ServiceConnectionContextCustomizer can trigger docker usage during AOT processing

[snicoll]

Processing a test with AOT that contains a @ServiceConnection field for a container can lead to:

17:19:28.013 [main] ERROR org.testcontainers.dockerclient.DockerClientProviderStrategy -- Could not find a valid Docker environment. Please check configuration. Attempted configurations were:
        UnixSocketClientProviderStrategy: failed with exception InvalidConfigurationException (Could not find unix domain socket). Root cause NoSuchFileException (/var/run/docker.sock)
        DockerDesktopClientProviderStrategy: failed with exception NullPointerException (Cannot invoke "java.nio.file.Path.toString()" because the return value of "org.testcontainers.dockerclient.DockerDesktopClientProviderStrategy.getSocketPath()" is null)As no valid configuration was found, execution cannot continue.
See https://www.testcontainers.org/on_failure.html for more details.
Exception in thread "main" org.testcontainers.containers.ContainerFetchException: Can't get Docker image: RemoteDockerImage(imageName=mysql:5.7, imagePullPolicy=DefaultPullPolicy(), imageNameSubstitutor=org.testcontainers.utility.ImageNameSubstitutor$LogWrappedImageNameSubstitutor@119020fb)
        at org.testcontainers.containers.GenericContainer.getDockerImageName(GenericContainer.java:1408)
        at org.springframework.boot.testcontainers.service.connection.ServiceConnectionContextCustomizerFactory.createSource(ServiceConnectionContextCustomizerFactory.java:77)
        at org.springframework.boot.testcontainers.service.connection.ServiceConnectionContextCustomizerFactory.lambda$findSources$0(ServiceConnectionContextCustomizerFactory.java:59)
        at org.springframework.core.annotation.TypeMappedAnnotations$AggregatesSpliterator.tryAdvance(TypeMappedAnnotations.java:607)
        at org.springframework.core.annotation.TypeMappedAnnotations$AggregatesSpliterator.tryAdvance(TypeMappedAnnotations.java:574)
        at java.base/java.util.Spliterator.forEachRemaining(Spliterator.java:332)
        at java.base/java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:762)
        at org.springframework.boot.testcontainers.service.connection.ServiceConnectionContextCustomizerFactory.lambda$findSources$1(ServiceConnectionContextCustomizerFactory.java:59)
        at org.springframework.util.ReflectionUtils.doWithFields(ReflectionUtils.java:711)
        at org.springframework.util.ReflectionUtils.doWithFields(ReflectionUtils.java:690)
        at org.springframework.boot.testcontainers.service.connection.ServiceConnectionContextCustomizerFactory.findSources(ServiceConnectionContextCustomizerFactory.java:56)
        at org.springframework.boot.testcontainers.service.connection.ServiceConnectionContextCustomizerFactory.createContextCustomizer(ServiceConnectionContextCustomizerFactory.java:51)
        at org.springframework.test.context.support.AbstractTestContextBootstrapper.getContextCustomizers(AbstractTestContextBootstrapper.java:384)
        at org.springframework.test.context.support.AbstractTestContextBootstrapper.buildMergedContextConfiguration(AbstractTestContextBootstrapper.java:356)
        at org.springframework.test.context.support.AbstractTestContextBootstrapper.buildDefaultMergedContextConfiguration(AbstractTestContextBootstrapper.java:291)
        at org.springframework.test.context.support.AbstractTestContextBootstrapper.buildMergedContextConfiguration(AbstractTestContextBootstrapper.java:239)
        at org.springframework.test.context.aot.TestContextAotGenerator.buildMergedContextConfiguration(TestContextAotGenerator.java:293)
        at org.springframework.test.context.aot.TestContextAotGenerator.lambda$processAheadOfTime$1(TestContextAotGenerator.java:136)
        at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:183)
        at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)
        at java.base/java.util.stream.SortedOps$RefSortingSink.end(SortedOps.java:395)
        at java.base/java.util.stream.DistinctOps$1$2.end(DistinctOps.java:168)
        at java.base/java.util.stream.Sink$ChainedReference.end(Sink.java:258)
        at java.base/java.util.stream.Sink$ChainedReference.end(Sink.java:258)
        at java.base/java.util.stream.Sink$ChainedReference.end(Sink.java:258)
        at java.base/java.util.stream.Sink$ChainedReference.end(Sink.java:258)
        at java.base/java.util.stream.Sink$ChainedReference.end(Sink.java:258)
        at java.base/java.util.stream.Sink$ChainedReference.end(Sink.java:258)
        at java.base/java.util.stream.Sink$ChainedReference.end(Sink.java:258)
        at java.base/java.util.stream.Sink$ChainedReference.end(Sink.java:258)
        at java.base/java.util.stream.Sink$ChainedReference.end(Sink.java:258)
        at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:510)
        at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)
        at java.base/java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:150)
        at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:173)
        at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
        at java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:596)
        at org.springframework.test.context.aot.TestContextAotGenerator.processAheadOfTime(TestContextAotGenerator.java:135)
        at org.springframework.test.context.aot.TestAotProcessor.performAotProcessing(TestAotProcessor.java:91)
        at org.springframework.test.context.aot.TestAotProcessor.doProcess(TestAotProcessor.java:72)
        at org.springframework.test.context.aot.TestAotProcessor.doProcess(TestAotProcessor.java:39)
        at org.springframework.context.aot.AbstractAotProcessor.process(AbstractAotProcessor.java:82)
        at org.springframework.boot.test.context.SpringBootTestAotProcessor.main(SpringBootTestAotProcessor.java:63)
Caused by: java.lang.IllegalStateException: Could not find a valid Docker environment. Please see logs and check configuration
        at org.testcontainers.dockerclient.DockerClientProviderStrategy.lambda$getFirstValidStrategy$7(DockerClientProviderStrategy.java:276)
        at java.base/java.util.Optional.orElseThrow(Optional.java:403)
        at org.testcontainers.dockerclient.DockerClientProviderStrategy.getFirstValidStrategy(DockerClientProviderStrategy.java:267)
        at org.testcontainers.DockerClientFactory.getOrInitializeStrategy(DockerClientFactory.java:150)
        at org.testcontainers.DockerClientFactory.client(DockerClientFactory.java:191)
        at org.testcontainers.images.LocalImagesCache.get(LocalImagesCache.java:31)
        at org.testcontainers.images.AbstractImagePullPolicy.shouldPull(AbstractImagePullPolicy.java:18)
        at org.testcontainers.images.RemoteDockerImage.resolve(RemoteDockerImage.java:70)
        at org.testcontainers.images.RemoteDockerImage.resolve(RemoteDockerImage.java:28)
        at org.testcontainers.utility.LazyFuture.getResolvedValue(LazyFuture.java:19)
        at org.testcontainers.utility.LazyFuture.get(LazyFuture.java:41)
        at org.testcontainers.containers.GenericContainer.getDockerImageName(GenericContainer.java:1406)
        ... 42 more

Docker shouldn't be required during AOT processing.