Bug 539698 - JavaSearchNameEnvironment disable module operation in <1.9

This change disables parts of
JavaSearchNameEnvironment.mapToClassPathLocation(), if the respective
project has compliance level of Java 1.8 or lower.

This is done to reduce impact of Java 1.9 module related changes for
Java 1.8 users, such as potential bugs and performance drops.

Change-Id: Ie2c68497b52da77c391d6da995f519e9cff5cd5a
Signed-off-by: Simeon Andreev <simeon.danailov.andreev@gmail.com>

1 files changed, 15 insertions, 2 deletions

diff --git a/org.eclipse.jdt.core/search/org/eclipse/jdt/internal/core/search/matching/JavaSearchNameEnvironment.java b/org.eclipse.jdt.core/search/org/eclipse/jdt/internal/core/search/matching/JavaSearchNameEnvironment.java
index 4aae053a23..a61e40abd2 100644
--- a/org.eclipse.jdt.core/search/org/eclipse/jdt/internal/core/search/matching/JavaSearchNameEnvironment.java
+++ b/org.eclipse.jdt.core/search/org/eclipse/jdt/internal/core/search/matching/JavaSearchNameEnvironment.java
@@ -70,7 +70,7 @@ public class JavaSearchNameEnvironment implements IModuleAwareNameEnvironment, S
 	Map<String, org.eclipse.jdt.core.ICompilationUnit> workingCopies;
 
 public JavaSearchNameEnvironment(IJavaProject javaProject, org.eclipse.jdt.core.ICompilationUnit[] copies) {
-	if (CompilerOptions.versionToJdkLevel(javaProject.getOption(JavaCore.COMPILER_COMPLIANCE, true)) >= ClassFileConstants.JDK9) {
+	if (isComplianceJava9OrHigher(javaProject)) {
 		this.moduleLocations = new HashMap<>();
 		this.moduleToClassPathLocations = new HashMap<>();
 	}
@@ -185,6 +185,13 @@ private ClasspathLocation mapToClassPathLocation(JavaModelManager manager, Packa
 		// problem opening zip file or getting root kind
 		// consider root corrupt and ignore
 	}
+	if (isComplianceJava9OrHigher(root.getJavaProject())) {
+		addModuleClassPathInfo(root, defaultModule, cp);
+	}
+	return cp;
+}
+
+private void addModuleClassPathInfo(PackageFragmentRoot root, IModuleDescription defaultModule, ClasspathLocation cp) {
 	IModuleDescription imd = root.getModuleDescription();
 	if (imd != null) {
 		String moduleName = addModuleClassPathInfo(cp, imd);
@@ -195,7 +202,6 @@ private ClasspathLocation mapToClassPathLocation(JavaModelManager manager, Packa
 	} else if (defaultModule != null) {
 		addModuleClassPathInfo(cp, defaultModule);
 	}
-	return cp;
 }
 private String addModuleClassPathInfo(ClasspathLocation cp, IModuleDescription imd) {
 	IModule mod = NameLookup.getModuleDescriptionInfo(imd);
@@ -396,4 +402,11 @@ public char[][] getAllAutomaticModules() {
 			.map(m -> m.name()).collect(Collectors.toSet());
 	return set.toArray(new char[set.size()][]);
 }
+
+private static boolean isComplianceJava9OrHigher(IJavaProject javaProject) {
+	if (javaProject == null) {
+		return false;
+	}
+	return CompilerOptions.versionToJdkLevel(javaProject.getOption(JavaCore.COMPILER_COMPLIANCE, true)) >= ClassFileConstants.JDK9;
+}
 }