go-configparser: Instructions file for GitHub Copilot

go-configparser Development Instructions

ALWAYS follow these instructions first and only fallback to additional search and context gathering if the information here is incomplete or found to be in error.

go-configparser is a Go library that implements a Python ConfigParser-compatible configuration file parser with support for interpolation, custom options, and all major ConfigParser features.

Quick Start & Validation

Bootstrap and validate the repository with these commands:

• go version -- ensure Go 1.21+ is installed
• go build -v ./... -- builds in ~7 seconds, NEVER CANCEL
• go test -v ./... -- runs in ~5 seconds with 93.1% test coverage, NEVER CANCEL
• go test -cover ./... -- shows test coverage statistics

Essential Development Commands

Building

• go build -v ./... -- build all packages (7 seconds)
• go build -- build current package only

Testing

• go test -v ./... -- run all tests with verbose output (5 seconds)
• go test -cover ./... -- run tests with coverage report
• go test ./chainmap -- run tests for chainmap subpackage only
• go test -check.f TestSpecificFunction -- run specific test (uses check framework)

Code Quality

• go vet ./... -- static analysis, runs instantly
• gofmt -l . -- check code formatting, runs instantly
• go mod tidy -- clean up module dependencies
• ~/go/bin/golangci-lint run -- comprehensive linting (install first with: go install github.com/golangci/golangci-lint/cmd/golangci-lint@latest, takes ~2 minutes to install)

CRITICAL: Always run before committing

• go build -v ./... -- ensure code builds
• go test -v ./... -- ensure tests pass
• go vet ./... -- static analysis
• gofmt -l . -- verify formatting (should return no output)

Validation Scenarios

ALWAYS test functionality after making changes by running this validation scenario:

1. Create a test program to validate core functionality:

package main

import (
    "fmt"
    "log"
    "github.com/bigkevmcd/go-configparser"
)

func main() {
    // Test parsing the example configuration file
    p, err := configparser.NewConfigParserFromFile("testdata/example.cfg")
    if err != nil {
        log.Fatal(err)
    }

    // Test basic functionality
    sections := p.Sections()
    fmt.Printf("Sections: %v\n", sections)

    // Test getting a value
    value, err := p.Get("follower", "FrobTimeout")
    if err != nil {
        log.Fatal(err)
    }
    fmt.Printf("FrobTimeout: %s\n", value)

    // Test interpolation
    interpolated, err := p.GetInterpolated("follower", "builder_command")
    if err != nil {
        log.Fatal(err)
    }
    fmt.Printf("Interpolated: %s\n", interpolated)
    
    fmt.Println("✓ Working correctly!")
}