Make disabling async a valid option not just for testing

http-server-jetty/src/main/java/io/micronaut/servlet/jetty/JettyFactory.java

@@ -117,10 +117,9 @@ protected Server jettyServer(
         final ServletHolder servletHolder = new ServletHolder(new DefaultMicronautServlet(applicationContext));
         contextHandler.addServlet(servletHolder, configuration.getMapping());
 
-        Boolean isAsync = applicationContext.getEnvironment()
-                .getProperty("micronaut.server.testing.async", Boolean.class, true);
+        boolean isAsync = configuration.isAsyncSupported();
         if (Boolean.FALSE.equals(isAsync)) {
-            LOG.warn("Async support disabled for testing purposes.");
+            LOG.debug("Servlet async mode is disabled");
         }
         servletHolder.setAsyncSupported(isAsync);
 

http-server-jetty/src/test/groovy/io/micronaut/servlet/jetty/JettyResponseEncoderSpec.groovy

@@ -23,7 +23,7 @@ import spock.lang.Specification
 
 @MicronautTest
 @Property(name = "spec.name", value = SPEC_NAME)
-@Property(name = "micronaut.server.testing.async", value = "false")
+@Property(name = "micronaut.servlet.async-supported", value = "false")
 class JettyResponseEncoderSpec extends Specification {
 
     private static final String SPEC_NAME = "JettyResponseEncoderSpec"

http-server-tomcat/src/main/java/io/micronaut/servlet/tomcat/TomcatFactory.java

@@ -106,9 +106,9 @@ protected Tomcat tomcatServer(Connector connector, MicronautServletConfiguration
                 new DefaultMicronautServlet(getApplicationContext())
         );
 
-        Boolean isAsync = getApplicationContext().getEnvironment().getProperty("micronaut.server.testing.async", Boolean.class, true);
+        boolean isAsync = configuration.isAsyncSupported();
         if (Boolean.FALSE.equals(isAsync)) {
-            LOG.warn("Async support disabled for testing purposes.");
+            LOG.debug("Servlet async mode is disabled");
         }
         servlet.setAsyncSupported(isAsync);
         servlet.addMapping(configuration.getMapping());

http-server-undertow/src/main/java/io/micronaut/servlet/undertow/UndertowFactory.java

@@ -222,9 +222,9 @@ public void release() {
                     }
                 }
         );
-        Boolean isAsync = getApplicationContext().getEnvironment().getProperty("micronaut.server.testing.async", Boolean.class, true);
+        boolean isAsync = servletConfiguration.isAsyncSupported();
         if (Boolean.FALSE.equals(isAsync)) {
-            LOG.warn("Async support disabled for testing purposes.");
+            LOG.debug("Servlet async mode is disabled");
         }
         servletInfo.setAsyncSupported(isAsync);
         servletInfo.addMapping(servletConfiguration.getMapping());

servlet-core/src/main/java/io/micronaut/servlet/http/ServletConfiguration.java

@@ -29,4 +29,13 @@ public interface ServletConfiguration {
      * @return True if it is.
      */
     boolean isAsyncFileServingEnabled();
+
+    /**
+     * Whether to do request processing asynchronously by default (defaults to {@code true}).
+     * @return True whether async is enabled
+     * @since 4.8.0
+     */
+    default boolean isAsyncSupported() {
+        return true;
+    }
 }

servlet-engine/src/main/java/io/micronaut/servlet/engine/MicronautServletConfiguration.java

@@ -17,10 +17,13 @@
 
 import io.micronaut.context.annotation.ConfigurationInject;
 import io.micronaut.context.annotation.ConfigurationProperties;
+import io.micronaut.context.annotation.Property;
 import io.micronaut.context.env.Environment;
 import io.micronaut.core.annotation.NonNull;
+import io.micronaut.core.annotation.Nullable;
 import io.micronaut.core.bind.annotation.Bindable;
 import io.micronaut.core.naming.Named;
+import io.micronaut.core.util.StringUtils;
 import io.micronaut.http.server.HttpServerConfiguration;
 import io.micronaut.servlet.http.ServletConfiguration;
 
@@ -46,6 +49,8 @@ public class MicronautServletConfiguration implements Named, ServletConfiguratio
     private final String name;
     private boolean asyncFileServingEnabled = true;
 
+    private boolean asyncSupported = true;
+
 
     /**
      * Default constructor.
@@ -73,6 +78,33 @@ public MicronautServletConfiguration(
         }
     }
 
+    @Override
+    public boolean isAsyncSupported() {
+        return asyncSupported;
+    }
+
+    /**
+     * Set whether async is supported or not.
+     * @param asyncSupported True if async is supported.
+     */
+    public void setAsyncSupported(boolean asyncSupported) {
+        this.asyncSupported = asyncSupported;
+    }
+
+    /**
+     * Legacy property to disable async for testing.
+     *
+     * @param asyncSupported Is async supported
+     * @deprecated Use {@link #setAsyncSupported(boolean)} instead
+     */
+    @Deprecated(forRemoval = true, since = "4.8.0")
+    @Property(name = "micronaut.server.testing.async")
+    public void setTestAsyncSupported(@Nullable Boolean asyncSupported) {
+        if (asyncSupported != null) {
+            this.asyncSupported = asyncSupported;
+        }
+    }
+
     /**
      * @return The servlet mapping.
      */
@@ -103,6 +135,6 @@ public void setAsyncFileServingEnabled(boolean enabled) {
 
     @Override
     public boolean isAsyncFileServingEnabled() {
-        return asyncFileServingEnabled;
+        return asyncSupported && asyncFileServingEnabled;
     }
 }