Add CLI tool and release automation

[pfrederiksen]

Summary

Adds a full-featured CLI with stdin/stdout support and GoReleaser-based release automation with Homebrew tap integration.

CLI Implementation

New Packages

• cmd/configdiff: CLI entry point with Cobra framework

  • main.go: Entry point with version vars for ldflags
  • root.go: Root command with all flags
  • version.go: Version command with build info
  • compare.go: Main comparison logic

• internal/cli: CLI support functions

  • input.go: File/stdin reading, format auto-detection
  • output.go: Output formatting (report/compact/json/patch)
  • options.go: CLI flags → library options mapping

CLI Features

# Basic comparison
configdiff old.yaml new.yaml

# Stdin support
kubectl get deploy myapp -o yaml | configdiff old.yaml -

# Output formats
configdiff old.yaml new.yaml -o compact
configdiff old.yaml new.yaml -o json
configdiff old.yaml new.yaml -o patch

# Advanced options
configdiff old.yaml new.yaml -i /metadata/generation -i /status/*
configdiff old.yaml new.yaml --array-key /spec/containers=name
configdiff old.yaml new.yaml --numeric-strings --bool-strings

# CI mode
configdiff old.yaml new.yaml --exit-code  # Exit 1 if diffs found

Release Automation

GoReleaser Configuration (.goreleaser.yml)

• Cross-platform builds: Linux, macOS, Windows (amd64, arm64, arm)
• Version info injection via ldflags (version, commit, date, builtBy)
• Archive generation with documentation
• Automatic Homebrew formula updates to pfrederiksen/homebrew-tap
• Smart changelog generation from conventional commits

Release Workflow (.github/workflows/release.yml)

• Triggers on version tags (v*)
• Runs full test suite before release
• Uses GoReleaser action for build and publish
• Uploads release artifacts
• Updates Homebrew tap automatically

CI Updates

• Added CLI binary build to existing CI workflow
• Ensures CLI compiles on all PRs

Dependencies

• github.com/spf13/cobra v1.10.2 - Industry standard CLI framework
• github.com/fatih/color v1.18.0 - Colored output support

Installation (After v0.1.0 Release)

# Homebrew (macOS/Linux)
brew install pfrederiksen/tap/configdiff

# Direct download
# Available on GitHub releases page with binaries for all platforms

Testing Done

✅ CLI compiles and runs
✅ Basic file comparison works
✅ Stdin support works (cat file | configdiff - file2)
✅ All output formats work (report, compact, json, patch)
✅ Exit code mode works correctly
✅ All flags parse correctly
✅ GoReleaser config validates locally
✅ Homebrew tap token configured

Next Steps

1. Merge this PR
2. Create v0.1.0 tag to trigger first release
3. Verify Homebrew formula is auto-generated
4. Update README with CLI installation and usage

Versioning

First release will be v0.1.0 (pre-1.0 initial release).

Breaking Changes

None - library API unchanged, CLI is a new addition.

🤖 Generated with Claude Code

[claude]

Code Review

Missing Test Coverage

This PR adds substantial new CLI code without corresponding test files, which violates the project's CLAUDE.md requirements:

Test-Driven Development: Comprehensive test coverage with unit, integration, and golden tests

Affected files without tests:

• internal/cli/input.go (94 lines) - view code
• internal/cli/options.go (107 lines) - view code
• internal/cli/output.go (57 lines) - view code
• cmd/configdiff/compare.go (85 lines) - view code
• cmd/configdiff/root.go (101 lines) - view code
• cmd/configdiff/version.go (22 lines) - view code

What needs tests:

1. internal/cli/input.go: Test ReadInput() and format detection

   • File reading vs stdin
   • Format detection from extensions (.yaml, .json, .hcl, .tf)
   • Content-based detection (JSON objects/arrays, YAML fallback)
   • Error cases (missing files, invalid data)

2. internal/cli/options.go: Test option parsing and validation

   • Validate() with various invalid inputs
   • ToLibraryOptions() conversion logic
   • Array key parsing (path=key format, path normalization)
   • Format override logic

3. internal/cli/output.go: Test output formatting

   • All output formats (report, compact, json, patch)
   • HasChanges() logic
   • NoColor and MaxValueLength options

4. cmd/configdiff/compare.go: Integration tests for the compare flow

   • End-to-end comparisons with different options
   • Error handling
   • Exit code behavior

The existing codebase demonstrates this standard - every other package has comprehensive test coverage. Consider following the project's table-driven test pattern (see parse/parse_test.go, diff/diff_test.go).

[claude]

Code review

No issues found. Checked for bugs and CLAUDE.md compliance.

[claude]

Code Review - Issue Found

Silent Error Handling Bug in cmd/configdiff/main.go

Location:

configdiff/cmd/configdiff/main.go

Lines 15 to 19 in db7fcab

	func main() {
	if err := rootCmd.Execute(); err != nil {
	os.Exit(1)
	}
	}

Problem: When the CLI encounters an error (file not found, invalid format, parse errors, etc.), it will exit silently with no error message displayed to the user.

Root Cause:

1. In root.go:49-50, the Cobra command is configured with SilenceErrors: true, which prevents Cobra from printing errors
2. In main.go, when an error occurs, the code exits without printing the error:

func main() {
	if err := rootCmd.Execute(); err != nil {
		os.Exit(1)  // No error message printed!
	}
}

Impact: Users will have no feedback when errors occur, making debugging and troubleshooting impossible.

Suggested Fix:

func main() {
	if err := rootCmd.Execute(); err != nil {
		fmt.Fprintf(os.Stderr, "Error: %v\n", err)
		os.Exit(1)
	}
}

This ensures users see error messages while still maintaining the SilenceErrors: true setting in root.go.

[claude]

Code review

I found one issue that needs to be addressed:

Missing Package Documentation

File: internal/cli/input.go (line 1)

The internal/cli package is missing package-level documentation. According to the Documentation-First requirement in CLAUDE.md, all packages should have GoDoc comments for all exports.

All other packages in the project follow this pattern:

• diff/diff.go
• parse/parse.go
• tree/tree.go

Please add a package-level comment before the package cli declaration in internal/cli/input.go explaining the purpose of this package, for example:

// Package cli provides command-line interface support for configdiff,
// including input handling, output formatting, and option mapping.
package cli

---

Summary: Checked for bugs and CLAUDE.md compliance. Found 1 issue related to missing documentation.

[pfrederiksen]

Test Coverage - Resolved ✅

The missing test coverage issue has been addressed. Added comprehensive test files:

• internal/cli/input_test.go (145 lines) - Tests for ReadInput(), format detection, error handling
• internal/cli/options_test.go (172 lines) - Tests for Validate(), ToLibraryOptions(), array key parsing
• internal/cli/output_test.go (146 lines) - Tests for all output formats, HasChanges()
• cmd/configdiff/main_test.go (86 lines) - Integration tests for CLI flow

Coverage Results:

• internal/cli: 88.7%
• cmd/configdiff: 58.0%
• Overall project: 83.9% (exceeds 80% threshold)

All tests follow the project's table-driven test pattern and passed in CI.

Commit: db7fcab

[pfrederiksen]

Silent Error Handling Bug - Resolved ✅

The silent error handling issue has been fixed.

Change made to cmd/configdiff/main.go:

func main() {
	if err := rootCmd.Execute(); err != nil {
		fmt.Fprintf(os.Stderr, "Error: %v\n", err)  // ← Error now printed to stderr
		os.Exit(1)
	}
}

Tested: Errors now properly display to users:

$ configdiff /nonexistent/file.yaml test.yaml
Error: failed to read file "/nonexistent/file.yaml": open /nonexistent/file.yaml: no such file or directory

Commit: 0e4f164296c1e5f37c5bafa66a0a8e2450d51e68

[pfrederiksen]

Missing Package Documentation - Resolved ✅

The missing package documentation issue has been addressed in PR #9 and released in v0.1.1.

Change made to internal/cli/input.go:

// Package cli provides command-line interface support for configdiff,
// including input handling, output formatting, and option mapping between
// CLI flags and library options.
package cli

Resolution:

• PR Add package documentation for internal/cli #9: Add package documentation for internal/cli #9
• Released in: v0.1.1
• Commit: 3521697

The internal/cli package now has the same documentation standard as all other packages in the project (diff, parse, tree, patch, report).