fix(yaml): double-quoted strings with '...' incorrectly trigger document end error (#23491)

### What does this PR do?

Fixes #23489

The YAML parser was incorrectly treating `...` inside double-quoted
strings as document end markers, causing parse errors for strings
containing ellipsis, particularly affecting internationalized text.

### Example of the bug:
```yaml
balance: "👛 لا تمتلك محفظة... !"
```

This would fail with: `error: Unexpected document end`

### Root cause:

The bug was introduced in commit fcbd57ac48 which attempted to optimize
document marker detection by using `self.line_indent == .none` instead
of tracking newlines with a local flag. However, this check was
incomplete - it didn't track whether we had just processed a newline
character.

### The fix:

Restored the `nl` (newline) flag pattern from the single-quoted scanner
and combined it with the `line_indent` check. Document markers `...` and
`---` are now only recognized when **all** of these conditions are met:

1. We're after a newline (`nl == true`)
2. We're at column 0 (`self.line_indent == .none`)
3. Followed by whitespace or EOF

This allows `...` to appear freely in double-quoted strings while still
correctly recognizing actual document end markers at the start of lines.

### How did you verify your code works?

1. Reproduced the original issue from #23489
2. Applied the fix and verified all test cases pass:
   - Original Arabic text with emoji: `"👛 لا تمتلك محفظة... !"`
   - Various `...` positions: start, middle, end
   - Both single and double quotes
   - Multiline strings with indented `...` (issue #22392)
3. Created regression test in `test/regression/issue/23489.test.ts`
4. Verified existing YAML tests still pass (514 pass, up from 513)

cc @dylan-conway for review

---------

Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
Co-authored-by: Dylan Conway <dylan.conway567@gmail.com>

src/interchange/yaml.zig

@@ -3117,7 +3117,7 @@ pub fn Parser(comptime enc: Encoding) type {
                 0 => return error.UnexpectedCharacter,
 
                 '.' => {
-                    if (nl and self.remainStartsWith("...") and self.isSWhiteOrBCharAt(3)) {
+                    if (nl and self.line_indent == .none and self.remainStartsWith("...") and self.isSWhiteOrBCharAt(3)) {
                         return error.UnexpectedDocumentEnd;
                     }
                     nl = false;
@@ -3127,7 +3127,7 @@ pub fn Parser(comptime enc: Encoding) type {
                 },
 
                 '-' => {
-                    if (nl and self.remainStartsWith("---") and self.isSWhiteOrBCharAt(3)) {
+                    if (nl and self.line_indent == .none and self.remainStartsWith("---") and self.isSWhiteOrBCharAt(3)) {
                         return error.UnexpectedDocumentStart;
                     }
                     nl = false;
@@ -3212,22 +3212,26 @@ pub fn Parser(comptime enc: Encoding) type {
             const scalar_indent = self.line_indent;
             var text: std.ArrayList(enc.unit()) = .init(self.allocator);
 
+            var nl = false;
+
             next: switch (self.next()) {
                 0 => return error.UnexpectedCharacter,
 
                 '.' => {
-                    if (self.line_indent == .none and self.remainStartsWith("...") and self.isSWhiteOrBCharAt(3)) {
+                    if (nl and self.line_indent == .none and self.remainStartsWith("...") and self.isSWhiteOrBCharAt(3)) {
                         return error.UnexpectedDocumentEnd;
                     }
+                    nl = false;
                     try text.append('.');
                     self.inc(1);
                     continue :next self.next();
                 },
 
                 '-' => {
-                    if (self.line_indent == .none and self.remainStartsWith("---") and self.isSWhiteOrBCharAt(3)) {
+                    if (nl and self.line_indent == .none and self.remainStartsWith("---") and self.isSWhiteOrBCharAt(3)) {
                         return error.UnexpectedDocumentStart;
                     }
+                    nl = false;
                     try text.append('-');
                     self.inc(1);
                     continue :next self.next();
@@ -3248,12 +3252,14 @@ pub fn Parser(comptime enc: Encoding) type {
                             return error.UnexpectedCharacter;
                         }
                     }
+                    nl = true;
                     continue :next self.next();
                 },
 
                 ' ',
                 '\t',
                 => {
+                    nl = false;
                     const off = self.pos;
                     self.inc(1);
                     self.skipSWhite();
@@ -3264,6 +3270,7 @@ pub fn Parser(comptime enc: Encoding) type {
                 },
 
                 '"' => {
+                    nl = false;
                     self.inc(1);
                     return .scalar(.{
                         .start = start,
@@ -3280,6 +3287,7 @@ pub fn Parser(comptime enc: Encoding) type {
                 },
 
                 '\\' => {
+                    nl = false;
                     self.inc(1);
                     switch (self.next()) {
                         '\r',
@@ -3350,6 +3358,7 @@ pub fn Parser(comptime enc: Encoding) type {
                 },
 
                 else => |c| {
+                    nl = false;
                     try text.append(c);
                     self.inc(1);
                     continue :next self.next();

test/js/bun/yaml/yaml.test.ts

@@ -494,6 +494,58 @@ document: 2
       expect(YAML.parse(yaml)).toEqual([{ document: 1 }, { document: 2 }]);
     });
 
+    test("document markers in quoted strings", () => {
+      const inputs = [
+        { expected: "hi ... hello", input: '"hi ... hello"' },
+        { expected: "hi ... hello", input: "'hi ... hello'" },
+        { expected: { foo: "hi ... hello" }, input: 'foo: "hi ... hello"' },
+        { expected: { foo: "hi ... hello" }, input: "foo: 'hi ... hello'" },
+        {
+          expected: "hi ... hello",
+          input: `"hi
+  ...
+  hello"`,
+        },
+        {
+          expected: "hi ... hello",
+          input: `'hi
+  ...
+  hello'`,
+        },
+        {
+          expected: { foo: "hi ... hello" },
+          input: `foo: "hi
+  ...
+  hello"`,
+        },
+        {
+          expected: { foo: "hi ... hello" },
+          input: `foo: 'hi
+  ...
+  hello'`,
+        },
+        {
+          expected: { foo: { bar: "hi ... hello" } },
+          input: `foo:
+  bar: "hi
+    ...
+    hello"`,
+        },
+        {
+          expected: { foo: { bar: "hi ... hello" } },
+          input: `foo:
+  bar: 'hi
+    ...
+    hello'`,
+        },
+      ];
+
+      for (const { input, expected } of inputs) {
+        expect(YAML.parse(input)).toEqual(expected);
+        expect(YAML.parse(YAML.stringify(YAML.parse(input)))).toEqual(expected);
+      }
+    });
+
     test("handles multiline strings", () => {
       const yaml = `
 literal: |

test/regression/issue/23489.test.ts

@@ -0,0 +1,58 @@
+import { YAML } from "bun";
+import { expect, test } from "bun:test";
+import { bunEnv, bunExe, tempDir } from "harness";
+
+test("YAML double-quoted strings with ... should not trigger document end error - issue #23489", () => {
+  // Test the original failing case with Arabic text and emoji
+  const yaml1 = 'balance_dont_have_wallet: "👛 لا تمتلك محفظة... !"';
+  const result1 = YAML.parse(yaml1);
+  expect(result1).toEqual({
+    balance_dont_have_wallet: "👛 لا تمتلك محفظة... !",
+  });
+
+  // Test various patterns of ... in double-quoted strings
+  const yaml2 = `test1: "this has ... dots"
+test2: "... at start"
+test3: "at end ..."
+test4: "👛 ... with emoji"`;
+  const result2 = YAML.parse(yaml2);
+  expect(result2).toEqual({
+    test1: "this has ... dots",
+    test2: "... at start",
+    test3: "at end ...",
+    test4: "👛 ... with emoji",
+  });
+
+  // Test that both single and double quotes work
+  const yaml3 = `single: 'this has ... dots'
+double: "this has ... dots"`;
+  const result3 = YAML.parse(yaml3);
+  expect(result3).toEqual({
+    single: "this has ... dots",
+    double: "this has ... dots",
+  });
+});
+
+test("YAML import with double-quoted strings containing ... - issue #23489", async () => {
+  using dir = tempDir("yaml-ellipsis", {
+    "test.yml": 'balance: "👛 لا تمتلك محفظة... !"',
+    "test.ts": `
+      import yaml from "./test.yml";
+      console.log(JSON.stringify(yaml));
+    `,
+  });
+
+  await using proc = Bun.spawn({
+    cmd: [bunExe(), "test.ts"],
+    env: bunEnv,
+    cwd: String(dir),
+    stdout: "pipe",
+    stderr: "pipe",
+  });
+
+  const [stdout, stderr, exitCode] = await Promise.all([proc.stdout.text(), proc.stderr.text(), proc.exited]);
+
+  expect(stderr).not.toContain("Unexpected document end");
+  expect(exitCode).toBe(0);
+  expect(stdout.trim()).toBe('{"balance":"👛 لا تمتلك محفظة... !"}');
+});