bug(flags): bool flags still fail validation despite default value

flag_set.go

@@ -366,19 +366,18 @@ func (fs *flagSet) apply(envVars map[string]string, args []string) error {
 		// By definition, for the same name - all flags have the same "HasValue" value, so it should be safe to just
 		// take it from the first one
 		if mfd.HasValue {
-
-			// Set the field's default value so it's marked as "applied" (and thus the "required" validation will ignore it)
-			if mfd.DefaultValue != "" {
-				if err := mfd.setValue(mfd.DefaultValue); err != nil {
-					return fmt.Errorf("failed applying default value for flag '%s': %w", mfd.Name, err)
-				}
-			}
 			stdFs.Func(mfd.Name, "", func(v string) error { return mfd.setValue(v) })
-
 		} else {
 			stdFs.BoolFunc(mfd.Name, "", func(string) error { return mfd.setValue("true") })
 		}
 
+		// Set the field's default value so it's marked as "applied" (and thus the "required" validation will ignore it)
+		if mfd.DefaultValue != "" {
+			if err := mfd.setValue(mfd.DefaultValue); err != nil {
+				return fmt.Errorf("failed applying default value for flag '%s': %w", mfd.Name, err)
+			}
+		}
+
 		// Set the value to the flag's corresponding environment variable, if one was given
 		// Important this is done here, so it overrides the default value set earlier
 		if v, found := envVars[*mfd.EnvVarName]; found {

flag_set_test.go

@@ -978,6 +978,26 @@ func TestFlagSetApply(t *testing.T) {
 			args:          []string{"--my-field1=VVV1"},
 			expectedError: `^required flag is missing: --my-field2$`,
 		},
+		"bool flag default value is considered": {
+			config: &struct {
+				F1 bool `name:"my-field1" required:"true"`
+			}{F1: false},
+			envVars: map[string]string{},
+			args:    []string{},
+			expectedConfig: &struct {
+				F1 bool `name:"my-field1" required:"true"`
+			}{F1: false},
+		},
+		"bool flag default value overridden by arg": {
+			config: &struct {
+				F1 bool `name:"my-field1" required:"true"`
+			}{F1: false},
+			envVars: map[string]string{},
+			args:    []string{"--my-field1"},
+			expectedConfig: &struct {
+				F1 bool `name:"my-field1" required:"true"`
+			}{F1: true},
+		},
 	}
 	for name, tc := range testCases {
 		tc := tc