Link parsing conflicts with autodetection when the link text happens to be recognized as something to link as well

[gentwo]

Consider the following markdown text:

[foo@bar.com](mailto://foo@bar.com)

In the above case, it appears that auto-detection overrides the original link (which does correctly identify the URL as mailto://foo@bar.com with the text of the link ie (foo@bar.com).

[Mr. Foo](mailto://foo@bar.com)

therefore works.

Not sure how this should be fixed, but one thought is that if a link text already has a link associated with it, then don't override with autodetect link... There may be more complicated use cases like:

[send a mail to foo@bar.com](mailto://foo@bar.com)

ie the link text range and the autodetect link text range may be different. I am going to attempt to fix this, but would like to hear feedback on the above suggestion or other ideas on a solution.

[gentwo]

Some additional information. The rationale for my conclusion is as follows: Debugging this: it looks like for the above text, the following sections of TSMarkdownParser.m are both called, with the first one being called first (with the correct URL) and the second one being called later (with the link text).

--> explicit link with link text

    [defaultParser addLinkParsingWithLinkFormattingBlock:^(NSMutableAttributedString *attributedString, NSRange range, NSString * _Nullable link) {
        if (!weakParser.skipLinkAttribute) {
            NSURL *url = [NSURL URLWithString:link] ?: [NSURL URLWithString:
                                                        [link stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
            if (url) {
                [attributedString addAttribute:NSLinkAttributeName
                                         value:url
                                         range:range];
            }
        }
        [attributedString addAttributes:weakParser.linkAttributes range:range];
    }];

--> Auto detection

    /* autodetection */
    
    [defaultParser addLinkDetectionWithLinkFormattingBlock:^(NSMutableAttributedString *attributedString, NSRange range, NSString * _Nullable link) {
        if (!weakParser.skipLinkAttribute) {
            [attributedString addAttribute:NSLinkAttributeName
                                     value:[NSURL URLWithString:link]
                                     range:range];
        }
        [attributedString addAttributes:weakParser.linkAttributes range:range];
    }];

[gentwo]

Test to confirm the above:

- (void)testStandardLinkParsingAutodetectionConflict {
  NSAttributedString *attributedString = [self.standardParser attributedStringFromMarkdown:@"Hello\n This is a [foo@bar.com](https://www.example.net/) to test Wi-Fi\nat home"];
  NSURL *link = [attributedString attribute:NSLinkAttributeName atIndex:20 effectiveRange:NULL];
  XCTAssertEqualObjects(link, [NSURL URLWithString:@"https://www.example.net/"]);
  XCTAssertTrue([attributedString.string rangeOfString:@"["].location == NSNotFound);
  XCTAssertTrue([attributedString.string rangeOfString:@"]"].location == NSNotFound);
  XCTAssertTrue([attributedString.string rangeOfString:@"("].location == NSNotFound);
  XCTAssertTrue([attributedString.string rangeOfString:@")"].location == NSNotFound);
  XCTAssertTrue([attributedString.string rangeOfString:@"foo@bar.com"].location != NSNotFound);
  NSNumber *underline = [attributedString attribute:NSUnderlineStyleAttributeName atIndex:20 effectiveRange:NULL];
  XCTAssertEqualObjects(underline, @(NSUnderlineStyleSingle));
  UIColor *linkColor = [attributedString attribute:NSForegroundColorAttributeName atIndex:20 effectiveRange:NULL];
  XCTAssertEqualObjects(linkColor, [UIColor blueColor]);

  NSURL *linkAtTheNextCharacter = [attributedString attribute:NSLinkAttributeName atIndex:21 effectiveRange:NULL]; 
  XCTAssertNil(linkAtTheNextCharacter); // THIS ASSERTION ALSO FAILS. DID NOT EXPECT THIS.
}

NOTE: The last assert also fails, which was unexpected.

[Coeur]

I didn't see assertion failures in your pull request.
Thank you for reporting the issue and fixing it. I'll make a new release in a few minutes.