Merge pull request microsoft#206057 from microsoft/aiday/doingChecksOnLineNumberAndLength

Doing checks on line number and length of array in `inlineCompletionsModel` file

Author: aiday-mar

src/vs/editor/contrib/inlineCompletions/browser/inlineCompletionsModel.ts

@@ -4,7 +4,7 @@
  *--------------------------------------------------------------------------------------------*/
 
 import { mapFindFirst } from 'vs/base/common/arraysFind';
-import { BugIndicatingError, onUnexpectedExternalError } from 'vs/base/common/errors';
+import { BugIndicatingError, onUnexpectedError, onUnexpectedExternalError } from 'vs/base/common/errors';
 import { Disposable } from 'vs/base/common/lifecycle';
 import { IObservable, IReader, ITransaction, autorun, derived, derivedHandleChanges, derivedOpts, recomputeInitiallyAndOnChange, observableSignal, observableValue, subtransaction, transaction } from 'vs/base/common/observable';
 import { commonPrefixLength, splitLinesIncludeSeparators } from 'vs/base/common/strings';
@@ -470,6 +470,10 @@ export class InlineCompletionsModel extends Disposable {
 }
 
 export function getSecondaryEdits(textModel: ITextModel, positions: readonly Position[], primaryEdit: SingleTextEdit): SingleTextEdit[] {
+	if (positions.length === 1) {
+		// No secondary cursor positions
+		return [];
+	}
 	const primaryPosition = positions[0];
 	const secondaryPositions = positions.slice(1);
 	const primaryEditStartPosition = primaryEdit.range.getStartPosition();
@@ -478,6 +482,13 @@ export function getSecondaryEdits(textModel: ITextModel, positions: readonly Pos
 		Range.fromPositions(primaryPosition, primaryEditEndPosition)
 	);
 	const positionWithinTextEdit = subtractPositions(primaryPosition, primaryEditStartPosition);
+	if (positionWithinTextEdit.lineNumber < 1) {
+		onUnexpectedError(new BugIndicatingError(
+			`positionWithinTextEdit line number should be bigger than 0.
+			Invalid subtraction between ${primaryPosition.toString()} and ${primaryEditStartPosition.toString()}`
+		));
+		return [];
+	}
 	const secondaryEditText = substringPos(primaryEdit.text, positionWithinTextEdit);
 	return secondaryPositions.map(pos => {
 		const posEnd = addPositions(subtractPositions(pos, primaryEditStartPosition), primaryEditEndPosition);