Throw ArgumentException for non-absolute path in GetVersionInfo (#25978)

* Throw ArgumentException for non-absolute path in GetVersionInfo

* Missing semicolon

* Path.IsPathRooted()

* Casing

* Fix Reference Include

* Fix test

* Fix test again

* Undo accidental change to .sln file

* Remove change to .sln entirely

* Update temp file, exception location

* Use FileStream

* Undo .sln change again

* Disable on uapnotuapaot

* Add Console.WriteLine to trigger exception on netfx

* Missing )

* Remove exception/redo test

* Update test case and comments

* Switch to just UAP

src/System.Diagnostics.FileVersionInfo/ref/System.Diagnostics.FileVersionInfo.csproj

@@ -13,6 +13,7 @@
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\System.Runtime\ref\System.Runtime.csproj" />
+    <ProjectReference Include="..\..\System.Runtime.Extensions\ref\System.Runtime.Extensions.csproj" />
   </ItemGroup>
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
 </Project>

src/System.Diagnostics.FileVersionInfo/src/System.Diagnostics.FileVersionInfo.csproj

@@ -60,6 +60,7 @@
     <Reference Include="System.IO.FileSystem" />
     <Reference Include="System.Resources.ResourceManager" />
     <Reference Include="System.Runtime" />
+    <Reference Include="System.Runtime.Extensions" />
     <Reference Include="System.Runtime.InteropServices" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetsUnix)' == 'true' OR '$(TargetGroup)' == 'uap'">

src/System.Diagnostics.FileVersionInfo/src/System/Diagnostics/FileVersionInfo.cs

@@ -265,6 +265,12 @@ namespace System.Diagnostics
         /// </summary>
         public static FileVersionInfo GetVersionInfo(string fileName)
         {
+            // Check if fileName is a full path. Relative paths can cause confusion if the local file has the .dll extension, 
+            // as .dll search paths can take over & look for system .dll's in that case.
+            if (!Path.IsPathFullyQualified(fileName))
+            {
+                fileName = Path.GetFullPath(fileName);
+            }
             // Check for the existence of the file. File.Exists returns false if Read permission is denied.
             if (!File.Exists(fileName))
             {

src/System.Diagnostics.FileVersionInfo/tests/System.Diagnostics.FileVersionInfo.Tests/FileVersionInfoTest.cs

@@ -102,6 +102,21 @@ namespace System.Diagnostics.Tests
                 FileVersionInfo.GetVersionInfo(Path.Combine(Directory.GetCurrentDirectory(), TestNotFoundFileName)));
         }
 
+        [Fact]
+        [SkipOnTargetFramework(TargetFrameworkMonikers.Uap, "Don't want to create temp file in app container current directory")]
+        [SkipOnTargetFramework(TargetFrameworkMonikers.NetFramework, "NetFX throws ArgumentException in this case")]
+        public void FileVersionInfo_RelativePath_CorrectFilePath()
+        {
+            using (new FileStream("kernelbase.dll", FileMode.CreateNew, FileAccess.ReadWrite, FileShare.None, 0x1000, FileOptions.DeleteOnClose))
+            {
+                FileVersionInfo fvi = FileVersionInfo.GetVersionInfo("kernelbase.dll");
+                //File name should be the full path to the local kernelbase.dll, not the relative path or the path to the system .dll
+                Assert.Equal(Path.GetFullPath("kernelbase.dll"), fvi.FileName);
+                //FileDescription should be null in the local kernelbase.dll
+                Assert.Equal(null, fvi.FileDescription);
+            }
+        }
+
         // Additional Tests Wanted:
         // [] File exists but we don't have permission to read it
         // [] DLL has unknown codepage info