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https://github.com/oven-sh/bun
synced 2026-02-09 10:28:47 +00:00
fix(parser): scope mismatch bug from parseSuffix (#23073)
### What does this PR do? esbuild returns `left` from the inner loop. This PR matches this behavior. Before it was breaking out of the inner loop and continuing through the outer loop, potentially parsing too far. fixes #22013 fixes #22384 ### How did you verify your code works? Added some tests. --------- Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
This commit is contained in:
Dylan Conway
@@ -827,24 +827,25 @@ pub fn ParseSuffix(
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const optional_chain = &optional_chain_;
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while (true) {
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if (p.lexer.loc().start == p.after_arrow_body_loc.start) {
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while (true) {
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switch (p.lexer.token) {
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.t_comma => {
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if (level.gte(.comma)) {
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break;
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}
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defer left_and_out.* = left_value;
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next_token: switch (p.lexer.token) {
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.t_comma => {
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if (level.gte(.comma)) {
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return;
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}
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try p.lexer.next();
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left.* = p.newExpr(E.Binary{
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.op = .bin_comma,
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.left = left.*,
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.right = try p.parseExpr(.comma),
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}, left.loc);
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},
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else => {
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break;
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},
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}
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try p.lexer.next();
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left.* = p.newExpr(E.Binary{
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.op = .bin_comma,
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.left = left.*,
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.right = try p.parseExpr(.comma),
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}, left.loc);
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continue :next_token p.lexer.token;
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},
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else => {
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return;
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},
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}
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}
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98
test/bundler/transpiler/scope-mismatch-panic.test.ts
Normal file
98
test/bundler/transpiler/scope-mismatch-panic.test.ts
Normal file
@@ -0,0 +1,98 @@
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import { describe, expect, test } from "bun:test";
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import { bunEnv, bunExe, tempDir } from "harness";
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describe("scope mismatch panic regression test", () => {
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test("should not panic with scope mismatch when arrow function is followed by array literal", async () => {
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// This test reproduces the exact panic that was fixed
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// The bug caused: "panic(main thread): Scope mismatch while visiting"
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using dir = tempDir("scope-mismatch", {
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"index.tsx": `
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const Layout = () => {
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return (
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<html>
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</html>
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)
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}
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['1', 'p'].forEach(i =>
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app.get(\`/\${i === 'home' ? '' : i}\`, c => c.html(
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<Layout selected={i}>
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Hello {i}
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</Layout>
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))
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)`,
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});
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// With the bug, this would panic with "Scope mismatch while visiting"
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// With the fix, it should fail with a normal ReferenceError for 'app'
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await using proc = Bun.spawn({
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cmd: [bunExe(), "index.tsx"],
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env: bunEnv,
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cwd: String(dir),
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stderr: "pipe",
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stdout: "pipe",
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});
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const [stdout, stderr, exitCode] = await Promise.all([proc.stdout.text(), proc.stderr.text(), proc.exited]);
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// The key assertion: should NOT panic with scope mismatch
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expect(stderr).not.toContain("panic");
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expect(stderr).not.toContain("Scope mismatch");
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// Should fail with a normal error instead (ReferenceError for undefined 'app')
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expect(stderr).toContain("ReferenceError");
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expect(stderr).toContain("app is not defined");
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expect(exitCode).not.toBe(0);
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});
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test("should not panic with simpler arrow function followed by array", async () => {
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using dir = tempDir("scope-mismatch-simple", {
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"test.js": `
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const fn = () => {
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return 1
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}
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['a', 'b'].forEach(x => console.log(x))`,
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});
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await using proc = Bun.spawn({
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cmd: [bunExe(), "test.js"],
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env: bunEnv,
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cwd: String(dir),
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stderr: "pipe",
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stdout: "pipe",
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});
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const [stdout, stderr, exitCode] = await Promise.all([proc.stdout.text(), proc.stderr.text(), proc.exited]);
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// Should not panic
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expect(stderr).not.toContain("panic");
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expect(stderr).not.toContain("Scope mismatch");
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// Should successfully execute
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expect(stdout).toBe("a\nb\n");
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expect(exitCode).toBe(0);
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});
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test("correctly rejects direct indexing into block body arrow function", async () => {
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using dir = tempDir("scope-mismatch-reject", {
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"test.js": `const fn = () => {return 1}['x']`,
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});
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await using proc = Bun.spawn({
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cmd: [bunExe(), "test.js"],
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env: bunEnv,
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cwd: String(dir),
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stderr: "pipe",
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stdout: "pipe",
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});
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const [stdout, stderr, exitCode] = await Promise.all([proc.stdout.text(), proc.stderr.text(), proc.exited]);
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// Should fail with a parse error, not a panic
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expect(stderr).not.toContain("panic");
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expect(stderr).not.toContain("Scope mismatch");
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expect(stderr).toContain("error"); // Parse error or similar
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expect(exitCode).not.toBe(0);
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});
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});
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@@ -3566,3 +3566,132 @@ it("Bun.Transpiler.transform stack overflows", async () => {
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const transpiler = new Bun.Transpiler();
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expect(async () => await transpiler.transform(code)).toThrow(`Maximum call stack size exceeded`);
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});
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describe("arrow function parsing after const declaration (scope mismatch bug)", () => {
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const transpiler = new Bun.Transpiler({ loader: "tsx" });
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it("reproduces the original scope mismatch bug with JSX", () => {
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// This is the exact pattern that caused the scope mismatch panic
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const code = `
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const Layout = () => {
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return (
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<html>
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</html>
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)
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}
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['1', 'p'].forEach(i =>
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app.get(\`/\${i === 'home' ? '' : i}\`, c => c.html(
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<Layout selected={i}>
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Hello {i}
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</Layout>
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))
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)`;
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// Without the fix, this would parse the array as indexing into the arrow function
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// causing a scope mismatch panic when visiting the AST
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const result = transpiler.transformSync(code);
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// The correct parse should have the array literal as a separate statement
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expect(result).toContain("forEach");
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// The bug would incorrectly parse as: })["1", "p"]
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expect(result).not.toContain(')["');
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expect(result).not.toContain('}["');
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});
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it("correctly parses array literal on next line after block body arrow function", () => {
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const code = `const Layout = () => {
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return 1
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}
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['1', 'p'].forEach(i => console.log(i))`;
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const result = transpiler.transformSync(code);
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expect(result).toContain("forEach");
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// The bug would cause the array to be parsed as indexing: Layout[...
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expect(result).not.toContain(')["');
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});
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it("correctly parses JSX arrow function followed by array literal", () => {
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const code = `const Layout = () => {
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return (
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<html>
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</html>
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)
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}
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['1', 'p'].forEach(i => console.log(i))`;
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const result = transpiler.transformSync(code);
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expect(result).toContain("forEach");
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expect(result).not.toContain("Layout[");
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});
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it("rejects indexing directly into block body arrow function without parens", () => {
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const code = `const Layout = () => {return 1}['x']`;
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// Should throw a parse error - either "Parse error" or the more specific message
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expect(() => transpiler.transformSync(code)).toThrow();
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});
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it("allows indexing into parenthesized arrow function", () => {
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const code = `const x = (() => {return {a: 1}})['a']`;
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const result = transpiler.transformSync(code);
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expect(result).toContain('["a"]');
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});
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it("correctly handles expression body arrow functions", () => {
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const code = `const Layout = () => 1
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['1', 'p'].forEach(i => console.log(i))`;
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const result = transpiler.transformSync(code);
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expect(result).toContain("forEach");
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});
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it("correctly handles arrow function with comma operator", () => {
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const code = `const a = () => {return 1}, b = 2`;
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const result = transpiler.transformSync(code);
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expect(result).toContain("b = 2");
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});
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it("correctly handles multiple arrow functions in const declaration", () => {
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const code = `const a = () => {return 1}, b = () => {return 2}
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['1', '2'].forEach(x => console.log(x))`;
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const result = transpiler.transformSync(code);
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expect(result).toContain("forEach");
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expect(result).not.toContain("b[");
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});
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it("preserves intentional array access with explicit semicolon", () => {
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const code = `const Layout = () => {return 1};
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['1', 'p'].forEach(i => console.log(i))`;
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const result = transpiler.transformSync(code);
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expect(result).toContain("forEach");
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expect(result).not.toContain("Layout[");
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});
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it("handles nested arrow functions correctly", () => {
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const code = `const outer = () => {
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const inner = () => {
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return 1
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}
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return inner
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}
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['test'].forEach(x => x)`;
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const result = transpiler.transformSync(code);
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expect(result).toContain("forEach");
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});
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it("handles arrow function followed by object literal", () => {
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const code = `const fn = () => {return 1}
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({a: 1, b: 2}).a`;
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const result = transpiler.transformSync(code);
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expect(result).toContain("a: 1");
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expect(result).not.toContain("fn(");
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});
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});
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