Fix serviceendpoint_generic_v2 to let the api throw the failure and properly update the authentication parameters.

[Levente Laszlo Papp (aklakina)]

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Description

The apply time input validation was causing a lot of issues as the code did not reimplement the conditional logic from the service endpoint validation. I have added a toggle that defaults to turn this feature off. This validation is still useful for small service connections but it is unusable for azure service connections for example.

Also there was a bug that skipped the authentication parameters from the update. Fixed that too.

PR 2/2 from #1505

Does this introduce a breaking change?

• Yes
• No

Test Result

Related Issue(s)

Fix #0000

Other information

[Levente Laszlo Papp (aklakina)]

Hi magodo (@magodo)

This PR is ready for review.

[magodo (magodo)]

I think this is more proper to be moved to CustomizeDiff so that this can happen during plan time instead of apply time, WDYT?

[Levente Laszlo Papp (aklakina)]

It runs both at plan time and apply time. The problem with plan time run is that the input parameters can be undeterministic in which case terraform provides a null object. This breaks plan time validation.

[magodo (magodo)]

These attributes are less likely to be unknown during plan time. You shall skip the validation if there is any unknown value. Whilst the CustomizeDiff also runs at apply time, where all the attributes will be known.

[Levente Laszlo Papp (aklakina)]

It is part of costumizediff

But the main problem is not that the values are unkown but that the api retruns a validation logic for each data field and we would need to implement the same logic parser as it is already implemented in the azure devops. So for example for azure service connection you would not be able to create it in the current state because both service principal and other login method inputs are present in the data field but the conditional logic is not parsed or processed so the diff just dies because it expects all the auth data which are conflicting.

[magodo (magodo)]

Could you pass the acctests and paste the run result here then I'm happy to merge this PR? Thx!

[Levente Laszlo Papp (aklakina)]

Hi magodo (@magodo), I finally had time to run the acc tests. Sadly they are not passing and seemingly the azure devops client is causing the error.

Here is the output:

and here is the stdout:
acctests.log

I tracked down the failure to the following line in the code:
https://github.com/aklakina/terraform-provider-azuredevops/blob/e5598111ada403e84fb117b8485d4885fc67281e/azuredevops/internal/service/serviceendpoint/resource_serviceendpoint_generic_v2.go#L126
Which calls the client to get all the types. This was working when the resource got added as the acctests all passed then and as you can see, this pr does not touch that code part.

Can you check if the ADO go client dev team knows about this?

[Levente Laszlo Papp (aklakina)]

hi magodo (@magodo)

Any news here?

[magodo (magodo)]

Sorry, I've no idea why the ADO service fails.

[Levente Laszlo Papp (aklakina)]

Technical Investigation: JSON Unmarshalling Issue

I've done some digging into the JSON unmarshalling error we've been seeing in the test runs, and I wanted to share what I found:

Error: error initializing service endpoint types: failed to retrieve service endpoint types: 
json: cannot unmarshal number into Go struct field InputValidation.Value.authenticationSchemes.inputDescriptors.validation.minValue of type *big.Float

What's Actually Happening

The issue is in the Azure DevOps Go SDK (vendor/github.com/microsoft/azure-devops-go-api/azuredevops/v7/forminput/models.go). The InputValidation struct defines its min/max value fields like this:

type InputValidation struct {
    MinValue *big.Float `json:"minValue,omitempty"`
    MaxValue *big.Float `json:"maxValue,omitempty"`
}

The problem is that Go's standard json.Unmarshal() can't convert JSON numbers directly into *big.Float types. It only works with basic types (string, int, float64, bool) or custom types that implement UnmarshalJSON() themselves. *big.Float doesn't have that built-in.

So when we call GetServiceEndpointTypes() and the API returns those numeric validation values, the JSON decoder just throws up its hands and fails.

Why This PR Solves It

By adding the validate_input toggle and defaulting it to false, we sidestep this issue entirely. When validation is disabled, we never try to unmarshal those problematic fields. Instead, we let Azure DevOps do the validation server-side, which is honestly more reliable anyway since it's the source of truth.

I think this is actually a better design than trying to replicate all of Azure DevOps' validation logic on the client side. The API will always have the most up-to-date rules, and users get clear error messages directly from Azure DevOps if their config is invalid.

Next Steps

If we wanted to fully enable client-side validation in the future, someone would need to file an issue with the Azure DevOps Go SDK to add proper JSON unmarshalling support for *big.Float. But for now, letting the API handle it is the pragmatic solution.