Fix parsing of boolean config parameters.

Other file formats like JSON or YAML would provide more type information, and unmarshalling would create correct types. Properties files aren't that useful, so we have to enforce some types by ourselves. We have to keep an eye on other types beside boolean, but this one seems sufficient for now.

Relates to urfave/cli#1376, which made our previous workaround (see #81 and #83) fail due to a private function in the InputSourceContext interface.

fileutil/properties_file_loader.go

@@ -12,6 +12,7 @@ import (
 	"net/url"
 	"os"
 	"runtime"
+	"strconv"
 	"strings"
 
 	"github.com/urfave/cli/v2"
@@ -50,9 +51,27 @@ func readPropertiesFile(filename string) (map[interface{}]interface{}, error) {
 		return nil, err
 	}
 
+	// Other file formats would provide more type information, and unmarshalling would
+	// create correct types. Properties files aren't that useful, so we have to enforce
+	// some types by ourselves. We have to keep an eye on other types beside boolean,
+	// but this one seems good enough for now.
+	coerceBooleanValues(config)
+
 	return config, nil
 }
 
+func coerceBooleanValues(m map[interface{}]interface{}) {
+	for k, v := range m {
+		switch v := v.(type) {
+		case string:
+			parsed, err := strconv.ParseBool(v)
+			if err == nil {
+				m[k] = parsed
+			}
+		}
+	}
+}
+
 type propertiesSourceContext struct {
 	FilePath string
 }
@@ -66,7 +85,7 @@ func NewPropertiesSourceFromFile(file string) (altsrc.InputSourceContext, error)
 		return nil, fmt.Errorf("Unable to load Properties file '%s': inner error: \n'%v'", ysc.FilePath, err.Error())
 	}
 
-	return &MapInputSource{valueMap: results}, nil
+	return altsrc.NewMapInputSource(file, results), nil
 }
 
 // NewPropertiesSourceFromFlagFunc creates a new Properties InputSourceContext from a provided flag name and source context.