gracefully fail due to git version less than 2.0

pkg/app/app.go

@@ -2,11 +2,13 @@ package app
 
 import (
 	"bufio"
+	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"strconv"
 	"strings"
 
 	"github.com/jesseduffield/lazygit/pkg/commands"
@@ -129,7 +131,33 @@ func NewApp(config config.AppConfigurer, filterPath string) (*App, error) {
 	return app, nil
 }
 
+func (app *App) validateGitVersion() error {
+	output, err := app.OSCommand.RunCommandWithOutput("git --version")
+	// if we get an error anywhere here we'll show the same status
+	minVersionError := errors.New(app.Tr.SLocalize("minGitVersionError"))
+	if err != nil {
+		return minVersionError
+	}
+	// output should be something like: 'git version 2.23.0'
+	// first number in the string should be greater than 0
+	split := strings.Split(output, " ")
+	gitVersion := split[len(split)-1]
+	majorVersion, err := strconv.Atoi(gitVersion[0:1])
+	if err != nil {
+		return minVersionError
+	}
+	if majorVersion < 2 {
+		return minVersionError
+	}
+
+	return nil
+}
+
 func (app *App) setupRepo() (bool, error) {
+	if err := app.validateGitVersion(); err != nil {
+		return false, err
+	}
+
 	// if we are not in a git repo, we ask if we want to `git init`
 	if err := app.OSCommand.RunCommand("git status"); err != nil {
 		cwd, err := os.Getwd()
@@ -216,6 +244,14 @@ func (app *App) Close() error {
 func (app *App) KnownError(err error) (string, bool) {
 	errorMessage := err.Error()
 
+	knownErrorMessages := []string{app.Tr.SLocalize("minGitVersionError")}
+
+	for _, message := range knownErrorMessages {
+		if errorMessage == message {
+			return message, true
+		}
+	}
+
 	mappings := []errorMapping{
 		{
 			originalError: "fatal: not a git repository",

pkg/i18n/english.go

@@ -1176,6 +1176,9 @@ func addEnglish(i18nObject *i18n.Bundle) error {
 		}, &i18n.Message{
 			ID:    "viewCommits",
 			Other: "view commits",
+		}, &i18n.Message{
+			ID:    "minGitVersionError",
+			Other: "Git version must be at least 2.0 (i.e. from 2014 onwards). Please upgrade your git version. Alternatively raise an issue at https://github.com/jesseduffield/lazygit/issues for lazygit to be more backwards compatible.",
 		},
 	)
 }