Fix serialization for FILE macro

Author: zbynek

src/main/java/org/jenkinsci/plugins/tokenmacro/impl/WorkspaceFileMacro.java

@@ -84,34 +84,51 @@ public MasterToSlaveCallable<String, IOException> getCallable(Run<?, ?> run, Str
         } catch (Exception e) {
             listener.error("Error retrieving environment: %s", e.getMessage());
         }
-        return new MasterToSlaveCallable<String, IOException>() {
-            @Override
-            public String call() throws IOException {
-
-                File file = new File(root, path);
-                if (!file.exists()) {
-                    return String.format(fileNotFoundMessage, path);
-                }
-
-                try {
-                    Charset charset = Charset.forName(charSet);
-                    try (BufferedReader reader =
-                            new BufferedReader(new InputStreamReader(new FileInputStream(file), charset))) {
-                        if (maxLines > 0) {
-                            return reader.lines().limit(maxLines).collect(Collectors.joining("\n"));
-                        } else {
-                            return reader.lines().collect(Collectors.joining("\n"));
-                        }
-                    }
-                } catch (IOException e) {
-                    return "ERROR: File '" + path + "' could not be read";
-                }
-            }
-        };
+        return new WorkspaceFileMasterToSlaveCallable(root, path, fileNotFoundMessage, charSet, maxLines);
     }
 
     @Override
     public boolean hasNestedContent() {
         return true;
     }
+
+    private static class WorkspaceFileMasterToSlaveCallable extends MasterToSlaveCallable<String, IOException> {
+        private final String root;
+        private final String path;
+        private final String fileNotFoundMessage;
+        private final String charSet;
+        private final int maxLines;
+
+        public WorkspaceFileMasterToSlaveCallable(
+                String root, String path, String fileNotFoundMessage, String charSet, int maxLines) {
+            this.root = root;
+            this.path = path;
+            this.fileNotFoundMessage = fileNotFoundMessage;
+            this.charSet = charSet;
+            this.maxLines = maxLines;
+        }
+
+        @Override
+        public String call() throws IOException {
+
+            File file = new File(root, path);
+            if (!file.exists()) {
+                return String.format(fileNotFoundMessage, path);
+            }
+
+            try {
+                Charset charset = Charset.forName(charSet);
+                try (BufferedReader reader =
+                        new BufferedReader(new InputStreamReader(new FileInputStream(file), charset))) {
+                    if (maxLines > 0) {
+                        return reader.lines().limit(maxLines).collect(Collectors.joining("\n"));
+                    } else {
+                        return reader.lines().collect(Collectors.joining("\n"));
+                    }
+                }
+            } catch (IOException e) {
+                return "ERROR: File '" + path + "' could not be read";
+            }
+        }
+    }
 }

src/test/java/org/jenkinsci/plugins/tokenmacro/PipelineTest.java

@@ -11,9 +11,12 @@
 import hudson.model.Run;
 import hudson.model.TaskListener;
 import hudson.remoting.Callable;
+import hudson.slaves.DumbSlave;
 import hudson.util.StreamTaskListener;
 import java.io.File;
 import java.io.IOException;
+import java.io.OutputStream;
+import java.nio.charset.StandardCharsets;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
@@ -35,9 +38,11 @@ public class PipelineTest {
     @Rule
     public final JenkinsRule j = new JenkinsRule();
 
+    private DumbSlave agent;
+
     @Before
     public void setup() throws Exception {
-        j.createOnlineSlave(Label.get("agents"));
+        agent = j.createOnlineSlave(Label.get("agents"));
     }
 
     @Test
@@ -72,6 +77,19 @@ public void testWorkspaceNeededWithAgent() throws Exception {
         j.assertLogContains("Workspace: foo", run);
     }
 
+    @Test
+    public void testFileNeededWithAgent() throws Exception {
+        WorkflowJob job = j.jenkins.createProject(WorkflowJob.class, "foo");
+        FilePath workspace = agent.getWorkspaceFor(job);
+        workspace.mkdirs();
+        try (OutputStream of = new FilePath(workspace, "in.txt").write()) {
+            of.write("42".getBytes(StandardCharsets.UTF_8));
+        }
+        job.setDefinition(new CpsFlowDefinition(getPipeline("{label 'agents'}", "${FILE,path=\"in.txt\"}"), true));
+        Run<?, ?> run = j.assertBuildStatusSuccess(job.scheduleBuild2(0));
+        j.assertLogContains("VERSION=42", run);
+    }
+
     @Test
     public void testEscapedExpandAll() throws Exception {
         WorkflowJob job = j.jenkins.createProject(WorkflowJob.class, "foo");