fix: check if builds.dir is a directory (#2587)

* fix: validate builds.main

* fix: pr comments

internal/builders/buildtarget/targets.go

@@ -147,7 +147,10 @@ func goVersion(build config.Build) ([]byte, error) {
 	cmd := exec.Command(build.GoBinary, "version")
 	// If the build.Dir is acessible, set the cmd dir to it in case
 	// of reletive path to GoBinary
-	if _, err := os.Stat(build.Dir); err == nil {
+	if fileInfo, err := os.Stat(build.Dir); err == nil {
+		if !fileInfo.IsDir() {
+			return nil, fmt.Errorf("invalid builds.dir property, it should be a directory: %s", build.Dir)
+		}
 		cmd.Dir = build.Dir
 	}
 	bts, err := cmd.CombinedOutput()

internal/builders/buildtarget/targets_test.go

@@ -271,6 +271,16 @@ func TestList(t *testing.T) {
 		require.Equal(t, []string{"linux_amd64"}, targets)
 	})
 
+	t.Run("error with dir", func(t *testing.T) {
+		_, err := List(config.Build{
+			Goos:     []string{"linux"},
+			Goarch:   []string{"amd64"},
+			GoBinary: "go",
+			Dir:      "targets.go",
+		})
+		require.EqualError(t, err, "invalid builds.dir property, it should be a directory: targets.go")
+	})
+
 	t.Run("fail", func(t *testing.T) {
 		_, err := List(config.Build{
 			Goos:     []string{"linux"},