Improve build diagnostics in CSharpProject

src/Microsoft.DotNet.Interactive.CSharpProject/RoslynWorkspaceUtilities/BuildCacheFileUtilities.cs

@@ -78,30 +78,45 @@ internal static class BuildCacheFileUtilities
 </Project>
 """;
 
-    internal static async Task<string> BuildAndCreateCacheFileAsync(string csprojFilePath)
+    internal static async Task BuildAndCreateCacheFileAsync(string csprojFilePath)
     {
+        if (string.IsNullOrEmpty(csprojFilePath))
+        {
+            throw new ArgumentException($"The csproj file path is null or empty");
+        }
+
+        if (!File.Exists(csprojFilePath))
+        {
+            throw new FileNotFoundException($"The csproj file does not exist: {csprojFilePath}");
+        }
+
         DirectoryInfo directoryInfo = new DirectoryInfo(Path.GetDirectoryName(csprojFilePath));
         FileInfo lastBuildErrorLogFile = new FileInfo(Path.Combine(directoryInfo.FullName, ".net-interactive-builderror"));
 
         CleanObjFolder(directoryInfo);
 
-        string tempDirectoryBuildTarget =
-            Path.Combine(Path.GetDirectoryName(csprojFilePath), DirectoryBuildTargetFilename);
-        File.WriteAllText(tempDirectoryBuildTarget, DirectoryBuildTargetsContent);
+        string tempDirectoryBuildTarget = Path.Combine(Path.GetDirectoryName(csprojFilePath), DirectoryBuildTargetFilename);
 
-        var args = "";
-        if (Path.Exists(csprojFilePath))
+        try
+        {
+            File.WriteAllText(tempDirectoryBuildTarget, DirectoryBuildTargetsContent);
+        }
+        catch (UnauthorizedAccessException ex)
+        {
+            throw new UnauthorizedAccessException($"Failed to create the target file due to unauthorized access: {tempDirectoryBuildTarget}", ex);
+        }
+        catch (IOException ex)
         {
-            args = $@"""{csprojFilePath}"" {args}";
+            throw new IOException($"Failed to create the target file due to an I/O error: {tempDirectoryBuildTarget}", ex);
         }
 
+        var args = $@"""{csprojFilePath}""";
+
         var result = await new Dotnet(directoryInfo).Build(args: args);
 
         if (result.ExitCode != 0)
         {
-            File.WriteAllText(
-                lastBuildErrorLogFile.FullName,
-                string.Join(Environment.NewLine, result.Error));
+            throw new InvalidOperationException($"Build failed with exit code {result.ExitCode}. See {lastBuildErrorLogFile.FullName} for details.");
         }
         else if (lastBuildErrorLogFile.Exists)
         {
@@ -111,9 +126,11 @@ internal static async Task<string> BuildAndCreateCacheFileAsync(string csprojFil
         // Clean up the temp project file
         File.Delete(tempDirectoryBuildTarget);
 
-        result.ThrowOnFailure();
-
-        return string.Empty;
+        var cacheFile = FindCacheFile(directoryInfo);
+        if (cacheFile == null || !cacheFile.Exists)
+        {
+            throw new FileNotFoundException($"Cache file not found after build completion in directory: {directoryInfo.FullName}");
+        }
     }
 
     private static void CleanObjFolder(DirectoryInfo directoryInfo)