[SLING-8312] Generics in OsgiContextBuilder allow compilation of code that cannot run

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: Testing OSGi Mock 2.4.6
• Component/s: Testing
• Assignee: Unassigned
• Reporter: Julian Sedding
• Created: 11/Mar/19 08:26
• Updated: 02/Apr/19 10:26

Description

While using the OsgiContextBuilder class, I noticed that e.g. when adding a ContextPlugin, my IDE's code completion created callback methods with an OsgiContextImpl argument. Since I want to initialize an OsgiContext that struck me as odd.

Suspecting that the generics are not quite right/ideal, I experimented a bit more and noticed that I can write and compile the following code, which leads to a runtime exception (note the SlingContext argument):

@Rule
public OsgiContext context = new OsgiContextBuilder()
    .plugin(new AbstractContextPlugin<SlingContext>() {
        @Override
        public void beforeSetUp(@NotNull SlingContext context) throws Exception {
            // ... initialize context for test ...
        }
    })
    .build();

The exception is:

java.lang.RuntimeException: Before setup failed (com.foo.OsgiTest$1@5b464ce8): org.apache.sling.testing.mock.sling.junit.SlingContext cannot be cast to org.apache.sling.testing.mock.osgi.junit.OsgiContext
	at org.apache.sling.testing.mock.osgi.context.ContextPlugins.executeBeforeSetUpCallback(ContextPlugins.java:201)
	at org.apache.sling.testing.mock.sling.junit.SlingContext$1.before(SlingContext.java:145)
	at org.junit.rules.ExternalResource$1.evaluate(ExternalResource.java:46)
	at org.junit.rules.RunRules.evaluate(RunRules.java:20)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:369)
	at org.apache.maven.surefire.junit4.JUnit4Provider.executeWithRerun(JUnit4Provider.java:275)
	at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:239)
	at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:160)
	at org.apache.maven.surefire.booter.ForkedBooter.invokeProviderInSameClassLoader(ForkedBooter.java:373)
	at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:334)
	at org.apache.maven.surefire.booter.ForkedBooter.execute(ForkedBooter.java:119)
	at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:407)
Caused by: java.lang.ClassCastException: org.apache.sling.testing.mock.sling.junit.SlingContext cannot be cast to org.apache.sling.testing.mock.osgi.junit.OsgiContext
	at com.foo.OsgiTest$1.beforeSetUp(ResourceCopierTest.java:18)
	at org.apache.sling.testing.mock.osgi.context.ContextPlugins.executeBeforeSetUpCallback(ContextPlugins.java:198)
	... 20 more

IMHO it would make sense to address this in a way that

• the IDE suggests the "correct" *Context class (i.e. OsgiContext for OsgiContextBuilder, SlingContext for SlingContextBuilder
• a SlingContextBuilder can consume plugins written for an OsgiContext (not currently possible because SlingContext extends OsgiContextImpl (and not OsgiContext
• only runnable code can be compiled

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