started running 1 pipeline(s).

[ranadeepsingh]

/azp run

[azure-pipelines]

Azure Pipelines:
Successfully started running 1 pipeline(s).

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.93%. Comparing base (04897ba) to head (9478318).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2605      +/-   ##
==========================================
+ Coverage   84.71%   85.93%   +1.22%     
==========================================
  Files         335      331       -4     
  Lines       17882    17404     -478     
  Branches     1639     1629      -10     
==========================================
- Hits        15148    14956     -192     
+ Misses       2734     2448     -286     

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