#4528 - optionally allow missing values to be tolerated to make the S…

…prig default function work. Unable to test the original case in unit tests as recover() doesn't seem to work for Go templates.

main.go

@@ -212,7 +212,7 @@ func main() {
 		cli.BoolFlag{
 			Name:   FlagAllowMissing,
 			Usage:  "if true, missing variables will be replaced with <no value> instead of generating an error",
-			EnvVar: "ALLOW_MISSING_FLAGS",
+			EnvVar: "ALLOW_MISSING",
 		},
 	}
 	app.Commands = []cli.Command{