I am trying to update branch policy of a branch in Azure DevOps repository. I am trying to do it using Rest API calls following documentation from here.

When I run this from Postman, the request completes successfully with status code '200 OK'. Upon checking the status of branch policy in Azure DevOps, I am able to see that the option "Limit merge types" is "on", however, no checkbox is checked under "Allowed merge types:".

Here is json payload which I used.

POST https://dev.azure.com/{{Org}}/{{ProjectName}}/_apis/policy/configurations?api-version=7.0

{
    "isEnabled": true,
    "isBlocking": true,
    "type": {
        "id": "fa4e907d-c16b-4a4c-9dfa-4916e5d171ab"
    },
    "settings": {
        "useSquashMerge": true,
        "scope": [
            {
                "refName": "refs/heads/test_branch_for_policy",
                "matchKind": "exact",
                "repositoryId": "11223344-480x-4u1h-x16k-112233445566"
            }
        ]
    }
}

It seems "useSquashMerge": true under settings is not being considered.

TL;DR use allowSquash instead of useSquashMerge.

This works when using Azure DevOps Services (cloud), not sure about Azure DevOps Server (hosted).

More details

Doing some research, I was able to find in Automating Branch Policies the right settings to configure the Limit Merge Types section of the branch policy:

• useSquashMerge
• allowNoFastForward
• allowSquash
• allowRebase
• allowRebaseMerge

All settings work in Azure DevOps Services except useSquashMerge. I couldn't find much information about it, but it seems to be used in TFS / Azure DevOps Server - see Merge strategy policy settings inconsistent.

Example

Executing the following code request on Postman:

https://dev.azure.com/my-organization/my-project/_apis/policy/configurations?api-version=7.0

Request body:

{
    "isEnabled": true,
    "isBlocking": true,
    "type": {
        "id": "fa4e907d-c16b-4a4c-9dfa-4916e5d171ab"
    },
    "settings": {
        "allowSquash": true,
        "useSquashMerge": true,
        "allowRebaseMerge": false,
        "allowRebase": false,
        "allowNoFastForward": false,
        "scope": [
            {
                "repositoryId": "1xxxx516-aaaa-4ce4-xxxx-d56abbbbb6ec",
                "refName": "refs/heads/main",
                "matchKind": "exact"
            }
        ]
    }
}

Response:

{
    "createdBy": {
        "displayName": "Some user",
        "url": "https://spsprodeus21.vssps.visualstudio.com/xxxx-xxxx-xxxx-xxxx-xxxx/_apis/Identities/xxxx-xxxx-xxxx-xxxx-xxxx",
        "_links": {
            "avatar": {
                "href": "https://dev.azure.com/my-organization/_apis/GraphProfile/MemberAvatars/aad.xxxxxx"
            }
        },
        "id": "7af0d439-aa9b-40cf-93a4-fb725b0694a7",
        "uniqueName": "john@hotmail.com",
        "imageUrl": "https://dev.azure.com/my-organization/_api/_common/identityImage?id=xxxx-xxxx-xxxx-xxxx-xxxx",
        "descriptor": "aad.xxxxxx"
    },
    "createdDate": "2024-07-13T13:18:59.5387814",
    "isEnabled": true,
    "isBlocking": true,
    "isDeleted": false,
    "settings": {
        "useSquashMerge": true,
        "allowNoFastForward": false,
        "allowSquash": true,
        "allowRebase": false,
        "allowRebaseMerge": false,
        "scope": [
            {
                "refName": "refs/heads/main",
                "matchKind": "Exact",
                "repositoryId": "1xxxx516-aaaa-4ce4-xxxx-d56abbbbb6ec"
            }
        ]
    },
    "isEnterpriseManaged": false,
    "_links": {
        "self": {
            "href": "https://dev.azure.com/my-organization/xxxx-xxxx-xxxx-xxxx-xxxx/_apis/policy/configurations/75"
        },
        "policyType": {
            "href": "https://dev.azure.com/my-organization/xxxx-xxxx-xxxx-xxxx-xxxx/_apis/policy/types/xxxx-xxxx-xxxx-xxxx-xxxx"
        }
    },
    "revision": 1,
    "id": 75,
    "url": "https://dev.azure.com/my-organization/xxxx-xxxx-xxxx-xxxx-xxxx/_apis/policy/configurations/75",
    "type": {
        "id": "xxxx-xxxx-xxxx-xxxx-xxxx",
        "url": "https://dev.azure.com/my-organization/xxxx-xxxx-xxxx-xxxx-xxxx/_apis/policy/types/xxxx-xxxx-xxxx-xxxx-xxxx",
        "displayName": "Require a merge strategy"
    }
}

Note:

• See Guidance for authentication - Azure DevOps for more details on how to authenticate with Azure DevOps REST API.