Bug 538461 : let MavenBuilder use a null scheduling rule

Added an experimental and semi-hidden  preference to make
the Maven builders scheduling rule null.
The preference will be visible when Eclipse is started with
the -Dm2e.showExperimentalFeatures=true flag (in eclipse.ini)

Change-Id: Ieb231142368927ed9d138afa400f1ad1cec175a1
Signed-off-by: Mickael Istria <mistria@redhat.com>

4 files changed, 16 insertions, 0 deletions

diff --git a/org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/M2EUIPluginActivator.java b/org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/M2EUIPluginActivator.java
index d1e5d1de..4cb6d17a 100644
--- a/org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/M2EUIPluginActivator.java
+++ b/org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/M2EUIPluginActivator.java
@@ -70,6 +70,8 @@ public class M2EUIPluginActivator extends AbstractUIPlugin {
 
   private MavenUpdateConfigurationChangeListener mavenUpdateConfigurationChangeListener;
 
+  public static final String PROP_SHOW_EXPERIMENTAL_FEATURES = "m2e.showExperimentalFeatures";
+
   @Override
   public void start(BundleContext context) throws Exception {
     super.start(context);
@@ -156,4 +158,8 @@ public class M2EUIPluginActivator extends AbstractUIPlugin {
     }
     return null;
   }
+
+  public static boolean showExperimentalFeatures() {
+    return Boolean.parseBoolean(System.getProperty(PROP_SHOW_EXPERIMENTAL_FEATURES));
+  }
 }
diff --git a/org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/Messages.java b/org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/Messages.java
index 1ba1ddbc..75178afe 100644
--- a/org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/Messages.java
+++ b/org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/Messages.java
@@ -721,6 +721,8 @@ public class Messages extends NLS {
 
   public static String preferencesDownloadJavadoc;
 
+  public static String preferencesNullSchedulingRule;
+
   public static String artifactComponentArtifact;
 
   public static String artifactComponentGroupId;
diff --git a/org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/messages.properties b/org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/messages.properties
index 9811f250..9f2383c2 100644
--- a/org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/messages.properties
+++ b/org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/messages.properties
@@ -419,6 +419,7 @@ preferencesGlobalChecksumPolicy_ignore=Ignore
 preferencesGlobalChecksumPolicy_warn=Warn
 preferencesGlobalChecksumPolicy_fail=Fail
 preferencesReindexButton=Re&index
+preferencesNullSchedulingRule=Minimize lock during build. This is highly experimental and may corrupt build results\nand/or your local Maven repository.\nPlease report any issues to http://bugs.eclipse.org/538461.
 projectSelectionDialogTitle=Select a Maven project
 resolverConfigurationAdvanced=Ad&vanced
 resolverConfigurationProfiles=&Profiles\:
@@ -488,3 +489,4 @@ wizardProjectPageProjectTitle=New Maven project
 wizardProjectPageProjectValidatorInvalidLocation=Invalid project location path
 wizardProjectPageProjectValidatorProjectLocation=Enter a location for the project.
 wizardProjectTitle=New Maven Project
+
diff --git a/org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/preferences/MavenPreferencePage.java b/org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/preferences/MavenPreferencePage.java
index 1aa6774f..56d60932 100644
--- a/org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/preferences/MavenPreferencePage.java
+++ b/org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/preferences/MavenPreferencePage.java
@@ -105,6 +105,12 @@ public class MavenPreferencePage extends FieldEditorPreferencePage implements IW
         Messages.preferencesGlobalChecksumPolicy_tooltip);
     addField(checksumPolicy);
 
+    if(M2EUIPluginActivator.showExperimentalFeatures()) {
+      BooleanFieldEditor nullSchedulingRule = new BooleanFieldEditor(
+          MavenPreferenceConstants.P_BUILDER_USE_NULL_SCHEDULING_RULE, Messages.preferencesNullSchedulingRule,
+          getFieldEditorParent());
+      addField(nullSchedulingRule);
+    }
   }
 
   @Override