feat(publish): a release keeps its colour, and a description for Explore

Publishing takes a description for Explore (rich text, as its JSON),
which Explore shows in place of the studyset's own: a studyset may
introduce itself to strangers otherwise than in the library, where its
author may leave it empty. Without one, as from older apps, the
studyset's description as before; one that isn't rich text, or over
100,000 characters, counts as none. A release also keeps the studyset's
colour, which Explore gives out with it; releases before have none. The
publication's releases say their description, for the next publish to
start from.

Migration release-colour adds a nullable column:
ALTER TABLE "studyset_release" ADD COLUMN "colorName" text;
the server before it reads and writes the table as ever.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

halkyon_learn_client/lib/src/protocol/client.dart

@@ -746,6 +746,11 @@ class EndpointPublish extends _isc.EndpointRef {
   /// Publishes your studyset [studysetId] with everything inside it as its
   /// next release, [notes] saying what changed; at the first, under the
   /// name [slug] in its location, which stays its name from then on.
+  /// [description] (rich text, as its JSON) is what Explore shows of it,
+  /// when given: a studyset may introduce itself to strangers otherwise
+  /// than in the library (decided 2026-10-14); without, the studyset's
+  /// own description. One that isn't rich text, or is larger than
+  /// [maxExploreDescription], counts as not given.
   ///
   /// Throws [PublishRefusedException] when it can't be published (see
   /// [PublishRefusal]), and [NotFoundException] for a studyset that isn't
@@ -753,14 +758,16 @@ class EndpointPublish extends _isc.EndpointRef {
   _ida.Future<_ij0cqo11.Publication> publish(
     _isc.UuidValue studysetId,
     String slug,
-    String notes,
+    String notes, {
-  ) => caller.callServerEndpoint<_ij0cqo11.Publication>(
+    String? description,
+  }) => caller.callServerEndpoint<_ij0cqo11.Publication>(
     'publish',
     'publish',
     {
       'studysetId': studysetId,
       'slug': slug,
       'notes': notes,
+      'description': description,
     },
   );
 

halkyon_learn_client/lib/src/protocol/explore/explore_entry.dart

@@ -31,6 +31,7 @@ abstract class ExploreEntry
     this.frontLanguage,
     this.backLanguage,
     this.basedOn,
+    this.colorName,
     required this.license,
     this.licenseHolder,
     this.licenseYear,
@@ -57,6 +58,7 @@ abstract class ExploreEntry
     String? frontLanguage,
     String? backLanguage,
     String? basedOn,
+    String? colorName,
     required String license,
     String? licenseHolder,
     int? licenseYear,
@@ -88,6 +90,7 @@ abstract class ExploreEntry
       frontLanguage: jsonSerialization['frontLanguage'] as String?,
       backLanguage: jsonSerialization['backLanguage'] as String?,
       basedOn: jsonSerialization['basedOn'] as String?,
+      colorName: jsonSerialization['colorName'] as String?,
       license: jsonSerialization['license'] as String,
       licenseHolder: jsonSerialization['licenseHolder'] as String?,
       licenseYear: jsonSerialization['licenseYear'] as int?,
@@ -135,6 +138,9 @@ abstract class ExploreEntry
   /// Where the published studyset it is a copy of is, for a copy.
   String? basedOn;
 
+  /// Its colour, by the app palette's name for it; null for none.
+  String? colorName;
+
   /// Its licence and credits.
   String license;
 
@@ -175,6 +181,7 @@ abstract class ExploreEntry
     String? frontLanguage,
     String? backLanguage,
     String? basedOn,
+    String? colorName,
     String? license,
     String? licenseHolder,
     int? licenseYear,
@@ -203,6 +210,7 @@ abstract class ExploreEntry
       if (frontLanguage != null) 'frontLanguage': frontLanguage,
       if (backLanguage != null) 'backLanguage': backLanguage,
       if (basedOn != null) 'basedOn': basedOn,
+      if (colorName != null) 'colorName': colorName,
       'license': license,
       if (licenseHolder != null) 'licenseHolder': licenseHolder,
       if (licenseYear != null) 'licenseYear': licenseYear,
@@ -233,6 +241,7 @@ abstract class ExploreEntry
       if (frontLanguage != null) 'frontLanguage': frontLanguage,
       if (backLanguage != null) 'backLanguage': backLanguage,
       if (basedOn != null) 'basedOn': basedOn,
+      if (colorName != null) 'colorName': colorName,
       'license': license,
       if (licenseHolder != null) 'licenseHolder': licenseHolder,
       if (licenseYear != null) 'licenseYear': licenseYear,
@@ -269,6 +278,7 @@ class _ExploreEntryImpl extends ExploreEntry {
     String? frontLanguage,
     String? backLanguage,
     String? basedOn,
+    String? colorName,
     required String license,
     String? licenseHolder,
     int? licenseYear,
@@ -293,6 +303,7 @@ class _ExploreEntryImpl extends ExploreEntry {
          frontLanguage: frontLanguage,
          backLanguage: backLanguage,
          basedOn: basedOn,
+         colorName: colorName,
          license: license,
          licenseHolder: licenseHolder,
          licenseYear: licenseYear,
@@ -323,6 +334,7 @@ class _ExploreEntryImpl extends ExploreEntry {
     Object? frontLanguage = _Undefined,
     Object? backLanguage = _Undefined,
     Object? basedOn = _Undefined,
+    Object? colorName = _Undefined,
     String? license,
     Object? licenseHolder = _Undefined,
     Object? licenseYear = _Undefined,
@@ -352,6 +364,7 @@ class _ExploreEntryImpl extends ExploreEntry {
           : this.frontLanguage,
       backLanguage: backLanguage is String? ? backLanguage : this.backLanguage,
       basedOn: basedOn is String? ? basedOn : this.basedOn,
+      colorName: colorName is String? ? colorName : this.colorName,
       license: license ?? this.license,
       licenseHolder: licenseHolder is String?
           ? licenseHolder

halkyon_learn_client/lib/src/protocol/publish/release_info.dart

@@ -25,6 +25,7 @@ abstract class ReleaseInfo
     required this.pathCount,
     required this.pdfCount,
     required this.releasedAt,
+    this.description,
   });
 
   factory ReleaseInfo({
@@ -37,6 +38,7 @@ abstract class ReleaseInfo
     required int pathCount,
     required int pdfCount,
     required DateTime releasedAt,
+    String? description,
   }) = _ReleaseInfoImpl;
 
   factory ReleaseInfo.fromJson(Map<String, dynamic> jsonSerialization) {
@@ -52,6 +54,7 @@ abstract class ReleaseInfo
       releasedAt: _isc.DateTimeJsonExtension.fromJson(
         jsonSerialization['releasedAt'],
       ),
+      description: jsonSerialization['description'] as String?,
     );
   }
 
@@ -77,6 +80,10 @@ abstract class ReleaseInfo
   /// When it was released, in UTC.
   DateTime releasedAt;
 
+  /// What Explore shows of it as its description (rich text, as its JSON);
+  /// null for none.
+  String? description;
+
   /// Returns a shallow copy of this [ReleaseInfo]
   /// with some or all fields replaced by the given arguments.
   @_isc.useResult
@@ -90,6 +97,7 @@ abstract class ReleaseInfo
     int? pathCount,
     int? pdfCount,
     DateTime? releasedAt,
+    String? description,
   });
   @override
   Map<String, dynamic> toJson() {
@@ -104,6 +112,7 @@ abstract class ReleaseInfo
       'pathCount': pathCount,
       'pdfCount': pdfCount,
       'releasedAt': releasedAt.toJson(),
+      if (description != null) 'description': description,
     };
   }
 
@@ -120,6 +129,7 @@ abstract class ReleaseInfo
       'pathCount': pathCount,
       'pdfCount': pdfCount,
       'releasedAt': releasedAt.toJson(),
+      if (description != null) 'description': description,
     };
   }
 
@@ -129,6 +139,8 @@ abstract class ReleaseInfo
   }
 }
 
+class _Undefined {}
+
 class _ReleaseInfoImpl extends ReleaseInfo {
   _ReleaseInfoImpl({
     required int version,
@@ -140,6 +152,7 @@ class _ReleaseInfoImpl extends ReleaseInfo {
     required int pathCount,
     required int pdfCount,
     required DateTime releasedAt,
+    String? description,
   }) : super._(
          version: version,
          notes: notes,
@@ -150,6 +163,7 @@ class _ReleaseInfoImpl extends ReleaseInfo {
          pathCount: pathCount,
          pdfCount: pdfCount,
          releasedAt: releasedAt,
+         description: description,
        );
 
   /// Returns a shallow copy of this [ReleaseInfo]
@@ -166,6 +180,7 @@ class _ReleaseInfoImpl extends ReleaseInfo {
     int? pathCount,
     int? pdfCount,
     DateTime? releasedAt,
+    Object? description = _Undefined,
   }) {
     return ReleaseInfo(
       version: version ?? this.version,
@@ -177,6 +192,7 @@ class _ReleaseInfoImpl extends ReleaseInfo {
       pathCount: pathCount ?? this.pathCount,
       pdfCount: pdfCount ?? this.pdfCount,
       releasedAt: releasedAt ?? this.releasedAt,
+      description: description is String? ? description : this.description,
     );
   }
 }

halkyon_learn_server/lib/src/explore/explore_endpoint.dart

@@ -235,6 +235,7 @@ class ExploreEndpoint extends Endpoint {
             frontLanguage: latest['frontLanguage'] as String?,
             backLanguage: latest['backLanguage'] as String?,
             basedOn: latest['basedOn'] as String?,
+            colorName: latest['colorName'] as String?,
             license: latest['license'] as String,
             licenseHolder: latest['licenseHolder'] as String?,
             licenseYear: latest['licenseYear'] as int?,

halkyon_learn_server/lib/src/explore/explore_entry.spy.yaml

@@ -23,6 +23,8 @@ fields:
   backLanguage: String?
   ### Where the published studyset it is a copy of is, for a copy.
   basedOn: String?
+  ### Its colour, by the app palette's name for it; null for none.
+  colorName: String?
   ### Its licence and credits.
   license: String
   licenseHolder: String?

halkyon_learn_server/lib/src/generated/endpoints.dart

@@ -1084,6 +1084,11 @@ class Endpoints extends _is.EndpointDispatch {
               type: _is.getType<String>(),
               nullable: false,
             ),
+            'description': _is.ParameterDescription(
+              name: 'description',
+              type: _is.getType<String?>(),
+              nullable: true,
+            ),
           },
           call:
               (
@@ -1095,6 +1100,7 @@ class Endpoints extends _is.EndpointDispatch {
                     params['studysetId'],
                     params['slug'],
                     params['notes'],
+                    description: params['description'],
                   ),
         ),
         'withdraw': _is.MethodConnector(

halkyon_learn_server/lib/src/generated/explore/explore_entry.dart

@@ -31,6 +31,7 @@ abstract class ExploreEntry
     this.frontLanguage,
     this.backLanguage,
     this.basedOn,
+    this.colorName,
     required this.license,
     this.licenseHolder,
     this.licenseYear,
@@ -57,6 +58,7 @@ abstract class ExploreEntry
     String? frontLanguage,
     String? backLanguage,
     String? basedOn,
+    String? colorName,
     required String license,
     String? licenseHolder,
     int? licenseYear,
@@ -88,6 +90,7 @@ abstract class ExploreEntry
       frontLanguage: jsonSerialization['frontLanguage'] as String?,
       backLanguage: jsonSerialization['backLanguage'] as String?,
       basedOn: jsonSerialization['basedOn'] as String?,
+      colorName: jsonSerialization['colorName'] as String?,
       license: jsonSerialization['license'] as String,
       licenseHolder: jsonSerialization['licenseHolder'] as String?,
       licenseYear: jsonSerialization['licenseYear'] as int?,
@@ -135,6 +138,9 @@ abstract class ExploreEntry
   /// Where the published studyset it is a copy of is, for a copy.
   String? basedOn;
 
+  /// Its colour, by the app palette's name for it; null for none.
+  String? colorName;
+
   /// Its licence and credits.
   String license;
 
@@ -175,6 +181,7 @@ abstract class ExploreEntry
     String? frontLanguage,
     String? backLanguage,
     String? basedOn,
+    String? colorName,
     String? license,
     String? licenseHolder,
     int? licenseYear,
@@ -203,6 +210,7 @@ abstract class ExploreEntry
       if (frontLanguage != null) 'frontLanguage': frontLanguage,
       if (backLanguage != null) 'backLanguage': backLanguage,
       if (basedOn != null) 'basedOn': basedOn,
+      if (colorName != null) 'colorName': colorName,
       'license': license,
       if (licenseHolder != null) 'licenseHolder': licenseHolder,
       if (licenseYear != null) 'licenseYear': licenseYear,
@@ -233,6 +241,7 @@ abstract class ExploreEntry
       if (frontLanguage != null) 'frontLanguage': frontLanguage,
       if (backLanguage != null) 'backLanguage': backLanguage,
       if (basedOn != null) 'basedOn': basedOn,
+      if (colorName != null) 'colorName': colorName,
       'license': license,
       if (licenseHolder != null) 'licenseHolder': licenseHolder,
       if (licenseYear != null) 'licenseYear': licenseYear,
@@ -269,6 +278,7 @@ class _ExploreEntryImpl extends ExploreEntry {
     String? frontLanguage,
     String? backLanguage,
     String? basedOn,
+    String? colorName,
     required String license,
     String? licenseHolder,
     int? licenseYear,
@@ -293,6 +303,7 @@ class _ExploreEntryImpl extends ExploreEntry {
          frontLanguage: frontLanguage,
          backLanguage: backLanguage,
          basedOn: basedOn,
+         colorName: colorName,
          license: license,
          licenseHolder: licenseHolder,
          licenseYear: licenseYear,
@@ -323,6 +334,7 @@ class _ExploreEntryImpl extends ExploreEntry {
     Object? frontLanguage = _Undefined,
     Object? backLanguage = _Undefined,
     Object? basedOn = _Undefined,
+    Object? colorName = _Undefined,
     String? license,
     Object? licenseHolder = _Undefined,
     Object? licenseYear = _Undefined,
@@ -352,6 +364,7 @@ class _ExploreEntryImpl extends ExploreEntry {
           : this.frontLanguage,
       backLanguage: backLanguage is String? ? backLanguage : this.backLanguage,
       basedOn: basedOn is String? ? basedOn : this.basedOn,
+      colorName: colorName is String? ? colorName : this.colorName,
       license: license ?? this.license,
       licenseHolder: licenseHolder is String?
           ? licenseHolder

halkyon_learn_server/lib/src/generated/protocol.dart

@@ -3415,6 +3415,12 @@ class Protocol extends _is.DatabaseSerializationManager {
           isNullable: true,
           dartType: 'String?',
         ),
+        _isp.ColumnDefinition(
+          name: 'colorName',
+          columnType: _isp.ColumnType.text,
+          isNullable: true,
+          dartType: 'String?',
+        ),
       ],
       foreignKeys: [
         _isp.ForeignKeyDefinition(

halkyon_learn_server/lib/src/generated/publish/release_info.dart

@@ -25,6 +25,7 @@ abstract class ReleaseInfo
     required this.pathCount,
     required this.pdfCount,
     required this.releasedAt,
+    this.description,
   });
 
   factory ReleaseInfo({
@@ -37,6 +38,7 @@ abstract class ReleaseInfo
     required int pathCount,
     required int pdfCount,
     required DateTime releasedAt,
+    String? description,
   }) = _ReleaseInfoImpl;
 
   factory ReleaseInfo.fromJson(Map<String, dynamic> jsonSerialization) {
@@ -52,6 +54,7 @@ abstract class ReleaseInfo
       releasedAt: _is.DateTimeJsonExtension.fromJson(
         jsonSerialization['releasedAt'],
       ),
+      description: jsonSerialization['description'] as String?,
     );
   }
 
@@ -77,6 +80,10 @@ abstract class ReleaseInfo
   /// When it was released, in UTC.
   DateTime releasedAt;
 
+  /// What Explore shows of it as its description (rich text, as its JSON);
+  /// null for none.
+  String? description;
+
   /// Returns a shallow copy of this [ReleaseInfo]
   /// with some or all fields replaced by the given arguments.
   @_is.useResult
@@ -90,6 +97,7 @@ abstract class ReleaseInfo
     int? pathCount,
     int? pdfCount,
     DateTime? releasedAt,
+    String? description,
   });
   @override
   Map<String, dynamic> toJson() {
@@ -104,6 +112,7 @@ abstract class ReleaseInfo
       'pathCount': pathCount,
       'pdfCount': pdfCount,
       'releasedAt': releasedAt.toJson(),
+      if (description != null) 'description': description,
     };
   }
 
@@ -120,6 +129,7 @@ abstract class ReleaseInfo
       'pathCount': pathCount,
       'pdfCount': pdfCount,
       'releasedAt': releasedAt.toJson(),
+      if (description != null) 'description': description,
     };
   }
 
@@ -129,6 +139,8 @@ abstract class ReleaseInfo
   }
 }
 
+class _Undefined {}
+
 class _ReleaseInfoImpl extends ReleaseInfo {
   _ReleaseInfoImpl({
     required int version,
@@ -140,6 +152,7 @@ class _ReleaseInfoImpl extends ReleaseInfo {
     required int pathCount,
     required int pdfCount,
     required DateTime releasedAt,
+    String? description,
   }) : super._(
          version: version,
          notes: notes,
@@ -150,6 +163,7 @@ class _ReleaseInfoImpl extends ReleaseInfo {
          pathCount: pathCount,
          pdfCount: pdfCount,
          releasedAt: releasedAt,
+         description: description,
        );
 
   /// Returns a shallow copy of this [ReleaseInfo]
@@ -166,6 +180,7 @@ class _ReleaseInfoImpl extends ReleaseInfo {
     int? pathCount,
     int? pdfCount,
     DateTime? releasedAt,
+    Object? description = _Undefined,
   }) {
     return ReleaseInfo(
       version: version ?? this.version,
@@ -177,6 +192,7 @@ class _ReleaseInfoImpl extends ReleaseInfo {
       pathCount: pathCount ?? this.pathCount,
       pdfCount: pdfCount ?? this.pdfCount,
       releasedAt: releasedAt ?? this.releasedAt,
+      description: description is String? ? description : this.description,
     );
   }
 }

halkyon_learn_server/lib/src/generated/publish/studyset_release.dart

@@ -38,6 +38,7 @@ abstract class StudysetRelease
     this.licenseHolder,
     this.licenseYear,
     this.basedOn,
+    this.colorName,
   }) : title = title ?? '';
 
   factory StudysetRelease({
@@ -62,6 +63,7 @@ abstract class StudysetRelease
     String? licenseHolder,
     int? licenseYear,
     String? basedOn,
+    String? colorName,
   }) = _StudysetReleaseImpl;
 
   factory StudysetRelease.fromJson(Map<String, dynamic> jsonSerialization) {
@@ -89,6 +91,7 @@ abstract class StudysetRelease
       licenseHolder: jsonSerialization['licenseHolder'] as String?,
       licenseYear: jsonSerialization['licenseYear'] as int?,
       basedOn: jsonSerialization['basedOn'] as String?,
+      colorName: jsonSerialization['colorName'] as String?,
     );
   }
 
@@ -131,7 +134,8 @@ abstract class StudysetRelease
   DateTime releasedAt;
 
   /// What Explore shows of it, as its studyset said then: the title, the
-  /// secondary title, the description (rich text, as its JSON), the
+  /// secondary title, the description (rich text, as its JSON; the one its
+  /// author wrote for Explore when publishing, else the studyset's), the
   /// languages (BCP 47) and the licence's credits. Kept beside the
   /// repository so the listing never reads git.
   String title;
@@ -152,6 +156,11 @@ abstract class StudysetRelease
   /// (`halkyon.eu/@alice/japanese`): what it is based on.
   String? basedOn;
 
+  /// Its colour, by the name the app's palette gives it (`cobalt`), as
+  /// the library shows it; null for none. Kept since 2026-10-14: releases
+  /// before have none.
+  String? colorName;
+
   @override
   _is.Table<int?> get table => t;
 
@@ -180,6 +189,7 @@ abstract class StudysetRelease
     String? licenseHolder,
     int? licenseYear,
     String? basedOn,
+    String? colorName,
   });
   @override
   Map<String, dynamic> toJson() {
@@ -206,6 +216,7 @@ abstract class StudysetRelease
       if (licenseHolder != null) 'licenseHolder': licenseHolder,
       if (licenseYear != null) 'licenseYear': licenseYear,
       if (basedOn != null) 'basedOn': basedOn,
+      if (colorName != null) 'colorName': colorName,
     };
   }
 
@@ -267,6 +278,7 @@ class _StudysetReleaseImpl extends StudysetRelease {
     String? licenseHolder,
     int? licenseYear,
     String? basedOn,
+    String? colorName,
   }) : super._(
          id: id,
          publishedStudysetId: publishedStudysetId,
@@ -289,6 +301,7 @@ class _StudysetReleaseImpl extends StudysetRelease {
          licenseHolder: licenseHolder,
          licenseYear: licenseYear,
          basedOn: basedOn,
+         colorName: colorName,
        );
 
   /// Returns a shallow copy of this [StudysetRelease]
@@ -317,6 +330,7 @@ class _StudysetReleaseImpl extends StudysetRelease {
     Object? licenseHolder = _Undefined,
     Object? licenseYear = _Undefined,
     Object? basedOn = _Undefined,
+    Object? colorName = _Undefined,
   }) {
     return StudysetRelease(
       id: id is int? ? id : this.id,
@@ -346,6 +360,7 @@ class _StudysetReleaseImpl extends StudysetRelease {
           : this.licenseHolder,
       licenseYear: licenseYear is int? ? licenseYear : this.licenseYear,
       basedOn: basedOn is String? ? basedOn : this.basedOn,
+      colorName: colorName is String? ? colorName : this.colorName,
     );
   }
 }
@@ -457,6 +472,11 @@ class StudysetReleaseUpdateTable extends _is.UpdateTable<StudysetReleaseTable> {
     table.basedOn,
     value,
   );
+
+  _is.ColumnValue<String, String> colorName(String? value) => _is.ColumnValue(
+    table.colorName,
+    value,
+  );
 }
 
 class StudysetReleaseTable extends _is.Table<int?> {
@@ -544,6 +564,10 @@ class StudysetReleaseTable extends _is.Table<int?> {
       'basedOn',
       this,
     );
+    colorName = _is.ColumnString(
+      'colorName',
+      this,
+    );
   }
 
   late final StudysetReleaseUpdateTable updateTable;
@@ -580,7 +604,8 @@ class StudysetReleaseTable extends _is.Table<int?> {
   late final _is.ColumnDateTime releasedAt;
 
   /// What Explore shows of it, as its studyset said then: the title, the
-  /// secondary title, the description (rich text, as its JSON), the
+  /// secondary title, the description (rich text, as its JSON; the one its
+  /// author wrote for Explore when publishing, else the studyset's), the
   /// languages (BCP 47) and the licence's credits. Kept beside the
   /// repository so the listing never reads git.
   late final _is.ColumnString title;
@@ -601,6 +626,11 @@ class StudysetReleaseTable extends _is.Table<int?> {
   /// (`halkyon.eu/@alice/japanese`): what it is based on.
   late final _is.ColumnString basedOn;
 
+  /// Its colour, by the name the app's palette gives it (`cobalt`), as
+  /// the library shows it; null for none. Kept since 2026-10-14: releases
+  /// before have none.
+  late final _is.ColumnString colorName;
+
   @override
   List<_is.Column> get columns => [
     id,
@@ -624,6 +654,7 @@ class StudysetReleaseTable extends _is.Table<int?> {
     licenseHolder,
     licenseYear,
     basedOn,
+    colorName,
   ];
 }
 

halkyon_learn_server/lib/src/publish/publish_endpoint.dart

@@ -80,6 +80,11 @@ class PublishEndpoint extends Endpoint {
   /// Publishes your studyset [studysetId] with everything inside it as its
   /// next release, [notes] saying what changed; at the first, under the
   /// name [slug] in its location, which stays its name from then on.
+  /// [description] (rich text, as its JSON) is what Explore shows of it,
+  /// when given: a studyset may introduce itself to strangers otherwise
+  /// than in the library (decided 2026-10-14); without, the studyset's
+  /// own description. One that isn't rich text, or is larger than
+  /// [maxExploreDescription], counts as not given.
   ///
   /// Throws [PublishRefusedException] when it can't be published (see
   /// [PublishRefusal]), and [NotFoundException] for a studyset that isn't
@@ -88,8 +93,9 @@ class PublishEndpoint extends Endpoint {
     Session session,
     UuidValue studysetId,
     String slug,
-    String notes,
+    String notes, {
-  ) async {
+    String? description,
+  }) async {
     final person = session.authenticated!.authUserId;
     final key = '${person.uuid}/${studysetId.uuid}';
     if (!_publishing.add(key)) {
@@ -102,6 +108,7 @@ class PublishEndpoint extends Endpoint {
         studysetId: studysetId,
         slug: slug.trim(),
         notes: notes.trim(),
+        description: _richText(description),
       );
     } finally {
       _publishing.remove(key);
@@ -140,6 +147,7 @@ class PublishEndpoint extends Endpoint {
     required UuidValue studysetId,
     required String slug,
     required String notes,
+    required String? description,
   }) async {
     // SELECT … FROM "public_profile" WHERE "authUserId" = $1
     final profile = await PublicProfile.db.findFirstRow(
@@ -309,7 +317,9 @@ class PublishEndpoint extends Endpoint {
             releasedAt: now,
             title: text('title') ?? '',
             secondaryTitle: text('secondaryTitle'),
-            description: switch (root['description']) {
+            description:
+                description ??
+                switch (root['description']) {
                   final Map<String, Object?> description => jsonEncode(
                     description,
                   ),
@@ -323,6 +333,7 @@ class PublishEndpoint extends Endpoint {
               _ => null,
             },
             basedOn: basedOn,
+            colorName: text('color'),
           ),
           transaction: transaction,
         );
@@ -525,6 +536,7 @@ class PublishEndpoint extends Endpoint {
             pathCount: release.pathCount,
             pdfCount: release.pdfCount,
             releasedAt: release.releasedAt,
+            description: release.description,
           ),
       ],
       withdrawn: published.withdrawnAt != null,
@@ -532,3 +544,23 @@ class PublishEndpoint extends Endpoint {
     );
   }
 }
+
+/// The largest description for Explore taken, as its JSON: some 50 pages
+/// of text, far beyond what Explore shows.
+const maxExploreDescription = 100000;
+
+/// [json] when it is rich text as the app writes it, `{"formatVersion": …,
+/// "editor": …}`, within [maxExploreDescription]; else null.
+String? _richText(String? json) {
+  if (json == null || json.length > maxExploreDescription) {
+    return null;
+  }
+  try {
+    return switch (jsonDecode(json)) {
+      {'formatVersion': int(), 'editor': Map<String, Object?>()} => json,
+      _ => null,
+    };
+  } on FormatException {
+    return null;
+  }
+}

halkyon_learn_server/lib/src/publish/release_info.spy.yaml

@@ -14,3 +14,6 @@ fields:
   pdfCount: int
   ### When it was released, in UTC.
   releasedAt: DateTime
+  ### What Explore shows of it as its description (rich text, as its JSON);
+  ### null for none.
+  description: String?

halkyon_learn_server/lib/src/publish/studyset_release.spy.yaml

@@ -24,7 +24,8 @@ fields:
   ### When it was released, in UTC.
   releasedAt: DateTime
   ### What Explore shows of it, as its studyset said then: the title, the
-  ### secondary title, the description (rich text, as its JSON), the
+  ### secondary title, the description (rich text, as its JSON; the one its
+  ### author wrote for Explore when publishing, else the studyset's), the
   ### languages (BCP 47) and the licence's credits. Kept beside the
   ### repository so the listing never reads git.
   title: String, default=''
@@ -37,6 +38,10 @@ fields:
   ### For a copy of a published studyset, where that one is
   ### (`halkyon.eu/@alice/japanese`): what it is based on.
   basedOn: String?
+  ### Its colour, by the name the app's palette gives it (`cobalt`), as
+  ### the library shows it; null for none. Kept since 2026-10-14: releases
+  ### before have none.
+  colorName: String?
 indexes:
   studyset_release_version_idx:
     fields: publishedStudysetId, version

halkyon_learn_server/migrations/20261014153932647-release-colour/migration.json

@@ -0,0 +1,33 @@
+{
+  "__className__": "serverpod.DatabaseMigration",
+  "actions": [
+    {
+      "__className__": "serverpod.DatabaseMigrationAction",
+      "type": "alterTable",
+      "alterTable": {
+        "__className__": "serverpod.TableMigration",
+        "name": "studyset_release",
+        "schema": "public",
+        "addColumns": [
+          {
+            "__className__": "serverpod.ColumnDefinition",
+            "name": "colorName",
+            "fieldName": "colorName",
+            "columnType": 0,
+            "isNullable": true,
+            "dartType": "String?"
+          }
+        ],
+        "deleteColumns": [],
+        "modifyColumns": [],
+        "addIndexes": [],
+        "deleteIndexes": [],
+        "addForeignKeys": [],
+        "deleteForeignKeys": [],
+        "warnings": []
+      }
+    }
+  ],
+  "warnings": [],
+  "migrationApiVersion": 1
+}

halkyon_learn_server/migrations/20261014153932647-release-colour/migration.sql

@@ -0,0 +1,49 @@
+BEGIN;
+
+--
+-- ACTION ALTER TABLE
+--
+ALTER TABLE "studyset_release" ADD COLUMN "colorName" text;
+
+--
+-- MIGRATION VERSION FOR halkyon_learn
+--
+INSERT INTO "serverpod_migrations" ("module", "version", "timestamp")
+    VALUES ('halkyon_learn', '20261014153932647-release-colour', now())
+    ON CONFLICT ("module")
+    DO UPDATE SET "version" = '20261014153932647-release-colour', "timestamp" = now();
+
+--
+-- MIGRATION VERSION FOR serverpod
+--
+INSERT INTO "serverpod_migrations" ("module", "version", "timestamp")
+    VALUES ('serverpod', '20260824182259319', now())
+    ON CONFLICT ("module")
+    DO UPDATE SET "version" = '20260824182259319', "timestamp" = now();
+
+--
+-- MIGRATION VERSION FOR serverpod_auth_idp
+--
+INSERT INTO "serverpod_migrations" ("module", "version", "timestamp")
+    VALUES ('serverpod_auth_idp', '20260924105404509', now())
+    ON CONFLICT ("module")
+    DO UPDATE SET "version" = '20260924105404509', "timestamp" = now();
+
+--
+-- MIGRATION VERSION FOR serverpod_offline_sync
+--
+INSERT INTO "serverpod_migrations" ("module", "version", "timestamp")
+    VALUES ('serverpod_offline_sync', '20260914143806119', now())
+    ON CONFLICT ("module")
+    DO UPDATE SET "version" = '20260914143806119', "timestamp" = now();
+
+--
+-- MIGRATION VERSION FOR serverpod_auth_core
+--
+INSERT INTO "serverpod_migrations" ("module", "version", "timestamp")
+    VALUES ('serverpod_auth_core', '20260924105232991', now())
+    ON CONFLICT ("module")
+    DO UPDATE SET "version" = '20260924105232991', "timestamp" = now();
+
+
+COMMIT;

halkyon_learn_server/migrations/migration_registry.txt

@@ -27,3 +27,4 @@
 20261010095547719-assistant-connector
 20261012162411835-studyset-deleted-at
 20261013035552510-dictionary-keys
+20261014153932647-release-colour

halkyon_learn_server/test/integration/publish/publish_test.dart

@@ -162,6 +162,7 @@ void main() {
                 'license': ?license,
                 'licenseHolder': 'Alice',
                 'study': {'newPerDay': 10},
+                'color': 'cobalt',
                 'published': ?copyOf,
                 'examPlans': [
                   {
@@ -528,6 +529,47 @@ void main() {
         );
       });
 
+      test("a release keeps the studyset's colour, and what its author wrote "
+          'for Explore as its description; what is no rich text counts as '
+          'nothing written', () async {
+        await profile(alice, 'alice');
+        final content = await japanese(alice);
+        final about = jsonEncode({
+          'formatVersion': 1,
+          'editor': {
+            'document': {'type': 'page'},
+          },
+        });
+
+        final published = await endpoints.publish.publish(
+          signedIn(alice),
+          content.root,
+          'japanese',
+          '',
+          description: about,
+        );
+
+        expect(published.releases.single.description, about);
+        final kept = await StudysetRelease.db.find(session);
+        expect(kept.single.colorName, 'cobalt');
+        expect(kept.single.description, about);
+
+        await revise(
+          alice,
+          content.word,
+          await revisionsOf(content.word),
+          '日本語',
+        );
+        final second = await endpoints.publish.publish(
+          signedIn(alice),
+          content.root,
+          'japanese',
+          '',
+          description: 'not rich text',
+        );
+        expect(second.releases.first.description, isNull);
+      });
+
       test(
         'a version git has but the database lost is never given again',
         () async {