Themes: add extra check so that in a mapping cannot override the , fix two such instances

assets/layers/climbing_gym/climbing_gym.json

@@ -135,7 +135,6 @@
             "de": "Kletterschuhe können hier ausgeliehen werden"
           },
           "addExtraTags": [
-            "service:climbing_shoes:rental:fee=",
             "service:climbing_shoes:rental:charge="
           ]
         },

assets/themes/campersite/campersite.json

@@ -231,12 +231,7 @@
               }
             },
             {
-              "if": {
-                "and": [
-                  "fee=no",
-                  "charge="
-                ]
-              },
+              "if": "fee=no",
               "then": {
                 "en": "Can be used for free",
                 "id": "Boleh digunakan tanpa bayaran",

src/Models/ThemeConfig/Conversion/Validation.ts

@@ -16,6 +16,7 @@ import FilterConfigJson from "../Json/FilterConfigJson"
 import DeleteConfig from "../DeleteConfig"
 import {QuestionableTagRenderingConfigJson} from "../Json/QuestionableTagRenderingConfigJson"
 import Validators from "../../../UI/InputElement/Validators"
+import TagRenderingConfig from "../TagRenderingConfig";
 
 class ValidateLanguageCompleteness extends DesugaringStep<any> {
     private readonly _languages: string[]
@@ -383,6 +384,51 @@ export class PrevalidateTheme extends Fuse<LayoutConfigJson> {
     }
 }
 
+export class DetectConflictingAddExtraTags extends DesugaringStep<TagRenderingConfigJson> {
+    constructor() {
+        super("The `if`-part in a mapping might set some keys. Those key are not allowed to be set in the `addExtraTags`, as this might result in conflicting values", [], "DetectConflictingAddExtraTags");
+    }
+
+    convert(json: TagRenderingConfigJson, context: string): {
+        result: TagRenderingConfigJson;
+        errors?: string[];
+        warnings?: string[];
+        information?: string[]
+    } {
+
+        if (!(json.mappings?.length > 0)) {
+            return {result: json}
+        }
+
+        const tagRendering = new TagRenderingConfig(json)
+
+        const errors = []
+        for (let i = 0; i < tagRendering.mappings.length; i++) {
+            const mapping = tagRendering.mappings[i];
+            if (!mapping.addExtraTags) {
+                continue
+            }
+            const keysInMapping = new Set(mapping.if.usedKeys())
+
+            const keysInAddExtraTags = mapping.addExtraTags.map(t => t.key)
+
+            const duplicateKeys = keysInAddExtraTags.filter(k => keysInMapping.has(k))
+            if (duplicateKeys.length > 0) {
+                errors.push(
+                    "At " + context + ".mappings[" + i + "]: AddExtraTags overrides a key that is set in the `if`-clause of this mapping. Selecting this answer might thus first set one value (needed to match as answer) and then override it with a different value, resulting in an unsaveable question. The offending `addExtraTags` is " + duplicateKeys.join(", ")
+                )
+            }
+        }
+
+
+        return {
+            result: json,
+            errors
+        };
+    }
+}
+
+
 export class DetectShadowedMappings extends DesugaringStep<TagRenderingConfigJson> {
     private readonly _calculatedTagNames: string[]
 
@@ -669,6 +715,7 @@ export class ValidateTagRenderings extends Fuse<TagRenderingConfigJson> {
         super(
             "Various validation on tagRenderingConfigs",
             new DetectShadowedMappings(layerConfig),
+            new DetectConflictingAddExtraTags(),
             new DetectMappingsWithImages(doesImageExist),
             new MiscTagRenderingChecks(options)
         )
@@ -865,6 +912,13 @@ export class ValidateLayer extends DesugaringStep<LayerConfigJson> {
                 }
             }
 
+            if (json.filter) {
+                const r = new On("filter", new Each( new ValidateFilter())).convert(json, context)
+                warnings.push(...(r.warnings ?? []))
+                errors.push(...(r.errors ?? []))
+                information.push(...(r.information ?? []))
+            }
+
             if (json.tagRenderings !== undefined) {
                 const r = new On(
                     "tagRenderings",
@@ -949,9 +1003,14 @@ export class ValidateFilter extends DesugaringStep<FilterConfigJson> {
         warnings?: string[]
         information?: string[]
     } {
+        if (typeof filter === "string") {
+            // Calling another filter, we skip
+            return {result: filter}
+        }
         const errors = []
         for (const option of filter.options) {
-            for (let i = 0; i < option.fields.length; i++) {
+
+            for (let i = 0; i < option.fields?.length ?? 0; i++) {
                 const field = option.fields[i]
                 const type = field.type ?? "string"
                 if (Validators.availableTypes.find((t) => t === type) === undefined) {