Implement semantic configuration file comparison utility

[Copilot]

Build a Go CLI tool that compares configuration files (YAML, JSON, TOML, INI) by semantic meaning rather than text diff. Handles nested structures, ignores key ordering, and outputs colored diffs or machine-readable JSON.

Architecture

• Unified AST (pkg/ast): Normalizes all formats into a common tree representation with typed nodes (Map, Array, String, Number, Bool, Null)
• Format parsers (pkg/parser): Auto-detects and parses each format into the AST using established libraries (yaml.v3, BurntSushi/toml, ini.v1)
• Comparison engine (pkg/diff): Traverses ASTs recursively, tracking paths with dot notation (e.g., server.host[0]), classifying changes as Added/Removed/Modified
• Output formatters (pkg/output): Renders diffs as colored terminal output, plain text, or JSON

Usage

# Colored diff with path tracking
$ go-config-diff config1.yaml config2.yaml
~ database.credentials.password
  - "secret123"
  + "newsecret456"
+ server.timeout
  + 60

# Machine-readable for CI/CD
$ go-config-diff -format=json old.toml new.toml
{
  "has_changes": true,
  "changes": [
    {
      "type": "modified",
      "path": "database.name",
      "old_value": "myapp",
      "new_value": "myapp_prod"
    }
  ]
}

Exit code 0 when identical, 1 when different. Order-independent map comparison ensures {"a": 1, "b": 2} equals {"b": 2, "a": 1}.

Implementation notes

• Parser outputs interface{} converted to AST via reflection for type safety
• INI sections mapped to nested objects (section name as key)
• Array comparison by index; future optimization could add content-based matching for reordered arrays
• Test coverage includes format detection, parsing, semantic equality, and nested structure comparison

Original prompt

Build a Go utility that compares configuration files (YAML, JSON, TOML, INI) semantically rather than line-by-line. Normalize structures, detect meaningful differences, and ignore ordering or formatting. Provide colored diffs and machine-readable output. Use Go parsers for each format and a unified internal AST model.

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[BaseMax]

@copilot Build a Go utility that compares configuration files (YAML, JSON, TOML, INI) semantically rather than line-by-line. Normalize structures, detect meaningful differences, and ignore ordering or formatting. Provide colored diffs and machine-readable output. Use Go parsers for each format and a unified internal AST model.