Fix #45892. Null check

src/vs/editor/common/model/pieceTreeTextBuffer/pieceTreeBase.ts

@@ -592,7 +592,13 @@ export class PieceTreeBase {
 		const searcher = new Searcher(searchData.wordSeparators, searchData.regex);
 
 		let startPostion = this.nodeAt2(searchRange.startLineNumber, searchRange.startColumn);
+		if (startPostion === null) {
+			return [];
+		}
 		let endPosition = this.nodeAt2(searchRange.endLineNumber, searchRange.endColumn);
+		if (endPosition === null) {
+			return [];
+		}
 		let start = this.positionInBuffer(startPostion.node, startPostion.remainder);
 		let end = this.positionInBuffer(endPosition.node, endPosition.remainder);
 

src/vs/editor/test/common/model/pieceTreeTextBuffer/pieceTreeTextBuffer.test.ts

@@ -14,6 +14,8 @@ import { SENTINEL, NodeColor, TreeNode } from 'vs/editor/common/model/pieceTreeT
 import { PieceTreeTextBuffer } from 'vs/editor/common/model/pieceTreeTextBuffer/pieceTreeTextBuffer';
 import { TextModel } from 'vs/editor/common/model/textModel';
 import { ITextSnapshot } from 'vs/platform/files/common/files';
+import { SearchData } from 'vs/editor/common/model/textModelSearch';
+import { WordCharacterClassifier } from 'vs/editor/common/controller/wordCharacterClassifier';
 
 const alphabet = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ\r\n';
 
@@ -1776,4 +1778,13 @@ suite('snapshot', () => {
 
 		assert.notEqual(model.getLinesContent().join('\n'), getValueInSnapshot(snapshot));
 	});
+});
+
+suite('chunk based search', () => {
+	test('#45892. For some cases, the buffer is empty but we still try to search', () => {
+		let pieceTree = createTextBuffer(['']);
+		pieceTree.delete(0, 1);
+		let ret = pieceTree.findMatchesLineByLine(new Range(1, 1, 1, 1), new SearchData(/abc/, new WordCharacterClassifier(',./'), 'abc'), true, 1000);
+		assert.equal(ret.length, 0);
+	});
 });