Issue jenkinsci#224 - Load lib classes before lib vars

FILL IN THE BLANKS. This is a preliminary commit just to ship WIP from
the abandoned `support-lazy-lib-class-load` branch.

src/main/groovy/com/lesfurets/jenkins/unit/global/lib/LibraryLoader.groovy

@@ -95,6 +95,16 @@ class LibraryLoader {
                 groovyClassLoader.addURL(varsPath.toUri().toURL())
                 groovyClassLoader.addURL(resourcesPath.toUri().toURL())
 
+                //FIXME here! hail Mary attempt to avoid a feature flag
+                // pre-load library classes using JPU groovy class loader
+                if (srcPath.toFile().exists()) {
+                    srcPath.toFile().eachFileRecurse (FILES) { File srcFile ->
+                        if (srcFile.name.endsWith(".groovy")) {
+                            Class clazz = groovyClassLoader.parseClass(srcFile)
+                            groovyClassLoader.loadClass(clazz.name)
+                        }
+                    }
+                }
                 if (varsPath.toFile().exists()) {
                     def ds = Files.list(varsPath)
                     ds.map { it.toFile() }
@@ -110,15 +120,6 @@ class LibraryLoader {
                     // prevent fd leak on the DirectoryStream from Files.list()
                     ds.close()
                 }
-                // pre-load library classes using JPU groovy class loader
-                if (srcPath.toFile().exists()) {
-                    srcPath.toFile().eachFileRecurse (FILES) { File srcFile ->
-                        if (srcFile.name.endsWith(".groovy")) {
-                            Class clazz = groovyClassLoader.parseClass(srcFile)
-                            groovyClassLoader.loadClass(clazz.name)
-                        }
-                    }
-                }
             }
             record.definedGlobalVars = globalVars
         } catch (Exception e) {

src/test/groovy/com/lesfurets/jenkins/TestInterceptingGCL.groovy

@@ -378,5 +378,35 @@ class TestInterceptingGCL extends BasePipelineTest {
         assertCallStack().contains("""test_annotation.sh(echo 'ClassB: I'm field of B')""")
     }
 
+    /**
+    * 1. Load library by annotation, with implicity, load lib classes lazily
+    * 2. Create instance of library class
+    * 3. Call a vars step that accepts that type as an argument, passing that instance
+    * 4. Make sure interception of pipeline methods works propertly
+    */
+    @Test
+    void test_cross_class_as_var_arg_implicit_annotation_lazy_load() throws Exception {
+        //This does not factor in the current test but does replicate the use 
+        //case in which the lazy load feature originated.
+        helper.cloneArgsOnMethodCallRegistration = false
+
+        //In contrast to the previous flag, this is exactly what we are tesing.
+        //FIXME here! restore if we really go this route
+        //helper.preloadLibraryClasses = false
+
+        final library = library().name("test_cross_class_usage")
+                        .defaultVersion("master")
+                        .allowOverride(false)
+                        .implicit(true)
+                        .targetPath(sharedLibCls)
+                        .retriever(projectSource(sharedLibCls))
+                        .build()
+        helper.registerSharedLibrary(library)
 
+        final pipeline = "test_var_with_lib_class_arg_annotation_lazy_load"
+        runScript("job/library/cross_class_pre_loaded/${pipeline}.jenkins")
+        printCallStack()
+        assertCallStack().contains("""${pipeline}.monster1(org.test.Monster1""")
+        assertCallStack().contains("""monster1.echo(Dracula makes quite a scary monster)""")
+    }
 }

src/test/jenkins/job/library/cross_class_pre_loaded/test_var_with_lib_class_arg_annotation_lazy_load.jenkins

@@ -0,0 +1,6 @@
+//Commenting the annotation appears to make no difference when load is implicit
+@Library("test_cross_class_usage")
+import org.test.Monster1
+
+vampire = new Monster1("Dracula")
+monster1(vampire)

src/test/resources/libs/test_cross_class_usage/src/org/test/Monster1.groovy

@@ -0,0 +1,9 @@
+package org.test
+
+class Monster1 {
+    String moniker
+
+    Monster1(String m) {
+      moniker = m
+    }
+}

src/test/resources/libs/test_cross_class_usage/vars/monster1.groovy

@@ -0,0 +1,5 @@
+import org.test.Monster1
+
+void call(Monster1 m1) {
+    echo "$m1.moniker makes quite a scary monster"
+}