Add ToRegex method to WildcardPattern class (PowerShell#26515)

Author: yotsuda

src/System.Management.Automation/engine/regex.cs

@@ -73,18 +73,6 @@ public sealed class WildcardPattern
         // Default is WildcardOptions.None.
         internal WildcardOptions Options { get; }
 
-        /// <summary>
-        /// Wildcard pattern converted to regex pattern.
-        /// </summary>
-        internal string PatternConvertedToRegex
-        {
-            get
-            {
-                var patternRegex = WildcardPatternToRegexParser.Parse(this);
-                return patternRegex.ToString();
-            }
-        }
-
         /// <summary>
         /// Initializes and instance of the WildcardPattern class
         /// for the specified wildcard pattern.
@@ -205,6 +193,35 @@ public bool IsMatch(string input)
             return input != null && _isMatch(input);
         }
 
+        /// <summary>
+        /// Converts the wildcard pattern to its regular expression equivalent.
+        /// </summary>
+        /// <returns>
+        /// A <see cref="Regex"/> object that represents the regular expression equivalent of the wildcard pattern.
+        /// The regex is configured with options matching the wildcard pattern's options.
+        /// </returns>
+        /// <remarks>
+        /// This method converts a wildcard pattern to a regular expression.
+        /// The conversion follows these rules:
+        /// <list type="bullet">
+        /// <item><description>* (asterisk) converts to .* (matches any string)</description></item>
+        /// <item><description>? (question mark) converts to . (matches any single character)</description></item>
+        /// <item><description>[abc] (bracket expression) converts to [abc] (matches any character in the set)</description></item>
+        /// <item><description>Literal characters are escaped as needed for regex</description></item>
+        /// </list>
+        /// </remarks>
+        /// <example>
+        /// <code>
+        /// var pattern = new WildcardPattern("*.txt");
+        /// Regex regex = pattern.ToRegex();
+        /// // regex.ToString() returns: "\.txt$"
+        /// </code>
+        /// </example>
+        public Regex ToRegex()
+        {
+            return WildcardPatternToRegexParser.Parse(this);
+        }
+
         /// <summary>
         /// Escape special chars, except for those specified in <paramref name="charsNotToEscape"/>, in a string by replacing them with their escape codes.
         /// </summary>

test/powershell/engine/WildcardPattern.Tests.ps1

@@ -0,0 +1,77 @@
+# Copyright (c) Microsoft Corporation.
+# Licensed under the MIT License.
+
+Describe "WildcardPattern.ToRegex Tests" -Tags "CI" {
+    It "Converts '<Pattern>' to regex pattern '<Expected>'" -TestCases @(
+        @{ Pattern = '*.txt'; Expected = '\.txt$' }
+        @{ Pattern = 'test?.log'; Expected = '^test.\.log$' }
+        @{ Pattern = 'file[0-9].txt'; Expected = '^file[0-9]\.txt$' }
+        @{ Pattern = 'test.log'; Expected = '^test\.log$' }
+        @{ Pattern = '*test*file*.txt'; Expected = 'test.*file.*\.txt$' }
+        @{ Pattern = 'file[0-9][a-z].txt'; Expected = '^file[0-9][a-z]\.txt$' }
+        @{ Pattern = 'test*'; Expected = '^test' }
+        @{ Pattern = '*test*'; Expected = 'test' }
+    ) {
+        param($Pattern, $Expected)
+        $wildcardPattern = [System.Management.Automation.WildcardPattern]::new($Pattern)
+        $regex = $wildcardPattern.ToRegex()
+        $regex | Should -BeOfType ([regex])
+        $regex.ToString() | Should -BeExactly $Expected
+    }
+
+    It "Converts '<Pattern>' with <OptionName> option" -TestCases @(
+        @{ Pattern = 'TEST'; OptionName = 'IgnoreCase'; Option = [System.Management.Automation.WildcardOptions]::IgnoreCase; Expected = '^TEST$'; ExpectedRegexOptions = 'IgnoreCase, Singleline'; TestString = 'test'; ExpectedMatch = $true }
+        @{ Pattern = 'test'; OptionName = 'CultureInvariant'; Option = [System.Management.Automation.WildcardOptions]::CultureInvariant; Expected = '^test$'; ExpectedRegexOptions = 'Singleline, CultureInvariant'; TestString = 'test'; ExpectedMatch = $true }
+        @{ Pattern = 'test*'; OptionName = 'Compiled'; Option = [System.Management.Automation.WildcardOptions]::Compiled; Expected = '^test'; ExpectedRegexOptions = 'Compiled, Singleline'; TestString = 'testing'; ExpectedMatch = $true }
+    ) {
+        param($Pattern, $OptionName, $Option, $Expected, $ExpectedRegexOptions, $TestString, $ExpectedMatch)
+        $wildcardPattern = [System.Management.Automation.WildcardPattern]::new($Pattern, $Option)
+        $regex = $wildcardPattern.ToRegex()
+        $regex | Should -BeOfType ([regex])
+        $regex.ToString() | Should -BeExactly $Expected
+        $regex.Options.ToString() | Should -BeExactly $ExpectedRegexOptions
+        $regex.IsMatch($TestString) | Should -Be $ExpectedMatch
+    }
+
+    It "Regex from '<Pattern>' matches '<TestString>': <ShouldMatch>" -TestCases @(
+        @{ Pattern = '*test*file*.txt'; TestString = 'mytestmyfile123.txt'; ShouldMatch = $true }
+        @{ Pattern = 'file[0-9][a-z].txt'; TestString = 'file5a.txt'; ShouldMatch = $true }
+        @{ Pattern = 'file[0-9][a-z].txt'; TestString = 'file55.txt'; ShouldMatch = $false }
+    ) {
+        param($Pattern, $TestString, $ShouldMatch)
+        $regex = [System.Management.Automation.WildcardPattern]::new($Pattern).ToRegex()
+        $regex.IsMatch($TestString) | Should -Be $ShouldMatch
+    }
+
+    Context "Edge cases" {
+        It "Handles empty pattern" {
+            $pattern = [System.Management.Automation.WildcardPattern]::new("")
+            $regex = $pattern.ToRegex()
+            $regex | Should -BeOfType ([regex])
+            $regex.ToString() | Should -Be "^$"
+        }
+
+        It "Handles pattern with only asterisk" {
+            $pattern = [System.Management.Automation.WildcardPattern]::new("*")
+            $regex = $pattern.ToRegex()
+            $regex | Should -BeOfType ([regex])
+            $regex.ToString() | Should -BeExactly ""
+            $regex.IsMatch("anything") | Should -BeTrue
+            $regex.IsMatch("") | Should -BeTrue
+        }
+
+        It "Handles escaped '<Char>' wildcard character" -TestCases @(
+            @{ Char = '*'; Pattern = 'file`*.txt'; Expected = '^file\*\.txt$' }
+            @{ Char = '?'; Pattern = 'file`?.txt'; Expected = '^file\?\.txt$' }
+            @{ Char = '['; Pattern = 'file`[.txt'; Expected = '^file\[\.txt$' }
+            @{ Char = ']'; Pattern = 'file`].txt'; Expected = '^file]\.txt$' }
+        ) {
+            param($Char, $Pattern, $Expected)
+            $wildcardPattern = [System.Management.Automation.WildcardPattern]::new($Pattern)
+            $regex = $wildcardPattern.ToRegex()
+            $regex | Should -BeOfType ([regex])
+            $regex.ToString() | Should -BeExactly $Expected
+        }
+
+    }
+}