[cadejacobson]

Updates the strings.Split and strings.Field calls to use the SplitSeq and FieldSeq iterators respectively to save an allocation as recommended by the go fix pipeline.

Each line changed here can be found in the most recent go fix section of the test ci in main here:
https://github.com/coreos/ignition/actions/runs/40920068661/job/123610575785#step:7:3039
https://github.com/coreos/ignition/actions/runs/40920068661/job/123610575785#step:7:3071
https://github.com/coreos/ignition/actions/runs/40920068661/job/123610575785#step:7:3158
https://github.com/coreos/ignition/actions/runs/40920068661/job/123610575785#step:7:3169
https://github.com/coreos/ignition/actions/runs/40920068661/job/123610575785#step:7:3204
https://github.com/coreos/ignition/actions/runs/40920068661/job/123610575785#step:7:3182

[coderabbitai]

No actionable comments were generated in the recent review.

Recent review info

Run configuration

• Source mode: Auto
• Repository: coreos/ignition
• Branch: main
• File: .coderabbit.yaml
• Commit: 1f39eb3
• Layers: Repository YAML
• Review profile: CHILL
• Plan: Advanced
• Run ID: c3fe7bed-f11b-4526-a237-e5f5ee86582e

Commits

Reviewing files that changed from the base of the PR and between 1f39eb3 and 14891cb.

Files selected for processing: 7

• docs/release-notes.d/string-iterators.change.md
• internal/exec/stages/disks/luks.go
• internal/exec/stages/disks/partitions.go
• internal/providers/cmdline/cmdline.go
• internal/providers/vmware/ovf_test.go
• internal/providers/zvm/zvm.go
• tests/positive/general/preemption.go

Included review availability: This review used your included allowance. Your plan provides up to 4 included reviews per hour; 3 remain after this review.

Recent review details

Context from checks skipped due to timeout: 4

• GitHub Check: CodeRabbit
• GitHub Check: Test (1.26.x)
• GitHub Check: Test (1.25.x)
• GitHub Check: tmt-tests

Additional context used

Code guidelines: 1

AGENTS.md — auto-discovered

Path-based instructions: 5

Execution stages are fixed (fetch-offline, fetch, disks, mount, files, umount).

CodeRabbit configuration file

Files:

• internal/exec/stages/disks/luks.go
• internal/exec/stages/disks/partitions.go

Platform providers must retry config fetch, allow empty config, and never guess the platform ID.

CodeRabbit configuration file

Files:

• internal/providers/zvm/zvm.go
• internal/providers/cmdline/cmdline.go
• internal/providers/vmware/ovf_test.go

Blackbox integration tests.

CodeRabbit configuration file

Files:

• tests/positive/general/preemption.go

Documentation served via GitHub Pages/Jekyll.

CodeRabbit configuration file

Files:

• docs/release-notes.d/string-iterators.change.md

Source excerpt: **License header**: Required on all `.go` files (Apache 2.0, 13-line header)

CodeRabbit inference engine (AGENTS.md)

Files:

• internal/exec/stages/disks/luks.go
• internal/providers/zvm/zvm.go
• internal/providers/cmdline/cmdline.go
• internal/exec/stages/disks/partitions.go
• tests/positive/general/preemption.go
• internal/providers/vmware/ovf_test.go

Learnings: 1

Learning: 2026-10-20T08:26:09.855Z

Learnt from: CR
Repo: coreos/ignition PR: 0
File: AGENTS.md:0-0
Timestamp: 2026-10-20T08:26:09.855Z
Learning: Source excerpt:
# Ignition

## Code Style

- **Formatting**: `gofmt` enforced (CI and `./test`)

Applied to files:

• internal/exec/stages/disks/luks.go

Additional comments: 7

internal/providers/cmdline/cmdline.go: 1

108-108: LGTM!

internal/exec/stages/disks/luks.go: 1

625-625: LGTM!

internal/exec/stages/disks/partitions.go: 1

255-256: LGTM!

internal/providers/zvm/zvm.go: 1

67-67: LGTM!

tests/positive/general/preemption.go: 1

60-60: LGTM!

internal/providers/vmware/ovf_test.go: 1

160-160: LGTM!

docs/release-notes.d/string-iterators.change.md: 1

1-1: LGTM!

Walkthrough

Several parsing and test loops now use string iterators instead of allocating slices from split strings or fields. A release-note fragment records the change. The parsing and processing logic remains unchanged.

Changes: String iterator adoption

Layer / File(s)	Summary
Replace slice-based string iteration internal/providers/cmdline/cmdline.go, internal/exec/stages/disks/luks.go, internal/exec/stages/disks/partitions.go, internal/providers/zvm/zvm.go, tests/positive/general/preemption.go, internal/providers/vmware/ovf_test.go, docs/release-notes.d/string-iterators.change.md	Loops use strings.FieldsSeq or strings.SplitSeq instead of iterating over slices created by strings.Fields or strings.Split. The release note describes the iterator change.

Priority: Low

Estimated code review effort: 2 (Simple) | ~8 minutes

Change: Refactor

Possibly related issues

• Issue 2353 describes the release-note fragment workflow used by this change.

Possibly related PRs

• coreos/ignition#2352: Adds validation and finalization tooling for release-note fragments used here.
• coreos/ignition#2347: Introduces the release-note fragment format used here.
• coreos/ignition#2346: Re-enables the go fix pipeline whose reported string-iterator changes are applied here.

Suggested reviewers: bgilbert

Merge Risk: Minimal · up to 14891

This allocation-focused change is ready to merge; no material current-head risk was identified.

Pre-merge checks: 5 · 1

Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documenta…	Write docstrings for the functions missing them to satisfy the coverage threshold.

Passed checks: 5 passed

Check name	Status	Explanation
Title check		The title follows the required format: it uses the subsystem prefix "internal", a lowercase imperative description, and no trailing period. It accurately summarizes the iterator allocation changes.
Description check		The description directly explains the changes from strings.Split and strings.Fields to strings.SplitSeq and strings.FieldsSeq, including the allocation benefit and supporting references.
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.
Commit Message Convention		The PR has one non-merge commit: internal: use string iterators to avoid allocations. internal is a valid subsystem path prefix, use starts the description in lowercase imperative mood, and the …

Full details: Commit Message Convention

Explanation

The PR has one non-merge commit: internal: use string iterators to avoid allocations. internal is a valid subsystem path prefix, use starts the description in lowercase imperative mood, and the message has no trailing period.

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 with cyclomatic complexity of at least 2. Documentation-only edits and deletions within surviving functions are included; unchanged diff context and fully deleted functions are excluded. Analyzed 6 functions across 6 files. (1 skipped: 1 unsupported.)

Resolution

Write docstrings for the functions missing them to satisfy the coverage threshold.

Finishing Touches

🧪 Generate unit tests (beta)

• Create a new PR

• Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

_{Comment @coderabbitai help to get the list of available commands.}

[github-actions]

Binary size report (bin/amd64/ignition)

	Size
Base (main)	33MiB
PR (#2354)	33MiB
Delta	+5.6KiB (0.02%)

[angelcerveraroldan]

I did not know that these methods existed, neat.

From the docs:

The iterator yields the same strings that would be returned by Fields(s), but without constructing the slice.

The iterator yields the same strings that would be returned by Split(s, sep), but without constructing the slice. It returns a single-use iterator

So it LGTM, thanks.