mirror of
https://github.com/oven-sh/bun
synced 2026-02-16 22:01:47 +00:00
Add typeof Bun DCE support for --target=bun
- Handle typeof Bun !== 'undefined' and typeof Bun === 'undefined' patterns
- Support both direct identifier (typeof Bun) and dot expressions (typeof globalThis.Bun)
- Works with strict (===, !==) and loose (==, !=) equality operators
- Handles reverse comparisons ('undefined' === typeof Bun)
- Dead code elimination now works for all common Bun detection patterns
Test coverage includes:
- Direct Bun identifier checks
- globalThis.Bun property checks
- process.versions.bun property checks
- typeof Bun patterns (all variations)
All patterns properly eliminate dead code while preserving runtime values.
This commit is contained in:
Claude Bot
@@ -764,6 +764,110 @@ pub const SideEffects = enum(u1) {
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}
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}
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}
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// Check for typeof Bun patterns in binary expressions
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if (exp == .e_binary) {
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const e_ = exp.e_binary;
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switch (e_.op) {
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.bin_strict_eq, .bin_strict_ne, .bin_loose_eq, .bin_loose_ne => {
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// Check for typeof Bun !== "undefined" or typeof Bun === "undefined"
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if (e_.left.data == .e_unary) {
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const unary = e_.left.data.e_unary;
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if (unary.op == .un_typeof) {
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// Handle typeof identifier (e.g., typeof Bun)
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if (unary.value.data == .e_identifier) {
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const ident = unary.value.data.e_identifier;
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if (p.define.forIdentifier(p.loadNameFromRef(ident.ref))) |define| {
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if (define.is_truthy()) {
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// Bun is truthy, so typeof Bun is NOT "undefined"
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if (e_.right.data == .e_string) {
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const str = e_.right.data.e_string;
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if (str.eqlComptime("undefined")) {
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// typeof Bun === "undefined" -> false
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// typeof Bun !== "undefined" -> true
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const is_not_equal = e_.op == .bin_strict_ne or e_.op == .bin_loose_ne;
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return Result{ .ok = true, .value = is_not_equal, .side_effects = .could_have_side_effects };
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}
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}
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}
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}
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}
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// Handle typeof dot expression (e.g., typeof globalThis.Bun)
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if (unary.value.data == .e_dot) {
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const dot = unary.value.data.e_dot;
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if (p.define.dots.get(dot.name)) |parts| {
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for (parts) |*define| {
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if (p.isDotDefineMatch(unary.value, define.parts)) {
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if (define.data.is_truthy()) {
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// globalThis.Bun is truthy, so typeof globalThis.Bun is NOT "undefined"
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if (e_.right.data == .e_string) {
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const str = e_.right.data.e_string;
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if (str.eqlComptime("undefined")) {
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// typeof globalThis.Bun === "undefined" -> false
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// typeof globalThis.Bun !== "undefined" -> true
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const is_not_equal = e_.op == .bin_strict_ne or e_.op == .bin_loose_ne;
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return Result{ .ok = true, .value = is_not_equal, .side_effects = .could_have_side_effects };
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}
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}
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}
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break;
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}
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}
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}
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}
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}
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}
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// Also check the reverse: "undefined" === typeof Bun
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if (e_.right.data == .e_unary) {
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const unary = e_.right.data.e_unary;
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if (unary.op == .un_typeof) {
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// Handle typeof identifier (e.g., typeof Bun)
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if (unary.value.data == .e_identifier) {
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const ident = unary.value.data.e_identifier;
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if (p.define.forIdentifier(p.loadNameFromRef(ident.ref))) |define| {
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if (define.is_truthy()) {
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// Bun is truthy, so typeof Bun is NOT "undefined"
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if (e_.left.data == .e_string) {
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const str = e_.left.data.e_string;
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if (str.eqlComptime("undefined")) {
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// "undefined" === typeof Bun -> false
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// "undefined" !== typeof Bun -> true
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const is_not_equal = e_.op == .bin_strict_ne or e_.op == .bin_loose_ne;
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return Result{ .ok = true, .value = is_not_equal, .side_effects = .could_have_side_effects };
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}
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}
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}
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}
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}
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// Handle typeof dot expression (e.g., typeof globalThis.Bun)
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if (unary.value.data == .e_dot) {
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const dot = unary.value.data.e_dot;
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if (p.define.dots.get(dot.name)) |parts| {
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for (parts) |*define| {
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if (p.isDotDefineMatch(unary.value, define.parts)) {
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if (define.data.is_truthy()) {
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// globalThis.Bun is truthy, so typeof globalThis.Bun is NOT "undefined"
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if (e_.left.data == .e_string) {
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const str = e_.left.data.e_string;
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if (str.eqlComptime("undefined")) {
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// "undefined" === typeof globalThis.Bun -> false
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// "undefined" !== typeof globalThis.Bun -> true
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const is_not_equal = e_.op == .bin_strict_ne or e_.op == .bin_loose_ne;
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return Result{ .ok = true, .value = is_not_equal, .side_effects = .could_have_side_effects };
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}
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}
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}
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break;
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}
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}
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}
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}
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}
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}
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},
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else => {},
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}
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}
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return toBooleanWithoutDCECheck(exp);
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}
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@@ -187,6 +187,73 @@ test("compare dead code elimination: --target=bun vs --target=node", async () =>
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expect(nodeBundle).toContain("process.versions.node");
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});
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test("dead code elimination for typeof Bun checks with --target=bun", async () => {
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using dir = tempDir("bun-typeof-dce", {
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"index.js": `
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// Test typeof Bun checks
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if (typeof Bun !== "undefined") {
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exports.test1 = "bun-typeof";
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} else {
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exports.test1 = "not-bun-typeof";
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require("fs").writeFileSync("typeof-fail.txt", "should not exist");
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}
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// Test typeof globalThis.Bun checks
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if (typeof globalThis.Bun !== "undefined") {
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exports.test2 = "bun-typeof-global";
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} else {
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exports.test2 = "not-bun-typeof-global";
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require("fs").writeFileSync("typeof-global-fail.txt", "should not exist");
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}
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// Test reverse order
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if ("undefined" === typeof Bun) {
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exports.test3 = "not-bun-reverse";
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require("fs").writeFileSync("reverse-fail.txt", "should not exist");
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} else {
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exports.test3 = "bun-reverse";
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}
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// Test != instead of !==
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if (typeof Bun != "undefined") {
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exports.test4 = "bun-loose-ne";
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} else {
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exports.test4 = "not-bun-loose-ne";
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}
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`,
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});
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// Build with --target=bun
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await using bundleProc = Bun.spawn({
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cmd: [bunExe(), "build", "index.js", "--target=bun", "--outfile=bundle.js"],
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env: bunEnv,
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cwd: String(dir),
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stderr: "pipe",
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});
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const bundleCode = await bundleProc.exited;
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expect(bundleCode).toBe(0);
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const bundled = await Bun.file(String(dir) + "/bundle.js").text();
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// All "not-bun" branches should be eliminated
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expect(bundled).not.toContain("not-bun-typeof");
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expect(bundled).not.toContain("not-bun-typeof-global");
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expect(bundled).not.toContain("not-bun-reverse");
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expect(bundled).not.toContain("not-bun-loose-ne");
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// None of the fail files should be referenced
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expect(bundled).not.toContain("typeof-fail.txt");
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expect(bundled).not.toContain("typeof-global-fail.txt");
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expect(bundled).not.toContain("reverse-fail.txt");
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// The "bun" branches should remain
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expect(bundled).toContain("bun-typeof");
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expect(bundled).toContain("bun-typeof-global");
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expect(bundled).toContain("bun-reverse");
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expect(bundled).toContain("bun-loose-ne");
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});
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test("--target=bun does not hardcode runtime values", async () => {
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using dir = tempDir("bun-no-hardcode", {
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"index.js": `
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