Remove Feature

Remove Feature from Stabilized Spec

What it does

Automates the removal of sugar features from stabilized OpenShift spec versions:

1. Validates the target spec directory and feature existence
2. Removes the feature's translation function call from translate.go
3. Removes the translation function definition from translate.go
4. Removes related test cases from translate_test.go
5. Bumps the max version in internal/doc/butane.yaml for doc transforms
6. Runs ./generate to regenerate spec documentation
7. Runs ./test to validate all changes

Prerequisites

• Go toolchain installed
• Target spec version is stabilized (directory does NOT end with _exp)
• Feature exists in the target spec's translate.go
• Feature has doc transform entries in internal/doc/butane.yaml

Usage

# Interactive mode - will ask for details
/remove-feature

# Specify the version and feature
/remove-feature --distro openshift --version v4_22 --feature grub

# With tracking reference
/remove-feature --distro openshift --version v4_22 --feature grub --ref MCO-630

Workflow

Step 1: Gather Requirements

If not provided via arguments, ask the user:

1. Distro: Which distro variant? (typically openshift)
2. Version: Which stabilized version? (e.g., v4_22)
3. Feature: Which feature to remove? (e.g., grub)
4. Reference: Optional tracking issue (e.g., MCO-630, #515)

Step 2: Pre-flight Validation

Run these checks:

# Verify target directory exists and is NOT experimental
ls -la config/{distro}/{version}/

# Verify version does NOT end with _exp
# CRITICAL: Only remove features from stabilized specs

# Check git status
git status --porcelain

Stop if:

• Target directory does not exist
• Version ends with _exp (experimental specs should be modified differently)
• Working directory has unexpected uncommitted changes

Step 3: Identify Feature Code

Read the target files to locate the feature:

# Read translate.go to find feature function
cat config/{distro}/{version}/translate.go

# Read translate_test.go to find test cases
cat config/{distro}/{version}/translate_test.go

# Read butane.yaml to find doc transform entries
cat internal/doc/butane.yaml

Identify:

1. The function call in the main translation pipeline (e.g., ts = translateUserGrubCfg(&cfg, &ts))
2. The function definition (e.g., func translateUserGrubCfg(...))
3. The test case block (e.g., // Test Grub config test struct)
4. The butane.yaml transform entries with replacement: "Unsupported" and max version

Stop if the feature code is not found in translate.go - it may have already been removed or never existed in this version.

Step 4: Remove Translation Function Call

File: config/{distro}/{version}/translate.go

Read the file and find the function call within the main ToMachineConfig{Version}Unvalidated() function.

Remove the line calling the feature's translation function. For example:

// REMOVE THIS LINE:
ts = translateUserGrubCfg(&cfg, &ts)

Use the Edit tool:

oldString: "\tts = translateUserGrubCfg(&cfg, &ts)\n"
newString: ""

Step 5: Remove Translation Function Definition

File: config/{distro}/{version}/translate.go

Remove the entire function definition. The function is typically at the end of the file.

For the GRUB removal pattern, remove the entire translateUserGrubCfg function:

// REMOVE THIS ENTIRE BLOCK:

// fcos config generates a user.cfg file using append; however, OpenShift config
// does not support append (since MCO does not support it). Let change the file to use contents
func translateUserGrubCfg(config *types.Config, ts *translate.TranslationSet) translate.TranslationSet {
    // ... function body ...
}

Use the Edit tool to remove from the comment above the function through the closing brace.

Step 6: Clean Up Dead Imports

After removing the function, check if any imports are now unused. Common imports that may become dead:

• For GRUB removal: no imports typically become dead (the remaining code uses the same packages)

If imports are dead, remove them. Run ./test later to catch any remaining issues.

Step 7: Remove Test Cases

File: config/{distro}/{version}/translate_test.go

Read the file and identify the test case block for the removed feature. Test cases are typically marked with a comment like // Test Grub config and consist of a struct literal in the test table.

Remove the entire test case struct. For GRUB removal, this includes:

• The comment marker (e.g., // Test Grub config)
• The Config input struct
• The expected result.MachineConfig output struct
• The expected translate.Translation slice

Use the Edit tool to remove the entire block. Be careful to:

• Include the leading comment
• Include all three struct elements (input, expected output, expected translations)
• Preserve the closing of the test table (} and for loop)

Step 8: Update Doc Descriptors

File: internal/doc/butane.yaml

Find the doc transform entries for the removed feature. These have the pattern:

transforms:
  - regex: ".*"
    replacement: "Unsupported"
    if:
      - variant: openshift
        max: {PREVIOUS_VERSION}

Determine the new max version:

• From the directory version v4_22, derive 4.22.0
• The current max should be the previous stabilized version (e.g., 4.21.0)
• Bump max to the new version: 4.22.0

Update ALL occurrences for the feature. For GRUB, there are 4 entries:

1. grub itself
2. grub.users
3. grub.users.name
4. grub.users.password_hash

Use the Edit tool for each occurrence:

oldString: "max: 4.21.0"
newString: "max: 4.22.0"

IMPORTANT: Only update max values within the feature's section. Verify the surrounding context (field names) to avoid changing unrelated transforms.

Alternatively, if all occurrences have the same old value, use replaceAll with enough context to scope the changes correctly.

Step 9: Regenerate Documentation

Run the documentation generator:

./generate

Expected outcome: The docs/config-openshift-{version}.md file is updated, with the removed feature's fields now showing "Unsupported" instead of their original descriptions.

Verify the change:

git diff docs/config-openshift-{version}.md

The diff should show lines like:

-* **_grub_** (object): describes the desired GRUB bootloader configuration.
+* **_grub_** (object): Unsupported

If ./generate fails, check the butane.yaml changes for syntax errors.

Step 10: Run Tests

./test

Expected outcome: All tests pass.

If tests fail:

1. Check for compilation errors (dead imports, missing functions)
2. Check for test expectation mismatches
3. Fix and re-run

Step 11: Report Results

Provide a comprehensive summary:

Feature "{feature}" removed from {distro}/{version}

Files Modified:
  - config/{distro}/{version}/translate.go (-N lines)
  - config/{distro}/{version}/translate_test.go (-N lines)
  - internal/doc/butane.yaml (N version bumps)
  - docs/config-{distro}-{version}.md (regenerated, N fields -> "Unsupported")

Tests: PASSED
Docs: REGENERATED

Suggested commit message:

  {distro}/{version}: Remove {feature_description}

  {reason for removal, e.g., "Support is still missing in the MCO."}

  See: {reference_link}
  See: #{github_issue}

Checklist Coverage

This skill automates the following steps:

• ✅ Remove feature translation function call from translate.go
• ✅ Remove feature translation function definition from translate.go
• ✅ Remove related test cases from translate_test.go
• ✅ Bump max version in internal/doc/butane.yaml for all feature fields
• ✅ Regenerate documentation via ./generate
• ✅ Validate changes via ./test

What's NOT Covered

• ❌ Determining which features to remove - requires knowledge of MCO support status
• ❌ Removing features from experimental specs - experimental specs should use different approaches
• ❌ Removing schema definitions - this skill only removes translation/test code; schemas are inherited from parent and remain (they just become dead code for that version)
• ❌ Removing validation logic - if the feature has validation in validate.go, that must be handled separately
• ❌ Creating git commits - user should review changes first
• ❌ Updating release notes - user should note the removal if appropriate

Example Output

/remove-feature --distro openshift --version v4_22 --feature grub --ref MCO-630

Validating prerequisites...
✅ Target directory exists: config/openshift/v4_22
✅ Version is stabilized (not experimental)
✅ Git working directory is clean

Identifying feature code...
✅ Found function call: ts = translateUserGrubCfg(&cfg, &ts)
✅ Found function definition: translateUserGrubCfg (21 lines)
✅ Found test case: // Test Grub config (83 lines)
✅ Found 4 butane.yaml transform entries (max: 4.21.0)

Phase 1: Remove translation code
  ✅ Removed function call from translate.go
  ✅ Removed function definition from translate.go (-22 lines)

Phase 2: Remove test cases
  ✅ Removed test case from translate_test.go (-83 lines)

Phase 3: Update doc descriptors
  ✅ Bumped max: 4.21.0 → 4.22.0 for grub (4 entries)

Phase 4: Regenerate docs
  ✅ ./generate completed
  ✅ docs/config-openshift-v4_22.md updated (4 fields → "Unsupported")

Phase 5: Validate
  ✅ ./test passed

Feature "grub" removed from openshift/v4_22

Suggested commit message:

  openshift/v4_22: Remove GRUB config support

  See: https://issues.redhat.com/browse/MCO-630
  See: #515

References

• Design document: .opencode/skills/remove-feature/DESIGN.md
• Examples: .opencode/skills/remove-feature/examples/
• Example commits: 4a2be91, 2d9a25e, aa6ad0b, 9821f9b, cd75f80, 1f65fb6
• Current experimental spec with GRUB code: config/openshift/v4_22_exp/translate.go:264-285
• Doc descriptors: internal/doc/butane.yaml:402-438