Configuration property to use only system sources

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

@@ -0,0 +1,17 @@
+package io.quarkus.deployment;
+
+import io.quarkus.runtime.annotations.ConfigItem;
+import io.quarkus.runtime.annotations.ConfigPhase;
+import io.quarkus.runtime.annotations.ConfigRoot;
+
+@ConfigRoot(name = ConfigItem.PARENT, phase = ConfigPhase.BUILD_TIME)
+public class ConfigBuildTimeConfig {
+    /**
+     * <p>
+     * Set this to <code>true</code> to read configuration from system properties and environment variables only. This
+     * only applies to runtime.
+     * </p>
+     */
+    @ConfigItem(name = "config.sources.system-only", defaultValue = "false")
+    public boolean systemOnly;
+}

core/deployment/src/main/java/io/quarkus/deployment/steps/ConfigBuildSteps.java

@@ -5,18 +5,22 @@
 import java.util.List;
 import java.util.OptionalInt;
 import java.util.Set;
+import java.util.function.BooleanSupplier;
 
 import org.eclipse.microprofile.config.spi.ConfigProviderResolver;
 import org.eclipse.microprofile.config.spi.ConfigSource;
 import org.eclipse.microprofile.config.spi.ConfigSourceProvider;
 import org.eclipse.microprofile.config.spi.Converter;
 
+import io.quarkus.deployment.ConfigBuildTimeConfig;
 import io.quarkus.deployment.GeneratedClassGizmoAdaptor;
 import io.quarkus.deployment.annotations.BuildProducer;
 import io.quarkus.deployment.annotations.BuildStep;
 import io.quarkus.deployment.builditem.GeneratedClassBuildItem;
 import io.quarkus.deployment.builditem.LiveReloadBuildItem;
+import io.quarkus.deployment.builditem.RunTimeConfigBuilderBuildItem;
 import io.quarkus.deployment.builditem.RunTimeConfigurationSourceBuildItem;
+import io.quarkus.deployment.builditem.StaticInitConfigBuilderBuildItem;
 import io.quarkus.deployment.builditem.nativeimage.RuntimeInitializedClassBuildItem;
 import io.quarkus.deployment.builditem.nativeimage.ServiceProviderBuildItem;
 import io.quarkus.deployment.util.ServiceUtil;
@@ -25,6 +29,7 @@
 import io.quarkus.gizmo.MethodCreator;
 import io.quarkus.gizmo.MethodDescriptor;
 import io.quarkus.gizmo.ResultHandle;
+import io.quarkus.runtime.configuration.SystemOnlySourcesConfigBuilder;
 import io.quarkus.runtime.graal.InetRunTime;
 import io.smallrye.config.ConfigSourceInterceptor;
 import io.smallrye.config.ConfigSourceInterceptorFactory;
@@ -97,4 +102,20 @@ void nativeServiceProviders(
     RuntimeInitializedClassBuildItem runtimeInitializedClass() {
         return new RuntimeInitializedClassBuildItem(InetRunTime.class.getName());
     }
+
+    @BuildStep(onlyIf = SystemOnlySources.class)
+    void systemOnlySources(BuildProducer<StaticInitConfigBuilderBuildItem> staticInitConfigBuilder,
+            BuildProducer<RunTimeConfigBuilderBuildItem> runTimeConfigBuilder) {
+        staticInitConfigBuilder.produce(new StaticInitConfigBuilderBuildItem(SystemOnlySourcesConfigBuilder.class.getName()));
+        runTimeConfigBuilder.produce(new RunTimeConfigBuilderBuildItem(SystemOnlySourcesConfigBuilder.class.getName()));
+    }
+
+    private static class SystemOnlySources implements BooleanSupplier {
+        ConfigBuildTimeConfig configBuildTimeConfig;
+
+        @Override
+        public boolean getAsBoolean() {
+            return configBuildTimeConfig.systemOnly;
+        }
+    }
 }

core/runtime/src/main/java/io/quarkus/runtime/configuration/SystemOnlySourcesConfigBuilder.java

@@ -0,0 +1,16 @@
+package io.quarkus.runtime.configuration;
+
+import io.smallrye.config.SmallRyeConfigBuilder;
+
+public class SystemOnlySourcesConfigBuilder implements ConfigBuilder {
+    @Override
+    public SmallRyeConfigBuilder configBuilder(final SmallRyeConfigBuilder builder) {
+        builder.getSourceProviders().clear();
+        return builder;
+    }
+
+    @Override
+    public int priority() {
+        return Integer.MAX_VALUE;
+    }
+}

devtools/cli/src/main/resources/application.properties

@@ -5,4 +5,5 @@ quarkus.native.resources.includes=quarkus.properties
 quarkus.native.additional-build-args=--initialize-at-run-time=org.apache.maven.wagon.shared.http.AbstractHttpClientWagon
 # Do not attempt to detect "unused removed beans" false positives during programmatic lookup 
 # at runtime to conserve some memory
-quarkus.arc.detect-unused-false-positives=false
+quarkus.arc.detect-unused-false-positives=false
+quarkus.config.sources.system-only=true

extensions/picocli/deployment/src/main/java/io/quarkus/picocli/deployment/PicocliDeploymentConfiguration.java

@@ -26,13 +26,4 @@ class PicocliDeploymentConfiguration {
      */
     @ConfigItem(name = "native-image.processing.enable", defaultValue = "true")
     boolean nativeImageProcessingEnabled;
-
-    /**
-     * <p>
-     * Set this to <code>true</code> to disable reading configuration from the default Config Sources. This includes
-     * `application.properties` and `.env` files.
-     * </p>
-     */
-    @ConfigItem(defaultValue = "false")
-    boolean disableDefaultConfigSources;
 }

extensions/picocli/deployment/src/main/java/io/quarkus/picocli/deployment/PicocliProcessor.java

@@ -21,10 +21,7 @@
 import io.quarkus.deployment.builditem.FeatureBuildItem;
 import io.quarkus.deployment.builditem.IndexDependencyBuildItem;
 import io.quarkus.deployment.builditem.QuarkusApplicationClassBuildItem;
-import io.quarkus.deployment.builditem.RunTimeConfigBuilderBuildItem;
-import io.quarkus.deployment.builditem.StaticInitConfigBuilderBuildItem;
 import io.quarkus.picocli.runtime.DefaultPicocliCommandLineFactory;
-import io.quarkus.picocli.runtime.PicocliConfigBuilder;
 import io.quarkus.picocli.runtime.PicocliRunner;
 import io.quarkus.picocli.runtime.annotations.TopCommand;
 import io.quarkus.runtime.annotations.QuarkusMain;
@@ -47,17 +44,6 @@ IndexDependencyBuildItem picocliIndexDependency() {
         return new IndexDependencyBuildItem("info.picocli", "picocli");
     }
 
-    @BuildStep
-    void configBuilder(
-            PicocliDeploymentConfiguration configuration,
-            BuildProducer<StaticInitConfigBuilderBuildItem> staticInitConfigBuilder,
-            BuildProducer<RunTimeConfigBuilderBuildItem> runTimeConfigBuilder) {
-        if (configuration.disableDefaultConfigSources) {
-            staticInitConfigBuilder.produce(new StaticInitConfigBuilderBuildItem(PicocliConfigBuilder.class.getName()));
-            runTimeConfigBuilder.produce(new RunTimeConfigBuilderBuildItem(PicocliConfigBuilder.class.getName()));
-        }
-    }
-
     @BuildStep
     void picocliRunner(ApplicationIndexBuildItem applicationIndex,
             CombinedIndexBuildItem combinedIndex,

extensions/picocli/deployment/src/test/java/io/quarkus/picocli/deployment/AvailableConfigSourcesTest.java

@@ -17,7 +17,7 @@
 public class AvailableConfigSourcesTest {
     @RegisterExtension
     static final QuarkusUnitTest TEST = new QuarkusUnitTest().withApplicationRoot(
-            (jar) -> jar.addAsResource(new StringAsset("quarkus.picocli.disable-default-config-sources=true\n" +
+            (jar) -> jar.addAsResource(new StringAsset("quarkus.config.sources.system-only=true\n" +
                     "my.prop=1234\n"), "application.properties"));
 
     @Inject