app: pre-declare errors

app/app.go

@@ -2,7 +2,6 @@ package app
 
 import (
 	"embed"
-	"errors"
 
 	"git.dotya.ml/mirre-mt/pcmt/app/settings"
 	"git.dotya.ml/mirre-mt/pcmt/ent"
@@ -68,7 +67,7 @@ func (a *App) Init(s *settings.Settings, logger *slogging.Logger, dbclient *ent.
 		return nil
 	}
 
-	return errors.New("ErrAppAlreadyInitialised")
+	return ErrAppAlreadyInitialised
 }
 
 // E returns app's *echo.Echo instance.
@@ -95,7 +94,7 @@ func (a *App) PrintConfiguration() {
 		return
 	}
 
-	panic(errors.New("somehow we got here with config unset - contact the developer"))
+	panic(ErrAppSettingsUnset)
 }
 
 func (a *App) SetSettings(s *settings.Settings) {

app/error.go

@@ -0,0 +1,8 @@
+package app
+
+import "errors"
+
+var (
+	ErrAppSettingsUnset      = errors.New("somehow we got here with settings unset - contact the developer")
+	ErrAppAlreadyInitialised = errors.New("app was already initialised")
+)