mv flag.SetBy -> value.UpdatedBy()

Move more mutable state out of flags!

CHANGELOG.md

@@ -10,7 +10,7 @@ below this description) is likely unreleased.
 
 ## Changed
 
-- Moved `SetBy` into the `Value` interface - this allows `Flag` to be readonly and we need to update `SetBy` anyway
+- Moved `SetBy` into the `Value` interface (`value.UpdatedBy()` - this allows `Flag` to be readonly and and makes the coupling between setting the value and updating `UpdatedBy` explicit
 
 # v0.0.25
 

app_parse.go

@@ -199,8 +199,7 @@ func resolveFlag(
 			}
 		}
 
-		if fl.SetBy == "" && len(strValues) > 0 {
-
+		if fl.Value.UpdatedBy() == value.UpdatedByUnset && len(strValues) > 0 {
 			_, isScalar := val.(value.ScalarValue)
 			if isScalar && len(strValues) > 1 {
 				return fmt.Errorf("flag error: %v: flag passed multiple times, it's value (type %v), can only be updated once", name, fl.Value.Description())
@@ -224,14 +223,13 @@ func resolveFlag(
 				if err != nil {
 					return fmt.Errorf("error updating flag %v from passed flag value %v: %w", name, v, err)
 				}
-				fl.SetBy = "passedflag"
 			}
 		}
 	}
 
 	// update from config
 	{
-		if canUpdate && fl.SetBy == "" && configReader != nil {
+		if canUpdate && fl.Value.UpdatedBy() == value.UpdatedByUnset && configReader != nil {
 			fpr, err := configReader.Search(fl.ConfigPath)
 			if err != nil {
 				return err
@@ -247,7 +245,6 @@ func resolveFlag(
 							err,
 						)
 					}
-					fl.SetBy = "config"
 				} else {
 					v, ok := fl.Value.(value.SliceValue)
 					if !ok {
@@ -264,7 +261,6 @@ func resolveFlag(
 							return fmt.Errorf("could not update container type value: err: %w", err)
 						}
 					}
-					fl.SetBy = "config"
 					fl.Value = v
 				}
 			}
@@ -273,15 +269,14 @@ func resolveFlag(
 
 	// update from envvars
 	{
-		if canUpdate && fl.SetBy == "" && len(fl.EnvVars) > 0 {
+		if canUpdate && fl.Value.UpdatedBy() == value.UpdatedByUnset && len(fl.EnvVars) > 0 {
 			for _, e := range fl.EnvVars {
 				val, exists := lookupEnv(e)
 				if exists {
 					err := fl.Value.Update(val, value.UpdatedByEnvVar)
 					if err != nil {
 						return fmt.Errorf("error updating flag %v from envvar %v: %w", name, val, err)
 					}
-					fl.SetBy = "envvar"
 					break // stop looking for envvars
 				}
 
@@ -291,9 +286,8 @@ func resolveFlag(
 
 	// update from default
 	{
-		if canUpdate && fl.SetBy == "" && fl.Value.HasDefault() {
+		if canUpdate && fl.Value.UpdatedBy() == value.UpdatedByUnset && fl.Value.HasDefault() {
 			fl.Value.ReplaceFromDefault(value.UpdatedByDefault)
-			fl.SetBy = "appdefault"
 		}
 	}
 
@@ -467,7 +461,8 @@ func (app *App) parseWithOptHolder(parseOptHolder ParseOptHolder) (*ParseResult,
 		}
 
 		if !gar.HelpPassed {
-			if fl.Required && fl.SetBy == "" {
+			// TODO: do I need all the checks
+			if fl.Required && fl.Value.UpdatedBy() == value.UpdatedByUnset {
 				return nil, fmt.Errorf("flag required but not set: %s", name)
 			}
 		}
@@ -488,7 +483,7 @@ func (app *App) parseWithOptHolder(parseOptHolder ParseOptHolder) (*ParseResult,
 
 	pfs := make(command.PassedFlags)
 	for name, fl := range ftar.AllowedFlags {
-		if fl.SetBy != "" {
+		if fl.Value.UpdatedBy() != value.UpdatedByUnset {
 			pfs[string(name)] = fl.Value.Get()
 		}
 	}

flag/flag.go

@@ -73,9 +73,6 @@ type Flag struct {
 	// IsCommandFlag is set when parsing. Set to true if the flag was attached to a command (as opposed to being inherited from a section)
 	IsCommandFlag bool
 
-	// SetBy might be set when parsing. Possible values: appdefault, config, passedflag
-	SetBy string
-
 	// Value is set when parsing. Use SetBy != "" to determine whether a value was actually passed  instead of being empty
 	Value value.Value
 }
@@ -90,7 +87,6 @@ func New(helpShort HelpShort, empty value.EmptyConstructor, opts ...FlagOpt) Fla
 		EnvVars:               nil,
 		Required:              false,
 		IsCommandFlag:         false,
-		SetBy:                 "",
 		UnsetSentinel:         "",
 		Value:                 nil,
 	}

help/detailed/detailed.go

@@ -115,14 +115,14 @@ func detailedPrintFlag(w io.Writer, color *gocolor.Color, name flag.Name, f *fla
 		)
 	}
 
-	if f.SetBy != "" {
+	if f.Value.UpdatedBy() != value.UpdatedByUnset {
 		switch v := f.Value.(type) {
 		case value.DictValue:
 			fmt.Fprintf(
 				w,
 				"    %s (set by %s):\n",
 				color.Add(color.Bold, "currentvalue"),
-				color.Add(color.Bold, f.SetBy),
+				color.Add(color.Bold, string(f.Value.UpdatedBy())),
 			)
 			m := v.StringMap()
 			for _, key := range common.SortedKeys(m) {
@@ -145,7 +145,7 @@ func detailedPrintFlag(w io.Writer, color *gocolor.Color, name flag.Name, f *fla
 			fmt.Fprintf(w,
 				"    %s (set by %s) :\n",
 				color.Add(color.Bold, "currentvalue"),
-				color.Add(color.Bold, f.SetBy),
+				color.Add(color.Bold, string(f.Value.UpdatedBy())),
 			)
 
 			for i, e := range v.StringSlice() {
@@ -166,7 +166,7 @@ func detailedPrintFlag(w io.Writer, color *gocolor.Color, name flag.Name, f *fla
 				w,
 				"    %s (set by %s) : %s\n",
 				color.Add(color.Bold, "currentvalue"),
-				color.Add(color.Bold, f.SetBy),
+				color.Add(color.Bold, string(f.Value.UpdatedBy())),
 				v.String(),
 			)
 		default:

value/dict/dict.go

@@ -143,6 +143,10 @@ func (v *dictValue[_]) Update(s string, u value.UpdatedBy) error {
 	return nil
 }
 
+func (v *dictValue[_]) UpdatedBy() value.UpdatedBy {
+	return v.updatedBy
+}
+
 func (v *dictValue[_]) ReplaceFromDefault(u value.UpdatedBy) {
 	if v.hasDefault {
 		v.vals = v.defaultVals

value/scalar/scalar.go

@@ -124,6 +124,10 @@ func (v *scalarValue[T]) Update(s string, u value.UpdatedBy) error {
 	return nil
 }
 
+func (v *scalarValue[_]) UpdatedBy() value.UpdatedBy {
+	return v.updatedBy
+}
+
 func (v *scalarValue[_]) ReplaceFromDefault(u value.UpdatedBy) {
 	if v.defaultVal != nil {
 		v.updatedBy = u

value/slice/slice.go

@@ -140,6 +140,10 @@ func (v *sliceValue[_]) Update(s string, u value.UpdatedBy) error {
 	return nil
 }
 
+func (v *sliceValue[_]) UpdatedBy() value.UpdatedBy {
+	return v.updatedBy
+}
+
 func (v *sliceValue[_]) ReplaceFromDefault(u value.UpdatedBy) {
 	if v.hasDefault {
 		v.vals = v.defaultVals

value/value.go

@@ -8,9 +8,9 @@ type UpdatedBy string
 
 const (
 	UpdatedByUnset   UpdatedBy = ""
-	UpdatedByDefault UpdatedBy = "default"
+	UpdatedByDefault UpdatedBy = "appdefault"
 	UpdatedByEnvVar  UpdatedBy = "envvar"
-	UpdatedByFlag    UpdatedBy = "flag"
+	UpdatedByFlag    UpdatedBy = "passedflag"
 	UpdatedByConfig  UpdatedBy = "config"
 )
 
@@ -41,6 +41,9 @@ type Value interface {
 	// and replaces scalar Values
 	Update(string, UpdatedBy) error
 
+	// UpdatedBy returns the source of the last update
+	UpdatedBy() UpdatedBy
+
 	// ReplaceFromDefault updates the Value from a pre-set default, if one exists. use HasDefault to check whether a default exists
 	ReplaceFromDefault(u UpdatedBy)
 }