fix(InputHandler): clear wrap below scroll margins after column ops

scrollLeft, scrollRight, insertColumns, and deleteColumns set
isWrapped=false on every line inside the scroll margins but left
the first line below scrollBottom unchanged. A soft wrap spanning
the bottom margin and the next row could leave a stale isWrapped
flag on the line below, breaking wrapped string translation.

Clear isWrapped on the buffer line below the bottom margin after
each of these column operations.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/common/InputHandler.test.ts

@@ -475,6 +475,13 @@ describe('InputHandler', () => {
       inputHandler.eraseInLine(Params.fromArray([1]));
       assert.equal(bufferService.buffer.lines.get(2)!.isWrapped, true);
 
+      // params[1] - full line erase at last column clears wrap on next line
+      await resetToBaseState();
+      bufferService.buffer.y = 1;
+      bufferService.buffer.x = bufferService.cols - 1;
+      inputHandler.eraseInLine(Params.fromArray([1]));
+      assert.equal(bufferService.buffer.lines.get(2)!.isWrapped, false);
+
       // params[2] - erase complete line
       await resetToBaseState();
       bufferService.buffer.y = 2;

src/common/InputHandler.ts

@@ -1202,6 +1202,21 @@ export class InputHandler extends Disposable implements IInputHandler {
     }
   }
 
+  /**
+   * Scroll-margin column operations clear isWrapped on lines inside the margins.
+   * Also clear the line below the bottom margin when it still continues a wrap chain.
+   */
+  private _clearWrapBelowScrollMargins(): void {
+    const rowBelowMargin = this._activeBuffer.scrollBottom + 1;
+    if (rowBelowMargin >= this._bufferService.rows) {
+      return;
+    }
+    const lineBelow = this._activeBuffer.lines.get(this._activeBuffer.ybase + rowBelowMargin);
+    if (lineBelow) {
+      lineBelow.isWrapped = false;
+    }
+  }
+
   /**
    * CSI Ps J  Erase in Display (ED).
    *     Ps = 0  -> Erase Below (default).
@@ -1246,7 +1261,7 @@ export class InputHandler extends Disposable implements IInputHandler {
         this._eraseInBufferLine(j, 0, this._activeBuffer.x + 1, true, respectProtect);
         if (this._activeBuffer.x + 1 >= this._bufferService.cols) {
           // Deleted entire previous line. This next line can no longer be wrapped.
-          const nextLine = this._activeBuffer.lines.get(j + 1);
+          const nextLine = this._activeBuffer.lines.get(this._activeBuffer.ybase + j + 1);
           if (nextLine) {
             nextLine.isWrapped = false;
           }
@@ -1324,6 +1339,12 @@ export class InputHandler extends Disposable implements IInputHandler {
         break;
       case 1:
         this._eraseInBufferLine(this._activeBuffer.y, 0, this._activeBuffer.x + 1, false, respectProtect);
+        if (this._activeBuffer.x + 1 >= this._bufferService.cols) {
+          const nextLine = this._activeBuffer.lines.get(this._activeBuffer.ybase + this._activeBuffer.y + 1);
+          if (nextLine) {
+            nextLine.isWrapped = false;
+          }
+        }
         break;
       case 2:
         this._eraseInBufferLine(this._activeBuffer.y, 0, this._bufferService.cols, true, respectProtect);
@@ -1515,6 +1536,7 @@ export class InputHandler extends Disposable implements IInputHandler {
       line.deleteCells(0, param, this._activeBuffer.getNullCell(this._eraseAttrData()));
       line.isWrapped = false;
     }
+    this._clearWrapBelowScrollMargins();
     this._dirtyRowTracker.markRangeDirty(this._activeBuffer.scrollTop, this._activeBuffer.scrollBottom);
     return true;
   }
@@ -1548,6 +1570,7 @@ export class InputHandler extends Disposable implements IInputHandler {
       line.insertCells(0, param, this._activeBuffer.getNullCell(this._eraseAttrData()));
       line.isWrapped = false;
     }
+    this._clearWrapBelowScrollMargins();
     this._dirtyRowTracker.markRangeDirty(this._activeBuffer.scrollTop, this._activeBuffer.scrollBottom);
     return true;
   }
@@ -1571,6 +1594,7 @@ export class InputHandler extends Disposable implements IInputHandler {
       line.insertCells(this._activeBuffer.x, param, this._activeBuffer.getNullCell(this._eraseAttrData()));
       line.isWrapped = false;
     }
+    this._clearWrapBelowScrollMargins();
     this._dirtyRowTracker.markRangeDirty(this._activeBuffer.scrollTop, this._activeBuffer.scrollBottom);
     return true;
   }
@@ -1594,6 +1618,7 @@ export class InputHandler extends Disposable implements IInputHandler {
       line.deleteCells(this._activeBuffer.x, param, this._activeBuffer.getNullCell(this._eraseAttrData()));
       line.isWrapped = false;
     }
+    this._clearWrapBelowScrollMargins();
     this._dirtyRowTracker.markRangeDirty(this._activeBuffer.scrollTop, this._activeBuffer.scrollBottom);
     return true;
   }