Bug 574227 - [test] fixed testSourceGenAfterDirChange

The creation of apt directories is not atomic and is done in two
threads in parallel. A race which thread won.

During some tests the builder thread was even so much delayed that the
folders have not been created at all.

Change-Id: I9b4e77ebf48b131ffd6c7559e7361f0e732ad8c5
Reviewed-on: https://git.eclipse.org/r/c/jdt/eclipse.jdt.core/+/182042
Tested-by: JDT Bot <jdt-bot@eclipse.org>
Reviewed-by: Andrey Loskutov <loskutov@gmx.de>

org.eclipse.jdt.apt.core/src/org/eclipse/jdt/apt/core/internal/generatedfile/GeneratedSourceFolderManager.java

@@ -85,10 +85,15 @@ public class GeneratedSourceFolderManager {
 	 * on when we get notified of relevant changes and on what locks we are
 	 * able to obtain.
 	 */
-	private IFolder _generatedSourceFolder = null;
+	private volatile IFolder _generatedSourceFolder;
 
 	private final boolean _isTestCode;
-
+
+	/**
+	 * Reflects whether apt is enabled as soon as it is enabled.
+	 * Only write access this in the thread which receives preferenceChanged:
+	 */
+	private volatile boolean _aptEnabled;
 
 	/**
 	 * Should be constructed only by AptProject.  Other clients should call
@@ -103,7 +108,8 @@ public GeneratedSourceFolderManager(AptProject aptProject, boolean isTestCode)
 		// Set _generatedSourceFolder only if APT is enabled, the folder exists,
 		// and the folder is on the classpath.
 		// Otherwise leave it null, which will cause us to try to fix things later on.
-		if (AptConfig.isEnabled(javaProject)) {
+		_aptEnabled = AptConfig.isEnabled(javaProject);
+		if (_aptEnabled) {
 			final IFolder folder = getFolder();
 			if (folder.exists()) {
 				if (isOnClasspath(folder)) {
@@ -200,7 +206,7 @@ public void ensureFolderExists(IFolder srcFolder) {
 	 */
 	public void ensureFolderExists(){
 		// If APT is disabled, do nothing.
-		if (!AptConfig.isEnabled(_aptProject.getJavaProject())) {
+		if (!_aptEnabled) {
 			return;
 		}
 
@@ -259,13 +265,18 @@ public void enabledPreferenceChanged()
 	{
 		final boolean enable = AptConfig.isEnabled(_aptProject.getJavaProject());
 		// Short-circuit if nothing changed.
-		if (enable == (_generatedSourceFolder != null)) {
+		if (enable == _aptEnabled) {
 			if( AptPlugin.DEBUG ) {
 				AptPlugin.trace("enabledChanged() doing nothing; state is already " + enable); //$NON-NLS-1$
 			}
 			// no change in state
 			return;
 		}
+		enabledPreferenceChangedTo(enable);
+	}
+
+	private void enabledPreferenceChangedTo(final boolean enable) {
+		_aptEnabled = enable;
 
 		if ( AptPlugin.DEBUG ) {
 			AptPlugin.trace("enabledChanged() changing state to " + enable +  //$NON-NLS-1$
@@ -290,8 +301,7 @@ public void enabledPreferenceChanged()
 	public void folderNamePreferenceChanged()
 	{
 		// if APT is disabled, we don't need to do anything
-		final boolean aptEnabled = AptConfig.isEnabled(_aptProject.getJavaProject());
-		if (!aptEnabled) {
+		if (!_aptEnabled) {
 			return;
 		}
 

org.eclipse.jdt.apt.core/src/org/eclipse/jdt/apt/core/util/AptConfig.java

@@ -768,6 +768,11 @@ public static void setEnabled(IJavaProject jproject, boolean enabled) {
 				enabled ? AptPreferenceConstants.ENABLED : AptPreferenceConstants.DISABLED);
 		// backward compatibility: also save old setting
 		setBoolean(jproject, AptPreferenceConstants.APT_ENABLED, enabled);
+		if (enabled) {
+			AptProject aptProject = AptPlugin.getAptProject(jproject);
+			aptProject.getGeneratedSourceFolderManager(true).ensureFolderExists();
+			aptProject.getGeneratedSourceFolderManager(false).ensureFolderExists();
+		}
 	}
 
 	/**

org.eclipse.jdt.apt.tests/src/org/eclipse/jdt/apt/tests/APITests.java

@@ -168,7 +168,7 @@ public void testMessagerAPI() throws Exception {
 		_logListener.clear();
 		fullBuild( project.getFullPath() );
 		expectingNoProblems();
-		assertTrue(_logListener.getList().isEmpty());
+		assertTrue(_logListener.getList().toString(), _logListener.getList().isEmpty());
 	}
 
 	/**

org.eclipse.jdt.apt.tests/src/org/eclipse/jdt/apt/tests/MirrorUtilTests.java

@@ -82,6 +82,7 @@ private void assertNoUnexpectedProblems() {
 
 	public void testMirrorUtils() throws Exception
 	{
-		assertEquals(ProcessorTestStatus.NO_ERRORS, ProcessorTestStatus.getErrors());
+		assertEquals("Unexpected errors: " + ProcessorTestStatus.getErrors(), ProcessorTestStatus.NO_ERRORS,
+				ProcessorTestStatus.getErrors());
 	}
 }

org.eclipse.jdt.apt.tests/src/org/eclipse/jdt/apt/tests/PreferencesTests.java

@@ -362,7 +362,7 @@ public void testConfigGenSrcDir() throws Exception {
 		testFolderName = testSrcFolder.getProjectRelativePath().toOSString();
 		// test 12: make sure we deleted the source folder when we disable apt
 		assertEquals(false, srcFolder.exists());
-		assertEquals(false, testSrcFolder.exists());
+		assertEquals("testSrcFolder '"+testSrcFolder+"' does still exist",false, testSrcFolder.exists());
 		// test 13: make sure we didn't overwrite the configure folder name
 		assertEquals(newName, folderName);
 		assertEquals(newTestName, testFolderName);