Make SplitPackageProcessor configurable

extensions/arc/deployment/src/main/java/io/quarkus/arc/deployment/ArcConfig.java

@@ -181,6 +181,18 @@ public class ArcConfig {
     @ConfigItem
     public ArcTestConfig test;
 
+    /**
+     * The list of packages that will not be checked for split package issues.
+     * <p>
+     * A package string representation can be:
+     * <ul>
+     * <li>a full name of the package, i.e. {@code org.acme.foo}</li>
+     * <li>a package name with suffix {@code .*}, i.e. {@code org.acme.*}, which matches a package that starts with provided
+     * value</li>
+     */
+    @ConfigItem
+    public Optional<List<String>> ignoredSplitPackages;
+
     public final boolean isRemoveUnusedBeansFieldValid() {
         return ALLOWED_REMOVE_UNUSED_BEANS_VALUES.contains(removeUnusedBeans.toLowerCase());
     }

extensions/arc/deployment/src/main/java/io/quarkus/arc/deployment/IgnoreSplitPackageBuildItem.java

@@ -0,0 +1,30 @@
+package io.quarkus.arc.deployment;
+
+import java.util.Collection;
+
+import io.quarkus.builder.item.MultiBuildItem;
+
+/**
+ * Allows extensions to programmatically exclude certain packages from split package detection which is executed by
+ * {@link SplitPackageProcessor}. Extensions are encouraged to solve split package issues and this build item should
+ * be used primarily as temporary workaround.
+ * <p>
+ * A package string representation can be:
+ * <ul>
+ * <li>a full name of the package, i.e. {@code org.acme.foo}</li>
+ * <li>a package name with suffix {@code .*}, i.e. {@code org.acme.*}, which matches a package that starts with provided
+ * value</li>
+ *
+ */
+public final class IgnoreSplitPackageBuildItem extends MultiBuildItem {
+
+    private Collection<String> excludedPackages;
+
+    public IgnoreSplitPackageBuildItem(Collection<String> excludedPackages) {
+        this.excludedPackages = excludedPackages;
+    }
+
+    public Collection<String> getExcludedPackages() {
+        return excludedPackages;
+    }
+}

extensions/arc/deployment/src/main/java/io/quarkus/arc/deployment/SplitPackageProcessor.java

@@ -1,9 +1,12 @@
 package io.quarkus.arc.deployment;
 
 import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.TreeSet;
@@ -27,6 +30,10 @@
  * Note that this processor is a best-effort because it only operates on {@code ApplicationArchivesBuildItem} which
  * means that if a 3rd party library isn't indexed, we aren't able to detect it even though it can still be a part of
  * resulting application. See also {@code io.quarkus.arc.processor.BeanArchives.IndexWrapper}.
+ * <p>
+ * This processor can be configured by users and extensions to skip validation for certain packages hence avoiding the
+ * warning in logs.
+ * See also {@link ArcConfig#ignoredSplitPackages} and {@link IgnoreSplitPackageBuildItem}
  */
 public class SplitPackageProcessor {
 
@@ -47,9 +54,21 @@ public boolean test(String packageName) {
 
     @BuildStep
     void splitPackageDetection(ApplicationArchivesBuildItem archivesBuildItem,
+            ArcConfig config,
+            List<IgnoreSplitPackageBuildItem> excludedPackages,
             // Dummy producer to make sure the build step executes
             BuildProducer<ValidationPhaseBuildItem.ValidationErrorBuildItem> dummy) {
         Map<String, Set<ApplicationArchive>> packageToArchiveMap = new HashMap<>();
+
+        // build up exclusion predicates from user defined config and extensions
+        List<Predicate> packageSkipPredicates = new ArrayList<>();
+        if (config.ignoredSplitPackages.isPresent()) {
+            packageSkipPredicates.addAll(initPredicates(config.ignoredSplitPackages.get()));
+        }
+        for (IgnoreSplitPackageBuildItem exclusionBuildItem : excludedPackages) {
+            packageSkipPredicates.addAll(initPredicates(exclusionBuildItem.getExcludedPackages()));
+        }
+
         // for all app archives
         for (ApplicationArchive archive : archivesBuildItem.getAllApplicationArchives()) {
             // and for each known class in each archive
@@ -70,6 +89,18 @@ void splitPackageDetection(ApplicationArchivesBuildItem archivesBuildItem,
                 continue;
             }
 
+            // skip packages based on pre-built predicates
+            boolean skipEvaluation = false;
+            for (Predicate<String> predicate : packageSkipPredicates) {
+                if (predicate.test(packageName)) {
+                    skipEvaluation = true;
+                    break;
+                }
+            }
+            if (skipEvaluation) {
+                continue;
+            }
+
             Set<ApplicationArchive> applicationArchives = packageToArchiveMap.get(packageName);
             if (applicationArchives.size() > 1) {
                 splitPackagesWarning.append("\n- \"" + packageName + "\" found in ");
@@ -107,4 +138,30 @@ void splitPackageDetection(ApplicationArchivesBuildItem archivesBuildItem,
                     "Following packages were detected in multiple archives: %s", splitPackagesWarning.toString());
         }
     }
+
+    private List<Predicate<String>> initPredicates(Collection<String> exclusions) {
+        final String packMatch = ".*";
+        List<Predicate<String>> predicates = new ArrayList<>();
+        for (String exclusionExpression : exclusions) {
+            if (exclusionExpression.endsWith(packMatch)) {
+                // Package ends with ".*"
+                final String pack = exclusionExpression.substring(0, exclusionExpression.length() - packMatch.length());
+                predicates.add(new Predicate<String>() {
+                    @Override
+                    public boolean test(String packageName) {
+                        return packageName.equals(pack) || packageName.startsWith(pack + ".");
+                    }
+                });
+            } else {
+                // Standard full package name
+                predicates.add(new Predicate<String>() {
+                    @Override
+                    public boolean test(String packageName) {
+                        return packageName.equals(exclusionExpression);
+                    }
+                });
+            }
+        }
+        return predicates;
+    }
 }