From 8319ac1ec65a676cfd6f51623367b8ab51f996af Mon Sep 17 00:00:00 2001
From: andig <andi@evcc.io>
Date: Tue, 28 Oct 2025 16:08:48 +0100
Subject: [PATCH] chore: simplify template validation (#24825)

---
 util/templates/init.go     | 15 +++++----------
 util/templates/template.go | 14 +++++++-------
 2 files changed, 12 insertions(+), 17 deletions(-)

diff --git a/util/templates/init.go b/util/templates/init.go
index 5db5b5570..91b6e54b7 100644
--- a/util/templates/init.go
+++ b/util/templates/init.go
@@ -77,18 +77,13 @@ func fromBytes(b []byte) (Template, error) {
 		TemplateDefinition: definition,
 	}
 
-	err := tmpl.ResolvePresets()
-	if err == nil {
-		err = tmpl.ResolveGroup()
-	}
-	if err == nil {
-		err = tmpl.UpdateParamsWithDefaults()
-	}
-	if err == nil {
-		err = tmpl.Validate()
+	for _, f := range []func() error{tmpl.ResolvePresets, tmpl.ResolveGroup, tmpl.UpdateParamsWithDefaults, tmpl.Validate} {
+		if err := f(); err != nil {
+			return tmpl, fmt.Errorf("template '%s': %w", tmpl.Template, err)
+		}
 	}
 
-	return tmpl, err
+	return tmpl, nil
 }
 
 func load(class Class) {
diff --git a/util/templates/template.go b/util/templates/template.go
index b2c688ebe..c5301a4dd 100644
--- a/util/templates/template.go
+++ b/util/templates/template.go
@@ -41,19 +41,19 @@ func (t *Template) UpdateParamsWithDefaults() error {
 func (t *Template) Validate() error {
 	for _, c := range t.Capabilities {
 		if !slices.Contains(ValidCapabilities, c) {
-			return fmt.Errorf("invalid capability '%s' in template %s", c, t.Template)
+			return fmt.Errorf("invalid capability: '%s'", c)
 		}
 	}
 
 	for _, c := range t.Countries {
 		if !c.IsValid() {
-			return fmt.Errorf("invalid country code '%s' in template %s", c, t.Template)
+			return fmt.Errorf("invalid country code: '%s'", c)
 		}
 	}
 
 	for _, r := range t.Requirements.EVCC {
 		if !slices.Contains(ValidRequirements, r) {
-			return fmt.Errorf("invalid requirement '%s' in template %s", r, t.Template)
+			return fmt.Errorf("invalid requirement: '%s'", r)
 		}
 	}
 
@@ -63,26 +63,26 @@ func (t *Template) Validate() error {
 		}
 
 		if p.Description.String("en") == "" || p.Description.String("de") == "" {
-			return fmt.Errorf("description for param %s cant be empty in template %s", p.Name, t.Template)
+			return fmt.Errorf("param %s: description can't be empty", p.Name)
 		}
 
 		maxLength := 50
 		actualLength := max(len(p.Description.String("en")), len(p.Description.String("de")))
 		if actualLength > maxLength {
-			return fmt.Errorf("description for param %s is too long in template %s. allowed: %d. actual length: %d. use help field for details instead.", p.Name, t.Template, maxLength, actualLength)
+			return fmt.Errorf("param %s: description too long (%d/%d allowed)- use help instead", p.Name, actualLength, maxLength)
 		}
 
 		switch p.Name {
 		case ParamUsage:
 			for _, c := range p.Choice {
 				if !slices.Contains(UsageStrings(), c) {
-					return fmt.Errorf("invalid usage choice '%s' in template %s", c, t.Template)
+					return fmt.Errorf("invalid usage: '%s'", c)
 				}
 			}
 		case ParamModbus:
 			for _, c := range p.Choice {
 				if !slices.Contains(ValidModbusChoices, c) {
-					return fmt.Errorf("invalid modbus choice '%s' in template %s", c, t.Template)
+					return fmt.Errorf("invalid modbus type: '%s'", c)
 				}
 			}
 		}