fix: adhere to lsp spec when calculating offsets

org.eclipse.lsp4e.test/src/org/eclipse/lsp4e/test/edit/LSPEclipseUtilsTest.java

@@ -30,6 +30,7 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.LinkedList;
+import java.util.Random;
 
 import org.eclipse.core.filesystem.EFS;
 import org.eclipse.core.internal.utils.FileUtil;
@@ -84,19 +85,33 @@ public void testOpenInEditorExternalFile() throws Exception {
 	}
 
 	@Test
-	public void testWorkspaceEdit() throws Exception {
+	public void testWorkspaceEdit_insertText() throws Exception {
+		TextEdit textEdit = new TextEdit(new Range(new Position(0, 0), new Position(0, 0)), "insert");
+		AbstractTextEditor editor = applyWorkspaceTextEdit(textEdit);
+		Assert.assertEquals("insertHere", ((StyledText)editor.getAdapter(Control.class)).getText());
+		Assert.assertEquals("insertHere", editor.getDocumentProvider().getDocument(editor.getEditorInput()).get());
+	}
+
+	@Test
+	public void testWorkspaceEdit_WithExaggeratedRange() throws Exception {
+		TextEdit textEdit = new TextEdit(new Range(new Position(0, 0), new Position(Integer.MAX_VALUE, Integer.MAX_VALUE)), "insert");
+		AbstractTextEditor editor = applyWorkspaceTextEdit(textEdit);
+		Assert.assertEquals("insert", ((StyledText)editor.getAdapter(Control.class)).getText());
+		Assert.assertEquals("insert", editor.getDocumentProvider().getDocument(editor.getEditorInput()).get());
+	}
+
+
+	private AbstractTextEditor applyWorkspaceTextEdit(TextEdit textEdit) throws CoreException, PartInitException {
 		IProject p = TestUtils.createProject(getClass().getSimpleName() + System.currentTimeMillis());
-		IFile f = TestUtils.createFile(p, "dummy", "Here");
+		IFile f = TestUtils.createFile(p, "dummy"+new Random().nextInt(), "Here");
 		AbstractTextEditor editor = (AbstractTextEditor)TestUtils.openEditor(f);
 		WorkspaceEdit workspaceEdit = new WorkspaceEdit(Collections.singletonMap(
 			LSPEclipseUtils.toUri(f).toString(),
-			Collections.singletonList(new TextEdit(new Range(new Position(0, 0), new Position(0, 0)), "insert"))));
+			Collections.singletonList(textEdit)));
 		LSPEclipseUtils.applyWorkspaceEdit(workspaceEdit);
-		Assert.assertEquals("insertHere", ((StyledText)editor.getAdapter(Control.class)).getText());
-		Assert.assertEquals("insertHere", editor.getDocumentProvider().getDocument(editor.getEditorInput()).get());
-
+		return editor;
 	}
-
+	
 	@Test
 	public void testWorkspaceEditMultipleChanges() throws Exception {
 		IProject p = TestUtils.createProject(getClass().getSimpleName() + System.currentTimeMillis());

org.eclipse.lsp4e/src/org/eclipse/lsp4e/LSPEclipseUtils.java

@@ -17,6 +17,7 @@
  *  Markus Ofterdinger (SAP SE) - Bug 552140 - NullPointerException in LSP4E
  *  Rubén Porras Campo (Avaloq) - Bug 576425 - Support Remote Files
  *  Pierre-Yves Bigourdan <pyvesdev@gmail.com> - Issue 29
+ *  Bastian Doetsch (Snyk Ltd)
  *******************************************************************************/
 package org.eclipse.lsp4e;
 
@@ -181,7 +182,29 @@ public static Position toPosition(int offset, IDocument document) throws BadLoca
 	}
 
 	public static int toOffset(Position position, IDocument document) throws BadLocationException {
-		return document.getLineOffset(position.getLine()) + position.getCharacter();
+		var line = position.getLine();
+		var character = position.getCharacter();
+
+		/*
+		 * The LSP spec allow for positions to specify the next line if a line should be
+		 * included completely, specifying the first character of the following line. If
+		 * this is at the end of the document, we therefore take the last document line
+		 * and set the character to line length - 1 (to remove delimiter)
+		 */
+		var zeroBasedDocumentLines = Math.max(0, document.getNumberOfLines() - 1);
+		if (zeroBasedDocumentLines < position.getLine()) {
+			line = zeroBasedDocumentLines;
+			character = getLineLength(document, line);
+		} else {
+			// We just take the line length to be more forgiving and adhere to the LSP spec.
+			character = Math.min(getLineLength(document, line), position.getCharacter());
+		}
+
+		return document.getLineOffset(line) + character;
+	}
+
+	private static int getLineLength(IDocument document, int line) throws BadLocationException {
+		return Math.max(0, document.getLineLength(line));
 	}
 
 	public static boolean isOffsetInRange(int offset, Range range, IDocument document) {

org.eclipse.lsp4e/src/org/eclipse/lsp4e/LanguageClientImpl.java

@@ -115,7 +115,9 @@ public final CompletableFuture<ApplyWorkspaceEditResponse> applyEdit(ApplyWorksp
 			final var job = new Job(Messages.serverEdit) {
 				@Override
 				public IStatus run(IProgressMonitor monitor) {
-					LSPEclipseUtils.applyWorkspaceEdit(params.getEdit(), params.getLabel());
+					UI.getDisplay().syncExec(() -> {
+						LSPEclipseUtils.applyWorkspaceEdit(params.getEdit(), params.getLabel());
+					});
 					return Status.OK_STATUS;
 				}
 			};