Fixes #3031 (#3041)

* Fixes #3031

* Leave original input in there

---------

Co-authored-by: Jarred Sumner <709451+Jarred-Sumner@users.noreply.github.com>

3 files changed, 105 insertions, 2 deletions

diff --git a/src/js_printer.zig b/src/js_printer.zig
index 54aa0150c..af820520e 100644
--- a/src/js_printer.zig
+++ b/src/js_printer.zig
@@ -1942,6 +1942,65 @@ fn NewPrinter(
             }
         }
 
+        fn printRawTemplateLiteral(p: *Printer, bytes: []const u8) void {
+            if (comptime is_json or !ascii_only) {
+                p.print(bytes);
+                return;
+            }
+
+            // Translate any non-ASCII to unicode escape sequences
+            // Note that this does not correctly handle malformed template literal strings
+            // template literal strings can contain invalid unicode code points
+            // and pretty much anything else
+            //
+            // we use WTF-8 here, but that's still not good enough.
+            //
+            var ascii_start: usize = 0;
+            var is_ascii = false;
+            var iter = CodepointIterator.init(bytes);
+            var cursor = CodepointIterator.Cursor{};
+
+            while (iter.next(&cursor)) {
+                switch (cursor.c) {
+                    // unlike other versions, we only want to mutate > 0x7F
+                    0...last_ascii => {
+                        if (!is_ascii) {
+                            ascii_start = cursor.i;
+                            is_ascii = true;
+                        }
+                    },
+                    else => {
+                        if (is_ascii) {
+                            p.print(bytes[ascii_start..cursor.i]);
+                            is_ascii = false;
+                        }
+
+                        switch (cursor.c) {
+                            0...0xFFFF => {
+                                p.print([_]u8{
+                                    '\\',
+                                    'u',
+                                    hex_chars[cursor.c >> 12],
+                                    hex_chars[(cursor.c >> 8) & 15],
+                                    hex_chars[(cursor.c >> 4) & 15],
+                                    hex_chars[cursor.c & 15],
+                                });
+                            },
+                            else => {
+                                p.print("\\u{");
+                                std.fmt.formatInt(cursor.c, 16, .lower, .{}, p) catch unreachable;
+                                p.print("}");
+                            },
+                        }
+                    },
+                }
+            }
+
+            if (is_ascii) {
+                p.print(bytes[ascii_start..]);
+            }
+        }
+
         pub fn printExpr(p: *Printer, expr: Expr, level: Level, _flags: ExprFlag.Set) void {
             var flags = _flags;
 
@@ -2553,7 +2612,7 @@ fn NewPrinter(
 
                     p.print("`");
                     switch (e.head) {
-                        .raw => |raw| p.print(raw),
+                        .raw => |raw| p.printRawTemplateLiteral(raw),
                         .cooked => |*cooked| {
                             if (cooked.isPresent()) {
                                 cooked.resolveRopeIfNeeded(p.options.allocator);
@@ -2567,7 +2626,7 @@ fn NewPrinter(
                         p.printExpr(part.value, .lowest, ExprFlag.None());
                         p.print("}");
                         switch (part.tail) {
-                            .raw => |raw| p.print(raw),
+                            .raw => |raw| p.printRawTemplateLiteral(raw),
                             .cooked => |*cooked| {
                                 if (cooked.isPresent()) {
                                     cooked.resolveRopeIfNeeded(p.options.allocator);
diff --git a/test/transpiler/template-literal-fixture-test.js b/test/transpiler/template-literal-fixture-test.js
new file mode 100644
index 000000000..20fbfbdb1
--- /dev/null
+++ b/test/transpiler/template-literal-fixture-test.js
@@ -0,0 +1,22 @@
+console.write ??= process.stdout.write.bind(process.stdout);
+var bufs = [];
+function template(...args) {
+  bufs.push(Buffer.from(args.join("")));
+}
+
+template`🐰123`;
+template`123🐰`;
+template`🐰`;
+template`🐰🐰`;
+template`🐰🐰123`;
+template`🐰123🐰123`;
+template`123🐰`;
+template`123🐰123`;
+template`🐰${(globalThis.boop ||= true)}🐰`;
+const outBuf = Buffer.concat(bufs);
+const out = outBuf.toString("base64");
+console.write(out);
+if (!outBuf.equals(Buffer.from(out, "base64"))) {
+  throw new Error("Buffer mismatch");
+}
+process.exit(0);
diff --git a/test/transpiler/template-literal.test.ts b/test/transpiler/template-literal.test.ts
new file mode 100644
index 000000000..a0fd2170f
--- /dev/null
+++ b/test/transpiler/template-literal.test.ts
@@ -0,0 +1,22 @@
+import { test, expect } from "bun:test";
+import { bunEnv, bunExe } from "harness";
+import { join } from "path";
+
+// When targeting Bun's runtime,
+// We must escape latin1 characters in raw template literals
+// This is somewhat brittle
+test("template literal", () => {
+  const { stdout, exitCode } = Bun.spawnSync({
+    cmd: [bunExe(), "run", join(import.meta.dir, "template-literal-fixture-test.js")],
+    env: bunEnv,
+    stdout: "pipe",
+    stderr: "inherit",
+  });
+
+  expect(exitCode).toBe(0);
+  expect(stdout.toString()).toBe(
+    // This is base64 encoded contents of the template literal
+    // this narrows down the test to the transpiler instead of the runtime
+    "8J+QsDEyMzEyM/CfkLDwn5Cw8J+QsPCfkLDwn5Cw8J+QsDEyM/CfkLAxMjPwn5CwMTIzMTIz8J+QsDEyM/CfkLAxMjPwn5CwLPCfkLB0cnVl",
+  );
+});