butane/util: emit large MachineConfig integers as decimals

[butcher-pudge-0]

Summary

• Fix MachineConfig YAML encoding of large integers such as sizeMiB/startMiB so values >= 1e6 are written as decimals (8389000) instead of scientific notation (8.389e+06).
• Preserve JSON numbers as int64 before YAML encoding in TranslateBytesYAML. json.Unmarshal into interface{} otherwise uses float64, and yaml.v3 then formats those values with scientific notation. MCO/Ignition cannot unmarshal that into *int.
• Add unit and OpenShift 4.18 regression tests covering the GitHub butane/MCO: MiB fileds are being in scientific notation (1e6, instead of 1000000) #2309 and OCPBUGS-114735 reproductions.

Fixes #2309
Fixes: https://redhat.atlassian.net/browse/OCPBUGS-114735

This is an alternative to #2310: that change YAML-unmarshals the intermediate JSON (and is still missing tests and a release note). This PR keeps a JSON decoder with UseNumber() so integers stay integers, and includes tests plus a release-note entry.

Test plan

• go test -mod=vendor ./butane/config/util ./butane/config/openshift/v4_18
• Transpile the butane/MCO: MiB fileds are being in scientific notation (1e6, instead of 1000000) #2309 Butane config without --raw and confirm sizeMiB: 8389000 (not 8.389e+06)
• Confirm size_mib: 1231872 renders as sizeMiB: 1231872 (not 1.231872e+06)

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📒 Files selected for processing (4)

• butane/config/openshift/v4_18/translate_test.go
• butane/config/util/util.go
• butane/config/util/util_test.go
• docs/release-notes.md

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Files:

• butane/config/openshift/v4_18/translate_test.go
• butane/config/util/util_test.go
• butane/config/util/util.go

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Files:

• butane/config/openshift/v4_18/translate_test.go
• butane/config/util/util_test.go
• butane/config/util/util.go

🔇 Additional comments (4)

butane/config/util/util.go (1)

158-159: LGTM!

Also applies to: 177-218

butane/config/util/util_test.go (1)

18-20: LGTM!

Also applies to: 29-29, 125-143

butane/config/openshift/v4_18/translate_test.go (1)

516-551: LGTM!

docs/release-notes.md (1)

17-20: LGTM!

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📝 Walkthrough

Walkthrough

Changes

MachineConfig YAML integer preservation

Layer / File(s)	Summary
JSON number conversion and utility coverage butane/config/util/util.go, butane/config/util/util_test.go	TranslateBytesYAML preserves JSON integer precision before YAML encoding. Tests cover large integers, decimal values, and scientific-notation exclusion.
OpenShift regression coverage and release note butane/config/openshift/v4_18/translate_test.go, docs/release-notes.md	OpenShift translation tests verify large and zero sizeMiB values. The release note documents decimal encoding for large integer fields.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Merge Risk: ⚪ Minimal · up to 03afb

This localized encoding change is merge-ready after normal checks and review; no actionable merge-blocking risk remains.

🚥 Pre-merge checks | ✅ 5 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 8 functions across 3 files. (1 skipped: 1…	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title uses the required subsystem-and-description format, uses imperative wording, starts the description with lowercase text, and accurately describes the main change.
Description check	✅ Passed	The description clearly explains the integer-encoding fix, affected fields, tests, linked issues, and release-note change.
Linked Issues check	✅ Passed	The implementation addresses issue #2309 by preserving large JSON integers as int64 so MachineConfig YAML emits decimal values instead of scientific notation. Regression tests cover the reported behav…
Out of Scope Changes check	✅ Passed	The code changes, regression tests, and release note all support the linked issue and pull request objective. No unrelated changes are present.
Commit Message Convention	✅ Passed	Both non-merge commits in the PR range conform. butane/util: emit large MachineConfig integers as decimals and butane: reference OCPBUGS-114735 in release notes and tests use valid subsystem prefi…

Full details: Linked Issues check

Explanation

The implementation addresses issue #2309 by preserving large JSON integers as int64 so MachineConfig YAML emits decimal values instead of scientific notation. Regression tests cover the reported behavior.

Full details: Docstring Coverage

Explanation

Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 8 functions across 3 files. (1 skipped: 1 unsupported.)

Full details: Commit Message Convention

Explanation

Both non-merge commits in the PR range conform. butane/util: emit large MachineConfig integers as decimals and butane: reference OCPBUGS-114735 in release notes and tests use valid subsystem prefixes, start their descriptions with lowercase imperative verbs, and have no trailing periods. No merge commits require review.

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[butcher-pudge-0]

Closing — starting over from scratch.