Compiled regex incorrectly removes the captures which captured in positive lookbehind assertions #117651
Description
Description
I saw u added a test yield return (@"(?<=(abc)+?123)", "abcabc123", RegexOptions.None, 0, 9, true, ""); on line 135 in file Regex.Match.Tests.cs.
Based on this, I found a new bug:
In Compiled mode, when leaving positive lookbehind assertions, the .NET regex engine will remove all the captures which captured by the last direct group construction(the last direct child node).
By the way, I found that when leaving negative assertions, the .NET regex engine would not delete captures which captured in the assertion on .NET8, but this bug fixed on .NET9.
For example:
using System;
using System.Text.RegularExpressions;
Console.WriteLine(new Regex("(?<!x())a",RegexOptions.Compiled).Match("a").Groups[1].Captures.Count);
Console.WriteLine(new Regex("(?!()x)a",RegexOptions.Compiled).Match("a").Groups[1].Captures.Count);Output on .NET8:
1
1
Maybe they are related?
Reproduction Steps
using System;
using System.Text.RegularExpressions;
string input = "abcabc123a";
string pattern="(?<=(abc)+?123)a";
//pattern="(?'1')(?<=(?'1'abc)+?(?#<=just delete the left capture)(?'1'abc)+?123)a";
//pattern="(?'1')(?<=(?'1'abc)+?(?'2')123)a";//the capture of group#1 was removed, but the capture of group#2 wasn't
//pattern="(?<=(abc){2,}?123)a";//two captures of group#1 which captured in the positive lookbehind assertions(?<=) are both deleted
//pattern="(?<=(abc){2}?123)a";//not deleted
//pattern=@"(?<=\1?(abc){2,}?123)a";//not deleted
//pattern="(?<=(?(1))(abc){2,}?123)a";//not deleted
//pattern="(?<=(?'-1')?(abc){2,}?123)a";//not deleted
//pattern="1(?=x(abc)+?)";input="1xabc";//not deleted in positinve lookahead assertions
//pattern="1(?=(abc)+?x)";input="1abcx";//not deleted in positinve lookahead assertions
try
{
Console.WriteLine("----------Compiled----------");
Match matchCompiled = new Regex(pattern, RegexOptions.Compiled).Match(input);
Console.WriteLine(matchCompiled.Value);
Console.WriteLine(matchCompiled.Groups[1].Captures.Count);
Console.WriteLine("Groups#1 Captures：");
foreach(Capture c in matchCompiled.Groups[1].Captures)
Console.WriteLine($"{c.Value}，{c.Index}，{c.Length}");
Console.WriteLine("----------Interpreted----------");
Match Interpreted= new Regex(pattern, RegexOptions.None).Match(input);
Console.WriteLine(Interpreted.Value);
Console.WriteLine(Interpreted.Groups[1].Captures.Count);
Console.WriteLine("Groups#1 Captures：");
foreach(Capture c in Interpreted.Groups[1].Captures)
Console.WriteLine($"{c.Value}，{c.Index}，{c.Length}");
Console.WriteLine("----------result comparion----------");
Console.WriteLine($"Result equal：{matchCompiled.Groups[1].Captures.Count == Interpreted.Groups[1].Captures.Count}");
}
catch(Exception ex)
{
Console.WriteLine(ex.Message);
}Expected behavior
Output:
----------Compiled----------
a
1
Groups#1 Captures：
abc，3，3
----------Interpreted----------
a
1
Groups#1 Captures：
abc，3，3
----------result comparion----------
Result equal：True
Actual behavior
Output:
----------Compiled----------
a
0
Groups#1 Captures：
----------Interpreted----------
a
1
Groups#1 Captures：
abc，3，3
----------result comparion----------
Result equal：False
Regression?
No response
Known Workarounds
No response
Configuration
No response
Other information
No response