fix: miscellaneous build and test fixes

[Matovidlo]

Summary

• Fix undefined ptr.Ptr reference in retry_test.go by using new() instead
• Set GOTOOLCHAIN=local and GONOSUMDB=* for xk6 Docker build to fix build issues

Notes

These are small independent fixes extracted from the notification subscriptions PR (#2528) to keep that branch focused.

[Copilot]

Pull request overview

This PR applies small build/test fixes extracted from PR #2528 to keep the notification subscriptions branch focused, addressing a Docker build reliability issue and a failing test compilation issue.

Changes:

• Configure Go environment variables in the xk6 Docker build stage (GOTOOLCHAIN=local, GONOSUMDB=*).
• Replace an undefined ptr.Ptr usage in retry_test.go with a different pointer-construction approach.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

File	Description
provisioning/stream/docker/k6/Dockerfile	Adds Go env configuration intended to stabilize xk6 builds in Docker environments.
internal/pkg/service/stream/storage/model/retry_test.go	Updates test expectations to construct *utctime.UTCTime values without ptr.Ptr.

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[claude]

Review Summary

This PR contains two fixes. The Dockerfile change is reasonable with a minor concern, but the test fix introduces invalid Go syntax that will fail to compile.

Critical: new(utctime.MustParse(...)) is not valid Go

The core fix in retry_test.go replaces ptr.Ptr(utctime.MustParse(...)) with new(utctime.MustParse(...)). However, new() in Go only accepts a type as its argument — not a value expression. new(utctime.MustParse("...")) will fail to compile with an error along the lines of: utctime.MustParse("...") is not a type.

The commit message references "the new() pattern already used throughout the rest of the test file" — but that pattern is equally invalid. The existing new(utctime.MustParse(...)) calls at lines 50–52, 71–73, 82–84, etc. are all compile errors inherited from PR #2528.

The correct way to take the address of a non-addressable value like a function return is to store it in a local variable first. A small test-local helper keeps things concise:

func mustParsePtr(s string) *utctime.UTCTime {
    t := utctime.MustParse(s)
    return &t
}

Production code in retry.go already demonstrates the idiomatic approach (lines 88–93 and 105–110 use &failedAtUTC / &retryAfterUTC). The entire test file needs to be updated with one of these patterns — not just the three lines changed here.

Minor: GONOSUMDB=* disables checksum verification for all modules

Setting GONOSUMDB=* skips the Go checksum database for every module in the build stage. While this unblocks restricted Docker network environments, it means tampered or substituted modules could enter the build undetected — weakening supply-chain integrity.

A more targeted scope reduces the risk:

ENV GONOSUMDB=go.k6.io,github.com/LeonAdato,github.com/domsolutions

Alternatively, investigate whether the build network can reach sum.golang.org directly. The GOTOOLCHAIN=local change is correct and well-motivated.

[hosekpeter]

lgtm