[FIXED JENKINS-9971] Fix NPE when validating remote for publish.

Add new validation to GitPublisher that checks the remote name
is a valid repository name.

Also update validatation in GitSCM to response null repo name
and url parameter values.

Author: kevinsawicki

src/main/java/hudson/plugins/git/GitPublisher.java

@@ -28,12 +28,15 @@
 import java.util.ArrayList;
 import java.util.List;
 
+import javax.servlet.ServletException;
+
 
 import org.apache.commons.lang.StringUtils;
 
 import org.kohsuke.stapler.AncestorInPath;
 import org.kohsuke.stapler.QueryParameter;
 import org.kohsuke.stapler.DataBoundConstructor;
+import org.kohsuke.stapler.StaplerRequest;
 
 import org.eclipse.jgit.transport.RemoteConfig;
 
@@ -402,6 +405,31 @@ public FormValidation doCheckTagName(@QueryParameter String value) {
         public FormValidation doCheckBranchName(@QueryParameter String value) {
             return checkFieldNotEmpty(value, "Branch Name");
         }
+        
+        public FormValidation doCheckRemote(
+                @AncestorInPath AbstractProject project, StaplerRequest req)
+                throws IOException, ServletException {
+            String remote = req.getParameter("value");
+            boolean isMerge = req.getParameter("isMerge") != null;
+
+            // Added isMerge because we don't want to allow empty remote names
+            // for tag/branch pushes.
+            if (remote.length() == 0 && isMerge)
+                return FormValidation.ok();
+
+            FormValidation validation = checkFieldNotEmpty(remote,
+                    "Remote Name");
+            if (validation.kind != FormValidation.Kind.OK)
+                return validation;
+
+            GitSCM scm = (GitSCM) project.getScm();
+            if (scm.getRepositoryByName(remote) == null)
+                return FormValidation
+                        .error("No remote repository configured with name '"
+                                + remote + "'");
+
+            return FormValidation.ok();
+        }
 
         public boolean isApplicable(Class<? extends AbstractProject> jobType) {
             return true;

src/main/java/hudson/plugins/git/GitSCM.java

@@ -1528,14 +1528,10 @@ public FormValidation doGitRemoteNameCheck(StaplerRequest req, StaplerResponse r
 
             String[] urls = req.getParameterValues("repo.url");
             String[] names = req.getParameterValues("repo.name");
-
-            names = GitUtils.fixupNames(names, urls);
-
-            for (String name : names) {
-                if (name.equals(mergeRemoteName)) {
-                    return FormValidation.ok();
-                }
-            }
+            if (urls != null && names != null)
+                for (String name : GitUtils.fixupNames(names, urls))
+                    if (name.equals(mergeRemoteName))
+                        return FormValidation.ok();
 
             return FormValidation.error("No remote repository configured with name '" + mergeRemoteName + "'");
         }

src/main/resources/hudson/plugins/git/GitPublisher/config.jelly

@@ -41,9 +41,7 @@
           <f:entry field="targetRepoName"
                    title="${%Target remote name}">
             <f:textbox
-                checkUrl="'${rootURL}/scm/GitSCM/gitRemoteNameCheck?value='+escape(this.value)
-                          +encodeAllInputs('&amp;', this.form, 'git.repo.name')
-                          +encodeAllInputs('&amp;', this.form, 'git.repo.url')"/>
+                checkUrl="'descriptorByName/GitPublisher/checkRemote?value='+escape(this.value)"/>
           </f:entry>
         </table>
         <div align="right">
@@ -65,9 +63,7 @@
           <f:entry field="targetRepoName"
                    title="${%Target remote name}">
             <f:textbox
-                checkUrl="'${rootURL}/scm/GitSCM/gitRemoteNameCheck?value='+escape(this.value)
-                          +encodeAllInputs('&amp;', this.form, 'git.repo.name')
-                          +encodeAllInputs('&amp;', this.form, 'git.repo.url')"/>
+                checkUrl="'descriptorByName/GitPublisher/checkRemote?value='+escape(this.value)" />
           </f:entry>
         </table>
         <div align="right">