feat(script): include task null outputs

Fixes kestra-io/plugin-scripts#195

core/src/main/java/io/kestra/core/models/executions/TaskRun.java

@@ -1,5 +1,6 @@
 package io.kestra.core.models.executions;
 
+import com.fasterxml.jackson.annotation.JsonInclude;
 import io.kestra.core.models.TenantInterface;
 import io.kestra.core.models.flows.State;
 import io.kestra.core.models.tasks.ResolvedTask;
@@ -49,6 +50,7 @@ public class TaskRun implements TenantInterface {
     List<TaskRunAttempt> attempts;
 
     @With
+    @JsonInclude(JsonInclude.Include.ALWAYS) // always include outputs so it's easier to reason about in expressions
     Map<String, Object> outputs;
 
     @NotNull

core/src/test/java/io/kestra/core/runners/NullOutputTest.java

@@ -0,0 +1,47 @@
+package io.kestra.core.runners;
+
+import io.kestra.core.junit.annotations.KestraTest;
+import io.kestra.core.junit.extensions.LoadFlows;
+import io.kestra.core.models.executions.Execution;
+import io.kestra.core.models.flows.State;
+import io.kestra.core.queues.QueueException;
+import io.kestra.core.utils.TestsUtils;
+import jakarta.inject.Inject;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.util.Map;
+import java.util.concurrent.TimeoutException;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.*;
+
+@KestraTest
+public class NullOutputTest {
+    @Inject
+    protected StandAloneRunner runner;
+
+    @Inject
+    protected RunnerUtils runnerUtils;
+
+    @BeforeEach
+    protected void init() throws IOException, URISyntaxException {
+        if (!runner.isRunning()) {
+            runner.run();
+        }
+    }
+
+    @Test
+    @LoadFlows("flows/valids/null-output.yaml")
+    void shouldIncludeNullOutput() throws QueueException, TimeoutException {
+        Execution execution = runnerUtils.runOne(null, "io.kestra.tests", "null-output");
+
+        assertThat(execution, notNullValue());
+        assertThat(execution.getState().getCurrent(), is(State.Type.SUCCESS));
+        assertThat(execution.getTaskRunList(), hasSize(1));
+        assertThat(execution.getTaskRunList().getFirst().getOutputs(), aMapWithSize(1));
+        assertThat(execution.getTaskRunList().getFirst().getOutputs().containsKey("value"), is(true));
+    }
+}

core/src/test/java/io/kestra/core/tasks/test/NullOutputTask.java

@@ -0,0 +1,30 @@
+package io.kestra.core.tasks.test;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import io.kestra.core.models.annotations.Plugin;
+import io.kestra.core.models.tasks.RunnableTask;
+import io.kestra.core.models.tasks.Task;
+import io.kestra.core.runners.RunContext;
+import lombok.*;
+import lombok.experimental.SuperBuilder;
+
+@SuperBuilder
+@ToString
+@EqualsAndHashCode
+@Getter
+@NoArgsConstructor
+@Plugin
+public class NullOutputTask extends Task implements RunnableTask<NullOutputTask.Output> {
+
+    @Override
+    public Output run(RunContext runContext) throws Exception {
+        return Output.builder().build();
+    }
+
+    @Builder
+    @Getter
+    public static class Output implements io.kestra.core.models.tasks.Output {
+        @JsonInclude(JsonInclude.Include.ALWAYS)
+        private String value;
+    }
+}

core/src/test/resources/flows/valids/null-output.yaml

@@ -0,0 +1,6 @@
+id: null-output
+namespace: io.kestra.tests
+
+tasks:
+  - id: null-output
+    type: io.kestra.core.tasks.test.NullOutputTask

script/src/main/java/io/kestra/plugin/scripts/exec/scripts/models/ScriptOutput.java

@@ -1,6 +1,7 @@
 package io.kestra.plugin.scripts.exec.scripts.models;
 
 import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import io.kestra.core.models.annotations.PluginProperty;
 import io.kestra.core.models.flows.State;
 import io.kestra.core.models.tasks.Output;
@@ -19,6 +20,7 @@ public class ScriptOutput implements Output {
     @Schema(
         title = "The value extracted from the output of the executed `commands`."
     )
+    @JsonInclude(JsonInclude.Include.ALWAYS) // always include vars so it's easier to reason about in expressions
     private final Map<String, Object> vars;
 
     @Schema(