Squashed commit of the following:

commit dc3b25f
Author: Mads Nielsen <man@praqma.net>
Date:   Thu Jan 11 10:30:27 2018 +0100

    Fix for Praqma#97

commit 034d32e
Author: Mads Nielsen <man@praqma.net>
Date:   Thu Jan 11 09:59:48 2018 +0100

    Fixed merge conflict. For Praqma#97

commit 15cd353
Author: Mads Nielsen <man@praqma.net>
Date:   Thu Jan 11 09:09:40 2018 +0100

    Implemented Praqma#97. Close issue Praqma#97

commit a06d856
Author: Mads Nielsen <man@praqma.net>
Date:   Thu Jan 11 08:49:12 2018 +0100

    Rename to IT to be picked up in integration test. For Praqma#97

commit 6768dfc
Author: Mads Nielsen <man@praqma.net>
Date:   Thu Jan 11 08:34:15 2018 +0100

    Implemented Praqma#97. Close

pom.xml

@@ -199,8 +199,6 @@
             <version>4.5.2</version>
         </dependency>
 
-
-
         <dependency>
             <groupId>org.jenkins-ci.plugins.workflow</groupId>
             <artifactId>workflow-aggregator</artifactId>
@@ -244,6 +242,14 @@
             <optional>true</optional>
         </dependency>
 
+        <dependency>
+            <groupId>org.jenkins-ci.plugins</groupId>
+            <artifactId>jenkins-multijob-plugin</artifactId>
+            <scope>test</scope>
+            <optional>true</optional>
+            <version>1.28</version>
+        </dependency>
+
         <dependency>
             <groupId>org.jenkins-ci.plugins</groupId>
             <artifactId>matrix-project</artifactId>
@@ -258,14 +264,22 @@
             <scope>test</scope>
         </dependency>
 
-
         <dependency>
             <groupId>org.mockito</groupId>
             <artifactId>mockito-all</artifactId>
             <version>1.9.5</version>
             <scope>test</scope>
         </dependency>
 
+        <!--
+            Added because of multijob plugin and maven job's depend on two older ant libraries.
+            We need to use the newest as plugins are not forwards compatible.
+        -->
+        <dependency>
+            <groupId>org.apache.ant</groupId>
+            <artifactId>ant</artifactId>
+            <version>1.9.2</version>
+        </dependency>
 
     </dependencies>
 

src/main/java/org/jenkinsci/plugins/pretestedintegration/PretestedIntegrationPostCheckout.java

@@ -2,14 +2,10 @@
 
 import com.cloudbees.plugins.credentials.CredentialsProvider;
 import com.cloudbees.plugins.credentials.common.StandardUsernameCredentials;
-import hudson.AbortException;
 import hudson.Extension;
 import hudson.FilePath;
 import hudson.Launcher;
-import hudson.matrix.MatrixAggregatable;
-import hudson.matrix.MatrixAggregator;
-import hudson.matrix.MatrixBuild;
-import hudson.matrix.MatrixConfiguration;
+import hudson.matrix.*;
 import hudson.model.*;
 import hudson.plugins.git.GitSCM;
 import hudson.plugins.git.extensions.impl.RelativeTargetDirectory;
@@ -23,12 +19,13 @@
 import org.jenkinsci.plugins.gitclient.GitClient;
 import org.jenkinsci.plugins.pretestedintegration.scm.git.GitBridge;
 import org.jenkinsci.plugins.pretestedintegration.scm.git.PretestTriggerCommitAction;
-import org.jenkinsci.plugins.pretestedintegration.scm.git.PretestedIntegrationAsGitPluginExt;
 import org.kohsuke.stapler.DataBoundConstructor;
 
 import java.io.IOException;
 import java.io.Serializable;
+import java.util.ArrayList;
 import java.util.Collections;
+import java.util.List;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -45,8 +42,7 @@ public class PretestedIntegrationPostCheckout extends Recorder implements Serial
      * Constructor for PretestedIntegrationPostCheckout
      */
     @DataBoundConstructor
-    public PretestedIntegrationPostCheckout() {
-    }
+    public PretestedIntegrationPostCheckout() { }
 
     ///**
     // * Gets the SCM Bridge of the BuildWrapper of this project.
@@ -85,7 +81,7 @@ private AbstractSCMBridge getScmBridge(AbstractBuild<?, ?> build, BuildListener
     */
 
     /**
-     * Calls the SCM-specific function according to the chosen SCM.
+     * Calls the SCM-specific function according to the chosen SCM. Only called for Non pipeline jobs
      *
      * @param build    The Build
      * @param launcher The Launcher
@@ -103,6 +99,7 @@ public boolean perform(AbstractBuild<?, ?> build, Launcher launcher, BuildListen
             RelativeTargetDirectory rtd = scm.getExtensions().get(RelativeTargetDirectory.class);
             try {
                 FilePath wsForUs = rtd != null ? rtd.getWorkingDirectory(scm, proj, build.getWorkspace(), build.getEnvironment(listener), listener) : build.getWorkspace();
+                printWarningIfUnsupported(proj.getClass(), listener);
                 perform((Run) build, wsForUs, launcher, listener);
             } catch (IOException ex) {
                 listener.getLogger().println("[PREINT] FATAL: Unable to determine workspace");
@@ -112,6 +109,35 @@ public boolean perform(AbstractBuild<?, ?> build, Launcher launcher, BuildListen
         return true;
     }
 
+    /**
+     * For #97. Whitelist certain job types. We include only those we support. We need not include pipeline jobs since
+     * they do not call the perform method.
+     */
+    private static final List<String> WHITELIST = new ArrayList<>();
+    static {
+        WHITELIST.add(FreeStyleProject.class.getName());
+        WHITELIST.add(MatrixProject.class.getName());
+        //Maven job type. Several kinds here. We can with 100% certainty say that we match everything with maven here
+        WHITELIST.add("hudson.maven");
+    }
+
+    public boolean isSupported(Class classname) {
+        for(String whiteListed : WHITELIST) {
+            if (classname.getName().contains(whiteListed)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    public void printWarningIfUnsupported(Class classname, BuildListener listener) {
+        if(!isSupported(classname)) {
+            String message = LOG_PREFIX+"Warning: Unsupported job type "+classname.getSimpleName()+" "+"plugin might not work as expected";
+            listener.getLogger().println(message);
+            LOGGER.log(Level.WARNING, message);
+        }
+    }
+
     /**
      * For a matrix project, push should only happen once.
      */
@@ -176,7 +202,6 @@ public BuildStepMonitor getRequiredMonitorService() {
     @Symbol("pretestedIntegration")
     @Extension(ordinal = Integer.MIN_VALUE)
     public static final class DescriptorImpl extends BuildStepDescriptor<Publisher> {
-
         /**
          * {@inheritDoc}
          */

src/main/resources/org/jenkinsci/plugins/pretestedintegration/PretestedIntegrationPostCheckout/config.jelly

@@ -0,0 +1,3 @@
+<?jelly escape-by-default='true'?>
+<j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">
+</j:jelly>

src/test/java/org/jenkinsci/plugins/pretestedintegration/integration/scm/git/GHI97_SupportChecksIT.java

@@ -0,0 +1,28 @@
+package org.jenkinsci.plugins.pretestedintegration.integration.scm.git;
+
+import com.tikal.jenkins.plugins.multijob.MultiJobProject;
+import hudson.matrix.MatrixProject;
+import hudson.model.FreeStyleProject;
+import hudson.model.ItemGroup;
+import org.jenkinsci.plugins.pretestedintegration.PretestedIntegrationPostCheckout;
+import org.junit.Test;
+
+import static junit.framework.Assert.assertFalse;
+import static junit.framework.Assert.assertTrue;
+
+public class GHI97_SupportChecksIT {
+
+    /**
+     * See GitHub issue #97
+     */
+    @Test
+    public void validateReturnsFromSupportedChecks_ValidatesGHI97()  {
+        PretestedIntegrationPostCheckout pipPost = new PretestedIntegrationPostCheckout();
+        MultiJobProject multiJobProject = new MultiJobProject(null, "MultiJobMustNotBeSupported");
+        FreeStyleProject freeStyleProject = new FreeStyleProject((ItemGroup)null, "FreeStyleProjectMustBeSupported");
+        MatrixProject matrix = new MatrixProject(null,"MatrixJobsMustBeSupported");
+        assertFalse(pipPost.isSupported(multiJobProject.getClass()));
+        assertTrue(pipPost.isSupported(freeStyleProject.getClass()));
+        assertTrue(pipPost.isSupported(matrix.getClass()));
+    }
+}

src/test/java/org/jenkinsci/plugins/pretestedintegration/integration/scm/git/GeneralBehaviourIT.java

@@ -5,29 +5,24 @@
 import hudson.model.FreeStyleProject;
 import hudson.model.Result;
 import hudson.plugins.git.BranchSpec;
+import hudson.plugins.git.GitSCM;
+import hudson.plugins.git.SubmoduleConfig;
+import hudson.plugins.git.UserRemoteConfig;
 import hudson.plugins.git.extensions.GitSCMExtension;
 import hudson.plugins.git.extensions.impl.CleanCheckout;
 import hudson.plugins.git.extensions.impl.PruneStaleBranch;
 import hudson.plugins.git.extensions.impl.RelativeTargetDirectory;
-import hudson.plugins.git.GitSCM;
-import hudson.plugins.git.SubmoduleConfig;
-import hudson.plugins.git.UserRemoteConfig;
-
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.Iterator;
-import java.util.List;
-
-import static junit.framework.Assert.assertTrue;
-import static junit.framework.TestCase.assertEquals;
-
 import org.eclipse.jgit.lib.Repository;
 import org.junit.Rule;
 import org.junit.Test;
 import org.jvnet.hudson.test.Bug;
 import org.jvnet.hudson.test.JenkinsRule;
 
+import java.util.*;
+
+import static junit.framework.Assert.assertTrue;
+import static junit.framework.TestCase.assertEquals;
+
 public class GeneralBehaviourIT {
 
     @Rule
@@ -392,4 +387,5 @@ public void validateSquashCommitMessageContents() throws Exception {
         }
 
     }
+
 }