Add support for file links that use a commit SHA

Assume that branch names don't contain a '/' (sic).

Author: jcansdale

src/GitHub.App/Services/GitHubContextService.cs

@@ -53,7 +53,7 @@ public GitHubContext FindContextFromUrl(string url)
                 Host = uri.Host,
                 Owner = uri.Owner,
                 RepositoryName = uri.RepositoryName,
-                Path = FindSubPath(uri, "/blob/master/"),
+                Path = FindPath(uri),
                 PullRequest = FindPullRequest(uri),
                 Line = FindLine(uri)
             };
@@ -170,6 +170,23 @@ public GitHubContext FindContextFromWindowTitle(string windowTitle)
             return lineNumber; // 1 based
         }
 
+        string FindPath(UriString uri)
+        {
+            var blob = FindSubPath(uri, "/blob/");
+            if (blob == null)
+            {
+                return null;
+            }
+
+            var pathIndex = blob.IndexOf('/');
+            if (pathIndex == -1)
+            {
+                return null;
+            }
+
+            return blob.Substring(pathIndex + 1);
+        }
+
         static int? FindPullRequest(UriString gitHubUrl)
         {
             var pullRequest = FindSubPath(gitHubUrl, "/pull/")?.Split('/').First();

test/GitHub.App.UnitTests/Services/GitHubContextServiceTests.cs

@@ -67,6 +67,7 @@ public void PullRequest(string url, int? expectPullRequest)
         [TestCase("https://github.com/github/VisualStudio", null)]
         [TestCase("https://github.com/github/VisualStudio/blob/master/README.md", "README.md")]
         [TestCase("https://github.com/github/VisualStudio/blob/master/README.md#notices", "README.md")]
+        [TestCase("https://github.com/github/VisualStudio/blob/0d264d50c57d701fa62d202f481075a6c6dbdce8/src/Code.cs#L86", "src/Code.cs")]
         public void Path(string url, string expectPath)
         {
             var target = new GitHubContextService();
@@ -76,12 +77,24 @@ public void Path(string url, string expectPath)
             Assert.That(context.Path, Is.EqualTo(expectPath));
         }
 
+        // HACK: We're assuming that branches don't contain a '/' (sic)
+        [TestCase("https://github.com/github/VisualStudio/blob/fixes/branch/buggy.cs", "branch/buggy.cs")]
+        public void ProblemPath(string url, string expectPath)
+        {
+            var target = new GitHubContextService();
+
+            var context = target.FindContextFromUrl(url);
+
+            Assert.That(context.Path, Is.EqualTo(expectPath));
+        }
+
         [TestCase("https://github.com", null)]
         [TestCase("https://github.com/github", null)]
         [TestCase("https://github.com/github/VisualStudio", null)]
         [TestCase("https://github.com/github/VisualStudio/blob/master/README.md", null)]
         [TestCase("https://github.com/github/VisualStudio/blob/master/README.md#notices", null)]
         [TestCase("https://github.com/github/VisualStudio/blob/master/src/GitHub.VisualStudio/GitHubPackage.cs#L38", 38)]
+        [TestCase("https://github.com/github/VisualStudio/blob/0d264d50c57d701fa62d202f481075a6c6dbdce8/src/Code.cs#L86", 86)]
         public void Line(string url, int? expectLine)
         {
             var target = new GitHubContextService();