From 6e49c700965c7c0ec1c1e502f4af5ef99d6d699b Mon Sep 17 00:00:00 2001
From: Armin Ronacher <armin.ronacher@active-4.com>
Date: Wed, 6 May 2026 10:54:54 +0200
Subject: [PATCH] fix(tui): preserve autocomplete punctuation context

---
 packages/tui/src/autocomplete.ts       | 30 ++++++++++---
 packages/tui/test/autocomplete.test.ts | 59 +++++++++++++++++++++++++-
 2 files changed, 81 insertions(+), 8 deletions(-)

diff --git a/packages/tui/src/autocomplete.ts b/packages/tui/src/autocomplete.ts
index 11b2a5a5a..e2591288f 100644
--- a/packages/tui/src/autocomplete.ts
+++ b/packages/tui/src/autocomplete.ts
@@ -57,22 +57,38 @@ function findLastDelimiter(text: string): number {
 }
 
 function isExplicitPathPrefixStart(prefix: string): boolean {
-	return prefix.startsWith(".") || prefix.startsWith("/") || prefix.startsWith("~/") || prefix === "~";
+	return (
+		prefix.startsWith("./") ||
+		prefix.startsWith("../") ||
+		prefix.startsWith("/") ||
+		prefix.startsWith("~/") ||
+		prefix === "~"
+	);
+}
+
+function isLeadingPunctuationRun(token: string, endIndex: number): boolean {
+	for (let i = 0; i <= endIndex; i += 1) {
+		if (!AUTOCOMPLETE_BOUNDARY_PUNCTUATION.has(token[i] ?? "")) {
+			return false;
+		}
+	}
+	return true;
+}
+
+function isLeadingDotfilePrefixStart(token: string, punctuationIndex: number, suffix: string): boolean {
+	return suffix.startsWith(".") && !suffix.startsWith("./") && isLeadingPunctuationRun(token, punctuationIndex);
 }
 
 function findPathPrefixStartInToken(token: string): number {
 	let tokenStart = 0;
-	while (AUTOCOMPLETE_BOUNDARY_PUNCTUATION.has(token[tokenStart] ?? "")) {
-		tokenStart += 1;
-	}
 
-	for (let i = tokenStart; i < token.length; i += 1) {
+	for (let i = 0; i < token.length; i += 1) {
 		if (!AUTOCOMPLETE_BOUNDARY_PUNCTUATION.has(token[i] ?? "")) {
 			continue;
 		}
 
 		const suffix = token.slice(i + 1);
-		if (isExplicitPathPrefixStart(suffix)) {
+		if (isExplicitPathPrefixStart(suffix) || isLeadingDotfilePrefixStart(token, i, suffix)) {
 			tokenStart = i + 1;
 		}
 	}
@@ -496,7 +512,7 @@ export class CombinedAutocompleteProvider implements AutocompleteProvider {
 		const tokenStart = lastDelimiterIndex === -1 ? 0 : lastDelimiterIndex + 1;
 		const token = text.slice(tokenStart);
 
-		for (let i = 0; i < token.length; i += 1) {
+		for (let i = token.length - 1; i >= 0; i -= 1) {
 			const absoluteIndex = tokenStart + i;
 			if (token[i] === "@" && isTokenStart(text, absoluteIndex)) {
 				return text.slice(absoluteIndex);
diff --git a/packages/tui/test/autocomplete.test.ts b/packages/tui/test/autocomplete.test.ts
index 2c16a9386..6cb3eae24 100644
--- a/packages/tui/test/autocomplete.test.ts
+++ b/packages/tui/test/autocomplete.test.ts
@@ -1,6 +1,6 @@
 import assert from "node:assert";
 import { spawnSync } from "node:child_process";
-import { mkdirSync, mkdtempSync, rmSync, symlinkSync, writeFileSync } from "node:fs";
+import { chmodSync, mkdirSync, mkdtempSync, rmSync, symlinkSync, writeFileSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { dirname, join } from "node:path";
 import { afterEach, beforeEach, describe, it, test } from "node:test";
@@ -114,6 +114,38 @@ describe("CombinedAutocompleteProvider", () => {
 		});
 	});
 
+	describe("@ prefix extraction", () => {
+		let rootDir = "";
+		let baseDir = "";
+		let fakeFdPath = "";
+
+		beforeEach(() => {
+			rootDir = mkdtempSync(join(tmpdir(), "pi-autocomplete-at-"));
+			baseDir = join(rootDir, "cwd");
+			mkdirSync(baseDir, { recursive: true });
+			fakeFdPath = join(rootDir, "fake-fd.js");
+			writeFileSync(fakeFdPath, '#!/usr/bin/env node\nprocess.stdout.write("old.ts\\nmain.ts\\n");\n');
+			chmodSync(fakeFdPath, 0o755);
+		});
+
+		afterEach(() => {
+			rmSync(rootDir, { recursive: true, force: true });
+		});
+
+		test("uses the nearest @ after punctuation", async () => {
+			const provider = new CombinedAutocompleteProvider([], baseDir, fakeFdPath);
+			const line = "(@old),(@mai";
+			const result = await getSuggestions(provider, [line], 0, line.length);
+
+			assert.notEqual(result, null, "Should return suggestions for the current @ prefix");
+			assert.strictEqual(result?.prefix, "@mai");
+			assert.deepStrictEqual(
+				result?.items.map((item) => item.value),
+				["@main.ts"],
+			);
+		});
+	});
+
 	describe("fd @ file suggestions", { skip: !isFdInstalled }, () => {
 		let rootDir = "";
 		let baseDir = "";
@@ -495,6 +527,7 @@ describe("CombinedAutocompleteProvider", () => {
 		test("does not split path prefixes containing punctuation", async () => {
 			setupFolder(baseDir, {
 				files: {
+					"(foo).txt": "content",
 					"foo(bar).txt": "content",
 					"name[part].txt": "content",
 				},
@@ -508,6 +541,30 @@ describe("CombinedAutocompleteProvider", () => {
 			assert.strictEqual(parenResult?.prefix, "./foo(");
 			assert.ok(parenResult?.items.some((item) => item.value === "./foo(bar).txt"));
 
+			const completedParenLine = "./foo(bar).t";
+			const completedParenResult = await getSuggestions(
+				provider,
+				[completedParenLine],
+				0,
+				completedParenLine.length,
+				true,
+			);
+			assert.notEqual(completedParenResult, null, "Should preserve punctuation before file extensions");
+			assert.strictEqual(completedParenResult?.prefix, "./foo(bar).t");
+			assert.ok(completedParenResult?.items.some((item) => item.value === "./foo(bar).txt"));
+
+			const leadingPunctuationLine = "(foo).t";
+			const leadingPunctuationResult = await getSuggestions(
+				provider,
+				[leadingPunctuationLine],
+				0,
+				leadingPunctuationLine.length,
+				true,
+			);
+			assert.notEqual(leadingPunctuationResult, null, "Should preserve leading punctuation in filenames");
+			assert.strictEqual(leadingPunctuationResult?.prefix, "(foo).t");
+			assert.ok(leadingPunctuationResult?.items.some((item) => item.value === "(foo).txt"));
+
 			const bracketLine = "./name[";
 			const bracketResult = await getSuggestions(provider, [bracketLine], 0, bracketLine.length, true);
 			assert.notEqual(bracketResult, null, "Should return suggestions for path containing brackets");