From d396a800f63d8c793bbdb9c078f96412ac895395 Mon Sep 17 00:00:00 2001
From: Shadowfacts <me@shadowfacts.net>
Date: Sun, 17 Dec 2023 18:32:00 -0500
Subject: [PATCH] Fix handling of mis-nested <a> tags

---
 .../HTMLStreamer/AttributedStringConverter.swift  |  9 +++++++--
 .../AttributedStringConverterTests.swift          | 15 +++++++++++++++
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/Sources/HTMLStreamer/AttributedStringConverter.swift b/Sources/HTMLStreamer/AttributedStringConverter.swift
index eb3c7e1..d2f3170 100644
--- a/Sources/HTMLStreamer/AttributedStringConverter.swift
+++ b/Sources/HTMLStreamer/AttributedStringConverter.swift
@@ -151,7 +151,7 @@ public struct AttributedStringConverter<Callbacks: AttributedStringCallbacks> {
     private mutating func handleEndTag(_ name: String) {
         switch name {
         case "a":
-            if case .link(.some(_)) = styleStack.last {
+            if case .link(.some(_)) = lastStyle(.link) {
                 finishRun()
             }
             removeLastStyle(.link)
@@ -186,7 +186,8 @@ public struct AttributedStringConverter<Callbacks: AttributedStringCallbacks> {
         }
     }
     
-    // needed to correctly handle mis-nested tags
+    // Finds the last currently-open style of the given type.
+    // We can't just use the last one because we need to handle mis-nested tags.
     private mutating func removeLastStyle(_ type: Style.StyleType) {
         var i = styleStack.index(before: styleStack.endIndex)
         while i >= styleStack.startIndex {
@@ -198,6 +199,10 @@ public struct AttributedStringConverter<Callbacks: AttributedStringCallbacks> {
         }
     }
     
+    private func lastStyle(_ type: Style.StyleType) -> Style? {
+        styleStack.last { $0.type == type }
+    }
+    
     private lazy var blockquoteParagraphStyle: NSParagraphStyle = {
         let style = configuration.paragraphStyle.mutableCopy() as! NSMutableParagraphStyle
         style.headIndent = 32
diff --git a/Tests/HTMLStreamerTests/AttributedStringConverterTests.swift b/Tests/HTMLStreamerTests/AttributedStringConverterTests.swift
index fda40fb..14e2d3d 100644
--- a/Tests/HTMLStreamerTests/AttributedStringConverterTests.swift
+++ b/Tests/HTMLStreamerTests/AttributedStringConverterTests.swift
@@ -119,6 +119,21 @@ final class AttributedStringConverterTests: XCTestCase {
         XCTAssertEqual(convert("<strong>bold <em>both</strong> italic</em>"), result)
     }
     
+    func testMisnestedLink() {
+        let result = NSMutableAttributedString()
+        result.append(NSAttributedString(string: "hello ", attributes: [
+            .link: URL(string: "https://example.com")!,
+            .font: font,
+            .paragraphStyle: NSParagraphStyle.default,
+        ]))
+        result.append(NSAttributedString(string: "world", attributes: [
+            .link: URL(string: "https://example.com")!,
+            .font: boldFont,
+            .paragraphStyle: NSParagraphStyle.default,
+        ]))
+        XCTAssertEqual(convert("<a href='https://example.com'>hello <b>world</a></b>"), result)
+    }
+    
     func testDel() {
         XCTAssertEqual(convert("<del>blah</del>"), NSAttributedString(string: "blah", attributes: [
             .font: font,