From 55aefe8a0338b77febeaa97b2a521c572e708752 Mon Sep 17 00:00:00 2001
From: Prabhu Jayakumar <j.prabhu91@gmail.com>
Date: Fri, 7 Aug 2020 15:15:13 +0530
Subject: [PATCH] [Issue #216] Validate if current directory has git executable
 in windows OS

---
 talisman.go               | 25 +++++++++++++++++++++++
 talisman_internal_test.go | 43 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 68 insertions(+)

diff --git a/talisman.go b/talisman.go
index 076ba5c2..f085327f 100644
--- a/talisman.go
+++ b/talisman.go
@@ -1,7 +1,9 @@
 package main
 
 import (
+	"github.com/spf13/afero"
 	flag "github.com/spf13/pflag"
+	"runtime"
 	"talisman/prompt"
 )
 
@@ -100,6 +102,11 @@ func main() {
 }
 
 func run(stdin io.Reader, _options options, promptContext prompt.PromptContext) (returnCode int) {
+	if err := validateGitExecutable(afero.NewOsFs(), runtime.GOOS); err != nil {
+		log.Printf("error validating git executable: %v", err)
+		return 1
+	}
+
 	if _options.debug {
 		log.SetLevel(log.DebugLevel)
 	} else {
@@ -145,3 +152,21 @@ func readRefAndSha(file io.Reader) (string, string, string, string) {
 	}
 	return refsAndShas[0], refsAndShas[1], refsAndShas[2], refsAndShas[3]
 }
+
+func validateGitExecutable(fs afero.Fs, operatingSystem string) error {
+	if operatingSystem == "windows" {
+		extensions := strings.ToLower(os.Getenv("PATHEXT"))
+		windowsExecutables := strings.Split(extensions, ";")
+		for _, executable := range windowsExecutables {
+			gitExecutable := fmt.Sprintf("git%s", executable)
+			exists, err := afero.Exists(fs, gitExecutable)
+			if err != nil {
+				return err
+			}
+			if exists {
+				return fmt.Errorf("not allowed to have git executable located in repository: %s", gitExecutable)
+			}
+		}
+	}
+	return nil
+}
diff --git a/talisman_internal_test.go b/talisman_internal_test.go
index 23610c35..7277c37a 100644
--- a/talisman_internal_test.go
+++ b/talisman_internal_test.go
@@ -1,6 +1,7 @@
 package main
 
 import (
+	"github.com/spf13/afero"
 	"io/ioutil"
 	"os"
 	"testing"
@@ -22,3 +23,45 @@ func TestParsingShasFromStdIn(t *testing.T) {
 	assert.Equal(t, "localSha", oldSha, "oldSha did not equal 'localSha', got: %s", oldSha)
 	assert.Equal(t, "remoteSha", newSha, "newSha did not equal 'remoteSha', got: %s", newSha)
 }
+
+func Test_validateGitExecutable(t *testing.T) {
+	t.Run("given operating systems is windows", func(t *testing.T) {
+
+		operatingSystem := "windows"
+		os.Setenv("PATHEXT", ".COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC")
+
+		t.Run("should return error if git executable exists in current directory", func(t *testing.T) {
+			fs := afero.NewMemMapFs()
+			gitExecutable := "git.exe"
+			afero.WriteFile(fs, gitExecutable, []byte("git executable"), 0700)
+			err := validateGitExecutable(fs, operatingSystem)
+			assert.EqualError(t, err, "not allowed to have git executable located in repository: git.exe")
+		})
+
+		t.Run("should return nil if git executable does not exist in current directory", func(t *testing.T) {
+			err := validateGitExecutable(afero.NewMemMapFs(), operatingSystem)
+			assert.NoError(t, err)
+		})
+
+	})
+
+	t.Run("given operating systems is linux", func(t *testing.T) {
+
+		operatingSystem := "linux"
+
+		t.Run("should return nil if git executable exists in current directory", func(t *testing.T) {
+			fs := afero.NewMemMapFs()
+			gitExecutable := "git.exe"
+			afero.WriteFile(fs, gitExecutable, []byte("git executable"), 0700)
+			err := validateGitExecutable(fs, operatingSystem)
+			assert.NoError(t, err)
+		})
+
+		t.Run("should return nil if git executable does not exist in current directory", func(t *testing.T) {
+			err := validateGitExecutable(afero.NewMemMapFs(), operatingSystem)
+			assert.NoError(t, err)
+		})
+
+	})
+
+}