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we should report breaking change for x-ms-discriminator-value change

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Feature
Clarity
Mostly clear
Activity status
Stale
Tech stack
csharp, openapi
Domain
api

Research direction

Start with the linked discussion and the x-ms-discriminator-value extension definition. Trace how the tool classifies discriminator changes between OpenAPI specifications. Done means changes to this value, including adding an explicit value where the model name was previously implicit, are reported as API-layer breaking changes.

Written by the indexing model from the issue text.

Description

See https://github.com/Azure/azure-rest-api-specs/pull/32483#discussion_r1948548308
As you can see the definition for x-ms-discriminator-value it indicates the discriminator property's value on the wire layer, therefore, any changes related to x-ms-discriminator-value should be considered as an api layer breaking change.

A side note, the default x-ms-discriminator-value for any models that contains discriminator property is the model name itself. Which means if there's a model named A that doesn't have x-ms-discriminator-value before, and they newly added x-ms-discriminator-value and set it as B, it's also a breaking change.

Dominant language
C#
Stars
290
Forks
50
Avg merge
2d 21h
Merged PRs (30d)
10

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