Remove worked examples from Skill objects in asset download script.

model/src/main/proto/topic.proto

@@ -88,8 +88,9 @@ message ConceptCard {
   // The core explanation of the skill being reviewed.
   SubtitledHtml explanation = 3;
 
-  // A list of worked examples to present to the learner.
-  repeated SubtitledHtml worked_example = 4;
+  // This field used to be a list of worked examples to present to the learner.
+  // The field was never used, and was removed in Oct 2025.
+  reserved 4;
 
   // Mapping from content_id to a VoiceoverMapping for each SubtitledHtml in this concept card that
   // has corresponding recorded audio to play.

scripts/src/java/org/oppia/android/scripts/assets/DownloadLessonList.kt

@@ -92,7 +92,9 @@ class LessonListDownloader(
 
   fun downloadLessonListAsync(lessonListOutputFile: File): Deferred<Unit> {
     return CoroutineScope(scriptBgDispatcher).async {
-      if (apiDebugDir != null) println("Config: Using ${apiDebugDir.path}/ for storing API responses (for debugging).")
+      if (apiDebugDir != null) {
+        println("Config: Using ${apiDebugDir.path}/ for storing API responses (for debugging).")
+      }
 
       val listResponse = downloadTopicListResponseDto()
       println()

scripts/src/java/org/oppia/android/scripts/assets/DownloadLessons.kt

@@ -14,9 +14,10 @@ import kotlinx.coroutines.flow.consumeAsFlow
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.flow.withIndex
-import kotlinx.coroutines.launch
 import kotlinx.coroutines.runBlocking
 import kotlinx.coroutines.withContext
+import org.oppia.android.scripts.assets.DtoProtoToLegacyProtoConverter.convertToClassroomIdList
+import org.oppia.android.scripts.assets.DtoProtoToLegacyProtoConverter.convertToClassroomRecord
 import org.oppia.android.scripts.assets.DtoProtoToLegacyProtoConverter.convertToConceptCardList
 import org.oppia.android.scripts.assets.DtoProtoToLegacyProtoConverter.convertToExploration
 import org.oppia.android.scripts.assets.DtoProtoToLegacyProtoConverter.convertToStoryRecord
@@ -95,12 +96,10 @@ import java.util.concurrent.ConcurrentHashMap
 import java.util.concurrent.ExecutorService
 import java.util.concurrent.Executors
 import java.util.concurrent.TimeUnit
-import org.oppia.android.scripts.assets.DtoProtoToLegacyProtoConverter.convertToClassroomIdList
-import org.oppia.android.scripts.assets.DtoProtoToLegacyProtoConverter.convertToClassroomRecord
+import kotlin.system.exitProcess
 import org.oppia.proto.v1.api.DownloadRequestStructureIdentifierDto.Builder as DownloadReqStructIdDtoBuilder
 import org.oppia.proto.v1.structure.DragAndDropSortInputInstanceDto.RuleSpecDto as DragDropSortRuleSpecDto
 import org.oppia.proto.v1.structure.ItemSelectionInputInstanceDto.RuleSpecDto as ItemSelRuleSpecDto
-import kotlin.system.exitProcess
 
 /*
   TODO: Thoughts for improving the script:
@@ -236,7 +235,9 @@ class LessonDownloader(
   private val memoizedLoadedImageData by lazy { ConcurrentHashMap<File, ByteArray>() }
 
   fun downloadLessons(outputDir: File, failOnError: Boolean) {
-    val downloadDeferred = CoroutineScope(coroutineDispatcher).async { downloadAllLessons(outputDir, failOnError) }
+    val downloadDeferred = CoroutineScope(coroutineDispatcher).async {
+      downloadAllLessons(outputDir, failOnError)
+    }
     val exceptionResult = runBlocking {
       runCatching { downloadDeferred.await() }.also { shutdownBlocking() }
     }
@@ -711,7 +712,10 @@ class LessonDownloader(
         issues.forEach { issue ->
           val missingLangs = issue.missingLanguages.joinToString { it.name }
           val presentLangs = issue.presentLanguages.joinToString { it.name }
-          println("  - Image ${issue.filename} exists in languages: $presentLangs, but is missing in: $missingLangs")
+          println(
+            "  - Image ${issue.filename} exists in languages: $presentLangs, " +
+              "but is missing in: $missingLangs"
+          )
         }
       }
     } else println("Images missing across translations: (Hidden)")
@@ -766,9 +770,14 @@ class LessonDownloader(
       println("(look at above output for specific images that require verification).")
     }
 
-    val hasAnyFailure = issues.isNotEmpty() || imageDownloadFailures.isNotEmpty() || renamedImages.isNotEmpty() || convertedImages.isNotEmpty()
+    val hasAnyFailure = (
+      issues.isNotEmpty() || imageDownloadFailures.isNotEmpty() ||
+        renamedImages.isNotEmpty() || convertedImages.isNotEmpty()
+      )
     if (hasAnyFailure && failOnError) {
-      throw Exception("Failed to cleanly download and convert all lessons and images. See failures above.")
+      throw Exception(
+        "Failed to cleanly download and convert all lessons and images. See failures above."
+      )
     }
 
 //    val translationMetrics = analyzer.computeTranslationsUsageReport()

scripts/src/java/org/oppia/android/scripts/assets/DtoProtoToLegacyProtoConverter.kt

@@ -77,6 +77,7 @@ import org.oppia.proto.v1.structure.InteractionInstanceDto.InteractionTypeCase.I
 import org.oppia.proto.v1.structure.InteractionInstanceDto.InteractionTypeCase.ITEM_SELECTION_INPUT
 import org.oppia.proto.v1.structure.InteractionInstanceDto.InteractionTypeCase.MATH_EQUATION_INPUT
 import org.oppia.proto.v1.structure.InteractionInstanceDto.InteractionTypeCase.MULTIPLE_CHOICE_INPUT
+import org.oppia.proto.v1.structure.InteractionInstanceDto.InteractionTypeCase.NUMBER_WITH_UNITS_INPUT
 import org.oppia.proto.v1.structure.InteractionInstanceDto.InteractionTypeCase.NUMERIC_EXPRESSION_INPUT
 import org.oppia.proto.v1.structure.InteractionInstanceDto.InteractionTypeCase.NUMERIC_INPUT
 import org.oppia.proto.v1.structure.InteractionInstanceDto.InteractionTypeCase.RATIO_EXPRESSION_INPUT
@@ -89,6 +90,8 @@ import org.oppia.proto.v1.structure.MathEquationInputInstanceDto
 import org.oppia.proto.v1.structure.MisconceptionDto
 import org.oppia.proto.v1.structure.MultipleChoiceInputInstanceDto
 import org.oppia.proto.v1.structure.NormalizedPoint2dDto
+import org.oppia.proto.v1.structure.NumberWithUnitsDto
+import org.oppia.proto.v1.structure.NumberWithUnitsInputInstanceDto
 import org.oppia.proto.v1.structure.NumericExpressionInputInstanceDto
 import org.oppia.proto.v1.structure.NumericInputInstanceDto
 import org.oppia.proto.v1.structure.OutcomeDto
@@ -112,13 +115,10 @@ import org.oppia.proto.v1.structure.AlgebraicExpressionInputInstanceDto.RuleSpec
 import org.oppia.proto.v1.structure.DragAndDropSortInputInstanceDto.RuleSpecDto as DragDropSortRuleSpecDto
 import org.oppia.proto.v1.structure.DragAndDropSortInputInstanceDto.RuleSpecDto.RuleTypeCase as DragDropSortRuleSpecTypeCase
 import org.oppia.proto.v1.structure.FractionInputInstanceDto.RuleSpecDto as FractionRuleSpecDto
-import org.oppia.proto.v1.structure.InteractionInstanceDto.InteractionTypeCase.NUMBER_WITH_UNITS_INPUT
 import org.oppia.proto.v1.structure.ItemSelectionInputInstanceDto.RuleSpecDto as ItemSelRuleSpecDto
 import org.oppia.proto.v1.structure.MathEquationInputInstanceDto.RuleSpecDto as MathEqRuleSpecDto
 import org.oppia.proto.v1.structure.MathEquationInputInstanceDto.RuleSpecDto.MatchesUpToTrivialManipulationsSpecDto as MathEqMatchesUpToTrivialManipulationsSpecDto
 import org.oppia.proto.v1.structure.MultipleChoiceInputInstanceDto.RuleSpecDto as MultChoiceRuleSpecDto
-import org.oppia.proto.v1.structure.NumberWithUnitsDto
-import org.oppia.proto.v1.structure.NumberWithUnitsInputInstanceDto
 import org.oppia.proto.v1.structure.NumberWithUnitsInputInstanceDto.RuleSpecDto as NumUnitsRuleSpecDto
 import org.oppia.proto.v1.structure.NumericExpressionInputInstanceDto.RuleSpecDto as NumExpRuleSpecDto
 import org.oppia.proto.v1.structure.NumericExpressionInputInstanceDto.RuleSpecDto.MatchesUpToTrivialManipulationsSpecDto as NumExpMatchesUpToTrivialManipulationsSpecDto

scripts/src/java/org/oppia/android/scripts/gae/GaeAndroidEndpointJsonImpl.kt

@@ -241,7 +241,9 @@ class GaeAndroidEndpointJsonImpl(
     return CoroutineScope(coroutineDispatcher).async {
       SUPPORTED_CLASSROOMS.map { classroomName ->
         CoroutineScope(coroutineDispatcher).async {
-          val classroomResult = activityService.fetchLatestClassroomAsync(classroomName).await().also {
+          val classroomResult = activityService.fetchLatestClassroomAsync(
+            classroomName
+          ).await().also {
             tracker.reportDownloaded(classroomName)
           }
           checkNotNull(classroomResult?.payload) { "Failed to fetch classroom: $classroomName." }
@@ -830,7 +832,7 @@ class GaeAndroidEndpointJsonImpl(
         "Continue", "FractionInput", "ItemSelectionInput", "MultipleChoiceInput",
         "NumericInput", "TextInput", "DragAndDropSortInput", "ImageClickInput",
         "RatioExpressionInput", "EndExploration", "NumericExpressionInput",
-        "AlgebraicExpressionInput", "MathEquationInput"//, "NumberWithUnits"
+        "AlgebraicExpressionInput", "MathEquationInput" // , "NumberWithUnits"
       )
 
     // TODO: Remove gif and png since we only want to use svg(z) and webp moving forward.
@@ -862,7 +864,7 @@ class GaeAndroidEndpointJsonImpl(
     private val SUPPORTED_DEFAULT_LANGUAGES = setOf(LanguageType.ENGLISH)
 
     // From feconf.
-    private const val SUPPORTED_STATE_SCHEMA_VERSION = 56
+    private const val SUPPORTED_STATE_SCHEMA_VERSION = 57
 
     private fun ClientCompatibilityContextDto.verifyCompatibility() {
       check(topicListRequestResponseProtoVersion == createLatestTopicListProtoVersion()) {

scripts/src/java/org/oppia/android/scripts/gae/compat/StructureCompatibilityChecker.kt

@@ -38,7 +38,6 @@ import org.oppia.android.scripts.gae.json.GaeSubtopicPage
 import org.oppia.android.scripts.gae.json.GaeSubtopicPageContents
 import org.oppia.android.scripts.gae.json.GaeTopic
 import org.oppia.android.scripts.gae.json.GaeTranslatedContent
-import org.oppia.android.scripts.gae.json.GaeWorkedExample
 import org.oppia.android.scripts.gae.json.GaeWrittenTranslation
 import org.oppia.android.scripts.gae.json.GaeWrittenTranslations
 import org.oppia.android.scripts.gae.json.VersionedStructure
@@ -259,20 +258,11 @@ class StructureCompatibilityChecker(
     defaultLanguage: LanguageType
   ): List<CompatibilityFailure> {
     return gaeSkillContents.explanation.checkHasValidHtml(origin) +
-      gaeSkillContents.workedExamples.flatMap { checkWorkedExampleCompatibility(origin, it) } +
       checkWrittenTranslationsCompatibility(
         origin, gaeSkillContents.writtenTranslations, expectedTranslatedContentIds, defaultLanguage
       ) + checkRecordedVoiceoversCompatibility(origin, gaeSkillContents.recordedVoiceovers)
   }
 
-  private fun checkWorkedExampleCompatibility(
-    origin: ContainerId,
-    gaeWorkedExample: GaeWorkedExample
-  ): List<CompatibilityFailure> {
-    return gaeWorkedExample.question.checkHasValidHtml(origin) +
-      gaeWorkedExample.explanation.checkHasValidHtml(origin)
-  }
-
   private fun checkWrittenTranslationsCompatibility(
     origin: ContainerId,
     gaeWrittenTranslations: GaeWrittenTranslations,

scripts/src/java/org/oppia/android/scripts/gae/compat/SubtitledHtmlCollector.kt

@@ -19,7 +19,6 @@ import org.oppia.android.scripts.gae.json.GaeSubtopic
 import org.oppia.android.scripts.gae.json.GaeSubtopicPage
 import org.oppia.android.scripts.gae.json.GaeTopic
 import org.oppia.android.scripts.gae.json.GaeTranslatedContent
-import org.oppia.android.scripts.gae.json.GaeWorkedExample
 import org.oppia.android.scripts.gae.json.GaeWrittenTranslation
 import org.oppia.android.scripts.gae.json.GaeWrittenTranslations
 import org.oppia.android.scripts.gae.proto.LocalizationTracker
@@ -143,14 +142,10 @@ class SubtitledHtmlCollector(private val localizationTracker: LocalizationTracke
 
   private fun GaeSkillContents.collectSubtitles(): Set<SubtitledText> {
     val explanationText = setOf(explanation.toSubtitle())
-    val workedExampleTexts = workedExamples.flatSet { it.collectSubtitles() }
     val translations = writtenTranslations.collectSubtitles()
-    return explanationText + workedExampleTexts + translations
+    return explanationText + translations
   }
 
-  private fun GaeWorkedExample.collectSubtitles(): Set<SubtitledText> =
-    setOf(question.toSubtitle(), explanation.toSubtitle())
-
   private fun GaeWrittenTranslations.collectSubtitles(): Set<SubtitledText> {
     return translationsMapping.values.flatSet {
       it.values.flatSet { translation -> translation.collectSubtitles() }

scripts/src/java/org/oppia/android/scripts/gae/compat/TopicPackRepository.kt

@@ -623,9 +623,12 @@ private sealed class VersionedStructureReference<I : StructureId, S> {
       Compatible -> LoadResult.Success(payload)
       is Incompatible -> {
         // TODO: Remove this once Oppia web supports pulling structures without schema migrations (see https://github.com/oppia/oppia/issues/21253).
-        val irrecoverableFailure = compatibilityResult.failures.firstOrNull { it is CompatibilityFailure.StateSchemaVersionTooNew }
+        val irrecoverableFailure = compatibilityResult.failures.firstOrNull {
+          it is CompatibilityFailure.StateSchemaVersionTooNew
+        }
         check(irrecoverableFailure == null) {
-          "Oppia web introduced a state schema upgrade. Cannot recover--this script needs to be updated: $irrecoverableFailure"
+          "Oppia web introduced a state schema upgrade. Cannot recover--this " +
+            "script needs to be updated: $irrecoverableFailure"
         }
         LoadResult.Failure<S>(compatibilityResult.failures)
       }
@@ -792,7 +795,9 @@ private class ExplorationFetcher(
   ): Deferred<VersionedStructure<CompleteExploration>?> {
     return CoroutineScope(coroutineDispatcher).async {
       val latestExp = service.fetchLatestExplorationAsync(id.id).await()
-      return@async latestExp?.let { it.copyWithNewPayload(service.downloadExploration(id, it.payload)) }
+      return@async latestExp?.let {
+        it.copyWithNewPayload(service.downloadExploration(id, it.payload))
+      }
     }
   }
 
@@ -803,7 +808,9 @@ private class ExplorationFetcher(
   ): Deferred<VersionedStructure<CompleteExploration>?> {
     return CoroutineScope(coroutineDispatcher).async {
       val latestExp = service.fetchSingleExplorationAsync(id.id, version).await()
-      return@async latestExp?.let { it.copyWithNewPayload(service.downloadExploration(id, it.payload)) }
+      return@async latestExp?.let {
+        it.copyWithNewPayload(service.downloadExploration(id, it.payload))
+      }
     }
   }
 
@@ -833,7 +840,9 @@ private class ExplorationFetcher(
       val missingTranslations = translations.mapIndexedNotNull { index, value ->
         index.takeIf { value == null } // Take only indexes corresponding to missing values.
       }.map { VALID_LANGUAGE_TYPES[it] }
-      check(missingTranslations.isEmpty()) { "Failed to fetch translations for exploration $id: $missingTranslations." }
+      check(missingTranslations.isEmpty()) {
+        "Failed to fetch translations for exploration $id: $missingTranslations."
+      }
       return CompleteExploration(
         exploration,
         receivedTranslations.associateBy {

scripts/src/java/org/oppia/android/scripts/gae/json/AndroidActivityHandlerService.kt

@@ -321,7 +321,10 @@ class AndroidActivityHandlerService(
         val metadata = RequestMetadata(request().method, request().url.toUrl().toExternalForm())
         val responseBodyText = memoizedRawResponses[metadata]
         if (responseBodyText?.contains("maxmemory") == true) {
-          throw IllegalStateException("Oppia web ran out of memory. Clear Redis memory cache and try again.", exception)
+          throw IllegalStateException(
+            "Oppia web ran out of memory. Clear Redis memory cache and try again.",
+            exception
+          )
         } else throw IllegalStateException(
           "Failed to call: ${request()}. Response body:\n\n$responseBodyText".redact(), exception
         )
@@ -370,7 +373,9 @@ class AndroidActivityHandlerService(
     type: String,
     id: String,
     version: Int,
-    crossinline fetch: (AndroidActivityRequests.SingleNonLocalized) -> Call<List<VersionedStructure<T>>>,
+    crossinline fetch: (
+      AndroidActivityRequests.SingleNonLocalized
+    ) -> Call<List<VersionedStructure<T>>>,
     noinline retrieveStructureVersion: ((T) -> Int)?
   ): Deferred<VersionedStructure<T>?> {
     return CoroutineScope(dispatcher).async {
@@ -423,7 +428,10 @@ class AndroidActivityHandlerService(
       val reqsCol = createRequests(requestsRequiringRemoteFetching.map { (_, req) -> req })
       val fetchResult = if (reqsCol.requests.isNotEmpty()) {
         // Only fetch if there are versions to retrieve.
-        val versionsToRetrieve = requestsRequiringRemoteFetching.map { (index, _) -> versions[index] }
+        val versionsToRetrieve = requestsRequiringRemoteFetching.map {
+          (index, _) ->
+          versions[index]
+        }
         fetch(reqsCol).resolveAsyncVersionsAsync(id, versionsToRetrieve).await().map { structure ->
           // Ensure that the returned structures have the correct remote versions (since the web
           // controller isn't consistent in when it provides a version).

scripts/src/java/org/oppia/android/scripts/gae/json/GaeCustomizationArgValue.kt

@@ -18,11 +18,11 @@ import org.oppia.proto.v1.structure.InteractionInstanceDto.InteractionTypeCase.I
 import org.oppia.proto.v1.structure.InteractionInstanceDto.InteractionTypeCase.ITEM_SELECTION_INPUT
 import org.oppia.proto.v1.structure.InteractionInstanceDto.InteractionTypeCase.MATH_EQUATION_INPUT
 import org.oppia.proto.v1.structure.InteractionInstanceDto.InteractionTypeCase.MULTIPLE_CHOICE_INPUT
+import org.oppia.proto.v1.structure.InteractionInstanceDto.InteractionTypeCase.NUMBER_WITH_UNITS_INPUT
 import org.oppia.proto.v1.structure.InteractionInstanceDto.InteractionTypeCase.NUMERIC_EXPRESSION_INPUT
 import org.oppia.proto.v1.structure.InteractionInstanceDto.InteractionTypeCase.NUMERIC_INPUT
 import org.oppia.proto.v1.structure.InteractionInstanceDto.InteractionTypeCase.RATIO_EXPRESSION_INPUT
 import org.oppia.proto.v1.structure.InteractionInstanceDto.InteractionTypeCase.TEXT_INPUT
-import org.oppia.proto.v1.structure.InteractionInstanceDto.InteractionTypeCase.NUMBER_WITH_UNITS_INPUT
 
 // TODO: Mention parsing this requires setting customization key name & interaction type in the parsing context.
 sealed class GaeCustomizationArgValue {