fix: fix selection feature because of XTerm bug

Add workaround for a bug in XTerm where selecting two or more lines programmatically includes a trailing CRLF.

See xtermjs/xterm.js#3552

Author: javier-godoy

src/main/resources/META-INF/frontend/fc-xterm/xterm-selection-mixin.ts

@@ -125,12 +125,19 @@ class SelectionAddon extends TerminalAddon<ISelectionMixin> {
 			if (this.__selectionAnchor!==undefined) {
 				let buffer = (terminal.buffer.active as any)._buffer;
 				let range = buffer.getWrappedRangeForLine(buffer.ybase+buffer.y);				
-				let pos = terminal.getSelectionPosition();					
+				let pos = terminal.getSelectionPosition();				
+				
+				//see https://github.com/xtermjs/xterm.js/issues/3552
+				pos.endColumn==0 && --pos.endRow;
+				
 				if (pos && pos.startRow>=range.first && pos.endRow<=range.last) {
-					//let selectionStart = pos.startRow * terminal.cols + pos.startColumn;
 					if (!this.__selectionRight) {
 						//cursor backward wrapped
-						terminal.write("\x1b[<" + this.__selectionLength + "L");
+						if (pos.endColumn==0) {
+							terminal.write("\x1b[<" + (this.__selectionLength-1) + "L");
+						} else {
+							terminal.write("\x1b[<" + this.__selectionLength + "L");
+						}
 					}
 					//delete characters wrapped
 					terminal.write("\x1b[<" + this.__selectionLength + "D");

src/test/java/com/flowingcode/vaadin/addons/xterm/integration/SelectionFeatureIT.java

@@ -98,7 +98,9 @@ public void testSelectionFeature() throws InterruptedException {
     term.write(text);
     assertThat(term.currentLine(), is(text));
     term.sendKeys(Keys.SHIFT, Keys.HOME);
-    assertThat(term.getSelection(), is(text));
+    // https://github.com/xtermjs/xterm.js/issues/3552
+    // Selecting a whole line using API includes trailing CRLF
+    assertThat(term.getSelection(), is(text + "\n"));
     term.sendKeys(Keys.DELETE);
     assertThat(term.currentLine(), isEmptyString());
 
@@ -107,10 +109,9 @@ public void testSelectionFeature() throws InterruptedException {
     assertThat(term.currentLine(), is(text));
     term.sendKeys(Keys.HOME);
     term.sendKeys(Keys.SHIFT, Keys.END);
-    assertThat(term.getSelection(), is(text));
+    assertThat(term.getSelection(), is(text + "\n"));
     term.sendKeys(Keys.DELETE);
     assertThat(term.currentLine(), isEmptyString());
-
   }
 
 }