var envVarNameRegexp = regexp.MustCompile("^" + envVarNameFmt + "$")

// IsEnvVarName tests if a string is a valid environment variable name.
func IsEnvVarName(value string) []string {
	var errs []string
	if !envVarNameRegexp.MatchString(value) {

	// or the old pod does not exist in the env.
	// We will let the feature gate decide whether to use relaxed rules.
	if oldPodEnvVarNames.Len() == 0 {
		return false
	}

	if len(validation.IsEnvVarName(name)) == 0 || len(validation.IsRelaxedEnvVarName(name)) != 0 {
		// It's either a valid name by strict rules or an invalid name under relaxed rules.
		// Either way, we'll use strict rules to validate.
		return false
	}

				for _, msg := range validation.IsRelaxedEnvVarName(ev.Name) {
					allErrs = append(allErrs, field.Invalid(idxPath.Child("name"), ev.Name, msg))
				}
			} else {
				for _, msg := range validation.IsEnvVarName(ev.Name) {
					allErrs = append(allErrs, field.Invalid(idxPath.Child("name"), ev.Name, msg))
				}
			}
		}
		allErrs = append(allErrs, validateEnvVarValueFrom(ev, idxPath.Child("valueFrom"), opts)...)
	}