Restarting workspace should take into account changes to eclipse.ini

Background:
===========
There are 3 return codes supported by Eclipse
- 0  - Normal exit
- 23 - Restart the eclipse with previous launcher arguments
- 24 - Restart the eclipse with the arguments provided by Eclipse
application itself

The above mentioned problem is not with the exit code 23. The reason is
that the eclipse launcher restarts itself in this case, hence eclipse.ini
is also reloaded. However eclipse launcher does not restart itself in case
of code 24 and parses the arguments provided by Eclipse application in
shared memory and simply relaunches java, which means that eclipse.ini will
not be reloaded.

For restarts, eclipse should be using code 23 but we had to switch to code
24 to fix following issue.
[[WorkbenchLauncher] Restart asks for the workspace to run](https://bugs.eclipse.org/bugs/show_bug.cgi?id=264072)
And then the fix of following built up on it.
[[Workspace chooser] "Older Workspace Version" dialog: "Cancel" button shouldn't close Eclipse but go back to workspace chooser](https://bugs.eclipse.org/bugs/show_bug.cgi?id=538830)

Fix:
====
For code 24, the arguments in shared memory are for launcher, so instead of
launcher just parsing the args and relaunching java, it should restart the
launcher with appropriate arguments. With relaunching the launcher,
eclipse.ini will be reloaded like its done for code 23.

Eclipse launcher is updated to relaunch for code 24 as well. Moreover,
there are 3 new launcher arguments introduced, 2 are internal to launcher
and one is external to launcher and can be set by eclipse application as a
relaunch argument.

- `--launcher.oldUserArgsStart` and `--launcher.oldUserArgsEnd`: The user
arguments passed to eclipse launcher for first start are tracked between
these arguments during relaunches. E.g., if eclipse was started as
`eclipse A B C` where A B C are some arguments to launcher and for
relaunch, Eclipse application mentioned `X Y Z` arguments then
relaunch command will be `eclipse --launcher.oldUserArgsStart A B C
--launcher.oldUserArgsEnd A B C X Y Z`. Moreover, launcher relaunch will
ignore all arguments between and including `--launcher.oldUserArgsStart`
and `--launcher.oldUserArgsEnd`.
- `--launcher.skipOldUserArgs`: If eclipse application wants to relaunch
with provided arguments only and ignore the older user args then it can
mention this argument. So for the case where eclipse was started as
`eclipse A B C` and Eclipse application mentioned `X Y Z` as relaunch
arguments along with `--launcher.skipOldUserArgs` then relaunch command
will be
`eclipse --launcher.oldUserArgsStart A B C --launcher.oldUserArgsEnd X Y Z`
where launcher relaunch will ignore all arguments between and including
`--launcher.oldUserArgsStart` and `--launcher.oldUserArgsEnd`.

For restarts, Eclipse application just mentions the `-data` argument now
as relaunch arguments instead of mentioning complete java args. However,
user can still mention more arguments for relaunch and Eclipse restart will
respect them as well and append the `-data` argument at the end of user
arguments.

bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/Workbench.java

@@ -139,6 +139,7 @@
 import org.eclipse.jface.viewers.ISelection;
 import org.eclipse.jface.window.IShellProvider;
 import org.eclipse.jface.window.Window;
+import org.eclipse.osgi.internal.location.LocationHelper;
 import org.eclipse.osgi.service.runnable.StartupMonitor;
 import org.eclipse.osgi.util.NLS;
 import org.eclipse.swt.SWT;
@@ -290,12 +291,8 @@ public final class Workbench extends EventManager implements IWorkbench, org.ecl
 
 	public static final String EDITOR_TAG = "Editor"; //$NON-NLS-1$
 
-	private static final String PROP_VM = "eclipse.vm"; //$NON-NLS-1$
-	private static final String PROP_VMARGS = "eclipse.vmargs"; //$NON-NLS-1$
-	private static final String PROP_COMMANDS = "eclipse.commands"; //$NON-NLS-1$
 	public static final String PROP_EXIT_CODE = "eclipse.exitcode"; //$NON-NLS-1$
 	private static final String CMD_DATA = "-data"; //$NON-NLS-1$
-	private static final String CMD_VMARGS = "-vmargs"; //$NON-NLS-1$
 
 	private static final class StartupProgressBundleListener implements SynchronousBundleListener {
 
@@ -2593,64 +2590,16 @@ public boolean restart(boolean useCurrrentWorkspace) {
 	 *         is not set
 	 */
 	private static String buildCommandLine(String workspace) {
-		String property = System.getProperty(PROP_VM);
-		if (property == null) {
-			if (!Platform.inDevelopmentMode()) {
-				// Don't log this when in development mode, since 'eclipse.vm'
-				// is never set in this case
-				WorkbenchPlugin.log(NLS.bind(WorkbenchMessages.Workbench_missingPropertyMessage, PROP_VM));
-			}
-			return null;
-		}
-
 		StringBuilder result = new StringBuilder(512);
-		result.append(property);
-		result.append('\n');
 
-		// append the vmargs and commands. Assume that these already end in \n
-		String vmargs = System.getProperty(PROP_VMARGS);
-		if (vmargs != null) {
-			result.append(vmargs);
-		}
+		String userData = System.getProperty(IApplicationContext.EXIT_DATA_PROPERTY);
+		if (userData != null && !userData.isBlank())
+			result.append(userData);
 
-		// append the rest of the args, replacing or adding -data as required
-		property = System.getProperty(PROP_COMMANDS);
-		if (property == null) {
-			result.append(CMD_DATA);
-			result.append('\n');
-			result.append(workspace);
-			result.append('\n');
-		} else {
-			// find the index of the arg to add/replace its value
-			int cmd_data_pos = property.lastIndexOf(CMD_DATA);
-			if (cmd_data_pos != -1) {
-				cmd_data_pos += CMD_DATA.length() + 1;
-				result.append(property.substring(0, cmd_data_pos));
-				result.append(workspace);
-				// append from the next arg
-				int nextArg = property.indexOf("\n-", cmd_data_pos - 1); //$NON-NLS-1$
-				if (nextArg != -1) {
-					result.append(property.substring(nextArg));
-				}
-			} else {
-				result.append(CMD_DATA);
-				result.append('\n');
-				result.append(workspace);
-				result.append('\n');
-				result.append(property);
-			}
-		}
-
-		// put the vmargs back at the very end (the eclipse.commands property
-		// already contains the -vm arg)
-		if (vmargs != null) {
-			if (result.charAt(result.length() - 1) != '\n') {
-				result.append('\n');
-			}
-			result.append(CMD_VMARGS);
-			result.append('\n');
-			result.append(vmargs);
-		}
+		result.append(CMD_DATA);
+		result.append('\n');
+		result.append(workspace);
+		result.append('\n');
 
 		return result.toString();
 	}
@@ -2662,13 +2611,15 @@ private static String buildCommandLine(String workspace) {
 	 * @param workspacePath the new workspace location
 	 * @return {@link IApplication#EXIT_OK} or {@link IApplication#EXIT_RELAUNCH}
 	 */
+	@SuppressWarnings("restriction")
 	public static Object setRestartArguments(String workspacePath) {
-		String property = System.getProperty(Workbench.PROP_VM);
-		if (property == null) {
+		if (Platform.inDevelopmentMode()
+				&& !Platform.getInstanceLocation().getURL().equals(LocationHelper.buildURL(workspacePath, true))) {
 			MessageDialog.openError(null, WorkbenchMessages.Workbench_problemsRestartErrorTitle,
-					NLS.bind(WorkbenchMessages.Workbench_problemsRestartErrorMessage, Workbench.PROP_VM));
-			return IApplication.EXIT_OK;
+					WorkbenchMessages.Workbench_problemsRestartErrorMessage);
+			return null;
 		}
+
 		String command_line = Workbench.buildCommandLine(workspacePath);
 		if (command_line == null) {
 			return IApplication.EXIT_OK;

bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/WorkbenchMessages.java

@@ -91,7 +91,6 @@ public class WorkbenchMessages extends NLS {
 	public static String SaveAll_toolTip;
 	public static String Workbench_revert;
 	public static String Workbench_revertToolTip;
-	public static String Workbench_missingPropertyMessage;
 	public static String Workbench_move;
 
 	public static String Workbench_moveToolTip;

bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/messages.properties

@@ -57,7 +57,6 @@ SaveAll_text = Sav&e All
 SaveAll_toolTip = Save All
 Workbench_revert = Rever&t
 Workbench_revertToolTip = Revert
-Workbench_missingPropertyMessage=Unable to relaunch the platform with the current workspace because the ''{0}'' property has not been set.
 Workbench_move = Mo&ve...
 Workbench_moveToolTip = Move
 Workbench_rename = Rena&me...
@@ -693,8 +692,8 @@ Startup_Loading_Workbench=Loading Workbench
 Workbench_problemsSavingMsg=Could not save workbench layout.
 Workbench_problemsRestoring=Problems occurred restoring workbench.
 Workbench_problemsSaving=Problems occurred saving workbench.
-Workbench_problemsRestartErrorTitle = Missing System Property
-Workbench_problemsRestartErrorMessage = Unable to relaunch the workbench because the {0} property has not been set.
+Workbench_problemsRestartErrorTitle = Restart with different workspace
+Workbench_problemsRestartErrorMessage = Restarting with different workspace does not work in development mode.
 
 PageLayout_missingRefPart=Referenced part does not exist yet: {0}.