Seal union types for consistency (#7016)

* Seal union types for consistency

* Update release notes

Author: stevejgordon

docs/release-notes/release-notes-8.0.1.asciidoc

@@ -4,9 +4,14 @@
 [discrete]
 === Bug fixes
 
-- Fix MultiSearchTemplateRequest serialization (issue: 
+- Fix MultiSearchTemplateRequest body serialization (issue: 
 https://github.com/elastic/elasticsearch-net/issues/7006[#7006])
 
+[discrete]
+=== Enhancements
+
+- Seal union types for consistency
+
 [discrete]
 === Breaking changes
 
@@ -28,9 +33,39 @@ original code-generated type not functioning correctly and therefore we have
 determined that this should ship ASAP.
 
 [discrete]
-=== MultiSearch type changes
+==== MultiSearch type changes
 
 The `Core.MSearch.SearchRequestItem` type has been sealed for consistency with 
 the design choices in the rest of the client. While technically breaking, we 
 have decided that this should be included in this release before any potential 
-derived types may exist in consuming applications.
+derived types may exist in consuming applications.
+
+[discrete]
+==== Sealing union types
+
+Code-generated types derived from `Union<T1, T2>` where incorrectly unsealed. 
+While technically breaking, we have decided that these should be sealed in this 
+patch release before any potential derived types may exist in consuming 
+applications. Sealing types by default aligns with our broader design choices 
+and this decision is described in the <<release-notes-8.0.0,8.0.0 release notes>>.
+
+Affected types:
+- `Aggregations.Buckets`
+- `Aggregations.FieldDateMatch`
+- `Aggregations.Percentiles`
+- `Analysis.CharFilter`
+- `Analysis.TokenFilter`
+- `Analysis.Tokenizer`
+- `ByteSize`
+- `Fuzziness`
+- `GeoHashPrecision`
+- `MultiGetResponseItem`
+- `MultiSearchResponseItem`
+- `QueryDsl.Like`
+- `QueryDsl.TermsQueryField`
+- `Script`
+- `Slices`
+- `SourceConfig`
+- `SourceConfigParam`
+- `Tasks.TaskInfos`
+- `TrackHits`

src/Elastic.Clients.Elasticsearch/_Generated/Types/Aggregations/Buckets.g.cs

@@ -26,7 +26,7 @@
 
 #nullable restore
 namespace Elastic.Clients.Elasticsearch.Aggregations;
-public partial class Buckets<TBucket> : Union<Dictionary<string, TBucket>, IReadOnlyCollection<TBucket>>
+public sealed partial class Buckets<TBucket> : Union<Dictionary<string, TBucket>, IReadOnlyCollection<TBucket>>
 {
 	public Buckets(Dictionary<string, TBucket> dictionary) : base(dictionary)
 	{

src/Elastic.Clients.Elasticsearch/_Generated/Types/Aggregations/FieldDateMath.g.cs

@@ -26,7 +26,7 @@
 
 #nullable restore
 namespace Elastic.Clients.Elasticsearch.Aggregations;
-public partial class FieldDateMath : Union<Elastic.Clients.Elasticsearch.DateMath, double>
+public sealed partial class FieldDateMath : Union<Elastic.Clients.Elasticsearch.DateMath, double>
 {
 	public FieldDateMath(Elastic.Clients.Elasticsearch.DateMath expr) : base(expr)
 	{

src/Elastic.Clients.Elasticsearch/_Generated/Types/Aggregations/Percentiles.g.cs

@@ -26,7 +26,7 @@
 
 #nullable restore
 namespace Elastic.Clients.Elasticsearch.Aggregations;
-public partial class Percentiles : Union<Dictionary<string, object>, IReadOnlyCollection<Elastic.Clients.Elasticsearch.Aggregations.ArrayPercentilesItem>>
+public sealed partial class Percentiles : Union<Dictionary<string, object>, IReadOnlyCollection<Elastic.Clients.Elasticsearch.Aggregations.ArrayPercentilesItem>>
 {
 	public Percentiles(Dictionary<string, object> dictionary) : base(dictionary)
 	{

src/Elastic.Clients.Elasticsearch/_Generated/Types/Analysis/CharFilter.g.cs

@@ -26,7 +26,7 @@
 
 #nullable restore
 namespace Elastic.Clients.Elasticsearch.Analysis;
-public partial class CharFilter : Union<string, Elastic.Clients.Elasticsearch.Analysis.CharFilterDefinitions>
+public sealed partial class CharFilter : Union<string, Elastic.Clients.Elasticsearch.Analysis.CharFilterDefinitions>
 {
 	public CharFilter(string name) : base(name)
 	{

src/Elastic.Clients.Elasticsearch/_Generated/Types/Analysis/TokenFilter.g.cs

@@ -26,7 +26,7 @@
 
 #nullable restore
 namespace Elastic.Clients.Elasticsearch.Analysis;
-public partial class TokenFilter : Union<string, Elastic.Clients.Elasticsearch.Analysis.TokenFilterDefinitions>
+public sealed partial class TokenFilter : Union<string, Elastic.Clients.Elasticsearch.Analysis.TokenFilterDefinitions>
 {
 	public TokenFilter(string name) : base(name)
 	{

src/Elastic.Clients.Elasticsearch/_Generated/Types/Analysis/Tokenizer.g.cs

@@ -26,7 +26,7 @@
 
 #nullable restore
 namespace Elastic.Clients.Elasticsearch.Analysis;
-public partial class Tokenizer : Union<string, Elastic.Clients.Elasticsearch.Analysis.TokenizerDefinitions>
+public sealed partial class Tokenizer : Union<string, Elastic.Clients.Elasticsearch.Analysis.TokenizerDefinitions>
 {
 	public Tokenizer(string name) : base(name)
 	{

src/Elastic.Clients.Elasticsearch/_Generated/Types/ByteSize.g.cs

@@ -26,7 +26,7 @@
 
 #nullable restore
 namespace Elastic.Clients.Elasticsearch;
-public partial class ByteSize : Union<long, string>
+public sealed partial class ByteSize : Union<long, string>
 {
 	public ByteSize(long byteSize) : base(byteSize)
 	{

src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/MultiGetResponseItem.g.cs

@@ -26,7 +26,7 @@
 
 #nullable restore
 namespace Elastic.Clients.Elasticsearch.Core.MGet;
-public partial class MultiGetResponseItem<TDocument> : Union<Elastic.Clients.Elasticsearch.Core.Get.GetResult<TDocument>, Elastic.Clients.Elasticsearch.Core.MGet.MultiGetError>
+public sealed partial class MultiGetResponseItem<TDocument> : Union<Elastic.Clients.Elasticsearch.Core.Get.GetResult<TDocument>, Elastic.Clients.Elasticsearch.Core.MGet.MultiGetError>
 {
 	public MultiGetResponseItem(Elastic.Clients.Elasticsearch.Core.Get.GetResult<TDocument> result) : base(result)
 	{

src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/MultiSearchResponseItem.g.cs

@@ -26,7 +26,7 @@
 
 #nullable restore
 namespace Elastic.Clients.Elasticsearch.Core.MSearch;
-public partial class MultiSearchResponseItem<TDocument> : Union<Elastic.Clients.Elasticsearch.Core.MSearch.MultiSearchItem<TDocument>, Elastic.Clients.Elasticsearch.ErrorResponseBase>
+public sealed partial class MultiSearchResponseItem<TDocument> : Union<Elastic.Clients.Elasticsearch.Core.MSearch.MultiSearchItem<TDocument>, Elastic.Clients.Elasticsearch.ErrorResponseBase>
 {
 	public MultiSearchResponseItem(Elastic.Clients.Elasticsearch.Core.MSearch.MultiSearchItem<TDocument> result) : base(result)
 	{

src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/SourceConfig.g.cs

@@ -26,7 +26,7 @@
 
 #nullable restore
 namespace Elastic.Clients.Elasticsearch.Core.Search;
-public partial class SourceConfig : Union<bool, Elastic.Clients.Elasticsearch.Core.Search.SourceFilter>
+public sealed partial class SourceConfig : Union<bool, Elastic.Clients.Elasticsearch.Core.Search.SourceFilter>
 {
 	public SourceConfig(bool fetch) : base(fetch)
 	{

src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/SourceConfigParam.g.cs

@@ -26,7 +26,7 @@
 
 #nullable restore
 namespace Elastic.Clients.Elasticsearch.Core.Search;
-public partial class SourceConfigParam : Union<bool, Elastic.Clients.Elasticsearch.Fields>
+public sealed partial class SourceConfigParam : Union<bool, Elastic.Clients.Elasticsearch.Fields>
 {
 	public SourceConfigParam(bool fetch) : base(fetch)
 	{

src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/TrackHits.g.cs

@@ -26,7 +26,7 @@
 
 #nullable restore
 namespace Elastic.Clients.Elasticsearch.Core.Search;
-public partial class TrackHits : Union<bool, int>
+public sealed partial class TrackHits : Union<bool, int>
 {
 	public TrackHits(bool enabled) : base(enabled)
 	{

src/Elastic.Clients.Elasticsearch/_Generated/Types/Fuzziness.g.cs

@@ -26,7 +26,7 @@
 
 #nullable restore
 namespace Elastic.Clients.Elasticsearch;
-public partial class Fuzziness : Union<string, int>
+public sealed partial class Fuzziness : Union<string, int>
 {
 	public Fuzziness(string fuzziness) : base(fuzziness)
 	{

src/Elastic.Clients.Elasticsearch/_Generated/Types/GeoHashPrecision.g.cs

@@ -26,7 +26,7 @@
 
 #nullable restore
 namespace Elastic.Clients.Elasticsearch;
-public partial class GeoHashPrecision : Union<double, string>
+public sealed partial class GeoHashPrecision : Union<double, string>
 {
 	public GeoHashPrecision(double geohash_length) : base(geohash_length)
 	{

src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/Like.g.cs

@@ -26,7 +26,7 @@
 
 #nullable restore
 namespace Elastic.Clients.Elasticsearch.QueryDsl;
-public partial class Like : Union<string, Elastic.Clients.Elasticsearch.QueryDsl.LikeDocument>
+public sealed partial class Like : Union<string, Elastic.Clients.Elasticsearch.QueryDsl.LikeDocument>
 {
 	public Like(string text) : base(text)
 	{

src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/TermsQueryField.g.cs

@@ -26,7 +26,7 @@
 
 #nullable restore
 namespace Elastic.Clients.Elasticsearch.QueryDsl;
-public partial class TermsQueryField : Union<IReadOnlyCollection<Elastic.Clients.Elasticsearch.FieldValue>, Elastic.Clients.Elasticsearch.QueryDsl.TermsLookup>
+public sealed partial class TermsQueryField : Union<IReadOnlyCollection<Elastic.Clients.Elasticsearch.FieldValue>, Elastic.Clients.Elasticsearch.QueryDsl.TermsLookup>
 {
 	public TermsQueryField(IReadOnlyCollection<Elastic.Clients.Elasticsearch.FieldValue> value) : base(value)
 	{

src/Elastic.Clients.Elasticsearch/_Generated/Types/Script.g.cs

@@ -26,7 +26,7 @@
 
 #nullable restore
 namespace Elastic.Clients.Elasticsearch;
-public partial class Script : Union<Elastic.Clients.Elasticsearch.InlineScript, Elastic.Clients.Elasticsearch.StoredScriptId>
+public sealed partial class Script : Union<Elastic.Clients.Elasticsearch.InlineScript, Elastic.Clients.Elasticsearch.StoredScriptId>
 {
 	public Script(Elastic.Clients.Elasticsearch.InlineScript inline) : base(inline)
 	{

src/Elastic.Clients.Elasticsearch/_Generated/Types/Slices.g.cs

@@ -26,7 +26,7 @@
 
 #nullable restore
 namespace Elastic.Clients.Elasticsearch;
-public partial class Slices : Union<int, Elastic.Clients.Elasticsearch.SlicesCalculation>
+public sealed partial class Slices : Union<int, Elastic.Clients.Elasticsearch.SlicesCalculation>
 {
 	public Slices(int value) : base(value)
 	{

src/Elastic.Clients.Elasticsearch/_Generated/Types/Tasks/TaskInfos.g.cs

@@ -26,7 +26,7 @@
 
 #nullable restore
 namespace Elastic.Clients.Elasticsearch.Tasks;
-public partial class TaskInfos : Union<IReadOnlyCollection<Elastic.Clients.Elasticsearch.Tasks.TaskInfo>, Dictionary<string, Elastic.Clients.Elasticsearch.Tasks.ParentTaskInfo>>
+public sealed partial class TaskInfos : Union<IReadOnlyCollection<Elastic.Clients.Elasticsearch.Tasks.TaskInfo>, Dictionary<string, Elastic.Clients.Elasticsearch.Tasks.ParentTaskInfo>>
 {
 	public TaskInfos(IReadOnlyCollection<Elastic.Clients.Elasticsearch.Tasks.TaskInfo> flat) : base(flat)
 	{