Use path type instead of an auto-expanding string

This is required to remove value.FromInstance, but also makes tests
possible without manipulating $HOME, and allows me to remove the (now
archived) go-homedir dependency

Closes #51

CHANGELOG.md

@@ -10,7 +10,7 @@ below this description) is likely unreleased.
 
 ## Added
 
-- `path.Path` type that users should call `Expand`/`MustExpand` on.
+- `path.Path` type that users should call `Expand`/`MustExpand` on. See `Removed`
 
 ## Changed
 

app.go

@@ -12,6 +12,7 @@ import (
 	"go.bbkane.com/warg/config"
 	"go.bbkane.com/warg/flag"
 	"go.bbkane.com/warg/help"
+	"go.bbkane.com/warg/path"
 	"go.bbkane.com/warg/section"
 	"go.bbkane.com/warg/value"
 	"go.bbkane.com/warg/value/scalar"
@@ -127,7 +128,7 @@ func ConfigFlag(
 	// TODO: put the new stuff at the front to be consistent with OverrideHelpFlag
 	configFlagName flag.Name,
 	// TODO: can I make this nicer?
-	scalarOpts []scalar.ScalarOpt[string],
+	scalarOpts []scalar.ScalarOpt[path.Path],
 	newConfigReader config.NewReader,
 	helpShort flag.HelpShort,
 	flagOpts ...flag.FlagOpt,

app_parse.go

@@ -10,6 +10,7 @@ import (
 	"go.bbkane.com/warg/config"
 	"go.bbkane.com/warg/flag"
 	"go.bbkane.com/warg/help/common"
+	"go.bbkane.com/warg/path"
 	"go.bbkane.com/warg/section"
 	"go.bbkane.com/warg/value"
 )
@@ -441,9 +442,13 @@ func (app *App) parseWithOptHolder(parseOptHolder ParseOptHolder) (*ParseResult,
 		if err != nil {
 			return nil, err
 		}
-		// NOTE: this *should* always be a string
-		configPath := app.configFlag.Value.Get().(string)
-		configReader, err = app.newConfigReader(configPath)
+		// NOTE: this should *always* be a path.
+		configPath := app.configFlag.Value.Get().(path.Path)
+		configPathStr, err := configPath.Expand()
+		if err != nil {
+			return nil, fmt.Errorf("error expanding config path ( %s ) : %w", configPath, err)
+		}
+		configReader, err = app.newConfigReader(configPathStr)
 		if err != nil {
 			return nil, fmt.Errorf("error reading config path ( %s ) : %w", configPath, err)
 		}