Ensure Null Safety in GitLabConnectionProperty.java

src/main/java/com/dabsquared/gitlabjenkins/connection/GitLabConnectionProperty.java

@@ -15,6 +15,7 @@
 import hudson.security.ACL;
 import hudson.util.FormValidation;
 import hudson.util.ListBoxModel;
+import java.util.Objects;
 import javax.ws.rs.ProcessingException;
 import javax.ws.rs.WebApplicationException;
 import jenkins.model.Jenkins;
@@ -109,57 +110,73 @@
 
         @Override
         public JobProperty<?> newInstance(StaplerRequest req, JSONObject formData) throws FormException {
-            return req.bindJSON(GitLabConnectionProperty.class, formData);
+            if (req != null) {
+                return req.bindJSON(GitLabConnectionProperty.class, formData);
+            } else {
+                throw new IllegalArgumentException("StaplerRequest 'req' cannot be null.");
+            }
         }
 
         public ListBoxModel doFillGitLabConnectionItems() {
             ListBoxModel options = new ListBoxModel();
-            GitLabConnectionConfig descriptor =
-                    (GitLabConnectionConfig) Jenkins.getInstance().getDescriptor(GitLabConnectionConfig.class);
-            for (GitLabConnection connection : descriptor.getConnections()) {
-                options.add(connection.getName(), connection.getName());
+            GitLabConnectionConfig descriptor = (GitLabConnectionConfig)
+                    Objects.requireNonNull(Jenkins.getInstance()).getDescriptor(GitLabConnectionConfig.class);
+
+            if (descriptor != null) {
+                for (GitLabConnection connection : descriptor.getConnections()) {
+                    options.add(connection.getName(), connection.getName());
+                }
+            } else {
+                throw new IllegalStateException("GitLabConnectionConfig descriptor cannot be null.");
             }
+
             return options;
         }
 
         public ListBoxModel doFillJobCredentialIdItems(
                 @AncestorInPath Item item, @QueryParameter String url, @QueryParameter String jobCredentialId) {
             StandardListBoxModel result = new StandardListBoxModel();
             if (item == null) {
                 if (!Jenkins.get().hasPermission(Jenkins.ADMINISTER)) {
                     return result.includeCurrentValue(jobCredentialId);
                 }
             } else {
                 if (!item.hasPermission(Item.EXTENDED_READ) && !item.hasPermission(CredentialsProvider.USE_ITEM)) {
                     return result.includeCurrentValue(jobCredentialId);
                 }
             }
             return result.includeEmptyValue()
                     .includeMatchingAs(
                             ACL.SYSTEM,
                             item,
                             StandardCredentials.class,
                             URIRequirementBuilder.fromUri(url).build(),
                             new GitLabCredentialMatcher())
                     .includeCurrentValue(jobCredentialId);
         }
 
         @RequirePOST
         @Restricted(DoNotUse.class)
         public FormValidation doTestConnection(
                 @QueryParameter String jobCredentialId,
                 @QueryParameter String gitLabConnection,
                 @AncestorInPath Item item) {
             item.checkPermission(Item.CONFIGURE);
             try {
                 GitLabConnection gitLabConnectionTested = null;
-                GitLabConnectionConfig descriptor =
-                        (GitLabConnectionConfig) Jenkins.getInstance().getDescriptor(GitLabConnectionConfig.class);
-                for (GitLabConnection connection : descriptor.getConnections()) {
-                    if (gitLabConnection.equals(connection.getName())) {
-                        gitLabConnectionTested = connection;
+                GitLabConnectionConfig descriptor = (GitLabConnectionConfig)
+                        Objects.requireNonNull(Jenkins.getInstance()).getDescriptor(GitLabConnectionConfig.class);
+
+                if (descriptor != null) {
+                    for (GitLabConnection connection : descriptor.getConnections()) {
+                        if (gitLabConnection.equals(connection.getName())) {
+                            gitLabConnectionTested = connection;
+                        }
                     }
+                } else {
+                    throw new IllegalStateException("GitLabConnectionConfig descriptor cannot be null.");
                 }
+
                 if (gitLabConnectionTested == null) {
                     return FormValidation.error(Messages.connection_error("The GitLab Connection does not exist"));
                 }