Change allowed_instance_types to accept list instead of space-delimit…

[PratibhaShrivastav18]

allowed_instance_types — Breaking Change

CLI (YAML input)

Before:

allowed_instance_types: Standard_DS3_v2 Standard_DS4_v2

After:

allowed_instance_types:
  - Standard_DS3_v2
  - Standard_DS4_v2

SDK

Before:

# str accepted
DeploymentTemplate(allowed_instance_types="Standard_DS3_v2 Standard_DS4_v2")

After:

# Only list accepted
DeploymentTemplate(allowed_instance_types=["Standard_DS3_v2", "Standard_DS4_v2"])

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• The pull request does not introduce [breaking changes]
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.

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[Copilot]

Pull request overview

This PR updates allowed_instance_types to be represented as a YAML/SDK list (rather than a single space-delimited string), aligning schema + entity serialization with the service’s array shape.

Changes:

• Updated DeploymentTemplateSchema to parse allowed_instance_types as List[str].
• Updated DeploymentTemplate to type allowed_instance_types as Optional[List[str]] and to serialize it directly as allowedInstanceTypes.
• Removed string-splitting conversion in DeploymentTemplateOperations._convert_dict_to_deployment_template, and updated one unit test to use a list.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
sdk/ml/azure-ai-ml/tests/deployment_template/unittests/test_deployment_template.py	Updates initialization assertion to use list form for allowed_instance_types.
sdk/ml/azure-ai-ml/azure/ai/ml/operations/_deployment_template_operations.py	Stops converting string allowed_instance_types into a list during dict-to-entity conversion.
sdk/ml/azure-ai-ml/azure/ai/ml/entities/_deployment/deployment_template.py	Changes allowed_instance_types typing to List[str] and passes through list directly in REST serialization.
sdk/ml/azure-ai-ml/azure/ai/ml/_schema/_deployment/template/deployment_template.py	Changes marshmallow schema field type from Str to List(Str).