paper: pick max build and not assume first is newest (#658)

Author: itzg

src/main/java/me/itzg/helpers/paper/PaperDownloadsClient.java

@@ -165,14 +165,20 @@ private Mono<VersionBuild> extractLatestVersionBuild(String project, RequestedCh
         return Flux.fromIterable(projectResponse.getVersions())
             .filter(versionResponse -> versionResponse.getBuilds() != null && !versionResponse.getBuilds().isEmpty())
             .concatMap(versionResponse ->
-                getBuild(project, versionResponse.getVersion().getId(), versionResponse.getBuilds().get(0))
+                getBuild(project, versionResponse.getVersion().getId(), getLatestBuild(versionResponse))
                     .map(buildResponse -> new VersionAndBuildResponse(versionResponse, buildResponse))
                 )
             .takeUntil(vAndB -> acceptableChannel(vAndB.buildResponse.getChannel(), requestedChannel))
             .last()
             .map(vAndB -> new VersionBuild(vAndB.versionResponse.getVersion().getId(), vAndB.buildResponse.getId()));
     }
 
+    private static Integer getLatestBuild(VersionResponse versionResponse) {
+        return versionResponse.getBuilds().stream()
+            .max(Integer::compare)
+            .orElseThrow(() -> new GenericException("No builds found for version " + versionResponse.getVersion().getId()));
+    }
+
     private boolean acceptableChannel(Channel channel, RequestedChannel requestedChannel) {
         for (final Channel mapped : requestedChannel.getMappedTo()) {
             if (mapped.equals(channel)) {

src/test/resources/__files/paper/v3/projects_paper_versions_with_alphas.json

@@ -35,17 +35,17 @@
         }
       },
       "builds": [
-        49,
-        48,
-        47,
-        46,
-        45,
-        44,
-        42,
-        41,
-        40,
+        37,
         38,
-        37
+        40,
+        41,
+        42,
+        44,
+        45,
+        46,
+        47,
+        48,
+        49
       ]
     },
     {