Fix intermittent build failure, ensuring docker test output is still usable

buildSrc/src/main/groovy/Docker.groovy

@@ -302,19 +302,8 @@ class Docker {
             // Single task with explicit inputs and outputs, to let gradle detect if it is up to date, and let docker
             // cache what it can.
 
-            // Sync outputs to the desired location
-            def syncAfterBuildAndRun = project.tasks.register("${taskName}Sync", Sync) { sync ->
-                sync.with {
-                    // run the provided closure first
-                    cfg.copyOut.execute(sync)
-
-                    // then set the from location
-                    from dockerCopyLocation
-                }
-            }
-
             // Note that if "showLogsOnSuccess" is true, we don't run this way, since that would omit logs when cached.
-            return project.tasks.register(taskName, CombinedDockerRunTask) { cacheableDockerTask ->
+            def buildAndRun = project.tasks.register("${taskName}Run", CombinedDockerRunTask) { cacheableDockerTask ->
                 cacheableDockerTask.with {
                     // mark inputs, depend on dockerfile task and input sync task
                     inputs.files(makeImage.get().outputs.files)
@@ -345,7 +334,36 @@ class Docker {
 
                     remotePath.set(cfg.containerOutPath)
                     outputDir.set(project.file(dockerCopyLocation))
-                    finalizedBy syncAfterBuildAndRun
+                }
+            }
+
+            // Handle copying failure. This is now distinct from the "actual" Sync task that depends directly
+            // on the CombinedDockerRunTask.
+            def syncAfterFail = project.tasks.register("${taskName}SyncAfterFail", Sync) { sync ->
+                sync.with {
+                    // run the provided closure first
+                    cfg.copyOut.execute(sync)
+
+                    // then set the from location
+                    from dockerCopyLocation
+
+                    onlyIf { buildAndRun.get().state.failure != null }
+                }
+            }
+            buildAndRun.configure {t ->
+                t.finalizedBy syncAfterFail
+            }
+
+            // Sync outputs to the desired location
+            return project.tasks.register(taskName, Sync) { sync ->
+                sync.with {
+                    dependsOn buildAndRun
+
+                    // run the provided closure first
+                    cfg.copyOut.execute(sync)
+
+                    // then set the from location
+                    from dockerCopyLocation
                 }
             }
         }

buildSrc/src/main/groovy/io/deephaven/tools/docker/CombinedDockerRunTask.groovy

@@ -111,7 +111,6 @@ class CombinedDockerRunTask extends AbstractDockerRemoteApiTask {
                     throw new GradleException("${failedMessage}, check logs for details")
                 }
             }
-
         } finally {
             if (containerId == null) {
                 return;