go-gremlins/gremlins

package diff

import (
    "bytes"
    "fmt"
    "os/exec"

    "github.com/bluekeyes/go-gitdiff/gitdiff"

    "github.com/go-gremlins/gremlins/internal/configuration"
    "github.com/go-gremlins/gremlins/internal/log"
)

func New() (Diff, error) {
    return NewWithCmd(exec.Command)
}

type execCmd interface {
    CombinedOutput() ([]byte, error)
}

func NewWithCmd[T execCmd](cmdContext func(name string, args ...string) T) (Diff, error) {
    diffRef := configuration.Get[string](configuration.UnleashDiffRef)
    if diffRef == "" {
        return nil, nil
    }

    log.Infoln("Gathering files diff...")

    cmd := cmdContext("git", "diff", "--merge-base", diffRef)

    out, err := cmd.CombinedOutput()
    if err != nil {
        return nil, fmt.Errorf("an error occured while calling git diff: %w\n\n%s", err, out)
    }

    files, _, err := gitdiff.Parse(bytes.NewReader(out))
    if err != nil {
        return nil, fmt.Errorf("an error occured while parsing diff: %w", err)
    }

    return newDiff(files), nil
}