From 8c94c97a283e816242523f5d723a1c567aa7f3fe Mon Sep 17 00:00:00 2001
From: Daniel Imms <2193314+Tyriar@users.noreply.github.com>
Date: Tue, 21 Dec 2021 10:49:58 -0800
Subject: [PATCH] Don't include trailing EOL when selecting multiple lines

Fixes #3552
---
 src/browser/selection/SelectionModel.test.ts | 8 ++++++++
 src/browser/selection/SelectionModel.ts      | 4 ++++
 2 files changed, 12 insertions(+)

diff --git a/src/browser/selection/SelectionModel.test.ts b/src/browser/selection/SelectionModel.test.ts
index c15cdd29..410902d7 100644
--- a/src/browser/selection/SelectionModel.test.ts
+++ b/src/browser/selection/SelectionModel.test.ts
@@ -122,5 +122,13 @@ describe('SelectionModel', () => {
       model.selectionEnd = [5, 2];
       assert.deepEqual(model.finalSelectionEnd, [5, 2]);
     });
+    it('should not include a trailing EOL when the selection ends at the end of a line', () => {
+      model.selectionStart = [0, 0];
+      model.selectionStartLength = 80;
+      assert.deepEqual(model.finalSelectionEnd, [80, 0]);
+      model.selectionStart = [0, 0];
+      model.selectionStartLength = 160;
+      assert.deepEqual(model.finalSelectionEnd, [80, 1]);
+    });
   });
 });
diff --git a/src/browser/selection/SelectionModel.ts b/src/browser/selection/SelectionModel.ts
index 1420444e..1d84446a 100644
--- a/src/browser/selection/SelectionModel.ts
+++ b/src/browser/selection/SelectionModel.ts
@@ -79,6 +79,10 @@ export class SelectionModel {
     if (!this.selectionEnd || this.areSelectionValuesReversed()) {
       const startPlusLength = this.selectionStart[0] + this.selectionStartLength;
       if (startPlusLength > this._bufferService.cols) {
+        // Ensure the trailing EOL isn't included when the selection ends on the right edge
+        if (startPlusLength % this._bufferService.cols === 0) {
+          return [this._bufferService.cols, this.selectionStart[1] + Math.floor(startPlusLength / this._bufferService.cols) - 1];
+        }
         return [startPlusLength % this._bufferService.cols, this.selectionStart[1] + Math.floor(startPlusLength / this._bufferService.cols)];
       }
       return [startPlusLength, this.selectionStart[1]];