Fix VMR file links (#4853)

#4841 (comment)

1. [Fix Vmr File Links](https://github.com/dotnet/arcade-services/pull/4853/commits/0d56e8213460983b14b9be7318fdf212860ff5ef)Some
url-creating methods were written for normal repos and were incompatible
with the vmr file structure

2. [Safely encode variable strings into url](https://github.com/dotnet/arcade-services/pull/4853/commits/5789e2f77fb1522b617a91704d9c44e0618f036a)Safely
encode string variables into the URLs in all the helper methods, as per
Copilot's suggestion, in order to avoid possible edge cases due to
special characters in any of the variables

Author: adamzip

src/Microsoft.DotNet.Darc/DarcLib/Helpers/GitRepoUrlUtils.cs

@@ -138,6 +138,14 @@ public static string GetRepoFileAtCommitUri(string repoUri, string commit, strin
             _ => throw new ArgumentException("Unknown git repository type", nameof(repoUri)),
         };
 
+    public static string GetVmrFileAtCommitUri(string vmrUri, string productDirectory, string commit, string filePath)
+        => ParseTypeFromUri(vmrUri) switch
+        {
+            GitRepoType.AzureDevOps => $"{vmrUri}?version=GC{commit}&path=src/{productDirectory}/{filePath}",
+            GitRepoType.GitHub => $"{vmrUri}/blob/{commit}/src/{productDirectory}/{filePath}",
+            _ => throw new ArgumentException("Unknown git repository type", nameof(vmrUri)),
+        };
+
     public static string GetRepoFileAtBranchUri(string repoUri, string branch, string filePath)
         => ParseTypeFromUri(repoUri) switch
         {
@@ -146,6 +154,14 @@ public static string GetRepoFileAtBranchUri(string repoUri, string branch, strin
             _ => throw new ArgumentException("Unknown git repository type", nameof(repoUri))
         };
 
+    public static string GetVmrFileAtBranchUri(string vmrUri, string productDirectory, string branch, string filePath)
+        => ParseTypeFromUri(vmrUri) switch
+        {
+            GitRepoType.AzureDevOps => $"{vmrUri}?version=GB{branch}&path=src/{productDirectory}/{filePath}",
+            GitRepoType.GitHub => $"{vmrUri}/blob/{branch}/src/{productDirectory}/{filePath}",
+            _ => throw new ArgumentException("Unknown git repository type", nameof(vmrUri))
+        };
+
     public static string GetRepoNameWithOrg(string uri)
     {
         var (repo, org) = GetRepoNameAndOwner(uri);

src/ProductConstructionService/ProductConstructionService.DependencyFlow/PullRequestConflictNotifier.cs

@@ -66,11 +66,11 @@ public async Task NotifyAboutConflictingUpdateAsync(
         foreach (var file in conflictException.FilesInConflict)
         {
             var sourceString = subscription.IsBackflow()
-                ? $"[🔍 view in VMR]({GitRepoUrlUtils.GetRepoFileAtCommitUri(update.SourceRepo, update.SourceSha, file)})"
-                : $"[🔍 view in {GitRepoUrlUtils.GetRepoNameWithOrg(update.SourceRepo)}]({GitRepoUrlUtils.GetRepoFileAtCommitUri(update.SourceRepo, update.SourceSha, file)})";
+                ? $"[🔍 View in VMR]({GitRepoUrlUtils.GetVmrFileAtCommitUri(update.SourceRepo, subscription.TargetDirectory, update.SourceSha, file)})"
+                : $"[🔍 View in {GitRepoUrlUtils.GetRepoNameWithOrg(update.SourceRepo)}]({GitRepoUrlUtils.GetRepoFileAtCommitUri(update.SourceRepo, update.SourceSha, file)})";
             var targetString = subscription.IsBackflow()
-                ? $"[🔍 view in {GitRepoUrlUtils.GetRepoNameWithOrg(subscription.TargetRepository)}]({GitRepoUrlUtils.GetRepoFileAtBranchUri(subscription.TargetRepository, subscription.TargetBranch, file)})"
-                : $"[🔍 view in VMR]({GitRepoUrlUtils.GetRepoFileAtBranchUri(subscription.TargetRepository, subscription.TargetBranch, file)})";
+                ? $"[🔍 View in {GitRepoUrlUtils.GetRepoNameWithOrg(subscription.TargetRepository)}]({GitRepoUrlUtils.GetRepoFileAtBranchUri(subscription.TargetRepository, subscription.TargetBranch, file)})"
+                : $"[🔍 View in VMR]({GitRepoUrlUtils.GetVmrFileAtBranchUri(subscription.TargetRepository, subscription.SourceDirectory, subscription.TargetBranch, file)})";
             sb.AppendLine($" - `{file}` - {sourceString} / {targetString}");
         }
         sb.AppendLine();