Update BWC versions to support multiple staged releases

build-tools-internal/src/integTest/resources/org/elasticsearch/gradle/internal/fake_git/remote/settings.gradle

@@ -14,6 +14,7 @@ include ":distribution:bwc:bugfix2"
 include ":distribution:bwc:minor"
 include ":distribution:bwc:major"
 include ":distribution:bwc:staged"
+include ":distribution:bwc:staged2"
 include ":distribution:bwc:maintenance"
 include ":distribution:archives:darwin-tar"
 include ":distribution:archives:oss-darwin-tar"

build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/BwcVersions.java

@@ -166,6 +166,7 @@ public class BwcVersions implements Serializable {
             .toList();
 
         boolean existingBugfix = false;
+        boolean existingStaged = false;
         for (int i = 0; i < featureFreezeBranches.size(); i++) {
             String branch = featureFreezeBranches.get(i);
             Version version = versions.stream()
@@ -193,7 +194,9 @@ public class BwcVersions implements Serializable {
             if (i == featureFreezeBranches.size() - 1) {
                 result.put(version, new UnreleasedVersionInfo(version, branch, ":distribution:bwc:maintenance"));
             } else if (version.getRevision() == 0) { // This is the next staged minor
-                result.put(version, new UnreleasedVersionInfo(version, branch, ":distribution:bwc:staged"));
+                String project = existingStaged ? "staged2" : "staged";
+                result.put(version, new UnreleasedVersionInfo(version, branch, ":distribution:bwc:" + project));
+                existingStaged = true;
             } else { // This is a bugfix
                 String project = existingBugfix ? "bugfix2" : "bugfix";
                 result.put(version, new UnreleasedVersionInfo(version, branch, ":distribution:bwc:" + project));

build-tools-internal/src/test/groovy/org/elasticsearch/gradle/internal/BwcVersionsSpec.groovy

@@ -77,6 +77,39 @@ class BwcVersionsSpec extends Specification {
         bwc.indexCompatible == [v('8.14.0'), v('8.14.1'), v('8.14.2'), v('8.15.0'), v('8.15.1'), v('8.15.2'), v('8.16.0'), v('8.16.1'), v('8.17.0'), v('8.18.0'), v('9.0.0')]
     }
 
+    def "current version is next major with two staged minors"() {
+        given:
+        addVersion('7.17.10', '8.9.0')
+        addVersion('8.15.0', '9.9.0')
+        addVersion('8.15.1', '9.9.0')
+        addVersion('8.15.2', '9.9.0')
+        addVersion('8.16.0', '9.10.0')
+        addVersion('8.16.1', '9.10.0')
+        addVersion('8.16.2', '9.10.0')
+        addVersion('8.17.0', '9.10.0')
+        addVersion('8.17.1', '9.10.0')
+        addVersion('8.18.0', '9.10.0')
+        addVersion('8.19.0', '9.10.0')
+        addVersion('9.0.0', '10.0.0')
+        addVersion('9.1.0', '10.1.0')
+
+        when:
+        def bwc = new BwcVersions(versionLines, v('9.1.0'), ['main', '9.0', '8.x', '8.18', '8.17', '8.16', '7.17'])
+        def unreleased = bwc.unreleased.collectEntries { [it, bwc.unreleasedInfo(it)] }
+
+        then:
+        unreleased == [
+            (v('8.16.2')): new UnreleasedVersionInfo(v('8.16.2'), '8.16', ':distribution:bwc:bugfix2'),
+            (v('8.17.1')): new UnreleasedVersionInfo(v('8.17.1'), '8.17', ':distribution:bwc:bugfix'),
+            (v('8.18.0')): new UnreleasedVersionInfo(v('8.18.0'), '8.18', ':distribution:bwc:staged2'),
+            (v('8.19.0')): new UnreleasedVersionInfo(v('8.19.0'), '8.x', ':distribution:bwc:minor'),
+            (v('9.0.0')): new UnreleasedVersionInfo(v('9.0.0'), '9.0', ':distribution:bwc:staged'),
+            (v('9.1.0')): new UnreleasedVersionInfo(v('9.1.0'), 'main', ':distribution'),
+        ]
+        bwc.wireCompatible == [v('8.19.0'), v('9.0.0'), v('9.1.0')]
+        bwc.indexCompatible == [v('8.15.0'), v('8.15.1'), v('8.15.2'), v('8.16.0'), v('8.16.1'), v('8.16.2'), v('8.17.0'), v('8.17.1'), v('8.18.0'), v('8.19.0'), v('9.0.0'), v('9.1.0')]
+    }
+
     def "current version is first new minor in major series"() {
         given:
         addVersion('7.17.10', '8.9.0')

settings.gradle

@@ -79,6 +79,7 @@ List projects = [
   'distribution:bwc:maintenance',
   'distribution:bwc:minor',
   'distribution:bwc:staged',
+  'distribution:bwc:staged2',
   'distribution:bwc:main',
   'distribution:tools:java-version-checker',
   'distribution:tools:cli-launcher',