Bug 309126: Build before launch does too much building with project references

3 files changed, 454 insertions, 96 deletions

diff --git a/launch/org.eclipse.cdt.launch/src/org/eclipse/cdt/launch/AbstractCLaunchDelegate2.java b/launch/org.eclipse.cdt.launch/src/org/eclipse/cdt/launch/AbstractCLaunchDelegate2.java
index ced7b2e3cfc..7c674773b13 100644
--- a/launch/org.eclipse.cdt.launch/src/org/eclipse/cdt/launch/AbstractCLaunchDelegate2.java
+++ b/launch/org.eclipse.cdt.launch/src/org/eclipse/cdt/launch/AbstractCLaunchDelegate2.java
@@ -11,30 +11,44 @@
 package org.eclipse.cdt.launch;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
 import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
 
+import org.eclipse.cdt.core.CCorePlugin;
 import org.eclipse.cdt.core.model.ICModelMarker;
 import org.eclipse.cdt.core.model.ICProject;
 import org.eclipse.cdt.core.settings.model.ICConfigurationDescription;
 import org.eclipse.cdt.core.settings.model.ICProjectDescription;
 import org.eclipse.cdt.debug.core.CDebugUtils;
 import org.eclipse.cdt.debug.core.ICDTLaunchConfigurationConstants;
+import org.eclipse.cdt.launch.internal.ui.BuildErrPrompter;
 import org.eclipse.cdt.launch.internal.ui.LaunchMessages;
-import org.eclipse.cdt.ui.newui.CDTPropertyManager;
+import org.eclipse.cdt.launch.internal.ui.LaunchUIPlugin;
+import org.eclipse.core.resources.ICommand;
 import org.eclipse.core.resources.IMarker;
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.resources.IResource;
+import org.eclipse.core.resources.IWorkspaceRunnable;
 import org.eclipse.core.resources.IncrementalProjectBuilder;
 import org.eclipse.core.resources.ResourcesPlugin;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.MultiStatus;
+import org.eclipse.core.runtime.OperationCanceledException;
 import org.eclipse.core.runtime.Status;
-import org.eclipse.core.runtime.SubProgressMonitor;
+import org.eclipse.core.runtime.SubMonitor;
+import org.eclipse.debug.core.DebugPlugin;
 import org.eclipse.debug.core.ILaunch;
 import org.eclipse.debug.core.ILaunchConfiguration;
+import org.eclipse.debug.core.IStatusHandler;
 import org.eclipse.debug.core.model.LaunchConfigurationDelegate;
+import org.eclipse.debug.internal.core.DebugCoreMessages;
+import org.eclipse.debug.internal.core.IInternalDebugCoreConstants;
 
 /**
  * AbstractCLaunchDelegate2 is used by most DSF based debuggers. It replaces AbstractCLaunchDelegate
@@ -53,8 +67,6 @@ public abstract class AbstractCLaunchDelegate2 extends LaunchConfigurationDelega
 
 	private boolean workspaceBuildBeforeLaunch;
 	private boolean requireCProject;
-	private IProject project;
-	private String preLaunchBuildConfiguration;
 
 	public AbstractCLaunchDelegate2() {
 		super();
@@ -89,10 +101,16 @@ public abstract class AbstractCLaunchDelegate2 extends LaunchConfigurationDelega
 		}
 		return referencedProjSet;
 	}
-	
+
 	/**
-	 * Returns the order list of projects to build before launching.
-	 *  Used in buildForLaunch() 
+	 * Even though we override the base behavior and only build the single
+	 * project referenced in the launch configuration (and not any of the
+	 * projects it references), we still want to implement this as the base will
+	 * also use the list to determine what files need be saved, and there it's
+	 * not much of a burden to include any referenced projects
+	 * 
+	 * @see org.eclipse.debug.core.model.LaunchConfigurationDelegate#getBuildOrder(org.eclipse.debug.core.ILaunchConfiguration,
+	 *      java.lang.String)
 	 */
 	@Override
 	protected IProject[] getBuildOrder(ILaunchConfiguration configuration, String mode) throws CoreException {
@@ -133,12 +151,6 @@ public abstract class AbstractCLaunchDelegate2 extends LaunchConfigurationDelega
 		return orderedProjects;
 	}
 
-	/* Used in finalLaunchCheck() */
-	@Override
-	protected IProject[] getProjectsForProblemSearch(ILaunchConfiguration configuration, String mode) throws CoreException {
-		return getBuildOrder(configuration, mode);
-	}
-
 	/**
 	 * Searches for compile errors in the specified project
 	 * Used in finalLaunchCheck() 
@@ -190,8 +202,7 @@ public abstract class AbstractCLaunchDelegate2 extends LaunchConfigurationDelega
 	}
 
 	/**
-	 * Builds the current project and all of it's prerequisite projects if
-	 * necessary. Respects specified build order if any exists.
+	 * Builds the project referenced in the launch configuration
 	 * 
 	 * @param configuration
 	 *            the configuration being launched
@@ -206,59 +217,295 @@ public abstract class AbstractCLaunchDelegate2 extends LaunchConfigurationDelega
 	 */
 	@Override
 	public boolean buildForLaunch(ILaunchConfiguration configuration, String mode, IProgressMonitor monitor) throws CoreException {
+		try {
+			SubMonitor submon = SubMonitor.convert(monitor, "", 1); //$NON-NLS-1$
 
-		workspaceBuildBeforeLaunch = true;
-		
-		// check the build before launch setting and honor it
-		int buildBeforeLaunchValue = configuration.getAttribute(ICDTLaunchConfigurationConstants.ATTR_BUILD_BEFORE_LAUNCH,
-				ICDTLaunchConfigurationConstants.BUILD_BEFORE_LAUNCH_USE_WORKSPACE_SETTING);
+			workspaceBuildBeforeLaunch = true;
 
-		// we shouldn't be getting called if the workspace setting is disabled, so assume we need to
-		// build unless the user explicitly disabled it in the main tab of the launch.
-		if (buildBeforeLaunchValue == ICDTLaunchConfigurationConstants.BUILD_BEFORE_LAUNCH_DISABLED) {
+			IProject project = null;
+			ICProject cProject = CDebugUtils.getCProject(configuration);
+			if (cProject != null) {
+				project = cProject.getProject();
+			}
+			
+			if (project == null) {
+				return false;
+			}
+			
+			// check the build before launch setting and honor it
+			int buildBeforeLaunchValue = configuration.getAttribute(ICDTLaunchConfigurationConstants.ATTR_BUILD_BEFORE_LAUNCH,
+					ICDTLaunchConfigurationConstants.BUILD_BEFORE_LAUNCH_USE_WORKSPACE_SETTING);
+	
+			// we shouldn't be getting called if the workspace setting is disabled, so assume we need to
+			// build unless the user explicitly disabled it in the main tab of the launch.
+			if (buildBeforeLaunchValue == ICDTLaunchConfigurationConstants.BUILD_BEFORE_LAUNCH_DISABLED) {
+				return false;
+			}
+	
+			// The attribute value will be "" if 'Use Active' is selected
+			String buildConfigID = configuration.getAttribute(ICDTLaunchConfigurationConstants.ATTR_PROJECT_BUILD_CONFIG_ID, ""); //$NON-NLS-1$
+			if (buildConfigID.length() == 0) {
+				buildConfigID = null;
+			}
+	
+			buildProject(project, buildConfigID, submon.newChild(1));
 			return false;
 		}
+		finally {
+			if (monitor != null) {
+				monitor.done();
+			}
+		}
+	}
 
-		setBuildConfiguration(configuration, project);
+	/**
+	 * This is an specialization of the platform method
+	 * LaunchConfigurationDelegate#buildProjects(IProject[], IProgressMonitor).
+	 * It builds only one project and it builds a particular CDT build
+	 * configuration of it. It was added to address bug 309126 and 312709 
+	 * 
+	 * @param project
+	 *            the project to build
+	 * @param buildConfigID
+	 *            the specific build configuration to build, or null to build
+	 *            the active one
+	 * @param monitor
+	 *            progress monitor
+	 * @throws CoreException
+	 */
+	protected void buildProject(final IProject project, final String buildConfigID, IProgressMonitor monitor) throws CoreException {
 
-		return super.buildForLaunch(configuration, mode, monitor);
+		// Some day, this will hopefully be a simple pass-thru to a cdt.core
+		// utility. See bug 313927
+		
+		IWorkspaceRunnable build = new IWorkspaceRunnable(){
+			public void run(IProgressMonitor pm) throws CoreException {
+				final int TOTAL_TICKS = 1000;
+				SubMonitor localmonitor = SubMonitor.convert(pm, "", TOTAL_TICKS); //$NON-NLS-1$
+
+				try {
+					// Number of times we'll end up calling IProject.build()
+					final int buildCount = (buildConfigID == null) ? 1 : project.getDescription().getBuildSpec().length;
+					final int subtaskTicks = TOTAL_TICKS / buildCount;
+					
+					if (buildConfigID != null) {
+						// Build a specific configuration
+						
+						// To pass args, we have to specify the builder name.
+						// There can be multiple so this can require multiple
+						// builds. Note that this happens under the covers in
+						// the 'else' (args-less) case below
+						Map<String,String> cfgIdArgs = AbstractCLaunchDelegate2.cfgIdsToMap(new String[] {buildConfigID}, new HashMap<String,String>());
+						cfgIdArgs.put(CONTENTS, CONTENTS_CONFIGURATION_IDS);						
+						ICommand[] commands = project.getDescription().getBuildSpec();
+						assert buildCount == commands.length;
+						for (ICommand command : commands) {
+							@SuppressWarnings("unchecked")
+							Map<String, String> args = command.getArguments();
+							if (args == null) {
+								args = new HashMap<String, String>(cfgIdArgs);
+							}
+							else {
+								args.putAll(cfgIdArgs);
+							}
+							
+							if (localmonitor.isCanceled()) {
+								throw new OperationCanceledException();
+							}
+							project.build(IncrementalProjectBuilder.INCREMENTAL_BUILD, command.getBuilderName(), args, localmonitor.newChild(subtaskTicks));
+						}
+					}
+					else {
+						// Build the active configuration
+						project.build(IncrementalProjectBuilder.INCREMENTAL_BUILD, localmonitor.newChild(subtaskTicks));
+					}
+				} finally {
+					if (pm != null) {
+						pm.done();
+					}
+				}
+			}
+		};
+		ResourcesPlugin.getWorkspace().run(build, monitor);
 	}
 
-	@Override
-	public boolean preLaunchCheck(ILaunchConfiguration configuration, String mode, IProgressMonitor monitor) throws CoreException {
-		ICProject cProject = CDebugUtils.getCProject(configuration);
-		if (cProject != null) {
-			project = cProject.getProject();
+	/** TODO: Temporarily duplicated from BuilderFactory. Remove when 313927 is addressed */
+	static final String CONFIGURATION_IDS = "org.eclipse.cdt.make.core.configurationIds"; //$NON-NLS-1$
+	
+	/** TODO: Temporarily duplicated from BuilderFactory. Remove when 313927 is addressed */
+	static final String CONTENTS = "org.eclipse.cdt.make.core.contents"; //$NON-NLS-1$
+	
+	/** TODO: Temporarily duplicated from BuilderFactory. Remove when 313927 is addressed */
+	static final String CONTENTS_CONFIGURATION_IDS = "org.eclipse.cdt.make.core.configurationIds"; //$NON-NLS-1$
+
+	/** TODO: Temporarily duplicated from BuilderFactory. Remove when 313927 is addressed */
+	private static Map<String, String> cfgIdsToMap(String ids[], Map<String, String> map){
+		map.put(CONFIGURATION_IDS, encodeList(Arrays.asList(ids)));
+		return map;
+	}
+
+	/** TODO: Temporarily duplicated from BuilderFactory. Remove when 313927 is addressed */
+	private static String encodeList(List<String> values) {
+		StringBuffer str = new StringBuffer();
+		Iterator<String> entries = values.iterator();
+		while (entries.hasNext()) {
+			String entry = entries.next();
+			str.append(escapeChars(entry, "|\\", '\\')); //$NON-NLS-1$
+			str.append("|"); //$NON-NLS-1$
+		}
+		return str.toString();
+	}
+
+	/** TODO: Temporarily duplicated from BuilderFactory. Remove when 313927 is addressed */
+	private static String escapeChars(String string, String escapeChars, char escapeChar) {
+		StringBuffer str = new StringBuffer(string);
+		for (int i = 0; i < str.length(); i++) {
+			if (escapeChars.indexOf(str.charAt(i)) != -1) {
+				str.insert(i, escapeChar);
+				i++;
+			}
 		}
-		return super.preLaunchCheck(configuration, mode, monitor);
+		return str.toString();
 	}
 
+
+	/**
+	 * The platform has a generic prompter object that redirects to an
+	 * appropriate prompter based on the status object. The value-add it
+	 * provides is that it can be invoked from a non-GUI thread.
+	 */
+	private static final IStatus uiPromptStatus = new Status(IStatus.ERROR, "org.eclipse.debug.ui", 200, IInternalDebugCoreConstants.EMPTY_STRING, null); //$NON-NLS-1$
+
+	/** Status object used to fish out our BuildErrPrompter */ 
+	private static final IStatus promptStatusMainProj = new Status(IStatus.ERROR, LaunchUIPlugin.getUniqueIdentifier(), BuildErrPrompter.STATUS_CODE_ERR_IN_MAIN_PROJ, IInternalDebugCoreConstants.EMPTY_STRING, null);
+	
+	/** Status object used to fish out our BuildErrPrompter */
+	private static final IStatus promptStatusReferencedProjs = new Status(IStatus.ERROR, LaunchUIPlugin.getUniqueIdentifier(), BuildErrPrompter.STATUS_CODE_ERR_IN_REFERENCED_PROJS, IInternalDebugCoreConstants.EMPTY_STRING, null);
+	
+	private Object[] createPrompterArgs(ILaunchConfiguration launchConfig) throws CoreException {
+		
+		IProject project = CDebugUtils.getCProject(launchConfig).getProject();
+		
+		Object[] args = new Object[3];
+		
+		// The launch configuration
+		args[0] = launchConfig;
+		
+		// The name of the project
+		args[1] = project.getName();
+		
+		// The name of the build configuration. Empty string if the
+		// setting is "Active" or the selected configuration is the
+		// active one, otherwise the name of the configuration.
+		args[2] = ""; //$NON-NLS-1$
+		String buildConfigId = launchConfig.getAttribute(ICDTLaunchConfigurationConstants.ATTR_PROJECT_BUILD_CONFIG_ID, ""); //$NON-NLS-1$
+		if (buildConfigId.length() > 0) {
+			ICProjectDescription desc = CCorePlugin.getDefault().getProjectDescription(project, false);
+			if (desc != null) {
+				ICConfigurationDescription cfgDescActive = desc.getActiveConfiguration();
+				ICConfigurationDescription cfgDesc = desc.getConfigurationById(buildConfigId);
+				if (cfgDesc != cfgDescActive) {
+					if (cfgDesc != null) {
+						args[2] = cfgDesc.getName();
+					}
+					else {
+						// TODO: not sure if and when this could ever happen, but just in case...
+						args[2] = "???";	 //$NON-NLS-1$
+					}
+				}
+			}
+		}
+		
+		return args;
+	}
+	
+	/* (non-Javadoc)
+	 * @see org.eclipse.debug.core.model.LaunchConfigurationDelegate#finalLaunchCheck(org.eclipse.debug.core.ILaunchConfiguration, java.lang.String, org.eclipse.core.runtime.IProgressMonitor)
+	 */
 	@Override
 	public boolean finalLaunchCheck(ILaunchConfiguration configuration, String mode, IProgressMonitor monitor) throws CoreException {
-		if (!workspaceBuildBeforeLaunch) {
-			// buildForLaunch was not called which means that the workspace pref is disabled.  see if the user enabled the
-			// launch specific setting in the main tab.  if so, we do call buildBeforeLaunch here.
-			if (ICDTLaunchConfigurationConstants.BUILD_BEFORE_LAUNCH_ENABLED == configuration.getAttribute(ICDTLaunchConfigurationConstants.ATTR_BUILD_BEFORE_LAUNCH,
-					ICDTLaunchConfigurationConstants.BUILD_BEFORE_LAUNCH_USE_WORKSPACE_SETTING)) {
-				
-				IProgressMonitor buildMonitor = new SubProgressMonitor(monitor, 10, SubProgressMonitor.PREPEND_MAIN_LABEL_TO_SUBTASK);
-				buildMonitor.beginTask(LaunchMessages.getString("AbstractCLaunchDelegate.BuildBeforeLaunch"), 10); //$NON-NLS-1$	
-				buildMonitor.subTask(LaunchMessages.getString("AbstractCLaunchDelegate.PerformingBuild")); //$NON-NLS-1$
-				if (buildForLaunch(configuration, mode, new SubProgressMonitor(buildMonitor, 7))) {
-					buildMonitor.subTask(LaunchMessages.getString("AbstractCLaunchDelegate.PerformingIncrementalBuild")); //$NON-NLS-1$
-					ResourcesPlugin.getWorkspace().build(IncrementalProjectBuilder.INCREMENTAL_BUILD, new SubProgressMonitor(buildMonitor, 3));				
+		try {
+			SubMonitor localMonitor = SubMonitor.convert(monitor, LaunchMessages.getString("AbstractCLaunchDelegate.BuildBeforeLaunch"), 10); //$NON-NLS-1$
+	
+			if (!workspaceBuildBeforeLaunch) {
+				// buildForLaunch was not called which means that the workspace pref is disabled.  see if the user enabled the
+				// launch specific setting in the main tab.  if so, we do call buildBeforeLaunch here.
+				if (ICDTLaunchConfigurationConstants.BUILD_BEFORE_LAUNCH_ENABLED == configuration.getAttribute(ICDTLaunchConfigurationConstants.ATTR_BUILD_BEFORE_LAUNCH,
+						ICDTLaunchConfigurationConstants.BUILD_BEFORE_LAUNCH_USE_WORKSPACE_SETTING)) {
+					
+					localMonitor.subTask(LaunchMessages.getString("AbstractCLaunchDelegate.PerformingBuild")); //$NON-NLS-1$
+					if (buildForLaunch(configuration, mode, localMonitor.newChild(7))) {
+						localMonitor.subTask(LaunchMessages.getString("AbstractCLaunchDelegate.PerformingIncrementalBuild")); //$NON-NLS-1$
+						ResourcesPlugin.getWorkspace().build(IncrementalProjectBuilder.INCREMENTAL_BUILD, localMonitor.newChild(3));				
+					}
+				}
+			}
+
+			// We can just call our super's implementation to have it check for
+			// build errors, but it is too generic. It doesn't know the concept
+			// of a CDT build configuration, and the fact that we requested the
+			// build of a particular one (which, btw, may not be the active one
+			// for the project). We want to put up a more informative error
+			// dialog if there are errors.
+			boolean continueLaunch = true;
+			ICProject cproject = CDebugUtils.getCProject(configuration);
+			if (cproject != null) {
+				IProject project = cproject.getProject();
+				localMonitor.subTask(DebugCoreMessages.LaunchConfigurationDelegate_6);
+				if (existsProblems(project)) {
+					// There's a build error in the main project
+					
+					// Put up the error dialog. 
+					IStatusHandler prompter = DebugPlugin.getDefault().getStatusHandler(uiPromptStatus);
+					if (prompter != null) {
+						continueLaunch = ((Boolean) prompter.handleStatus(promptStatusMainProj, createPrompterArgs(configuration))).booleanValue();
+					}
+					else {
+						assert false;					
+					}
 				}
 				else {
-					buildMonitor.worked(3); /* No incremental build required */
+					// No build error in the main project but see if there's one
+					// in any of its referenced projects
+					IProject[] projects = getBuildOrder(configuration, mode);
+					for (IProject proj : projects) {
+						// The array will contain the top level project.
+						// Ignore it since we handled it above
+						if (proj == project) {
+							continue;
+						}
+						
+						if (existsProblems(proj)) {
+							// Put up the error dialog. 
+							IStatusHandler prompter = DebugPlugin.getDefault().getStatusHandler(uiPromptStatus);
+							prompter = DebugPlugin.getDefault().getStatusHandler(uiPromptStatus);
+							if (prompter != null) {
+								continueLaunch = ((Boolean) prompter.handleStatus(promptStatusReferencedProjs, createPrompterArgs(configuration))).booleanValue();
+							}
+							else {
+								assert false;					
+							}
+
+							// The error message says "one or more" and doesn't mention names.
+							break;
+						}
+					}
 				}
 			}
+			
+			// Note that we do not call our super implementation (platform).
+			// That's because it'll just re-do everything we've done here in a
+			// non-customized way. However, we need to keep an eye out for any
+			// future additions to the platform's logic.
+			
+			return continueLaunch;
+		}
+		finally {
+			workspaceBuildBeforeLaunch = false;	// reset for future run
+			if (monitor != null) {
+				monitor.done();
+			}
 		}
-		boolean continueLaunch = super.finalLaunchCheck(configuration, mode, monitor);
-
-		if (continueLaunch) // If no problems then restore the previous build configuration. Otherwise leave it so the user can fix the build issues.
-			resetBuildConfiguration(project);
-		
-		return continueLaunch;
 }
 
 	protected ICProject verifyCProject(ILaunchConfiguration config) throws CoreException {
@@ -285,52 +532,6 @@ public abstract class AbstractCLaunchDelegate2 extends LaunchConfigurationDelega
 	}
 
 	/**
-	 * Sets up a project for building by making sure the active configuration is the one used
-	 * when the launch was created.
-	 * @param configuration
-	 * @param buildProject
-	 */
-	private void setBuildConfiguration(ILaunchConfiguration configuration, IProject buildProject) {
-		
-		try {
-			if (buildProject != null)
-			{
-				String buildConfigID = configuration.getAttribute(ICDTLaunchConfigurationConstants.ATTR_PROJECT_BUILD_CONFIG_ID, ""); //$NON-NLS-1$
-				ICProjectDescription projDes = CDTPropertyManager.getProjectDescription(buildProject);
-				
-				if (buildConfigID.length() > 0 && projDes != null)
-				{
-					ICConfigurationDescription buildConfiguration = projDes.getConfigurationById(buildConfigID);
-					if (buildConfiguration != null) {
-						preLaunchBuildConfiguration = projDes.getActiveConfiguration().getId();
-						buildConfiguration.setActive();
-						CDTPropertyManager.performOk(null);
-					}
-				}
-			}
-			
-		} catch (CoreException e) {}
-	}
-
-	private void resetBuildConfiguration(IProject buildProject) {
-		// Restore the active configuration if it was changed for the launch
-		if (preLaunchBuildConfiguration != null) {
-			ICProjectDescription projDes = CDTPropertyManager.getProjectDescription(buildProject);
-			
-			if (preLaunchBuildConfiguration.length() > 0 && projDes != null)
-			{
-				ICConfigurationDescription buildConfiguration = projDes.getConfigurationById(preLaunchBuildConfiguration);
-				if (buildConfiguration != null) {
-					buildConfiguration.setActive();
-					CDTPropertyManager.performOk(null);
-				}
-			}
-
-		}
-		preLaunchBuildConfiguration = null;
-	}
-
-	/**
 	 * @return the ID of the plugin hosting the launch delegate. It's used to
 	 *         create {@link IStatus} objects.
 	 */
diff --git a/launch/org.eclipse.cdt.launch/src/org/eclipse/cdt/launch/internal/ui/BuildErrPrompter.java b/launch/org.eclipse.cdt.launch/src/org/eclipse/cdt/launch/internal/ui/BuildErrPrompter.java
new file mode 100644
index 00000000000..24699b4737d
--- /dev/null
+++ b/launch/org.eclipse.cdt.launch/src/org/eclipse/cdt/launch/internal/ui/BuildErrPrompter.java
@@ -0,0 +1,152 @@
+/*******************************************************************************
+ * Copyright (c) 2000, 2010 IBM Corporation, Freescale Semiconductor and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *     Freescale Semiconductor - customized for use in CDT
+ *******************************************************************************/
+
+package org.eclipse.cdt.launch.internal.ui;
+
+import java.text.MessageFormat;
+
+import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.runtime.IStatus;
+import org.eclipse.debug.core.ILaunchConfiguration;
+import org.eclipse.debug.core.IStatusHandler;
+import org.eclipse.debug.internal.ui.DebugUIPlugin;
+import org.eclipse.debug.internal.ui.IInternalDebugUIConstants;
+import org.eclipse.debug.internal.ui.launchConfigurations.LaunchConfigurationsMessages;
+import org.eclipse.debug.ui.DebugUITools;
+import org.eclipse.jface.dialogs.IDialogConstants;
+import org.eclipse.jface.dialogs.MessageDialog;
+import org.eclipse.jface.dialogs.MessageDialogWithToggle;
+import org.eclipse.jface.preference.IPreferenceStore;
+import org.eclipse.swt.widgets.Shell;
+
+/**
+ * This class is a customization of the platform's
+ * CompileErrorProjectPromptStatusHandler. We use it to put up a more
+ * CDT-centric message when building before a launch and there is an error in
+ * the project. We want to let the user know what specific build configuration
+ * is having a build error when the configuration is not the active one.
+ * See https://bugs.eclipse.org/bugs/show_bug.cgi?id=309126#c11
+ */
+public class BuildErrPrompter implements IStatusHandler {
+
+	/**
+	 * Status code indicating there was an error in the main project. Linked to
+	 * BuildErrPrompter via our statusHandlers extension (see plugin.xml)
+	 */
+	public static final int STATUS_CODE_ERR_IN_MAIN_PROJ = 1002;
+
+	/**
+	 * Status code indicating there was an error in a project referenced by the
+	 * main project. Linked to BuildErrPrompter via our statusHandlers extension
+	 * (see plugin.xml)
+	 */
+	public static final int STATUS_CODE_ERR_IN_REFERENCED_PROJS = 1003;
+
+	/**
+	 * Source is an array of three things, in the following order
+	 * <ul>
+	 * <li>launch configuration that was invoked
+	 * <li>the name of the project the launch first attempted to build
+	 * <li>the name of the build configuration that was built, or empty string
+	 * if it was the active one. This argument should be non-empty ONLY if a
+	 * not-active configuration was built.
+	 * <ul>
+	 * 
+	 * @see org.eclipse.debug.core.IStatusHandler#handleStatus(org.eclipse.core.runtime.IStatus,
+	 *      java.lang.Object)
+	 */
+	public Object handleStatus(IStatus status, Object source) throws CoreException {
+
+		if (!(source instanceof Object[])) {
+			assert false : "status handler not given expected arguments"; //$NON-NLS-1$
+			return Boolean.TRUE;
+		}
+
+		Object[] args = (Object[])source;
+		if (args.length != 3 ||
+			!(args[0] instanceof ILaunchConfiguration) ||
+			!(args[1] instanceof String) ||
+			!(args[2] instanceof String)) {
+			assert false : "status handler not given expected arguments"; //$NON-NLS-1$
+			return Boolean.TRUE;
+		}
+
+		final ILaunchConfiguration launchConfig = (ILaunchConfiguration)args[0];
+		final String projectName = (String)args[1];
+		final String buildConfigName = (String)args[2];
+
+		// The platform does this check; we should, too
+		if (DebugUITools.isPrivate(launchConfig)) {
+			return Boolean.TRUE;
+		}
+	
+		Shell shell = DebugUIPlugin.getShell();
+		String title =  LaunchConfigurationsMessages.CompileErrorPromptStatusHandler_0; 
+		String message;
+		if (status.getCode() == STATUS_CODE_ERR_IN_MAIN_PROJ) {
+			if (buildConfigName.length() > 0) {
+				message = MessageFormat.format(
+						LaunchMessages.getString("BuildErrPrompter.error_in_specific_config"), projectName, buildConfigName);  //$NON-NLS-1$
+			}
+			else {
+				message = MessageFormat.format(
+						LaunchMessages.getString("BuildErrPrompter.error_in_active_config"), projectName);  //$NON-NLS-1$
+			}
+		}
+		else if (status.getCode() == STATUS_CODE_ERR_IN_REFERENCED_PROJS) {
+			if (buildConfigName.length() > 0) {
+				message = MessageFormat.format(
+						LaunchMessages.getString("BuildErrPrompter.error_in_referenced_project_specific"), //$NON-NLS-1$ 
+						projectName, buildConfigName);  
+			}
+			else {
+				message = MessageFormat.format(
+						LaunchMessages.getString("BuildErrPrompter.error_in_referenced_project_active"), //$NON-NLS-1$						
+						projectName);  
+			}
+		}
+		else {
+			assert false : "this prompter was called for an unexpected status"; //$NON-NLS-1$
+			return Boolean.TRUE;
+		}
+		
+		// The rest is monkey-see, monkey-do (copied from
+		// CompileErrorProjectPromptStatusHandler)
+		
+		IPreferenceStore store = DebugUIPlugin.getDefault().getPreferenceStore(); 
+		String pref = store.getString(IInternalDebugUIConstants.PREF_CONTINUE_WITH_COMPILE_ERROR);
+		if (pref != null) {
+			if (pref.equals(MessageDialogWithToggle.ALWAYS)) {
+				return Boolean.TRUE;
+			}
+		}
+		MessageDialogWithToggle dialog = new MessageDialogWithToggle(shell, 
+				title, 
+				null, 
+				message, 
+				MessageDialog.QUESTION,
+				new String[] {IDialogConstants.PROCEED_LABEL, IDialogConstants.CANCEL_LABEL}, 
+				0,
+				LaunchConfigurationsMessages.CompileErrorProjectPromptStatusHandler_1,
+				false);
+        int open = dialog.open();
+		if (open == IDialogConstants.PROCEED_ID) {
+        	if(dialog.getToggleState()) {
+        		store.setValue(IInternalDebugUIConstants.PREF_CONTINUE_WITH_COMPILE_ERROR, MessageDialogWithToggle.ALWAYS);
+        	}
+            return Boolean.TRUE;
+        } 
+        else {
+            return Boolean.FALSE;
+        }
+	}
+}
diff --git a/launch/org.eclipse.cdt.launch/src/org/eclipse/cdt/launch/internal/ui/LaunchMessages.properties b/launch/org.eclipse.cdt.launch/src/org/eclipse/cdt/launch/internal/ui/LaunchMessages.properties
index c9b1b62b423..33c8c6a503c 100644
--- a/launch/org.eclipse.cdt.launch/src/org/eclipse/cdt/launch/internal/ui/LaunchMessages.properties
+++ b/launch/org.eclipse.cdt.launch/src/org/eclipse/cdt/launch/internal/ui/LaunchMessages.properties
@@ -199,3 +199,8 @@ MultiLaunchConfigurationTabGroup.15=Launch {0} is filtered.
 MultiLaunchConfigurationTabGroup.16=Must have at least one valid enabled launch.
 ProjectRenameChange.name=Update launch configuration "{0}"
 ProjectRenameChange.saveFailed=Failed to save updated launch configuration "{0}"
+
+BuildErrPrompter.error_in_specific_config=Errors exist in project \"{0}\" having built not-active build configuration \"{1}\". Proceed with launch?
+BuildErrPrompter.error_in_active_config=Errors exist in the active configuration of project \"{0}\". Proceed with launch?
+BuildErrPrompter.error_in_referenced_project_specific=One or more projects referenced by project \"{0}\", build configuration \"{1}\" has build errors. See Problems view for details. Keep in mind that the errors may be in build configurations that are not the active ones. Continue anyway?
+BuildErrPrompter.error_in_referenced_project_active=One or more projects referenced by the active configuration of project \"{0}\" has build errors. See Problems view for details. Keep in mind that the errors may be in build configurations that are not the active ones. Continue anyway?
\ No newline at end of file