EsSitemapReader: Fix AOT serialization of ES search body (#2969)

* EsSitemapReader: Fix AOT serialization of ES search body

Anonymous types in BuildSearchBody and ClosePitAsync cannot be serialized
by System.Text.Json in AOT/trimmed mode (no reflection), causing malformed
request bodies and 400 errors from ES in CI.

Replace anonymous types with JsonObject/JsonArray (AOT-safe) and use
PostData.String() instead of PostData.Serializable().

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Fix CA2241 warning in ApplicabilitySwitchTests

The "because" string contained `{8 hex digits}` which the CA2241 analyzer
interprets as a format placeholder. Remove the redundant reason string
since the regex pattern is self-documenting.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Fix misleading test name: first page has PIT, just no search_after

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Fix remaining AOT trim analysis errors in EsSitemapReader

- JsonArray.Add<JsonValue>() has RequiresUnreferencedCodeAttribute;
  use implicit JsonNode conversion instead
- JsonSerializer.Serialize<Dictionary>() requires reflection;
  use JsonObject.ToJsonString() instead

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: reakaleek

src/services/Elastic.Documentation.Assembler/Building/EsSitemapReader.cs

@@ -31,7 +31,7 @@ public async IAsyncEnumerable<SitemapEntry> ReadAllAsync([EnumeratorCancellation
 			do
 			{
 				var body = BuildSearchBody(pitId, lastSortValues);
-				var response = await transport.PostAsync<JsonResponse>("/_search", PostData.Serializable(body), ct);
+				var response = await transport.PostAsync<JsonResponse>("/_search", PostData.String(body), ct);
 
 				if (!response.ApiCallDetails.HasSuccessfulStatusCode)
 					throw new InvalidOperationException(
@@ -109,7 +109,8 @@ private async Task ClosePitAsync(string pitId, Cancel ct)
 	{
 		try
 		{
-			_ = await transport.DeleteAsync<VoidResponse>("/_pit", new DefaultRequestParameters(), PostData.Serializable(new { id = pitId }), ct);
+			var body = new JsonObject { ["id"] = pitId }.ToJsonString();
+			_ = await transport.DeleteAsync<VoidResponse>("/_pit", new DefaultRequestParameters(), PostData.String(body), ct);
 			logger.LogInformation("Closed PIT");
 		}
 		catch (OperationCanceledException)
@@ -122,20 +123,41 @@ private async Task ClosePitAsync(string pitId, Cancel ct)
 		}
 	}
 
-	internal static object BuildSearchBody(string pitId, string[]? searchAfter)
+	// Returns pre-built JSON string because this assembly is published with AOT trimming.
+	// System.Text.Json cannot serialize anonymous types or unregistered objects via reflection in AOT mode,
+	// so we build the JSON with JsonObject/JsonArray and send it via PostData.String() instead of PostData.Serializable().
+	internal static string BuildSearchBody(string pitId, string[]? searchAfter)
 	{
-		var body = new Dictionary<string, object>
+		var body = new JsonObject
 		{
 			["size"] = PageSize,
-			["_source"] = new[] { "url", "last_updated" },
-			["query"] = new { @bool = new { must_not = new[] { new { term = new { hidden = true } } } } },
-			["pit"] = new { id = pitId, keep_alive = PitKeepAlive },
-			["sort"] = new[] { new { url = "asc" } }
+			["_source"] = new JsonArray("url", "last_updated"),
+			["query"] = new JsonObject
+			{
+				["bool"] = new JsonObject
+				{
+					["must_not"] = new JsonArray(new JsonObject
+					{
+						["term"] = new JsonObject { ["hidden"] = true }
+					})
+				}
+			},
+			["pit"] = new JsonObject
+			{
+				["id"] = pitId,
+				["keep_alive"] = PitKeepAlive
+			},
+			["sort"] = new JsonArray(new JsonObject { ["url"] = "asc" })
 		};
 
 		if (searchAfter is { Length: > 0 })
-			body["search_after"] = searchAfter;
+		{
+			var sortArray = new JsonArray();
+			foreach (var value in searchAfter)
+				sortArray.Add((JsonNode)value);
+			body["search_after"] = sortArray;
+		}
 
-		return body;
+		return body.ToJsonString();
 	}
 }

tests/Elastic.Documentation.Build.Tests/SitemapTests.cs

@@ -95,11 +95,10 @@ public void Generate_OrdersUrlsAlphabetically()
 	}
 
 	[Fact]
-	public void BuildSearchBody_FirstPage_HasNoPitAndNoSearchAfter()
+	public void BuildSearchBody_FirstPage_HasPitButNoSearchAfter()
 	{
 		// Act
-		var body = EsSitemapReader.BuildSearchBody("test-pit-id", null);
-		var json = JsonSerializer.Serialize(body);
+		var json = EsSitemapReader.BuildSearchBody("test-pit-id", null);
 
 		// Assert
 		json.Should().Contain("\"pit\"");
@@ -113,8 +112,7 @@ public void BuildSearchBody_FirstPage_HasNoPitAndNoSearchAfter()
 	public void BuildSearchBody_SubsequentPage_IncludesSearchAfter()
 	{
 		// Act
-		var body = EsSitemapReader.BuildSearchBody("test-pit-id", ["/docs/last-url"]);
-		var json = JsonSerializer.Serialize(body);
+		var json = EsSitemapReader.BuildSearchBody("test-pit-id", ["/docs/last-url"]);
 
 		// Assert
 		json.Should().Contain("\"search_after\"");
@@ -125,8 +123,7 @@ public void BuildSearchBody_SubsequentPage_IncludesSearchAfter()
 	public void BuildSearchBody_EscapesSpecialCharactersInPitId()
 	{
 		// Act
-		var body = EsSitemapReader.BuildSearchBody("pit-with-\"quotes\"", null);
-		var json = JsonSerializer.Serialize(body);
+		var json = EsSitemapReader.BuildSearchBody("pit-with-\"quotes\"", null);
 		var doc = JsonDocument.Parse(json);
 
 		// Assert — verify the value round-trips correctly through serialization

tests/Elastic.Markdown.Tests/Directives/ApplicabilitySwitchTests.cs

@@ -217,7 +217,7 @@ public void GeneratesConsistentSyncKeysForYamlObjects()
 
 			// Also verify the key has the expected format
 			key1.Should().StartWith("applies-", "Sync key should start with 'applies-' prefix");
-			key1.Should().MatchRegex(@"^applies-[0-9A-F]{8}$", "Sync key should be in format 'applies-{8 hex digits}'");
+			key1.Should().MatchRegex(@"^applies-[0-9A-F]{8}$");
 		}
 	}