fix

Author: bajrangCoder

src/cm/indentedLineWrapping.ts

@@ -28,9 +28,12 @@ export function wrappedIndentColumns(
 ): number {
 	const extra =
 		mode === "indent" ? tabSize : mode === "deepIndent" ? 2 * tabSize : 0;
-	// Unindented/minified lines need no tab scan, even when they are megabytes long.
 	if (mode === "none" || limit <= 0) return 0;
-	if (!extra && text[0] !== " " && text[0] !== "\t") return 0;
+	if (text[0] !== " " && text[0] !== "\t") {
+		// Extra levels are whole tab stops, so content tabs cannot affect them.
+		// Keep the width cap tab-aligned too, avoiding a scan even in narrow panes.
+		return Math.min(extra, Math.floor(limit / tabSize) * tabSize);
+	}
 	// Include content tabs deliberately: negative text-indent changes the origin
 	// of every tab stop on the first visual row. For "  key\tvalue", using 2ch
 	// shifts "value" left by two columns in Chromium; 4ch preserves its position.

tests/unit/indentedLineWrapping.test.ts

@@ -1,5 +1,5 @@
 import { wrappedIndentColumns } from "cm/indentedLineWrapping";
-import { describe, expect, it } from "vitest";
+import { describe, expect, it, vi } from "vitest";
 
 describe("wrapped line indentation", () => {
 	it("preserves space indentation and stops at content", () => {
@@ -37,4 +37,24 @@ describe("wrapped line indentation", () => {
 		expect(wrappedIndentColumns("  key\tvalue", 4, 7, "deepIndent")).toBe(4);
 		expect(wrappedIndentColumns("    code", 4, 7, "deepIndent")).toBe(7);
 	});
+	it("caps unindented lines at whole tab stops without depending on content tabs", () => {
+		for (const text of ["code", "key\tvalue"]) {
+			expect(wrappedIndentColumns(text, 4, 7, "deepIndent")).toBe(4);
+			expect(wrappedIndentColumns(text, 4, 3, "indent")).toBe(0);
+		}
+	});
+	it("skips the full-line tab search for large unindented lines in extra-indent modes", () => {
+		const text = "x".repeat(1_000_000) + "\tvalue";
+		const search = vi.spyOn(String.prototype, "includes");
+		let calls: number;
+		try {
+			wrappedIndentColumns(text, 4, 40, "indent");
+			wrappedIndentColumns(text, 4, 40, "deepIndent");
+			wrappedIndentColumns(text, 4, 7, "deepIndent");
+			calls = search.mock.calls.length;
+		} finally {
+			search.mockRestore();
+		}
+		expect(calls).toBe(0);
+	});
 });