Quarkus code-gen (Gradle): Fix behavior to filter unavailable services

Java Services (those in `META-INF/services/*` files) that are defined in the (Gradle) project that uses the Quarkus Gradle plugin, are not available when Quarkus code generation runs. This is simply a task-dependency requirement in Gradle, because Java compilation happens after code generation. If a Java service, for example a Smallrye config sources, is present and the (Smallrye) configuration is needed by a Quarkus extension, the build fails during Quarkus code generation with an error message like this:
```
org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':quarkusGenerateCode'.
...
Caused by: org.gradle.workers.internal.DefaultWorkerExecutor$WorkExecutionException: A failure occurred while executing io.quarkus.gradle.tasks.worker.CodeGenWorker
...
Caused by: java.util.ServiceConfigurationError: io.smallrye.config.ConfigSourceFactory: Provider xyz not found
```

`io.quarkus.deployment.CodeGenerator` has a mechanism to filter out unavailable services via `getUnavailableConfigServices()`. However the callback passed to `io.quarkus.paths.PathTree.apply()` can stop before all roots/trees (`io.quarkus.paths.PathTree.getRoots()`) have been "asked" (`MultiRootPathTree`), because the callback can return a non-`null` value. This "early stop" happens before the root/tree containing the source with the `META-INF/services/*` has been processed.

The bug is only triggered, if a Java service is defined in the Gradle project using the Quarkus Gradle plugin and if a Quarkus extension using the configuration is a dependency of that project.

This change updates the callback implementation to collect all unavailable services from all `PathTree` roots/trees.

An integration test using the Gradle plugin is included as well.

Two logging/spelling mistakes have been fixed as well.

Fixes #36716

core/deployment/src/main/java/io/quarkus/deployment/CodeGenerator.java

@@ -361,39 +361,36 @@ public static <T> T readConfig(ApplicationModel appModel, LaunchMode launchMode,
     private static Map<String, List<String>> getUnavailableConfigServices(ResolvedDependency dep, ClassLoader classLoader)
             throws CodeGenException {
         try (OpenPathTree openTree = dep.getContentTree().open()) {
-            return openTree.apply(META_INF_SERVICES, visit -> {
+            var unavailableServices = new HashMap<String, List<String>>();
+            openTree.apply(META_INF_SERVICES, visit -> {
                 if (visit == null) {
-                    // the application module does not include META-INF/services entry
-                    return Map.of();
+                    // the application module does not include META-INF/services entry. Return `null` here, to let
+                    // MultiRootPathTree.apply() look into all roots.
+                    return null;
                 }
-                Map<String, List<String>> unavailableServices = Map.of();
                 var servicesDir = visit.getPath();
                 for (String serviceClass : CONFIG_SERVICES) {
                     var serviceFile = servicesDir.resolve(serviceClass);
                     if (!Files.exists(serviceFile)) {
                         continue;
                     }
-                    final List<String> implList;
+                    var unavailableList = unavailableServices.computeIfAbsent(META_INF_SERVICES + serviceClass,
+                            k -> new ArrayList<>());
                     try {
-                        implList = Files.readAllLines(serviceFile);
+                        Files.readAllLines(serviceFile).stream()
+                                .map(String::trim)
+                                // skip comments and empty lines
+                                .filter(line -> !line.startsWith("#") && !line.isEmpty())
+                                .filter(className -> classLoader.getResource(className.replace('.', '/') + ".class") == null)
+                                .forEach(unavailableList::add);
                     } catch (IOException e) {
                         throw new UncheckedIOException("Failed to read " + serviceFile, e);
                     }
-                    final List<String> unavailableList = new ArrayList<>(implList.size());
-                    for (String impl : implList) {
-                        if (classLoader.getResource(impl.replace('.', '/') + ".class") == null) {
-                            unavailableList.add(impl);
-                        }
-                    }
-                    if (!unavailableList.isEmpty()) {
-                        if (unavailableServices.isEmpty()) {
-                            unavailableServices = new HashMap<>();
-                        }
-                        unavailableServices.put(META_INF_SERVICES + serviceClass, unavailableList);
-                    }
                 }
-                return unavailableServices;
+                // Always return null to let MultiRootPathTree.apply() look into all roots.
+                return null;
             });
+            return unavailableServices;
         } catch (IOException e) {
             throw new CodeGenException("Failed to read " + dep.getResolvedPaths(), e);
         }

devtools/gradle/gradle-application-plugin/src/main/java/io/quarkus/gradle/tasks/QuarkusGenerateCode.java

@@ -106,7 +106,7 @@ public void generateCode() {
 
         File outputPath = getGeneratedOutputDirectory().get().getAsFile();
 
-        getLogger().debug("Will trigger preparing sources for source directory: {} buildDir: {}",
+        getLogger().debug("Will trigger preparing sources for source directories: {} buildDir: {}",
                 sourcesDirectories, buildDir.getAbsolutePath());
 
         WorkQueue workQueue = workQueue(configMap, () -> extension().codeGenForkOptions);

devtools/gradle/gradle-application-plugin/src/main/java/io/quarkus/gradle/tasks/worker/CodeGenWorker.java

@@ -86,7 +86,8 @@ public void execute() {
         } catch (BootstrapException | IllegalAccessException | InvocationTargetException | ClassNotFoundException e) {
             // Gradle "abbreviates" the stacktrace to something human-readable, but here the underlying cause might
             // get lost in the error output, so add 'e' to the message.
-            throw new GradleException("Failed to generate sources in the QuarkusPrepare task for " + gav + " due to " + e, e);
+            throw new GradleException("Failed to generate sources in the QuarkusGenerateCode task for " + gav + " due to " + e,
+                    e);
         }
     }
 }

integration-tests/gradle/src/main/resources/custom-config-sources/build.gradle

@@ -0,0 +1,23 @@
+plugins {
+    id 'java'
+    id 'io.quarkus'
+}
+
+repositories {
+    mavenLocal {
+        content {
+            includeGroupByRegex 'io.quarkus.*'
+        }
+    }
+    mavenCentral()
+}
+
+dependencies {
+    implementation enforcedPlatform("${quarkusPlatformGroupId}:${quarkusPlatformArtifactId}:${quarkusPlatformVersion}")
+    implementation "io.quarkus:quarkus-grpc" // Need a `CodeGenProvider` on the class path for this test!
+    compileOnly "io.smallrye.config:smallrye-config-core"
+}
+
+compileJava {
+    options.compilerArgs << '-parameters'
+}

integration-tests/gradle/src/main/resources/custom-config-sources/gradle.properties

@@ -0,0 +1,2 @@
+quarkusPlatformArtifactId=quarkus-bom
+quarkusPlatformGroupId=io.quarkus

integration-tests/gradle/src/main/resources/custom-config-sources/settings.gradle

@@ -0,0 +1,15 @@
+pluginManagement {
+    repositories {
+        mavenLocal {
+            content {
+                includeGroupByRegex 'io.quarkus.*'
+            }
+        }
+        mavenCentral()
+        gradlePluginPortal()
+    }
+    plugins {
+      id 'io.quarkus' version "${quarkusPluginVersion}"
+    }
+}
+rootProject.name='custom-config-sources'

integration-tests/gradle/src/main/resources/custom-config-sources/src/main/java/org/acme/InMemoryConfigSource.java

@@ -0,0 +1,35 @@
+package org.acme;
+
+import org.eclipse.microprofile.config.spi.ConfigSource;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
+public class InMemoryConfigSource implements ConfigSource {
+    private static final Map<String, String> configuration = new HashMap<>();
+
+    static {
+        configuration.put("my.prop", "1234");
+    }
+
+    @Override
+    public int getOrdinal() {
+        return 275;
+    }
+
+    @Override
+    public Set<String> getPropertyNames() {
+        return configuration.keySet();
+    }
+
+    @Override
+    public String getValue(final String propertyName) {
+        return configuration.get(propertyName);
+    }
+
+    @Override
+    public String getName() {
+        return InMemoryConfigSource.class.getSimpleName();
+    }
+}

integration-tests/gradle/src/main/resources/custom-config-sources/src/main/java/org/acme/MyConfigSourceFactory.java

@@ -0,0 +1,14 @@
+package org.acme;
+
+import io.smallrye.config.ConfigSourceContext;
+import io.smallrye.config.ConfigSourceFactory;
+import org.eclipse.microprofile.config.spi.ConfigSource;
+
+import java.util.List;
+
+public class MyConfigSourceFactory implements ConfigSourceFactory {
+    @Override
+    public Iterable<ConfigSource> getConfigSources(ConfigSourceContext context) {
+        return List.of(new InMemoryConfigSource());
+    }
+}

integration-tests/gradle/src/main/resources/custom-config-sources/src/main/resources/META-INF/services/io.smallrye.config.ConfigSourceFactory

@@ -0,0 +1 @@
+org.acme.MyConfigSourceFactory

integration-tests/gradle/src/main/resources/custom-config-sources/src/main/resources/META-INF/services/org.eclipse.microprofile.config.spi.ConfigSource

@@ -0,0 +1 @@
+org.acme.InMemoryConfigSource

integration-tests/gradle/src/main/resources/custom-config-sources/src/main/resources/application.properties

@@ -0,0 +1 @@
+# Need an empty application.properties to trigger config loading mandatory for CustomConfigSourcesTest

integration-tests/gradle/src/test/java/io/quarkus/gradle/CustomConfigSourcesTest.java

@@ -0,0 +1,19 @@
+package io.quarkus.gradle;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.jupiter.api.Test;
+
+public class CustomConfigSourcesTest extends QuarkusGradleWrapperTestBase {
+
+    @Test
+    public void testCustomConfigSources() throws Exception {
+        var projectDir = getProjectDir("custom-config-sources");
+
+        // The test is successful, if the build works, see https://github.com/quarkusio/quarkus/issues/36716
+        runGradleWrapper(projectDir, "clean", "build", "--no-build-cache");
+
+        var p = projectDir.toPath().resolve("build").resolve("quarkus-app").resolve("quarkus-run.jar");
+        assertThat(p).exists();
+    }
+}