Themes: automatically remove filters that are useless because they would filter everything or nothing; fix some logic bugs and add tests

src/Logic/Tags/And.ts

@@ -124,7 +124,7 @@ export class And extends TagsFilter {
      * t0.shadows(t0) // => true
      * t1.shadows(t1) // => true
      * t2.shadows(t2) // => true
-     * t0.shadows(t1) // => false
+     * t0.shadows(t1) // => true
      * t0.shadows(t2) // => false
      * t1.shadows(t0) // => false
      * t1.shadows(t2) // => false
@@ -135,13 +135,18 @@ export class And extends TagsFilter {
      * const t1 = new And([new Tag("shop","clothes"), new Or([new Tag("brand","XYZ"),new Tag("brand:wikidata","Q1234")])])
      * const t2 = new And([new RegexTag("shop","mall",true), new Or([TagUtils.Tag("shop~*"), new Tag("craft","shoemaker")])])
      * t1.shadows(t2) // => true
+     *
+     * const t1 = new Tag("a","b")
+     * const t2 = new And([new Tag("x","y"), new Tag("a","b")])
+     * t2.shadows(t1) // => true
+     * t1.shadows(t2) // => false
      */
     shadows(other: TagsFilter): boolean {
-        const phrases: TagsFilter[] = other instanceof And ? other.and : [other]
+        // The phrases of the _other_ and
+        const phrases: readonly TagsFilter[] = other instanceof And ? other.and : [other]
         // A phrase might be shadowed by a certain subsection. We keep track of this here
         const shadowedOthers = phrases.map(() => false)
         for (const selfTag of this.and) {
-            let shadowsSome = false
             let shadowsAll = true
             for (let i = 0; i < phrases.length; i++) {
                 const otherTag = phrases[i]
@@ -149,7 +154,6 @@ export class And extends TagsFilter {
                 if (doesShadow) {
                     shadowedOthers[i] = true
                 }
-                shadowsSome ||= doesShadow
                 shadowsAll &&= doesShadow
             }
             // If A => X and A => Y, then
@@ -157,9 +161,6 @@ export class And extends TagsFilter {
             if (shadowsAll) {
                 return true
             }
-            if (!shadowsSome) {
-                return false
-            }
         }
         return !shadowedOthers.some((v) => !v)
     }

src/Logic/Tags/TagUtils.ts

@@ -690,6 +690,9 @@ export class TagUtils {
         return result
     }
 
+    /**
+     * TagUtils.removeKnownParts(TagUtils.Tag({and: ["vending=excrement_bag"}),TagUtils.Tag({and: ["amenity=waste_basket", "vending=excrement_bag"]}), true) // => true
+     */
     public static removeKnownParts(
         tag: TagsFilter,
         known: TagsFilter,
@@ -702,7 +705,7 @@ export class TagUtils {
         if (tagOrBool instanceof And) {
             return tagOrBool.removePhraseConsideredKnown(known, valueOfKnown)
         }
-        return tagOrBool
+        return new And([tagOrBool]).removePhraseConsideredKnown(known, valueOfKnown)
     }
 
     /**

src/Models/ThemeConfig/Conversion/ExpandFilter.ts

@@ -13,7 +13,7 @@ import { Or } from "../../../Logic/Tags/Or"
 import Translations from "../../../UI/i18n/Translations"
 import { FlatTag, OptimizedTag, TagsFilterClosed } from "../../../Logic/Tags/TagTypes"
 import { TagsFilter } from "../../../Logic/Tags/TagsFilter"
-import { And } from "../../../Logic/Tags/And"
+import { Translation } from "../../../UI/i18n/Translation"
 
 export class PruneFilters extends DesugaringStep<LayerConfigJson> {
     constructor() {
@@ -24,11 +24,30 @@ export class PruneFilters extends DesugaringStep<LayerConfigJson> {
         )
     }
 
+    /**
+     * Prunes a filter; returns null/undefined if keeping the filter is useless
+     */
     private prune(
         sourceTags: FlatTag,
         filter: FilterConfigJson,
         context: ConversionContext
     ): FilterConfigJson {
+
+        if (filter.options.length === 1) {
+            const option = filter.options[0]
+            const tags = TagUtils.Tag(option.osmTags)
+            const optimized = TagUtils.removeKnownParts(tags, sourceTags, true)
+            if (optimized === true) {
+                context.warn("Removing filter as always known: ", new Translation(option.question).textFor("en"))
+                return undefined
+            }
+            if (optimized === false) {
+                context.warn("Removing filter as not possible: ", new Translation(option.question).textFor("en"))
+                return undefined
+            }
+        }
+
+
         if (!filter.strict) {
             return filter
         }
@@ -47,7 +66,7 @@ export class PruneFilters extends DesugaringStep<LayerConfigJson> {
                 if (!option.osmTags) {
                     return option
                 }
-                let basetags = TagUtils.Tag(option.osmTags)
+                const basetags = TagUtils.Tag(option.osmTags)
                 return {
                     ...option,
                     osmTags: (<TagsFilter>TagUtils.removeKnownParts(basetags, sourceTags)).asJson(),
@@ -65,6 +84,8 @@ export class PruneFilters extends DesugaringStep<LayerConfigJson> {
                         ")"
                 )
         }
+
+
         return { ...filter, options: newOptions, strict: undefined }
     }
 
@@ -78,9 +99,9 @@ export class PruneFilters extends DesugaringStep<LayerConfigJson> {
         const sourceTags = TagUtils.Tag(json.source["osmTags"])
         return {
             ...json,
-            filter: json.filter?.map((obj) =>
+            filter: Utils.NoNull(json.filter?.map((obj) =>
                 this.prune(sourceTags, <FilterConfigJson>obj, context)
-            ),
+            )),
         }
     }
 }