Reworking value source API

command_test.go

@@ -51,7 +51,7 @@ func buildExtendedTestCommand() *Command {
  Name: "another-flag",
  Aliases: []string{"b"},
  Usage: "another usage text",
- Sources: ValueSources{EnvSource("EXAMPLE_VARIABLE_NAME")},
+ Sources: EnvVars("EXAMPLE_VARIABLE_NAME"),
  },
  &BoolFlag{
  Name: "hidden-flag",

flag_bool_with_inverse.go

@@ -89,7 +89,7 @@ func (parent *BoolWithInverseFlag) initialize() {
  parent.negativeFlag = &BoolFlag{
  Category: child.Category,
  DefaultText: child.DefaultText,
- Sources: append(ValueSources{}, child.Sources...),
+ Sources: ValueSourceChain{Chain: append([]ValueSource{}, child.Sources.Chain...)},
  Usage: child.Usage,
  Required: child.Required,
  Hidden: child.Hidden,
@@ -108,10 +108,11 @@ func (parent *BoolWithInverseFlag) initialize() {
  parent.negativeFlag.Name = parent.inverseName()
  parent.negativeFlag.Aliases = parent.inverseAliases()
 
- if len(child.Sources) > 0 {
- parent.negativeFlag.Sources = make(ValueSources, len(child.Sources))
+ if len(child.Sources.Chain) > 0 {
+ parent.negativeFlag.Sources = ValueSourceChain{Chain: make([]ValueSource, len(child.Sources.Chain))}
+
  for idx, envVar := range child.GetEnvVars() {
- parent.negativeFlag.Sources[idx] = EnvSource(strings.ToUpper(parent.InversePrefix) + envVar)
+ parent.negativeFlag.Sources.Chain[idx] = &envVarValueSource{Key: strings.ToUpper(parent.InversePrefix) + envVar}
  }
  }
 }

flag_bool_with_inverse_test.go

@@ -199,7 +199,7 @@ func TestBoolWithInverseEnvVars(t *testing.T) {
  return &BoolWithInverseFlag{
  BoolFlag: &BoolFlag{
  Name: "env",
- Sources: ValueSources{EnvSource("ENV")},
+ Sources: EnvVars("ENV"),
  },
  }
  }

flag_impl.go

@@ -86,7 +86,7 @@
  DefaultText string // default text of the flag for usage purposes
  Usage string // usage string for help output
 
- Sources ValueSources // sources to load flag value from
+ Sources ValueSourceChain // sources to load flag value from
 
  Required bool // whether the flag is required or not
  Hidden bool // whether to hide the flag in help output
@@ -132,16 +132,22 @@
  if !f.applied || !f.Persistent {
  newVal := f.Value
 
- if val, source, found := f.Sources.Get(); found {
+ if val, source, found := f.Sources.LookupWithSource(); found {
  tmpVal := f.creator.Create(f.Value, new(T), f.Config)
  if val != "" || reflect.TypeOf(f.Value).Kind() == reflect.String {
  if err := tmpVal.Set(val); err != nil {
- return fmt.Errorf("could not parse %q as %T value from %s for flag %s: %s", val, f.Value, source, f.Name, err)
+ return fmt.Errorf(
+ "could not parse %[1]q as %[2]T value from %[3]s for flag %[4]s: %[5]s",
+ val, f.Value, source, f.Name, err,
+ )
  }
  } else if val == "" && reflect.TypeOf(f.Value).Kind() == reflect.Bool {
  val = "false"
  if err := tmpVal.Set(val); err != nil {
- return fmt.Errorf("could not parse %q as %T value from %s for flag %s: %s", val, f.Value, source, f.Name, err)
+ return fmt.Errorf(
+ "could not parse %[1]q as %[2]T value from %[3]s for flag %[4]s: %[5]s",
+ val, f.Value, source, f.Name, err,
+ )
  }
  }
 
@@ -206,13 +212,15 @@
 
 // GetEnvVars returns the env vars for this flag
 func (f *FlagBase[T, C, V]) GetEnvVars() []string {
- var envs []string
- for _, src := range f.Sources {
- if esrc, ok := src.(EnvSource); ok {
- envs = append(envs, string(esrc))
+ vals := []string{}
+
+ for _, src := range f.Sources.Chain {
+ if v, ok := src.(*envVarValueSource); ok {
+ vals = append(vals, v.Key)
  }
  }
- return envs
+
+ return vals
 }
 
 // TakesValue returns true if the flag takes a value, otherwise false