AOT processing does not work when Devtools is on the classpath

[wilkinsona]

When Devtools is on the classpath, AOT processing does not hook in correctly and the app starts up fully. Here's some output from demo-aot-native having added a dependency on spring-boot-devtools:

[INFO] --- spring-boot-maven-plugin:3.0.0-SNAPSHOT:process-aot (process-aot) @ demo-aot-native ---
Downloading from spring-snapshots: https://repo.spring.io/snapshot/org/springframework/boot/spring-boot-buildpack-platform/3.0.0-SNAPSHOT/maven-metadata.xml
Downloaded from spring-snapshots: https://repo.spring.io/snapshot/org/springframework/boot/spring-boot-buildpack-platform/3.0.0-SNAPSHOT/maven-metadata.xml (2.4 kB at 9.7 kB/s)
Downloading from spring-snapshots: https://repo.spring.io/snapshot/org/springframework/boot/spring-boot-buildpack-platform/3.0.0-SNAPSHOT/spring-boot-buildpack-platform-3.0.0-20220927.064405-833.pom
Downloaded from spring-snapshots: https://repo.spring.io/snapshot/org/springframework/boot/spring-boot-buildpack-platform/3.0.0-SNAPSHOT/spring-boot-buildpack-platform-3.0.0-20220927.064405-833.pom (3.4 kB at 13 kB/s)
Downloading from spring-snapshots: https://repo.spring.io/snapshot/org/springframework/boot/spring-boot-loader-tools/3.0.0-SNAPSHOT/maven-metadata.xml
Downloaded from spring-snapshots: https://repo.spring.io/snapshot/org/springframework/boot/spring-boot-loader-tools/3.0.0-SNAPSHOT/maven-metadata.xml (2.4 kB at 9.7 kB/s)
Downloading from spring-snapshots: https://repo.spring.io/snapshot/org/springframework/boot/spring-boot-loader-tools/3.0.0-SNAPSHOT/spring-boot-loader-tools-3.0.0-20220927.064405-833.pom
Downloaded from spring-snapshots: https://repo.spring.io/snapshot/org/springframework/boot/spring-boot-loader-tools/3.0.0-SNAPSHOT/spring-boot-loader-tools-3.0.0-20220927.064405-833.pom (2.3 kB at 8.8 kB/s)
Downloading from spring-snapshots: https://repo.spring.io/snapshot/org/springframework/boot/spring-boot-buildpack-platform/3.0.0-SNAPSHOT/spring-boot-buildpack-platform-3.0.0-20220927.064405-833.jar
Downloading from spring-snapshots: https://repo.spring.io/snapshot/org/springframework/boot/spring-boot-loader-tools/3.0.0-SNAPSHOT/spring-boot-loader-tools-3.0.0-20220927.064405-833.jar
Downloaded from spring-snapshots: https://repo.spring.io/snapshot/org/springframework/boot/spring-boot-loader-tools/3.0.0-SNAPSHOT/spring-boot-loader-tools-3.0.0-20220927.064405-833.jar (246 kB at 325 kB/s)
Downloaded from spring-snapshots: https://repo.spring.io/snapshot/org/springframework/boot/spring-boot-buildpack-platform/3.0.0-SNAPSHOT/spring-boot-buildpack-platform-3.0.0-20220927.064405-833.jar (247 kB at 307 kB/s)

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::       (v3.0.0-SNAPSHOT)

2022-09-27T08:07:30.004+01:00  INFO 55771 --- [  restartedMain] c.example.demo.DemoAotNativeApplication  : Starting DemoAotNativeApplication using Java 17.0.4 on wilkinsona-a01.vmware.com with PID 55771 (/Users/awilkinson/dev/snicoll/demo-aot-native/target/classes started by awilkinson in /Users/awilkinson/dev/snicoll/demo-aot-native)
2022-09-27T08:07:30.007+01:00  INFO 55771 --- [  restartedMain] c.example.demo.DemoAotNativeApplication  : No active profile set, falling back to 1 default profile: "default"
2022-09-27T08:07:30.056+01:00  INFO 55771 --- [  restartedMain] .e.DevToolsPropertyDefaultsPostProcessor : Devtools property defaults active! Set 'spring.devtools.add-properties' to 'false' to disable
2022-09-27T08:07:30.057+01:00  INFO 55771 --- [  restartedMain] .e.DevToolsPropertyDefaultsPostProcessor : For additional web related logging consider setting the 'logging.level.web' property to 'DEBUG'
2022-09-27T08:07:30.883+01:00  INFO 55771 --- [  restartedMain] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2022-09-27T08:07:30.890+01:00  INFO 55771 --- [  restartedMain] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2022-09-27T08:07:30.890+01:00  INFO 55771 --- [  restartedMain] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/10.0.23]
2022-09-27T08:07:30.936+01:00  INFO 55771 --- [  restartedMain] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2022-09-27T08:07:30.938+01:00  INFO 55771 --- [  restartedMain] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 878 ms
2022-09-27T08:07:31.200+01:00  INFO 55771 --- [  restartedMain] o.s.b.d.a.OptionalLiveReloadServer       : LiveReload server is running on port 35729
2022-09-27T08:07:31.221+01:00  INFO 55771 --- [  restartedMain] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2022-09-27T08:07:31.228+01:00  INFO 55771 --- [  restartedMain] c.example.demo.DemoAotNativeApplication  : Started DemoAotNativeApplication in 1.557 seconds (process running for 1.867)

Generally speaking, Gradle will not be affected by this problem. When used, the developmentOnly configuration prevents the Devtools dependency from polluting the AOT processing classpath.