fix: preserve fractional scale target minimum

[Elvand-Lie]

Changes

• 🐛 Preserve the 0.01 minimum for scale.target in the generated func.yaml schema instead of emitting 0.

/kind bug

Fixes #4066

Problem

ScaleOptions.Target declares jsonschema_extras:"minimum=0.01", but the pinned github.com/alecthomas/jsonschema implementation parses minimum extras with strconv.Atoi. Because the parse error is discarded, the fractional value is emitted as minimum: 0. This makes the generated schema weaker than runtime validation, which rejects target values below 0.01.

Fix

After the normal schema reflection pass, restore the fractional minimum for ScaleOptions.Target from its existing jsonschema_extras tag before the schema is marshalled. The correction is intentionally scoped to the currently affected field and does not duplicate the 0.01 value inside the generator.

Test

Added a regression test that verifies:

• ScaleOptions.target.minimum is emitted as 0.01
• the neighbouring utilization bounds remain 1 and 100
• regenerating schema/func_yaml-schema.json changes only minimum: 0 to minimum: 0.01

Validated locally with:

go test -race -count=1 ./schema/... ./pkg/functions/...
go test -count=1 ./schema/generator/ -run TestTargetMinimumIsPreserved
go vet ./schema/generator/...
git diff --check

Note on #4063

#4063 moves the target field to KPAScaleOptions and currently uses exclusiveMinimum=true as a workaround for this truncation. Its generated schema still contains minimum: 0, so under JSON Schema draft-04 it currently represents target > 0.

When the two changes are reconciled, this correction will need to follow KPAScaleOptions.Target and the exclusiveMinimum=true workaround should be removed. Keeping both after restoring minimum: 0.01 would instead require target > 0.01, while runtime validation accepts target >= 0.01.

#4063 is separate and is not modified by this PR.

Release Note

The generated func.yaml schema now preserves the 0.01 minimum for scale.target.

[knative-prow]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: Elvand-Lie
Once this PR has been reviewed and has the lgtm label, please assign matejvasek for approval. For more information see the Code Review Process.

The full list of commands accepted by this bot can be found here.

Details

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[knative-prow]

Hi @Elvand-Lie. Thanks for your PR.

I'm waiting for a knative member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work.

Tip

We noticed you've done this a few times! Consider joining the org to skip this step and gain /lgtm and other bot rights. We recommend asking approvers on your previous PRs to sponsor you.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Details

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[lkingland]

Thanks for the contribution. I think this will need a rebase as the scale option has a PR coming in now which moves it up to top-level.