[JENKINS-50437] Env vars using PATH+SOMETHING syntax clear the previous env var

src/main/java/org/csanchez/jenkins/plugins/kubernetes/KubernetesComputer.java

@@ -45,14 +45,4 @@ public String toString() {
         return String.format("KubernetesComputer name: %s slave: %s", getName(), getNode());
     }
 
-    /*
-    Return empty EnvVars since we don't want to inject jnlp agent system variables;
-    */
-    @Override
-      public EnvVars getEnvironment() throws IOException, InterruptedException {
-        return new EnvVars();
-    }
-
-
-
 }

src/main/java/org/csanchez/jenkins/plugins/kubernetes/pipeline/ContainerExecDecorator.java

@@ -49,6 +49,7 @@
 import hudson.Launcher;
 import hudson.LauncherDecorator;
 import hudson.Proc;
+import hudson.model.Computer;
 import hudson.model.Node;
 import io.fabric8.kubernetes.api.model.ContainerStatus;
 import io.fabric8.kubernetes.api.model.Pod;
@@ -212,28 +213,28 @@ public Launcher decorate(final Launcher launcher, final Node node) {
             @Override
             public Proc launch(ProcStarter starter) throws IOException {
                 LOGGER.log(Level.FINEST, "Launch proc with environment: {0}", Arrays.toString(starter.envs()));
-                boolean quiet = starter.quiet();
-                FilePath pwd = starter.pwd();
-                List<String> procStarter = Arrays.asList(starter.envs());
-                List<String> cmdEnvs = new ArrayList<String>();
-                // One issue that cropped up was that when executing sh commands, we would get the jnlp agent's injected
-                // environment variables as well, causing obvious problems such as JAVA_HOME being overwritten. The
-                // unsatisfying answer was to check for the presence of JENKINS_HOME in the cmdenvs and skip if present.
-                // check if the cmd is sourced from Jenkins, rather than another plugin;
-                // Currently, build level properties will be provided by the Run Context anyways.
-                boolean javaHome_detected = false;
-                for (String env : procStarter) {
-                    if (env.equalsIgnoreCase("JAVA_HOME")) {
-                        LOGGER.log(Level.FINEST, "Detected JAVA_HOME in {0}", env);
-                        javaHome_detected = true;
-                        break;
+                String[] envVars = starter.envs();
+                if (node != null) { // It seems this is possible despite the method javadoc saying it is non-null
+                    final Computer computer = node.toComputer();
+                    if (computer != null) {
+                        List<String> resultEnvVar = new ArrayList<>();
+                        try {
+                            EnvVars environment = computer.getEnvironment();
+                            String[] envs = starter.envs();
+                            for (String keyValue : envs) {
+                                String[] split = keyValue.split("=", 2);
+                                if (!split[1].equals(environment.get(split[0]))) {
+                                    // Only keep environment variables that differ from Computer's environment
+                                    resultEnvVar.add(keyValue);
+                                }
+                            }
+                            envVars = resultEnvVar.toArray(new String[resultEnvVar.size()]);
+                        } catch (InterruptedException e) {
+                            throw new IOException("Unable to retrieve environment variables", e);
+                        }
                     }
                 }
-                if (!javaHome_detected) {
-                    cmdEnvs = procStarter;
-                }
-                String[] commands = getCommands(starter);
-                return doLaunch(quiet, cmdEnvs.toArray(new String[cmdEnvs.size()]), starter.stdout(), pwd, commands);
+                return doLaunch(starter.quiet(), envVars, starter.stdout(), starter.pwd(), getCommands(starter));
             }
 
             private Proc doLaunch(boolean quiet, String [] cmdEnvs,  OutputStream outputForCaller, FilePath pwd, String... commands) throws IOException {

src/test/java/org/csanchez/jenkins/plugins/kubernetes/pipeline/KubernetesPipelineTest.java

@@ -152,6 +152,8 @@ public void runWithEnvVariablesInContext() throws Exception {
         WorkflowRun b = p.scheduleBuild2(0).waitForStart();
         assertNotNull(b);
         r.assertBuildStatusSuccess(r.waitForCompletion(b));
+        r.assertLogContains("The initial value of POD_ENV_VAR is pod-env-var-value", b);
+        r.assertLogContains("The value of POD_ENV_VAR outside container is /bin/mvn:pod-env-var-value", b);
         r.assertLogContains("The value of FROM_ENV_DEFINITION is ABC", b);
         r.assertLogContains("The value of FROM_WITHENV_DEFINITION is DEF", b);
         r.assertLogContains("The value of WITH_QUOTE is \"WITH_QUOTE", b);
@@ -160,6 +162,7 @@ public void runWithEnvVariablesInContext() throws Exception {
         r.assertLogContains("The value of AFTER_ESCAPED_QUOTE is AFTER_ESCAPED_QUOTE\\\"", b);
         r.assertLogContains("The value of SINGLE_QUOTE is BEFORE'AFTER", b);
         r.assertLogContains("The value of WITH_NEWLINE is before newline\nafter newline", b);
+        r.assertLogContains("The value of POD_ENV_VAR is /bin/mvn:pod-env-var-value", b);
         r.assertLogContains("The value of WILL.NOT is ", b);
     }
 

src/test/resources/org/csanchez/jenkins/plugins/kubernetes/pipeline/runWithEnvVarsFromContext.groovy

@@ -1,5 +1,8 @@
 //noinspection GrPackage
 podTemplate(label: 'mypod',
+    envVars: [
+        envVar(key: 'POD_ENV_VAR', value: 'pod-env-var-value'),
+    ],
     containers: [
         containerTemplate(name: 'busybox', image: 'busybox', ttyEnabled: true, command: '/bin/cat'),
     ]) {
@@ -8,6 +11,11 @@ podTemplate(label: 'mypod',
     env.FROM_ENV_DEFINITION = "ABC"
     node ('mypod') {
         stage('Run busybox') {
+            sh 'echo before withEnv'
+            sh '''
+                echo "The initial value of POD_ENV_VAR is $POD_ENV_VAR"
+            '''
+
             withEnv([
                     'FROM_WITHENV_DEFINITION=DEF',
                     'WITH_QUOTE="WITH_QUOTE',
@@ -16,8 +24,13 @@ podTemplate(label: 'mypod',
                     "SINGLE_QUOTE=BEFORE'AFTER",
                     'AFTER_ESCAPED_QUOTE=AFTER_ESCAPED_QUOTE\\"',
                     'WITH_NEWLINE=before newline\nafter newline',
+                    'POD_ENV_VAR+MAVEN=/bin/mvn',
                     'WILL.NOT=BEUSED'
             ]) {
+                sh 'echo outside container'
+                sh '''
+                    echo "The value of POD_ENV_VAR outside container is $POD_ENV_VAR"
+                '''
                 container('busybox') {
                     sh 'echo inside container'
                     sh '''
@@ -30,6 +43,7 @@ podTemplate(label: 'mypod',
                         echo "The value of SINGLE_QUOTE is $SINGLE_QUOTE"
                         echo "The value of WITH_NEWLINE is $WITH_NEWLINE"
                         echo "The value of WILL.NOT is $WILL.NOT"
+                        echo "The value of POD_ENV_VAR is $POD_ENV_VAR"
                     '''
                 }
             }