Handle unicode in absolute URI path for combine. (#111710)

* Handle unicode in absolute URI path for combine.
* Adding debug assert

Co-authored-by: Miha Zupan <[email protected]>

Author: rokonec

src/libraries/System.Private.Uri/src/System/UriExt.cs

@@ -1053,30 +1053,42 @@ private void CreateThisFromUri(Uri otherUri)
         {
             DebugAssertInCtor();
 
-            // Clone the other URI but develop own UriInfo member
-            _info = null!;
-
             _flags = otherUri._flags;
-            if (InFact(Flags.MinimalUriInfoSet))
+
+            if (InFact(Flags.AllUriInfoSet))
+            {
+                // We can share it now without mutation concern, for since AllUriInfoSet it is immutable.
+                _info = otherUri._info;
+            }
+            else
             {
-                _flags &= ~(Flags.MinimalUriInfoSet | Flags.AllUriInfoSet | Flags.IndexMask);
-                // Port / Path offset
-                int portIndex = otherUri._info.Offset.Path;
-                if (InFact(Flags.NotDefaultPort))
+                Debug.Assert(!InFact(Flags.HasUnicode) || otherUri.IsNotAbsoluteUri);
+                // Clone the other URI but develop own UriInfo member
+                // We cannot just reference otherUri._info as this UriInfo will be mutated later
+                // which could be happening concurrently and in a not thread safe manner.
+                _info = null!;
+
+                if (InFact(Flags.MinimalUriInfoSet))
                 {
-                    // Find the start of the port.  Account for non-canonical ports like :00123
-                    while (otherUri._string[portIndex] != ':' && portIndex > otherUri._info.Offset.Host)
+                    _flags &= ~(Flags.MinimalUriInfoSet | Flags.AllUriInfoSet | Flags.IndexMask);
+                    // Port / Path offset
+                    int portIndex = otherUri._info.Offset.Path;
+                    if (InFact(Flags.NotDefaultPort))
                     {
-                        portIndex--;
-                    }
-                    if (otherUri._string[portIndex] != ':')
-                    {
-                        // Something wrong with the NotDefaultPort flag.  Reset to path index
-                        Debug.Fail("Uri failed to locate custom port at index: " + portIndex);
-                        portIndex = otherUri._info.Offset.Path;
+                        // Find the start of the port.  Account for non-canonical ports like :00123
+                        while (otherUri._string[portIndex] != ':' && portIndex > otherUri._info.Offset.Host)
+                        {
+                            portIndex--;
+                        }
+                        if (otherUri._string[portIndex] != ':')
+                        {
+                            // Something wrong with the NotDefaultPort flag.  Reset to path index
+                            Debug.Fail("Uri failed to locate custom port at index: " + portIndex);
+                            portIndex = otherUri._info.Offset.Path;
+                        }
                     }
+                    _flags |= (Flags)portIndex; // Port or path
                 }
-                _flags |= (Flags)portIndex; // Port or path
             }
 
             _syntax = otherUri._syntax;

src/libraries/System.Private.Uri/tests/FunctionalTests/UriTests.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 using System.Threading;
 using System.Threading.Tasks;
@@ -729,6 +730,25 @@ public static void Uri_CombineUsesNewUriString()
             Assert.Equal(Combined, new Uri(baseUri, RelativeUriString).AbsoluteUri);
         }
 
+        [Theory]
+        [InlineData("http://bar/Testue/testImage.jpg", "http://bar/Testue/testImage.jpg", "http://bar/Testue/testImage.jpg", "bar")]
+        [InlineData(@"\\nas\Testue\testImage.jpg", "file://nas/Testue/testImage.jpg", "file://nas/Testue/testImage.jpg", "nas")]
+        // Tests that internal Uri info were properly applied during a Combine operation when URI contains non-ascii character.
+        [InlineData("http://bar/Test\u00fc/testImage.jpg", "http://bar/Test\u00fc/testImage.jpg", "http://bar/Test%C3%BC/testImage.jpg", "bar")]
+        [InlineData("\\\\nas\\Test\u00fc\\testImage.jpg", "file://nas/Test\u00fc/testImage.jpg", "file://nas/Test%C3%BC/testImage.jpg", "nas")]
+        public static void Uri_CombineWithAbsoluteUriResultInAbsoluteSchemaIgnoringOriginalBase(string relativeUri, string expectedUri, string expectedAbsoluteUri, string expectedHost)
+        {
+            string baseUriString = "combine-scheme://foo";
+
+            var baseUri = new Uri(baseUriString, UriKind.Absolute);
+            var uri = new Uri(relativeUri);
+            var resultUri = new Uri(baseUri, uri);
+
+            Assert.Equal(expectedUri, resultUri.ToString());
+            Assert.Equal(expectedAbsoluteUri, resultUri.AbsoluteUri);
+            Assert.Equal(expectedHost, resultUri.Host);
+        }
+
         [Fact]
         public static void Uri_CachesIdnHost()
         {