Merge pull request diffblue#284 from diffblue/marek/bugfix/do_not_generate_empty_jar

SEC-142: Bugfix: prevent generation of empty JAR (when no class files are found).

Author: marek-trtik

driver/mkbench.py

@@ -146,18 +146,19 @@ def collect_java_binaries(app_binary_dirs, temp_dir, output_json, verbosity):
         classes_temp_dir = os.path.join(temp_dir, "CLASSES")
         assert not os.path.exists(classes_temp_dir)
         os.makedirs(classes_temp_dir)
-        for class_src_pathname, class_file_info in classes_info["results"].items():
-            class_dst_pathname = os.path.join(classes_temp_dir, class_file_info["name"].replace(".", "/") + ".class")
-            if not os.path.isdir(os.path.dirname(class_dst_pathname)):
-                os.makedirs(os.path.dirname(class_dst_pathname))
-            if os.path.isfile(class_dst_pathname) and not filecmp.cmp(class_src_pathname, class_dst_pathname):
-                print("WARNING: Detected multiple versions of the Java class file '" +
-                      class_src_pathname + "'. Picking one arbitrarily!")
-            shutil.copyfile(class_src_pathname, class_dst_pathname)
-        classes_jar_file = os.path.join(temp_dir, "collected_classes.jar")
-        with utility.PushCwd(classes_temp_dir):
-            os.system("jar cf \"" + classes_jar_file + "\" .")
-        java_binaries.jar_files.append(classes_jar_file)
+        if len(classes_info["results"]) != 0:
+            for class_src_pathname, class_file_info in classes_info["results"].items():
+                class_dst_pathname = os.path.join(classes_temp_dir, class_file_info["name"].replace(".", "/") + ".class")
+                if not os.path.isdir(os.path.dirname(class_dst_pathname)):
+                    os.makedirs(os.path.dirname(class_dst_pathname))
+                if os.path.isfile(class_dst_pathname) and not filecmp.cmp(class_src_pathname, class_dst_pathname):
+                    print("WARNING: Detected multiple versions of the Java class file '" +
+                          class_src_pathname + "'. Picking one arbitrarily!")
+                shutil.copyfile(class_src_pathname, class_dst_pathname)
+            classes_jar_file = os.path.join(temp_dir, "collected_classes.jar")
+            with utility.PushCwd(classes_temp_dir):
+                os.system("jar cf \"" + classes_jar_file + "\" .")
+            java_binaries.jar_files.append(classes_jar_file)
 
     # We write the lists of collected Java binaries into the output JSON file.
     if not os.path.isdir(os.path.dirname(output_json)):